[Asterisk-code-review] res sorcery memory cache: Backport to 13 (asterisk[13])

Mark Michelson asteriskteam at digium.com
Thu Jul 9 08:58:06 CDT 2015


Mark Michelson has uploaded a new change for review.

  https://gerrit.asterisk.org/854

Change subject: res_sorcery_memory_cache: Backport to 13
......................................................................

res_sorcery_memory_cache: Backport to 13

Gerrit is complaining of conflicts when trying to create a patch series
of all of the cherry-picked master commits, so I have instead squashed
it all into one commit.

ASTERISK-25067 #close
Reported by: Matt Jordan

Change-Id: I6dda90343fae24a75dc5beec84980024e8d61eb9
---
M include/asterisk/sorcery.h
M main/sorcery.c
A res/res_sorcery_memory_cache.c
A tests/test_sorcery_memory_cache_thrash.c
4 files changed, 3,204 insertions(+), 0 deletions(-)


  git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/54/854/1

diff --git a/include/asterisk/sorcery.h b/include/asterisk/sorcery.h
index 30fb0dd..027ec00 100644
--- a/include/asterisk/sorcery.h
+++ b/include/asterisk/sorcery.h
@@ -1290,6 +1290,15 @@
 int ast_sorcery_is_object_field_registered(const struct ast_sorcery_object_type *object_type,
 		const char *field_name);
 
+/*!
+ * \brief Get the module that has opened the provided sorcery instance.
+ *
+ * \param sorcery The sorcery instance
+ *
+ * \return The module
+ */
+const char *ast_sorcery_get_module(const struct ast_sorcery *sorcery);
+
 #if defined(__cplusplus) || defined(c_plusplus)
 }
 #endif
diff --git a/main/sorcery.c b/main/sorcery.c
index af812ad..8e48403 100644
--- a/main/sorcery.c
+++ b/main/sorcery.c
@@ -2356,3 +2356,8 @@
 	ao2_cleanup(object_field);
 	return res;
 }
+
+const char *ast_sorcery_get_module(const struct ast_sorcery *sorcery)
+{
+	return sorcery->module_name;
+}
diff --git a/res/res_sorcery_memory_cache.c b/res/res_sorcery_memory_cache.c
new file mode 100644
index 0000000..f0fc055
--- /dev/null
+++ b/res/res_sorcery_memory_cache.c
@@ -0,0 +1,2572 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2015, Digium, Inc.
+ *
+ * Joshua Colp <jcolp at digium.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*!
+ * \file
+ *
+ * \brief Sorcery Memory Cache Object Wizard
+ *
+ * \author Joshua Colp <jcolp at digium.com>
+ */
+
+/*** MODULEINFO
+	<support_level>core</support_level>
+ ***/
+
+#include "asterisk.h"
+
+#include "asterisk/module.h"
+#include "asterisk/sorcery.h"
+#include "asterisk/astobj2.h"
+#include "asterisk/sched.h"
+#include "asterisk/test.h"
+#include "asterisk/heap.h"
+#include "asterisk/cli.h"
+#include "asterisk/manager.h"
+
+/*** DOCUMENTATION
+	<manager name="SorceryMemoryCacheExpireObject" language="en_US">
+		<synopsis>
+			Expire (remove) an object from a sorcery memory cache.
+		</synopsis>
+		<syntax>
+			<xi:include xpointer="xpointer(/docs/manager[@name='Login']/syntax/parameter[@name='ActionID'])" />
+			<parameter name="Cache" required="true">
+				<para>The name of the cache to expire the object from.</para>
+			</parameter>
+			<parameter name="Object" required="true">
+				<para>The name of the object to expire.</para>
+			</parameter>
+		</syntax>
+		<description>
+			<para>Expires (removes) an object from a sorcery memory cache.</para>
+		</description>
+	</manager>
+	<manager name="SorceryMemoryCacheExpire" language="en_US">
+		<synopsis>
+			Expire (remove) ALL objects from a sorcery memory cache.
+		</synopsis>
+		<syntax>
+			<xi:include xpointer="xpointer(/docs/manager[@name='Login']/syntax/parameter[@name='ActionID'])" />
+			<parameter name="Cache" required="true">
+				<para>The name of the cache to expire all objects from.</para>
+			</parameter>
+		</syntax>
+		<description>
+			<para>Expires (removes) ALL objects from a sorcery memory cache.</para>
+		</description>
+	</manager>
+	<manager name="SorceryMemoryCacheStaleObject" language="en_US">
+		<synopsis>
+			Mark an object in a sorcery memory cache as stale.
+		</synopsis>
+		<syntax>
+			<xi:include xpointer="xpointer(/docs/manager[@name='Login']/syntax/parameter[@name='ActionID'])" />
+			<parameter name="Cache" required="true">
+				<para>The name of the cache to mark the object as stale in.</para>
+			</parameter>
+			<parameter name="Object" required="true">
+				<para>The name of the object to mark as stale.</para>
+			</parameter>
+		</syntax>
+		<description>
+			<para>Marks an object as stale within a sorcery memory cache.</para>
+		</description>
+	</manager>
+	<manager name="SorceryMemoryCacheStale" language="en_US">
+		<synopsis>
+			Marks ALL objects in a sorcery memory cache as stale.
+		</synopsis>
+		<syntax>
+			<xi:include xpointer="xpointer(/docs/manager[@name='Login']/syntax/parameter[@name='ActionID'])" />
+			<parameter name="Cache" required="true">
+				<para>The name of the cache to mark all object as stale in.</para>
+			</parameter>
+		</syntax>
+		<description>
+			<para>Marks ALL objects in a sorcery memory cache as stale.</para>
+		</description>
+	</manager>
+ ***/
+
+/*! \brief Structure for storing a memory cache */
+struct sorcery_memory_cache {
+	/*! \brief The name of the memory cache */
+	char *name;
+	/*! \brief Objects in the cache */
+	struct ao2_container *objects;
+	/*! \brief The maximum number of objects permitted in the cache, 0 if no limit */
+	unsigned int maximum_objects;
+	/*! \brief The maximum time (in seconds) an object will stay in the cache, 0 if no limit */
+	unsigned int object_lifetime_maximum;
+	/*! \brief The amount of time (in seconds) before an object is marked as stale, 0 if disabled */
+	unsigned int object_lifetime_stale;
+	/** \brief Whether all objects are expired when the object type is reloaded, 0 if disabled */
+	unsigned int expire_on_reload;
+	/*! \brief Heap of cached objects. Oldest object is at the top. */
+	struct ast_heap *object_heap;
+	/*! \brief Scheduler item for expiring oldest object. */
+	int expire_id;
+#ifdef TEST_FRAMEWORK
+	/*! \brief Variable used to indicate we should notify a test when we reach empty */
+	unsigned int cache_notify;
+	/*! \brief Mutex lock used for signaling when the cache has reached empty */
+	ast_mutex_t lock;
+	/*! \brief Condition used for signaling when the cache has reached empty */
+	ast_cond_t cond;
+	/*! \brief Variable that is set when the cache has reached empty */
+	unsigned int cache_completed;
+#endif
+};
+
+/*! \brief Structure for stored a cached object */
+struct sorcery_memory_cached_object {
+	/*! \brief The cached object */
+	void *object;
+	/*! \brief The time at which the object was created */
+	struct timeval created;
+	/*! \brief index required by heap */
+	ssize_t __heap_index;
+	/*! \brief scheduler id of stale update task */
+	int stale_update_sched_id;
+};
+
+static void *sorcery_memory_cache_open(const char *data);
+static int sorcery_memory_cache_create(const struct ast_sorcery *sorcery, void *data, void *object);
+static void sorcery_memory_cache_load(void *data, const struct ast_sorcery *sorcery, const char *type);
+static void sorcery_memory_cache_reload(void *data, const struct ast_sorcery *sorcery, const char *type);
+static void *sorcery_memory_cache_retrieve_id(const struct ast_sorcery *sorcery, void *data, const char *type,
+	const char *id);
+static int sorcery_memory_cache_delete(const struct ast_sorcery *sorcery, void *data, void *object);
+static void sorcery_memory_cache_close(void *data);
+
+static struct ast_sorcery_wizard memory_cache_object_wizard = {
+	.name = "memory_cache",
+	.open = sorcery_memory_cache_open,
+	.create = sorcery_memory_cache_create,
+	.update = sorcery_memory_cache_create,
+	.delete = sorcery_memory_cache_delete,
+	.load = sorcery_memory_cache_load,
+	.reload = sorcery_memory_cache_reload,
+	.retrieve_id = sorcery_memory_cache_retrieve_id,
+	.close = sorcery_memory_cache_close,
+};
+
+/*! \brief The bucket size for the container of caches */
+#define CACHES_CONTAINER_BUCKET_SIZE 53
+
+/*! \brief The default bucket size for the container of objects in the cache */
+#define CACHE_CONTAINER_BUCKET_SIZE 53
+
+/*! \brief Height of heap for cache object heap. Allows 31 initial objects */
+#define CACHE_HEAP_INIT_HEIGHT 5
+
+/*! \brief Container of created caches */
+static struct ao2_container *caches;
+
+/*! \brief Scheduler for cache management */
+static struct ast_sched_context *sched;
+
+#define STALE_UPDATE_THREAD_ID 0x5EED1E55
+AST_THREADSTORAGE(stale_update_id_storage);
+
+static int is_stale_update(void)
+{
+	uint32_t *stale_update_thread_id;
+
+	stale_update_thread_id = ast_threadstorage_get(&stale_update_id_storage,
+		sizeof(*stale_update_thread_id));
+	if (!stale_update_thread_id) {
+		return 0;
+	}
+
+	return *stale_update_thread_id == STALE_UPDATE_THREAD_ID;
+}
+
+static void start_stale_update(void)
+{
+	uint32_t *stale_update_thread_id;
+
+	stale_update_thread_id = ast_threadstorage_get(&stale_update_id_storage,
+		sizeof(*stale_update_thread_id));
+	if (!stale_update_thread_id) {
+		ast_log(LOG_ERROR, "Could not set stale update ID for sorcery memory cache thread\n");
+		return;
+	}
+
+	*stale_update_thread_id = STALE_UPDATE_THREAD_ID;
+}
+
+static void end_stale_update(void)
+{
+	uint32_t *stale_update_thread_id;
+
+	stale_update_thread_id = ast_threadstorage_get(&stale_update_id_storage,
+		sizeof(*stale_update_thread_id));
+	if (!stale_update_thread_id) {
+		ast_log(LOG_ERROR, "Could not set stale update ID for sorcery memory cache thread\n");
+		return;
+	}
+
+	*stale_update_thread_id = 0;
+}
+
+/*!
+ * \internal
+ * \brief Hashing function for the container holding caches
+ *
+ * \param obj A sorcery memory cache or name of one
+ * \param flags Hashing flags
+ *
+ * \return The hash of the memory cache name
+ */
+static int sorcery_memory_cache_hash(const void *obj, int flags)
+{
+	const struct sorcery_memory_cache *cache = obj;
+	const char *name = obj;
+	int hash;
+
+	switch (flags & (OBJ_SEARCH_OBJECT | OBJ_SEARCH_KEY | OBJ_SEARCH_PARTIAL_KEY)) {
+	default:
+	case OBJ_SEARCH_OBJECT:
+		name = cache->name;
+		/* Fall through */
+	case OBJ_SEARCH_KEY:
+		hash = ast_str_hash(name);
+		break;
+	case OBJ_SEARCH_PARTIAL_KEY:
+		/* Should never happen in hash callback. */
+		ast_assert(0);
+		hash = 0;
+		break;
+	}
+	return hash;
+}
+
+/*!
+ * \internal
+ * \brief Comparison function for the container holding caches
+ *
+ * \param obj A sorcery memory cache
+ * \param arg A sorcery memory cache, or name of one
+ * \param flags Comparison flags
+ *
+ * \retval CMP_MATCH if the name is the same
+ * \retval 0 if the name does not match
+ */
+static int sorcery_memory_cache_cmp(void *obj, void *arg, int flags)
+{
+	const struct sorcery_memory_cache *left = obj;
+	const struct sorcery_memory_cache *right = arg;
+	const char *right_name = arg;
+	int cmp;
+
+	switch (flags & (OBJ_SEARCH_OBJECT | OBJ_SEARCH_KEY | OBJ_SEARCH_PARTIAL_KEY)) {
+	default:
+	case OBJ_SEARCH_OBJECT:
+		right_name = right->name;
+		/* Fall through */
+	case OBJ_SEARCH_KEY:
+		cmp = strcmp(left->name, right_name);
+		break;
+	case OBJ_SEARCH_PARTIAL_KEY:
+		cmp = strncmp(left->name, right_name, strlen(right_name));
+		break;
+	}
+	return cmp ? 0 : CMP_MATCH;
+}
+
+/*!
+ * \internal
+ * \brief Hashing function for the container holding cached objects
+ *
+ * \param obj A cached object or id of one
+ * \param flags Hashing flags
+ *
+ * \return The hash of the cached object id
+ */
+static int sorcery_memory_cached_object_hash(const void *obj, int flags)
+{
+	const struct sorcery_memory_cached_object *cached = obj;
+	const char *name = obj;
+	int hash;
+
+	switch (flags & (OBJ_SEARCH_OBJECT | OBJ_SEARCH_KEY | OBJ_SEARCH_PARTIAL_KEY)) {
+	default:
+	case OBJ_SEARCH_OBJECT:
+		name = ast_sorcery_object_get_id(cached->object);
+		/* Fall through */
+	case OBJ_SEARCH_KEY:
+		hash = ast_str_hash(name);
+		break;
+	case OBJ_SEARCH_PARTIAL_KEY:
+		/* Should never happen in hash callback. */
+		ast_assert(0);
+		hash = 0;
+		break;
+	}
+	return hash;
+}
+
+/*!
+ * \internal
+ * \brief Comparison function for the container holding cached objects
+ *
+ * \param obj A cached object
+ * \param arg A cached object, or id of one
+ * \param flags Comparison flags
+ *
+ * \retval CMP_MATCH if the id is the same
+ * \retval 0 if the id does not match
+ */
+static int sorcery_memory_cached_object_cmp(void *obj, void *arg, int flags)
+{
+	struct sorcery_memory_cached_object *left = obj;
+	struct sorcery_memory_cached_object *right = arg;
+	const char *right_name = arg;
+	int cmp;
+
+	switch (flags & (OBJ_SEARCH_OBJECT | OBJ_SEARCH_KEY | OBJ_SEARCH_PARTIAL_KEY)) {
+	default:
+	case OBJ_SEARCH_OBJECT:
+		right_name = ast_sorcery_object_get_id(right->object);
+		/* Fall through */
+	case OBJ_SEARCH_KEY:
+		cmp = strcmp(ast_sorcery_object_get_id(left->object), right_name);
+		break;
+	case OBJ_SEARCH_PARTIAL_KEY:
+		cmp = strncmp(ast_sorcery_object_get_id(left->object), right_name, strlen(right_name));
+		break;
+	}
+	return cmp ? 0 : CMP_MATCH;
+}
+
+/*!
+ * \internal
+ * \brief Destructor function for a sorcery memory cache
+ *
+ * \param obj A sorcery memory cache
+ */
+static void sorcery_memory_cache_destructor(void *obj)
+{
+	struct sorcery_memory_cache *cache = obj;
+
+	ast_free(cache->name);
+	ao2_cleanup(cache->objects);
+	if (cache->object_heap) {
+		ast_heap_destroy(cache->object_heap);
+	}
+}
+
+/*!
+ * \internal
+ * \brief Destructor function for sorcery memory cached objects
+ *
+ * \param obj A sorcery memory cached object
+ */
+static void sorcery_memory_cached_object_destructor(void *obj)
+{
+	struct sorcery_memory_cached_object *cached = obj;
+
+	ao2_cleanup(cached->object);
+}
+
+static int schedule_cache_expiration(struct sorcery_memory_cache *cache);
+
+/*!
+ * \internal
+ * \brief Remove an object from the cache.
+ *
+ * This removes the item from both the hashtable and the heap.
+ *
+ * \pre cache->objects is write-locked
+ *
+ * \param cache The cache from which the object is being removed.
+ * \param id The sorcery object id of the object to remove.
+ * \param reschedule Reschedule cache expiration if this was the oldest object.
+ *
+ * \retval 0 Success
+ * \retval non-zero Failure
+ */
+static int remove_from_cache(struct sorcery_memory_cache *cache, const char *id, int reschedule)
+{
+	struct sorcery_memory_cached_object *hash_object;
+	struct sorcery_memory_cached_object *oldest_object;
+	struct sorcery_memory_cached_object *heap_object;
+
+	hash_object = ao2_find(cache->objects, id,
+		OBJ_SEARCH_KEY | OBJ_UNLINK | OBJ_NOLOCK);
+	if (!hash_object) {
+		return -1;
+	}
+
+	ast_assert(!strcmp(ast_sorcery_object_get_id(hash_object->object), id));
+
+	oldest_object = ast_heap_peek(cache->object_heap, 1);
+	heap_object = ast_heap_remove(cache->object_heap, hash_object);
+
+	ast_assert(heap_object == hash_object);
+
+	ao2_ref(hash_object, -1);
+
+	if (reschedule && (oldest_object == heap_object)) {
+		schedule_cache_expiration(cache);
+	}
+
+	return 0;
+}
+
+/*!
+ * \internal
+ * \brief Scheduler callback invoked to expire old objects
+ *
+ * \param data The opaque callback data (in our case, the memory cache)
+ */
+static int expire_objects_from_cache(const void *data)
+{
+	struct sorcery_memory_cache *cache = (struct sorcery_memory_cache *)data;
+	struct sorcery_memory_cached_object *cached;
+
+	ao2_wrlock(cache->objects);
+
+	cache->expire_id = -1;
+
+	/* This is an optimization for objects which have been cached close to eachother */
+	while ((cached = ast_heap_peek(cache->object_heap, 1))) {
+		int expiration;
+
+		expiration = ast_tvdiff_ms(ast_tvadd(cached->created, ast_samp2tv(cache->object_lifetime_maximum, 1)), ast_tvnow());
+
+		/* If the current oldest object has not yet expired stop and reschedule for it */
+		if (expiration > 0) {
+			break;
+		}
+
+		remove_from_cache(cache, ast_sorcery_object_get_id(cached->object), 0);
+	}
+
+	schedule_cache_expiration(cache);
+
+	ao2_unlock(cache->objects);
+
+	ao2_ref(cache, -1);
+
+	return 0;
+}
+
+/*!
+ * \internal
+ * \brief Remove all objects from the cache.
+ *
+ * This removes ALL objects from both the hash table and heap.
+ *
+ * \pre cache->objects is write-locked
+ *
+ * \param cache The cache to empty.
+ */
+static void remove_all_from_cache(struct sorcery_memory_cache *cache)
+{
+	while (ast_heap_pop(cache->object_heap));
+
+	ao2_callback(cache->objects, OBJ_UNLINK | OBJ_NOLOCK | OBJ_NODATA | OBJ_MULTIPLE,
+		NULL, NULL);
+
+	AST_SCHED_DEL_UNREF(sched, cache->expire_id, ao2_ref(cache, -1));
+}
+
+/*!
+ * \internal
+ * \brief AO2 callback function for making an object stale immediately
+ *
+ * This changes the creation time of an object so it appears as though it is stale immediately.
+ *
+ * \param obj The cached object
+ * \param arg The cache itself
+ * \param flags Unused flags
+ */
+static int object_stale_callback(void *obj, void *arg, int flags)
+{
+	struct sorcery_memory_cached_object *cached = obj;
+	struct sorcery_memory_cache *cache = arg;
+
+	/* Since our granularity is seconds it's possible for something to retrieve us within a window
+	 * where we wouldn't be treated as stale. To ensure that doesn't happen we use the configured stale
+	 * time plus a second.
+	 */
+	cached->created = ast_tvsub(cached->created, ast_samp2tv(cache->object_lifetime_stale + 1, 1));
+
+	return CMP_MATCH;
+}
+
+/*!
+ * \internal
+ * \brief Mark an object as stale explicitly.
+ *
+ * This changes the creation time of an object so it appears as though it is stale immediately.
+ *
+ * \pre cache->objects is read-locked
+ *
+ * \param cache The cache the object is in
+ * \param id The unique identifier of the object
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+static int mark_object_as_stale_in_cache(struct sorcery_memory_cache *cache, const char *id)
+{
+	struct sorcery_memory_cached_object *cached;
+
+	cached = ao2_find(cache->objects, id, OBJ_SEARCH_KEY | OBJ_NOLOCK);
+	if (!cached) {
+		return -1;
+	}
+
+	ast_assert(!strcmp(ast_sorcery_object_get_id(cached->object), id));
+
+	object_stale_callback(cached, cache, 0);
+	ao2_ref(cached, -1);
+
+	return 0;
+}
+
+/*!
+ * \internal
+ * \brief Mark all objects as stale within a cache.
+ *
+ * This changes the creation time of ALL objects so they appear as though they are stale.
+ *
+ * \pre cache->objects is read-locked
+ *
+ * \param cache
+ */
+static void mark_all_as_stale_in_cache(struct sorcery_memory_cache *cache)
+{
+	ao2_callback(cache->objects, OBJ_NOLOCK | OBJ_NODATA | OBJ_MULTIPLE, object_stale_callback, cache);
+}
+
+/*!
+ * \internal
+ * \brief Schedule a callback for cached object expiration.
+ *
+ * \pre cache->objects is write-locked
+ *
+ * \param cache The cache that is having its callback scheduled.
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+static int schedule_cache_expiration(struct sorcery_memory_cache *cache)
+{
+	struct sorcery_memory_cached_object *cached;
+	int expiration = 0;
+
+	if (!cache->object_lifetime_maximum) {
+		return 0;
+	}
+
+	if (cache->expire_id != -1) {
+		/* If we can't unschedule this expiration then it is currently attempting to run,
+		 * so let it run - it just means that it'll be the one scheduling instead of us.
+		 */
+		if (ast_sched_del(sched, cache->expire_id)) {
+			return 0;
+		}
+
+		/* Since it successfully cancelled we need to drop the ref to the cache it had */
+		ao2_ref(cache, -1);
+		cache->expire_id = -1;
+	}
+
+	cached = ast_heap_peek(cache->object_heap, 1);
+	if (!cached) {
+#ifdef TEST_FRAMEWORK
+		ast_mutex_lock(&cache->lock);
+		cache->cache_completed = 1;
+		ast_cond_signal(&cache->cond);
+		ast_mutex_unlock(&cache->lock);
+#endif
+		return 0;
+	}
+
+	expiration = MAX(ast_tvdiff_ms(ast_tvadd(cached->created, ast_samp2tv(cache->object_lifetime_maximum, 1)), ast_tvnow()),
+		1);
+
+	cache->expire_id = ast_sched_add(sched, expiration, expire_objects_from_cache, ao2_bump(cache));
+	if (cache->expire_id < 0) {
+		ao2_ref(cache, -1);
+		return -1;
+	}
+
+	return 0;
+}
+
+/*!
+ * \internal
+ * \brief Remove the oldest item from the cache.
+ *
+ * \pre cache->objects is write-locked
+ *
+ * \param cache The cache from which to remove the oldest object
+ *
+ * \retval 0 Success
+ * \retval non-zero Failure
+ */
+static int remove_oldest_from_cache(struct sorcery_memory_cache *cache)
+{
+	struct sorcery_memory_cached_object *heap_old_object;
+	struct sorcery_memory_cached_object *hash_old_object;
+
+	heap_old_object = ast_heap_pop(cache->object_heap);
+	if (!heap_old_object) {
+		return -1;
+	}
+	hash_old_object = ao2_find(cache->objects, heap_old_object,
+		OBJ_SEARCH_OBJECT | OBJ_UNLINK | OBJ_NOLOCK);
+
+	ast_assert(heap_old_object == hash_old_object);
+
+	ao2_ref(hash_old_object, -1);
+
+	schedule_cache_expiration(cache);
+
+	return 0;
+}
+
+/*!
+ * \internal
+ * \brief Add a new object to the cache.
+ *
+ * \pre cache->objects is write-locked
+ *
+ * \param cache The cache in which to add the new object
+ * \param cached_object The object to add to the cache
+ *
+ * \retval 0 Success
+ * \retval non-zero Failure
+ */
+static int add_to_cache(struct sorcery_memory_cache *cache,
+		struct sorcery_memory_cached_object *cached_object)
+{
+	if (!ao2_link_flags(cache->objects, cached_object, OBJ_NOLOCK)) {
+		return -1;
+	}
+
+	if (ast_heap_push(cache->object_heap, cached_object)) {
+		ao2_find(cache->objects, cached_object,
+			OBJ_SEARCH_OBJECT | OBJ_UNLINK | OBJ_NODATA | OBJ_NOLOCK);
+		return -1;
+	}
+
+	if (cache->expire_id == -1) {
+		schedule_cache_expiration(cache);
+	}
+
+	return 0;
+}
+
+/*!
+ * \internal
+ * \brief Callback function to cache an object in a memory cache
+ *
+ * \param sorcery The sorcery instance
+ * \param data The sorcery memory cache
+ * \param object The object to cache
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+static int sorcery_memory_cache_create(const struct ast_sorcery *sorcery, void *data, void *object)
+{
+	struct sorcery_memory_cache *cache = data;
+	struct sorcery_memory_cached_object *cached;
+
+	cached = ao2_alloc(sizeof(*cached), sorcery_memory_cached_object_destructor);
+	if (!cached) {
+		return -1;
+	}
+	cached->object = ao2_bump(object);
+	cached->created = ast_tvnow();
+	cached->stale_update_sched_id = -1;
+
+	/* As there is no guarantee that this won't be called by multiple threads wanting to cache
+	 * the same object we remove any old ones, which turns this into a create/update function
+	 * in reality. As well since there's no guarantee that the object in the cache is the same
+	 * one here we remove any old objects using the object identifier.
+	 */
+
+	ao2_wrlock(cache->objects);
+	remove_from_cache(cache, ast_sorcery_object_get_id(object), 1);
+	if (cache->maximum_objects && ao2_container_count(cache->objects) >= cache->maximum_objects) {
+		if (remove_oldest_from_cache(cache)) {
+			ast_log(LOG_ERROR, "Unable to make room in cache for sorcery object '%s'.\n",
+				ast_sorcery_object_get_id(object));
+			ao2_ref(cached, -1);
+			ao2_unlock(cache->objects);
+			return -1;
+		}
+		ast_assert(ao2_container_count(cache->objects) != cache->maximum_objects);
+	}
+	if (add_to_cache(cache, cached)) {
+		ast_log(LOG_ERROR, "Unable to add object '%s' to the cache\n",
+			ast_sorcery_object_get_id(object));
+		ao2_ref(cached, -1);
+		ao2_unlock(cache->objects);
+		return -1;
+	}
+	ao2_unlock(cache->objects);
+
+	ao2_ref(cached, -1);
+	return 0;
+}
+
+struct stale_update_task_data {
+	struct ast_sorcery *sorcery;
+	struct sorcery_memory_cache *cache;
+	void *object;
+};
+
+static void stale_update_task_data_destructor(void *obj)
+{
+	struct stale_update_task_data *task_data = obj;
+
+	ao2_cleanup(task_data->cache);
+	ao2_cleanup(task_data->object);
+	ast_sorcery_unref(task_data->sorcery);
+}
+
+static struct stale_update_task_data *stale_update_task_data_alloc(struct ast_sorcery *sorcery,
+		struct sorcery_memory_cache *cache, const char *type, void *object)
+{
+	struct stale_update_task_data *task_data;
+
+	task_data = ao2_alloc_options(sizeof(*task_data), stale_update_task_data_destructor,
+		AO2_ALLOC_OPT_LOCK_NOLOCK);
+	if (!task_data) {
+		return NULL;
+	}
+
+	task_data->sorcery = ao2_bump(sorcery);
+	task_data->cache = ao2_bump(cache);
+	task_data->object = ao2_bump(object);
+
+	return task_data;
+}
+
+static int stale_item_update(const void *data)
+{
+	struct stale_update_task_data *task_data = (struct stale_update_task_data *) data;
+	void *object;
+
+	start_stale_update();
+
+	object = ast_sorcery_retrieve_by_id(task_data->sorcery,
+		ast_sorcery_object_get_type(task_data->object),
+		ast_sorcery_object_get_id(task_data->object));
+	if (!object) {
+		ast_debug(1, "Backend no longer has object type '%s' ID '%s'. Removing from cache\n",
+			ast_sorcery_object_get_type(task_data->object),
+			ast_sorcery_object_get_id(task_data->object));
+		sorcery_memory_cache_delete(task_data->sorcery, task_data->cache,
+			task_data->object);
+	} else {
+		ast_debug(1, "Refreshing stale cache object type '%s' ID '%s'\n",
+			ast_sorcery_object_get_type(task_data->object),
+			ast_sorcery_object_get_id(task_data->object));
+		sorcery_memory_cache_create(task_data->sorcery, task_data->cache,
+			object);
+	}
+
+	ast_test_suite_event_notify("SORCERY_MEMORY_CACHE_REFRESHED", "Cache: %s\r\nType: %s\r\nName: %s\r\n",
+		task_data->cache->name, ast_sorcery_object_get_type(task_data->object),
+		ast_sorcery_object_get_id(task_data->object));
+
+	ao2_ref(task_data, -1);
+	end_stale_update();
+
+	return 0;
+}
+
+/*!
+ * \internal
+ * \brief Callback function to retrieve an object from a memory cache
+ *
+ * \param sorcery The sorcery instance
+ * \param data The sorcery memory cache
+ * \param type The type of the object to retrieve
+ * \param id The id of the object to retrieve
+ *
+ * \retval non-NULL success
+ * \retval NULL failure
+ */
+static void *sorcery_memory_cache_retrieve_id(const struct ast_sorcery *sorcery, void *data, const char *type, const char *id)
+{
+	struct sorcery_memory_cache *cache = data;
+	struct sorcery_memory_cached_object *cached;
+	void *object;
+
+	if (is_stale_update()) {
+		return NULL;
+	}
+
+	cached = ao2_find(cache->objects, id, OBJ_SEARCH_KEY);
+	if (!cached) {
+		return NULL;
+	}
+
+	ast_assert(!strcmp(ast_sorcery_object_get_id(cached->object), id));
+
+	if (cache->object_lifetime_stale) {
+		struct timeval elapsed;
+
+		elapsed = ast_tvsub(ast_tvnow(), cached->created);
+		if (elapsed.tv_sec > cache->object_lifetime_stale) {
+			ao2_lock(cached);
+			if (cached->stale_update_sched_id == -1) {
+				struct stale_update_task_data *task_data;
+
+				task_data = stale_update_task_data_alloc((struct ast_sorcery *)sorcery, cache,
+					type, cached->object);
+				if (task_data) {
+					ast_debug(1, "Cached sorcery object type '%s' ID '%s' is stale. Refreshing\n",
+						type, id);
+					cached->stale_update_sched_id = ast_sched_add(sched, 1, stale_item_update, task_data);
+				} else {
+					ast_log(LOG_ERROR, "Unable to update stale cached object type '%s', ID '%s'.\n",
+						type, id);
+				}
+			}
+			ao2_unlock(cached);
+		}
+	}
+
+	object = ao2_bump(cached->object);
+	ao2_ref(cached, -1);
+
+	return object;
+}
+
+/*!
+ * \internal
+ * \brief Callback function to finish configuring the memory cache
+ *
+ * \param data The sorcery memory cache
+ * \param sorcery The sorcery instance
+ * \param type The type of object being loaded
+ */
+static void sorcery_memory_cache_load(void *data, const struct ast_sorcery *sorcery, const char *type)
+{
+	struct sorcery_memory_cache *cache = data;
+
+	/* If no name was explicitly specified generate one given the sorcery instance and object type */
+	if (ast_strlen_zero(cache->name)) {
+		ast_asprintf(&cache->name, "%s/%s", ast_sorcery_get_module(sorcery), type);
+	}
+
+	ao2_link(caches, cache);
+	ast_debug(1, "Memory cache '%s' associated with sorcery instance '%p' of module '%s' with object type '%s'\n",
+		cache->name, sorcery, ast_sorcery_get_module(sorcery), type);
+}
+
+/*!
+ * \internal
+ * \brief Callback function to expire objects from the memory cache on reload (if configured)
+ *
+ * \param data The sorcery memory cache
+ * \param sorcery The sorcery instance
+ * \param type The type of object being reloaded
+ */
+static void sorcery_memory_cache_reload(void *data, const struct ast_sorcery *sorcery, const char *type)
+{
+	struct sorcery_memory_cache *cache = data;
+
+	if (!cache->expire_on_reload) {
+		return;
+	}
+
+	ao2_wrlock(cache->objects);
+	remove_all_from_cache(cache);
+	ao2_unlock(cache->objects);
+}
+
+/*!
+ * \internal
+ * \brief Function used to take an unsigned integer based configuration option and parse it
+ *
+ * \param value The string value of the configuration option
+ * \param result The unsigned integer to place the result in
+ *
+ * \retval 0 failure
+ * \retval 1 success
+ */
+static int configuration_parse_unsigned_integer(const char *value, unsigned int *result)
+{
+	if (ast_strlen_zero(value) || !strncmp(value, "-", 1)) {
+		return 0;
+	}
+
+	return sscanf(value, "%30u", result);
+}
+
+static int age_cmp(void *a, void *b)
+{
+	return ast_tvcmp(((struct sorcery_memory_cached_object *) b)->created,
+			((struct sorcery_memory_cached_object *) a)->created);
+}
+
+/*!
+ * \internal
+ * \brief Callback function to create a new sorcery memory cache using provided configuration
+ *
+ * \param data A stringified configuration for the memory cache
+ *
+ * \retval non-NULL success
+ * \retval NULL failure
+ */
+static void *sorcery_memory_cache_open(const char *data)
+{
+	char *options = ast_strdup(data), *option;
+	RAII_VAR(struct sorcery_memory_cache *, cache, NULL, ao2_cleanup);
+
+	cache = ao2_alloc_options(sizeof(*cache), sorcery_memory_cache_destructor, AO2_ALLOC_OPT_LOCK_NOLOCK);
+	if (!cache) {
+		return NULL;
+	}
+
+	cache->expire_id = -1;
+
+	/* If no configuration options have been provided this memory cache will operate in a default
+	 * configuration.
+	 */
+	while (!ast_strlen_zero(options) && (option = strsep(&options, ","))) {
+		char *name = strsep(&option, "="), *value = option;
+
+		if (!strcasecmp(name, "name")) {
+			if (ast_strlen_zero(value)) {
+				ast_log(LOG_ERROR, "A name must be specified for the memory cache\n");
+				return NULL;
+			}
+			ast_free(cache->name);
+			cache->name = ast_strdup(value);
+		} else if (!strcasecmp(name, "maximum_objects")) {
+			if (configuration_parse_unsigned_integer(value, &cache->maximum_objects) != 1) {
+				ast_log(LOG_ERROR, "Unsupported maximum objects value of '%s' used for memory cache\n",
+					value);
+				return NULL;
+			}
+		} else if (!strcasecmp(name, "object_lifetime_maximum")) {
+			if (configuration_parse_unsigned_integer(value, &cache->object_lifetime_maximum) != 1) {
+				ast_log(LOG_ERROR, "Unsupported object maximum lifetime value of '%s' used for memory cache\n",
+					value);
+				return NULL;
+			}
+		} else if (!strcasecmp(name, "object_lifetime_stale")) {
+			if (configuration_parse_unsigned_integer(value, &cache->object_lifetime_stale) != 1) {
+				ast_log(LOG_ERROR, "Unsupported object stale lifetime value of '%s' used for memory cache\n",
+					value);
+				return NULL;
+			}
+		} else if (!strcasecmp(name, "expire_on_reload")) {
+			cache->expire_on_reload = ast_true(value);
+		} else {
+			ast_log(LOG_ERROR, "Unsupported option '%s' used for memory cache\n", name);
+			return NULL;
+		}
+	}
+
+	cache->objects = ao2_container_alloc_options(AO2_ALLOC_OPT_LOCK_RWLOCK,
+		cache->maximum_objects ? cache->maximum_objects : CACHE_CONTAINER_BUCKET_SIZE,
+		sorcery_memory_cached_object_hash, sorcery_memory_cached_object_cmp);
+	if (!cache->objects) {
+		ast_log(LOG_ERROR, "Could not create a container to hold cached objects for memory cache\n");
+		return NULL;
+	}
+
+	cache->object_heap = ast_heap_create(CACHE_HEAP_INIT_HEIGHT, age_cmp,
+		offsetof(struct sorcery_memory_cached_object, __heap_index));
+	if (!cache->object_heap) {
+		ast_log(LOG_ERROR, "Could not create heap to hold cached objects\n");
+		return NULL;
+	}
+
+	/* The memory cache is not linked to the caches container until the load callback is invoked.
+	 * Linking occurs there so an intelligent cache name can be constructed using the module of
+	 * the sorcery instance and the specific object type if no cache name was specified as part
+	 * of the configuration.
+	 */
+
+	/* This is done as RAII_VAR will drop the reference */
+	return ao2_bump(cache);
+}
+
+/*!
+ * \internal
+ * \brief Callback function to delete an object from a memory cache
+ *
+ * \param sorcery The sorcery instance
+ * \param data The sorcery memory cache
+ * \param object The object to cache
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+static int sorcery_memory_cache_delete(const struct ast_sorcery *sorcery, void *data, void *object)
+{
+	struct sorcery_memory_cache *cache = data;
+	int res;
+
+	ao2_wrlock(cache->objects);
+	res = remove_from_cache(cache, ast_sorcery_object_get_id(object), 1);
+	ao2_unlock(cache->objects);
+
+	if (res) {
+		ast_log(LOG_ERROR, "Unable to delete object '%s' from sorcery cache\n", ast_sorcery_object_get_id(object));
+	}
+
+	return res;
+}
+
+/*!
+ * \internal
+ * \brief Callback function to terminate a memory cache
+ *
+ * \param data The sorcery memory cache
+ */
+static void sorcery_memory_cache_close(void *data)
+{
+	struct sorcery_memory_cache *cache = data;
+
+	/* This can occur if a cache is created but never loaded */
+	if (!ast_strlen_zero(cache->name)) {
+		ao2_unlink(caches, cache);
+	}
+
+	if (cache->object_lifetime_maximum) {
+		/* If object lifetime support is enabled we need to explicitly drop all cached objects here
+		 * and stop the scheduled task. Failure to do so could potentially keep the cache around for
+		 * a prolonged period of time.
+		 */
+		ao2_wrlock(cache->objects);
+		ao2_callback(cache->objects, OBJ_UNLINK | OBJ_NOLOCK | OBJ_NODATA | OBJ_MULTIPLE,
+			NULL, NULL);
+		AST_SCHED_DEL_UNREF(sched, cache->expire_id, ao2_ref(cache, -1));
+		ao2_unlock(cache->objects);
+	}
+
+	ao2_ref(cache, -1);
+}
+
+/*!
+ * \internal
+ * \brief CLI tab completion for cache names
+ */
+static char *sorcery_memory_cache_complete_name(const char *word, int state)
+{
+	struct sorcery_memory_cache *cache;
+	struct ao2_iterator it_caches;
+	int wordlen = strlen(word);
+	int which = 0;
+	char *result = NULL;
+
+	it_caches = ao2_iterator_init(caches, 0);
+	while ((cache = ao2_iterator_next(&it_caches))) {
+		if (!strncasecmp(word, cache->name, wordlen)
+			&& ++which > state) {
+			result = ast_strdup(cache->name);
+		}
+		ao2_ref(cache, -1);
+		if (result) {
+			break;
+		}
+	}
+	ao2_iterator_destroy(&it_caches);
+	return result;
+}
+
+/*!
+ * \internal
+ * \brief CLI command implementation for 'sorcery memory cache show'
+ */
+static char *sorcery_memory_cache_show(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
+{
+	struct sorcery_memory_cache *cache;
+
+	switch (cmd) {
+	case CLI_INIT:
+		e->command = "sorcery memory cache show";
+		e->usage =
+		    "Usage: sorcery memory cache show <name>\n"
+		    "       Show sorcery memory cache configuration and statistics.\n";
+		return NULL;
+	case CLI_GENERATE:
+		if (a->pos == 4) {
+			return sorcery_memory_cache_complete_name(a->word, a->n);
+		} else {
+			return NULL;
+		}
+	}
+
+	if (a->argc != 5) {
+		return CLI_SHOWUSAGE;
+	}
+
+	cache = ao2_find(caches, a->argv[4], OBJ_SEARCH_KEY);
+	if (!cache) {
+		ast_cli(a->fd, "Specified sorcery memory cache '%s' does not exist\n", a->argv[4]);
+		return CLI_FAILURE;
+	}
+
+	ast_cli(a->fd, "Sorcery memory cache: %s\n", cache->name);
+	ast_cli(a->fd, "Number of objects within cache: %d\n", ao2_container_count(cache->objects));
+	if (cache->maximum_objects) {
+		ast_cli(a->fd, "Maximum allowed objects: %d\n", cache->maximum_objects);
+	} else {
+		ast_cli(a->fd, "There is no limit on the maximum number of objects in the cache\n");
+	}
+	if (cache->object_lifetime_maximum) {
+		ast_cli(a->fd, "Number of seconds before object expires: %d\n", cache->object_lifetime_maximum);
+	} else {
+		ast_cli(a->fd, "Object expiration is not enabled - cached objects will not expire\n");
+	}
+	if (cache->object_lifetime_stale) {
+		ast_cli(a->fd, "Number of seconds before object becomes stale: %d\n", cache->object_lifetime_stale);
+	} else {
+		ast_cli(a->fd, "Object staleness is not enabled - cached objects will not go stale\n");
+	}
+	ast_cli(a->fd, "Expire all objects on reload: %s\n", AST_CLI_ONOFF(cache->expire_on_reload));
+
+	ao2_ref(cache, -1);
+
+	return CLI_SUCCESS;
+}
+
+/*! \brief Structure used to pass data for printing cached object information */
+struct print_object_details {
+	/*! \brief The sorcery memory cache */
+	struct sorcery_memory_cache *cache;
+	/*! \brief The CLI arguments */
+	struct ast_cli_args *a;
+};
+
+/*!
+ * \internal
+ * \brief Callback function for displaying object within the cache
+ */
+static int sorcery_memory_cache_print_object(void *obj, void *arg, int flags)
+{
+#define FORMAT "%-25.25s %-15u %-15u \n"
+	struct sorcery_memory_cached_object *cached = obj;
+	struct print_object_details *details = arg;
+	int seconds_until_expire = 0, seconds_until_stale = 0;
+
+	if (details->cache->object_lifetime_maximum) {
+		seconds_until_expire = ast_tvdiff_ms(ast_tvadd(cached->created, ast_samp2tv(details->cache->object_lifetime_maximum, 1)), ast_tvnow()) / 1000;
+	}
+	if (details->cache->object_lifetime_stale) {
+		seconds_until_stale = ast_tvdiff_ms(ast_tvadd(cached->created, ast_samp2tv(details->cache->object_lifetime_stale, 1)), ast_tvnow()) / 1000;
+	}
+
+	ast_cli(details->a->fd, FORMAT, ast_sorcery_object_get_id(cached->object), MAX(seconds_until_stale, 0), MAX(seconds_until_expire, 0));
+
+	return CMP_MATCH;
+#undef FORMAT
+}
+
+/*!
+ * \internal
+ * \brief CLI command implementation for 'sorcery memory cache dump'
+ */
+static char *sorcery_memory_cache_dump(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
+{
+#define FORMAT "%-25.25s %-15.15s %-15.15s \n"
+	struct sorcery_memory_cache *cache;
+	struct print_object_details details;
+
+	switch (cmd) {
+	case CLI_INIT:
+		e->command = "sorcery memory cache dump";
+		e->usage =
+		    "Usage: sorcery memory cache dump <name>\n"
+		    "       Dump a list of the objects within the cache, listed by object identifier.\n";
+		return NULL;
+	case CLI_GENERATE:
+		if (a->pos == 4) {
+			return sorcery_memory_cache_complete_name(a->word, a->n);
+		} else {
+			return NULL;
+		}
+	}
+
+	if (a->argc != 5) {
+		return CLI_SHOWUSAGE;
+	}
+
+	cache = ao2_find(caches, a->argv[4], OBJ_SEARCH_KEY);
+	if (!cache) {
+		ast_cli(a->fd, "Specified sorcery memory cache '%s' does not exist\n", a->argv[4]);
+		return CLI_FAILURE;
+	}
+
+	details.cache = cache;
+	details.a = a;
+
+	ast_cli(a->fd, "Dumping sorcery memory cache '%s':\n", cache->name);
+	if (!cache->object_lifetime_stale) {
+		ast_cli(a->fd, " * Staleness is not enabled - objects will not go stale\n");
+	}
+	if (!cache->object_lifetime_maximum) {
+		ast_cli(a->fd, " * Object lifetime is not enabled - objects will not expire\n");
+	}
+	ast_cli(a->fd, FORMAT, "Object Name", "Stale In", "Expires In");
+	ast_cli(a->fd, FORMAT, "-------------------------", "---------------", "---------------");
+	ao2_callback(cache->objects, OBJ_NODATA | OBJ_MULTIPLE, sorcery_memory_cache_print_object, &details);
+	ast_cli(a->fd, FORMAT, "-------------------------", "---------------", "---------------");
+	ast_cli(a->fd, "Total number of objects cached: %d\n", ao2_container_count(cache->objects));
+
+	ao2_ref(cache, -1);
+
+	return CLI_SUCCESS;
+#undef FORMAT
+}
+
+/*!
+ * \internal
+ * \brief CLI tab completion for cached object names
+ */
+static char *sorcery_memory_cache_complete_object_name(const char *cache_name, const char *word, int state)
+{
+	struct sorcery_memory_cache *cache;
+	struct sorcery_memory_cached_object *cached;
+	struct ao2_iterator it_cached;
+	int wordlen = strlen(word);
+	int which = 0;
+	char *result = NULL;
+
+	cache = ao2_find(caches, cache_name, OBJ_SEARCH_KEY);
+	if (!cache) {
+		return NULL;
+	}
+
+	it_cached = ao2_iterator_init(cache->objects, 0);
+	while ((cached = ao2_iterator_next(&it_cached))) {
+		if (!strncasecmp(word, ast_sorcery_object_get_id(cached->object), wordlen)
+			&& ++which > state) {
+			result = ast_strdup(ast_sorcery_object_get_id(cached->object));
+		}
+		ao2_ref(cached, -1);
+		if (result) {
+			break;
+		}
+	}
+	ao2_iterator_destroy(&it_cached);
+
+	ao2_ref(cache, -1);
+
+	return result;
+}
+
+/*!
+ * \internal
+ * \brief CLI command implementation for 'sorcery memory cache expire'
+ */
+static char *sorcery_memory_cache_expire(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
+{
+	struct sorcery_memory_cache *cache;
+
+	switch (cmd) {
+	case CLI_INIT:
+		e->command = "sorcery memory cache expire";
+		e->usage =
+		    "Usage: sorcery memory cache expire <cache name> [object name]\n"
+		    "       Expire a specific object or ALL objects within a sorcery memory cache.\n";
+		return NULL;
+	case CLI_GENERATE:
+		if (a->pos == 4) {
+			return sorcery_memory_cache_complete_name(a->word, a->n);
+		} else if (a->pos == 5) {
+			return sorcery_memory_cache_complete_object_name(a->argv[4], a->word, a->n);
+		} else {
+			return NULL;
+		}
+	}
+
+	if (a->argc > 6) {
+		return CLI_SHOWUSAGE;
+	}
+
+	cache = ao2_find(caches, a->argv[4], OBJ_SEARCH_KEY);
+	if (!cache) {
+		ast_cli(a->fd, "Specified sorcery memory cache '%s' does not exist\n", a->argv[4]);
+		return CLI_FAILURE;
+	}
+
+	ao2_wrlock(cache->objects);
+	if (a->argc == 5) {
+		remove_all_from_cache(cache);
+		ast_cli(a->fd, "All objects have been removed from cache '%s'\n", a->argv[4]);
+	} else {
+		if (!remove_from_cache(cache, a->argv[5], 1)) {
+			ast_cli(a->fd, "Successfully expired object '%s' from cache '%s'\n", a->argv[5], a->argv[4]);
+		} else {
+			ast_cli(a->fd, "Object '%s' was not expired from cache '%s' as it was not found\n", a->argv[5],
+				a->argv[4]);
+		}
+	}
+	ao2_unlock(cache->objects);
+
+	ao2_ref(cache, -1);
+
+	return CLI_SUCCESS;
+}
+
+/*!
+ * \internal
+ * \brief CLI command implementation for 'sorcery memory cache stale'
+ */
+static char *sorcery_memory_cache_stale(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
+{
+	struct sorcery_memory_cache *cache;
+
+	switch (cmd) {
+	case CLI_INIT:
+		e->command = "sorcery memory cache stale";
+		e->usage =
+		    "Usage: sorcery memory cache stale <cache name> [object name]\n"
+		    "       Mark a specific object or ALL objects as stale in a sorcery memory cache.\n";
+		return NULL;
+	case CLI_GENERATE:
+		if (a->pos == 4) {
+			return sorcery_memory_cache_complete_name(a->word, a->n);
+		} else if (a->pos == 5) {
+			return sorcery_memory_cache_complete_object_name(a->argv[4], a->word, a->n);
+		} else {
+			return NULL;
+		}
+	}
+
+	if (a->argc > 6) {
+		return CLI_SHOWUSAGE;
+	}
+
+	cache = ao2_find(caches, a->argv[4], OBJ_SEARCH_KEY);
+	if (!cache) {
+		ast_cli(a->fd, "Specified sorcery memory cache '%s' does not exist\n", a->argv[4]);
+		return CLI_FAILURE;
+	}
+
+	if (!cache->object_lifetime_stale) {
+		ast_cli(a->fd, "Specified sorcery memory cache '%s' does not have staleness enabled\n", a->argv[4]);
+		ao2_ref(cache, -1);
+		return CLI_FAILURE;
+	}
+
+	ao2_rdlock(cache->objects);
+	if (a->argc == 5) {
+		mark_all_as_stale_in_cache(cache);
+		ast_cli(a->fd, "Marked all objects in sorcery memory cache '%s' as stale\n", a->argv[4]);
+	} else {
+		if (!mark_object_as_stale_in_cache(cache, a->argv[5])) {
+			ast_cli(a->fd, "Successfully marked object '%s' in memory cache '%s' as stale\n",
+				a->argv[5], a->argv[4]);
+		} else {
+			ast_cli(a->fd, "Object '%s' in sorcery memory cache '%s' could not be marked as stale as it was not found\n",
+				a->argv[5], a->argv[4]);
+		}
+	}
+	ao2_unlock(cache->objects);
+
+	ao2_ref(cache, -1);
+
+	return CLI_SUCCESS;
+}
+
+static struct ast_cli_entry cli_memory_cache[] = {
+	AST_CLI_DEFINE(sorcery_memory_cache_show, "Show sorcery memory cache information"),
+	AST_CLI_DEFINE(sorcery_memory_cache_dump, "Dump all objects within a sorcery memory cache"),
+	AST_CLI_DEFINE(sorcery_memory_cache_expire, "Expire a specific object or ALL objects within a sorcery memory cache"),
+	AST_CLI_DEFINE(sorcery_memory_cache_stale, "Mark a specific object or ALL objects as stale within a sorcery memory cache"),
+};
+
+/*!
+ * \internal
+ * \brief AMI command implementation for 'SorceryMemoryCacheExpireObject'
+ */
+static int sorcery_memory_cache_ami_expire_object(struct mansession *s, const struct message *m)
+{
+	const char *cache_name = astman_get_header(m, "Cache");
+	const char *object_name = astman_get_header(m, "Object");
+	struct sorcery_memory_cache *cache;
+	int res;
+
+	if (ast_strlen_zero(cache_name)) {
+		astman_send_error(s, m, "SorceryMemoryCacheExpireObject requires that a cache name be provided.\n");
+		return 0;
+	} else if (ast_strlen_zero(object_name)) {
+		astman_send_error(s, m, "SorceryMemoryCacheExpireObject requires that an object name be provided\n");
+		return 0;
+	}
+
+	cache = ao2_find(caches, cache_name, OBJ_SEARCH_KEY);
+	if (!cache) {
+		astman_send_error(s, m, "The provided cache does not exist\n");
+		return 0;
+	}
+
+	ao2_wrlock(cache->objects);
+	res = remove_from_cache(cache, object_name, 1);
+	ao2_unlock(cache->objects);
+
+	ao2_ref(cache, -1);
+
+	if (!res) {
+		astman_send_ack(s, m, "The provided object was expired from the cache\n");
+	} else {
+		astman_send_error(s, m, "The provided object could not be expired from the cache\n");
+	}
+
+	return 0;
+}
+
+/*!
+ * \internal
+ * \brief AMI command implementation for 'SorceryMemoryCacheExpire'
+ */
+static int sorcery_memory_cache_ami_expire(struct mansession *s, const struct message *m)
+{
+	const char *cache_name = astman_get_header(m, "Cache");
+	struct sorcery_memory_cache *cache;
+
+	if (ast_strlen_zero(cache_name)) {
+		astman_send_error(s, m, "SorceryMemoryCacheExpire requires that a cache name be provided.\n");
+		return 0;
+	}
+
+	cache = ao2_find(caches, cache_name, OBJ_SEARCH_KEY);
+	if (!cache) {
+		astman_send_error(s, m, "The provided cache does not exist\n");
+		return 0;
+	}
+
+	ao2_wrlock(cache->objects);
+	remove_all_from_cache(cache);
+	ao2_unlock(cache->objects);
+
+	ao2_ref(cache, -1);
+
+	astman_send_ack(s, m, "All objects were expired from the cache\n");
+
+	return 0;
+}
+
+/*!
+ * \internal
+ * \brief AMI command implementation for 'SorceryMemoryCacheStaleObject'
+ */
+static int sorcery_memory_cache_ami_stale_object(struct mansession *s, const struct message *m)
+{
+	const char *cache_name = astman_get_header(m, "Cache");
+	const char *object_name = astman_get_header(m, "Object");
+	struct sorcery_memory_cache *cache;
+	int res;
+
+	if (ast_strlen_zero(cache_name)) {
+		astman_send_error(s, m, "SorceryMemoryCacheStaleObject requires that a cache name be provided.\n");
+		return 0;
+	} else if (ast_strlen_zero(object_name)) {
+		astman_send_error(s, m, "SorceryMemoryCacheStaleObject requires that an object name be provided\n");
+		return 0;
+	}
+
+	cache = ao2_find(caches, cache_name, OBJ_SEARCH_KEY);
+	if (!cache) {
+		astman_send_error(s, m, "The provided cache does not exist\n");
+		return 0;
+	}
+
+	ao2_rdlock(cache->objects);
+	res = mark_object_as_stale_in_cache(cache, object_name);
+	ao2_unlock(cache->objects);
+
+	ao2_ref(cache, -1);
+
+	if (!res) {
+		astman_send_ack(s, m, "The provided object was marked as stale in the cache\n");
+	} else {
+		astman_send_error(s, m, "The provided object could not be marked as stale in the cache\n");
+	}
+
+	return 0;
+}
+
+/*!
+ * \internal
+ * \brief AMI command implementation for 'SorceryMemoryCacheStale'
+ */
+static int sorcery_memory_cache_ami_stale(struct mansession *s, const struct message *m)
+{
+	const char *cache_name = astman_get_header(m, "Cache");
+	struct sorcery_memory_cache *cache;
+
+	if (ast_strlen_zero(cache_name)) {
+		astman_send_error(s, m, "SorceryMemoryCacheStale requires that a cache name be provided.\n");
+		return 0;
+	}
+
+	cache = ao2_find(caches, cache_name, OBJ_SEARCH_KEY);
+	if (!cache) {
+		astman_send_error(s, m, "The provided cache does not exist\n");
+		return 0;
+	}
+
+	ao2_rdlock(cache->objects);
+	mark_all_as_stale_in_cache(cache);
+	ao2_unlock(cache->objects);
+
+	ao2_ref(cache, -1);
+
+	astman_send_ack(s, m, "All objects were marked as stale in the cache\n");
+
+	return 0;
+}
+
+#ifdef TEST_FRAMEWORK
+
+/*! \brief Dummy sorcery object */
+struct test_sorcery_object {
+	SORCERY_OBJECT(details);
+};
+
+/*!
+ * \internal
+ * \brief Allocator for test object
+ *
+ * \param id The identifier for the object
+ *
+ * \retval non-NULL success
+ * \retval NULL failure
+ */
+static void *test_sorcery_object_alloc(const char *id)
+{
+	return ast_sorcery_generic_alloc(sizeof(struct test_sorcery_object), NULL);
+}
+
+/*!
+ * \internal
+ * \brief Allocator for test sorcery instance
+ *
+ * \retval non-NULL success
+ * \retval NULL failure
+ */
+static struct ast_sorcery *alloc_and_initialize_sorcery(void)
+{
+	struct ast_sorcery *sorcery;
+
+	if (!(sorcery = ast_sorcery_open())) {
+		return NULL;
+	}
+
+	if ((ast_sorcery_apply_default(sorcery, "test", "memory", NULL) != AST_SORCERY_APPLY_SUCCESS) ||
+		ast_sorcery_internal_object_register(sorcery, "test", test_sorcery_object_alloc, NULL, NULL)) {
+		ast_sorcery_unref(sorcery);
+		return NULL;
+	}
+
+	return sorcery;
+}
+
+AST_TEST_DEFINE(open_with_valid_options)
+{
+	int res = AST_TEST_PASS;
+	struct sorcery_memory_cache *cache;
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "open_with_valid_options";
+		info->category = "/res/res_sorcery_memory_cache/";
+		info->summary = "Attempt to create sorcery memory caches using valid options";
+		info->description = "This test performs the following:\n"
+			"\t* Creates a memory cache with default configuration\n"
+			"\t* Creates a memory cache with a maximum object count of 10 and verifies it\n"
+			"\t* Creates a memory cache with a maximum object lifetime of 60 and verifies it\n"
+			"\t* Creates a memory cache with a stale object lifetime of 90 and verifies it\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	cache = sorcery_memory_cache_open("");
+	if (!cache) {
+		ast_test_status_update(test, "Failed to create a sorcery memory cache using default configuration\n");
+		res = AST_TEST_FAIL;
+	} else {
+		sorcery_memory_cache_close(cache);
+	}
+
+	cache = sorcery_memory_cache_open("maximum_objects=10");
+	if (!cache) {
+		ast_test_status_update(test, "Failed to create a sorcery memory cache with a maximum object count of 10\n");
+		res = AST_TEST_FAIL;
+	} else {
+		if (cache->maximum_objects != 10) {
+			ast_test_status_update(test, "Created a sorcery memory cache with a maximum object count of 10 but it has '%u'\n",
+				cache->maximum_objects);
+		}
+		sorcery_memory_cache_close(cache);
+	}
+
+	cache = sorcery_memory_cache_open("object_lifetime_maximum=60");
+	if (!cache) {
+		ast_test_status_update(test, "Failed to create a sorcery memory cache with a maximum object lifetime of 60\n");
+		res = AST_TEST_FAIL;
+	} else {
+		if (cache->object_lifetime_maximum != 60) {
+			ast_test_status_update(test, "Created a sorcery memory cache with a maximum object lifetime of 60 but it has '%u'\n",
+				cache->object_lifetime_maximum);
+		}
+		sorcery_memory_cache_close(cache);
+	}
+
+	cache = sorcery_memory_cache_open("object_lifetime_stale=90");
+	if (!cache) {
+		ast_test_status_update(test, "Failed to create a sorcery memory cache with a stale object lifetime of 90\n");
+		res = AST_TEST_FAIL;
+	} else {
+		if (cache->object_lifetime_stale != 90) {
+			ast_test_status_update(test, "Created a sorcery memory cache with a stale object lifetime of 90 but it has '%u'\n",
+				cache->object_lifetime_stale);
+		}
+		sorcery_memory_cache_close(cache);
+	}
+
+
+	return res;
+}
+
+AST_TEST_DEFINE(open_with_invalid_options)
+{
+	int res = AST_TEST_PASS;
+	struct sorcery_memory_cache *cache;
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "open_with_invalid_options";
+		info->category = "/res/res_sorcery_memory_cache/";
+		info->summary = "Attempt to create sorcery memory caches using invalid options";
+		info->description = "This test attempts to perform the following:\n"
+			"\t* Create a memory cache with an empty name\n"
+			"\t* Create a memory cache with a maximum object count of -1\n"
+			"\t* Create a memory cache with a maximum object count of toast\n"
+			"\t* Create a memory cache with a maximum object lifetime of -1\n"
+			"\t* Create a memory cache with a maximum object lifetime of toast\n"
+			"\t* Create a memory cache with a stale object lifetime of -1\n"
+			"\t* Create a memory cache with a stale object lifetime of toast\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	cache = sorcery_memory_cache_open("name=");
+	if (cache) {
+		ast_test_status_update(test, "Created a sorcery memory cache with an empty name\n");
+		sorcery_memory_cache_close(cache);
+		res = AST_TEST_FAIL;
+	}
+
+	cache = sorcery_memory_cache_open("maximum_objects=-1");
+	if (cache) {
+		ast_test_status_update(test, "Created a sorcery memory cache with a maximum object count of -1\n");
+		sorcery_memory_cache_close(cache);
+		res = AST_TEST_FAIL;
+	}
+
+	cache = sorcery_memory_cache_open("maximum_objects=toast");
+	if (cache) {
+		ast_test_status_update(test, "Created a sorcery memory cache with a maximum object count of toast\n");
+		sorcery_memory_cache_close(cache);
+		res = AST_TEST_FAIL;
+	}
+
+	cache = sorcery_memory_cache_open("object_lifetime_maximum=-1");
+	if (cache) {
+		ast_test_status_update(test, "Created a sorcery memory cache with an object lifetime maximum of -1\n");
+		sorcery_memory_cache_close(cache);
+		res = AST_TEST_FAIL;
+	}
+
+	cache = sorcery_memory_cache_open("object_lifetime_maximum=toast");
+	if (cache) {
+		ast_test_status_update(test, "Created a sorcery memory cache with an object lifetime maximum of toast\n");
+		sorcery_memory_cache_close(cache);
+		res = AST_TEST_FAIL;
+	}
+
+	cache = sorcery_memory_cache_open("object_lifetime_stale=-1");
+	if (cache) {
+		ast_test_status_update(test, "Created a sorcery memory cache with a stale object lifetime of -1\n");
+		sorcery_memory_cache_close(cache);
+		res = AST_TEST_FAIL;
+	}
+
+	cache = sorcery_memory_cache_open("object_lifetime_stale=toast");
+	if (cache) {
+		ast_test_status_update(test, "Created a sorcery memory cache with a stale object lifetime of toast\n");
+		sorcery_memory_cache_close(cache);
+		res = AST_TEST_FAIL;
+	}
+
+	cache = sorcery_memory_cache_open("tacos");
+	if (cache) {
+		ast_test_status_update(test, "Created a sorcery memory cache with an invalid configuration option 'tacos'\n");
+		sorcery_memory_cache_close(cache);
+		res = AST_TEST_FAIL;
+	}
+
+	return res;
+}
+
+AST_TEST_DEFINE(create_and_retrieve)
+{
+	int res = AST_TEST_FAIL;
+	struct ast_sorcery *sorcery = NULL;
+	struct sorcery_memory_cache *cache = NULL;
+	RAII_VAR(void *, object, NULL, ao2_cleanup);
+	RAII_VAR(void *, cached_object, NULL, ao2_cleanup);
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "create";
+		info->category = "/res/res_sorcery_memory_cache/";
+		info->summary = "Attempt to create an object in the cache";
+		info->description = "This test performs the following:\n"
+			"\t* Creates a memory cache with default options\n"
+			"\t* Creates a sorcery instance with a test object\n"
+			"\t* Creates a test object with an id of test\n"
+			"\t* Pushes the test object into the memory cache\n"
+			"\t* Confirms that the test object is in the cache\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	cache = sorcery_memory_cache_open("");
+	if (!cache) {
+		ast_test_status_update(test, "Failed to create a sorcery memory cache using default options\n");
+		goto cleanup;
+	}
+
+	if (ao2_container_count(cache->objects)) {
+		ast_test_status_update(test, "Memory cache contains cached objects before we added one\n");
+		goto cleanup;
+	}
+
+	sorcery = alloc_and_initialize_sorcery();
+	if (!sorcery) {
+		ast_test_status_update(test, "Failed to create a test sorcery instance\n");
+		goto cleanup;
+	}
+
+	object = ast_sorcery_alloc(sorcery, "test", "test");
+	if (!object) {
+		ast_test_status_update(test, "Failed to allocate a test object\n");
+		goto cleanup;
+	}
+
+	sorcery_memory_cache_create(sorcery, cache, object);
+
+	if (!ao2_container_count(cache->objects)) {
+		ast_test_status_update(test, "Added test object to memory cache but cache remains empty\n");
+		goto cleanup;
+	}
+
+	cached_object = sorcery_memory_cache_retrieve_id(sorcery, cache, "test", "test");
+	if (!cached_object) {
+		ast_test_status_update(test, "Object placed into memory cache could not be retrieved\n");
+		goto cleanup;
+	}
+
+	if (cached_object != object) {
+		ast_test_status_update(test, "Object retrieved from memory cached is not the one we cached\n");
+		goto cleanup;
+	}
+
+	res = AST_TEST_PASS;
+
+cleanup:
+	if (cache) {
+		sorcery_memory_cache_close(cache);
+	}
+	if (sorcery) {
+		ast_sorcery_unref(sorcery);
+	}
+
+	return res;
+}
+
+AST_TEST_DEFINE(update)
+{
+	int res = AST_TEST_FAIL;
+	struct ast_sorcery *sorcery = NULL;
+	struct sorcery_memory_cache *cache = NULL;
+	RAII_VAR(void *, original_object, NULL, ao2_cleanup);
+	RAII_VAR(void *, updated_object, NULL, ao2_cleanup);
+	RAII_VAR(void *, cached_object, NULL, ao2_cleanup);
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "create";
+		info->category = "/res/res_sorcery_memory_cache/";
+		info->summary = "Attempt to create and then update an object in the cache";
+		info->description = "This test performs the following:\n"
+			"\t* Creates a memory cache with default options\n"
+			"\t* Creates a sorcery instance with a test object\n"
+			"\t* Creates a test object with an id of test\n"
+			"\t* Pushes the test object into the memory cache\n"
+			"\t* Confirms that the test object is in the cache\n"
+			"\t* Creates a new test object with the same id of test\n"
+			"\t* Pushes the new test object into the memory cache\n"
+			"\t* Confirms that the new test object has replaced the old one\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	cache = sorcery_memory_cache_open("");
+	if (!cache) {
+		ast_test_status_update(test, "Failed to create a sorcery memory cache using default options\n");
+		goto cleanup;
+	}
+
+	if (ao2_container_count(cache->objects)) {
+		ast_test_status_update(test, "Memory cache contains cached objects before we added one\n");
+		goto cleanup;
+	}
+
+	sorcery = alloc_and_initialize_sorcery();
+	if (!sorcery) {
+		ast_test_status_update(test, "Failed to create a test sorcery instance\n");
+		goto cleanup;
+	}
+
+	original_object = ast_sorcery_alloc(sorcery, "test", "test");
+	if (!original_object) {
+		ast_test_status_update(test, "Failed to allocate a test object\n");
+		goto cleanup;
+	}
+
+	sorcery_memory_cache_create(sorcery, cache, original_object);
+
+	updated_object = ast_sorcery_alloc(sorcery, "test", "test");
+	if (!updated_object) {
+		ast_test_status_update(test, "Failed to allocate an updated test object\n");
+		goto cleanup;
+	}
+
+	sorcery_memory_cache_create(sorcery, cache, updated_object);
+
+	if (ao2_container_count(cache->objects) != 1) {
+		ast_test_status_update(test, "Added updated test object to memory cache but cache now contains %d objects instead of 1\n",
+			ao2_container_count(cache->objects));
+		goto cleanup;
+	}
+
+	cached_object = sorcery_memory_cache_retrieve_id(sorcery, cache, "test", "test");
+	if (!cached_object) {
+		ast_test_status_update(test, "Updated object placed into memory cache could not be retrieved\n");
+		goto cleanup;
+	}
+
+	if (cached_object == original_object) {
+		ast_test_status_update(test, "Updated object placed into memory cache but old one is being retrieved\n");
+		goto cleanup;
+	} else if (cached_object != updated_object) {
+		ast_test_status_update(test, "Updated object placed into memory cache but different one is being retrieved\n");
+		goto cleanup;
+	}
+
+	res = AST_TEST_PASS;
+
+cleanup:
+	if (cache) {
+		sorcery_memory_cache_close(cache);
+	}
+	if (sorcery) {
+		ast_sorcery_unref(sorcery);
+	}
+
+	return res;
+}
+
+AST_TEST_DEFINE(delete)
+{
+	int res = AST_TEST_FAIL;
+	struct ast_sorcery *sorcery = NULL;
+	struct sorcery_memory_cache *cache = NULL;
+	RAII_VAR(void *, object, NULL, ao2_cleanup);
+	RAII_VAR(void *, cached_object, NULL, ao2_cleanup);
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "delete";
+		info->category = "/res/res_sorcery_memory_cache/";
+		info->summary = "Attempt to create and then delete an object in the cache";
+		info->description = "This test performs the following:\n"
+			"\t* Creates a memory cache with default options\n"
+			"\t* Creates a sorcery instance with a test object\n"
+			"\t* Creates a test object with an id of test\n"
+			"\t* Pushes the test object into the memory cache\n"
+			"\t* Confirms that the test object is in the cache\n"
+			"\t* Deletes the test object from the cache\n"
+			"\t* Confirms that the test object is no longer in the cache\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	cache = sorcery_memory_cache_open("");
+	if (!cache) {
+		ast_test_status_update(test, "Failed to create a sorcery memory cache using default options\n");
+		goto cleanup;
+	}
+
+	if (ao2_container_count(cache->objects)) {
+		ast_test_status_update(test, "Memory cache contains cached objects before we added one\n");
+		goto cleanup;
+	}
+
+	sorcery = alloc_and_initialize_sorcery();
+	if (!sorcery) {
+		ast_test_status_update(test, "Failed to create a test sorcery instance\n");
+		goto cleanup;
+	}
+
+	object = ast_sorcery_alloc(sorcery, "test", "test");
+	if (!object) {
+		ast_test_status_update(test, "Failed to allocate a test object\n");
+		goto cleanup;
+	}
+
+	sorcery_memory_cache_create(sorcery, cache, object);
+
+	if (!ao2_container_count(cache->objects)) {
+		ast_test_status_update(test, "Added test object to memory cache but cache contains no objects\n");
+		goto cleanup;
+	}
+
+	cached_object = sorcery_memory_cache_retrieve_id(sorcery, cache, "test", "test");
+	if (!cached_object) {
+		ast_test_status_update(test, "Test object placed into memory cache could not be retrieved\n");
+		goto cleanup;
+	}
+
+	ao2_ref(cached_object, -1);
+	cached_object = NULL;
+
+	sorcery_memory_cache_delete(sorcery, cache, object);
+
+	cached_object = sorcery_memory_cache_retrieve_id(sorcery, cache, "test", "test");
+	if (cached_object) {
+		ast_test_status_update(test, "Test object deleted from memory cache can still be retrieved\n");
+		goto cleanup;
+	}
+
+	res = AST_TEST_PASS;
+
+cleanup:
+	if (cache) {
+		sorcery_memory_cache_close(cache);
+	}
+	if (sorcery) {
+		ast_sorcery_unref(sorcery);
+	}
+
+	return res;
+}
+
+static int check_cache_content(struct ast_test *test, struct ast_sorcery *sorcery, struct sorcery_memory_cache *cache,
+		const char **in_cache, size_t num_in_cache, const char **not_in_cache, size_t num_not_in_cache)
+{
+	int i;
+	int res = 0;
+	RAII_VAR(void *, cached_object, NULL, ao2_cleanup);
+
+	for (i = 0; i < num_in_cache; ++i) {
+		cached_object = sorcery_memory_cache_retrieve_id(sorcery, cache, "test", in_cache[i]);
+		if (!cached_object) {
+			ast_test_status_update(test, "Failed to retrieve '%s' object from the cache\n",
+					in_cache[i]);
+			res = -1;
+		}
+		ao2_ref(cached_object, -1);
+	}
+
+	for (i = 0; i < num_not_in_cache; ++i) {
+		cached_object = sorcery_memory_cache_retrieve_id(sorcery, cache, "test", not_in_cache[i]);
+		if (cached_object) {
+			ast_test_status_update(test, "Retrieved '%s' object from the cache unexpectedly\n",
+					not_in_cache[i]);
+			ao2_ref(cached_object, -1);
+			res = -1;
+		}
+	}
+
+	return res;
+}
+
+AST_TEST_DEFINE(maximum_objects)
+{
+	int res = AST_TEST_FAIL;
+	struct ast_sorcery *sorcery = NULL;
+	struct sorcery_memory_cache *cache = NULL;
+	RAII_VAR(void *, alice, NULL, ao2_cleanup);
+	RAII_VAR(void *, bob, NULL, ao2_cleanup);
+	RAII_VAR(void *, charlie, NULL, ao2_cleanup);
+	RAII_VAR(void *, cached_object, NULL, ao2_cleanup);
+	const char *in_cache[2];
+	const char *not_in_cache[2];
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "maximum_objects";
+		info->category = "/res/res_sorcery_memory_cache/";
+		info->summary = "Ensure that the 'maximum_objects' option works as expected";
+		info->description = "This test performs the following:\n"
+			"\t* Creates a memory cache with maximum_objects=2\n"
+			"\t* Creates a sorcery instance\n"
+			"\t* Creates a three test objects: alice, bob, charlie, and david\n"
+			"\t* Pushes alice and bob into the memory cache\n"
+			"\t* Confirms that alice and bob are in the memory cache\n"
+			"\t* Pushes charlie into the memory cache\n"
+			"\t* Confirms that bob and charlie are in the memory cache\n"
+			"\t* Deletes charlie from the memory cache\n"
+			"\t* Confirms that only bob is in the memory cache\n"
+			"\t* Pushes alice into the memory cache\n"
+			"\t* Confirms that bob and alice are in the memory cache\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	cache = sorcery_memory_cache_open("maximum_objects=2");
+	if (!cache) {
+		ast_test_status_update(test, "Failed to create a sorcery memory cache with maximum_objects=2\n");
+		goto cleanup;
+	}
+
+	if (ao2_container_count(cache->objects)) {
+		ast_test_status_update(test, "Memory cache contains cached objects before we added one\n");
+		goto cleanup;
+	}
+
+	sorcery = alloc_and_initialize_sorcery();
+	if (!sorcery) {
+		ast_test_status_update(test, "Failed to create a test sorcery instance\n");
+		goto cleanup;
+	}
+
+	alice = ast_sorcery_alloc(sorcery, "test", "alice");
+	bob = ast_sorcery_alloc(sorcery, "test", "bob");
+	charlie = ast_sorcery_alloc(sorcery, "test", "charlie");
+
+	if (!alice || !bob || !charlie) {
+		ast_test_status_update(test, "Failed to allocate sorcery object(s)\n");
+		goto cleanup;
+	}
+
+	sorcery_memory_cache_create(sorcery, cache, alice);
+	in_cache[0] = "alice";
+	in_cache[1] = NULL;
+	not_in_cache[0] = "bob";
+	not_in_cache[1] = "charlie";
+	if (check_cache_content(test, sorcery, cache, in_cache, 1, not_in_cache, 2)) {
+		goto cleanup;
+	}
+
+	/* Delays are added to ensure that we are not adding cache entries within the
+	 * same microsecond
+	 */
+	usleep(1000);
+
+	sorcery_memory_cache_create(sorcery, cache, bob);
+	in_cache[0] = "alice";
+	in_cache[1] = "bob";
+	not_in_cache[0] = "charlie";
+	not_in_cache[1] = NULL;
+	if (check_cache_content(test, sorcery, cache, in_cache, 2, not_in_cache, 1)) {
+		goto cleanup;
+	}
+
+	usleep(1000);
+
+	sorcery_memory_cache_create(sorcery, cache, charlie);
+	in_cache[0] = "bob";
+	in_cache[1] = "charlie";
+	not_in_cache[0] = "alice";
+	not_in_cache[1] = NULL;
+	if (check_cache_content(test, sorcery, cache, in_cache, 2, not_in_cache, 1)) {
+		goto cleanup;
+	}
+	usleep(1000);
+
+	sorcery_memory_cache_delete(sorcery, cache, charlie);
+	in_cache[0] = "bob";
+	in_cache[1] = NULL;
+	not_in_cache[0] = "alice";
+	not_in_cache[1] = "charlie";
+	if (check_cache_content(test, sorcery, cache, in_cache, 1, not_in_cache, 2)) {
+		goto cleanup;
+	}
+	usleep(1000);
+
+	sorcery_memory_cache_create(sorcery, cache, alice);
+	in_cache[0] = "bob";
+	in_cache[1] = "alice";
+	not_in_cache[0] = "charlie";
+	not_in_cache[1] = NULL;
+	if (check_cache_content(test, sorcery, cache, in_cache, 2, not_in_cache, 1)) {
+		goto cleanup;
+	}
+
+	res = AST_TEST_PASS;
+
+cleanup:
+	if (cache) {
+		sorcery_memory_cache_close(cache);
+	}
+	if (sorcery) {
+		ast_sorcery_unref(sorcery);
+	}
+
+	return res;
+}
+
+AST_TEST_DEFINE(expiration)
+{
+	int res = AST_TEST_FAIL;
+	struct ast_sorcery *sorcery = NULL;
+	struct sorcery_memory_cache *cache = NULL;
+	int i;
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "expiration";
+		info->category = "/res/res_sorcery_memory_cache/";
+		info->summary = "Add objects to a cache configured with maximum lifetime, confirm they are removed";
+		info->description = "This test performs the following:\n"
+			"\t* Creates a memory cache with a maximum object lifetime of 5 seconds\n"
+			"\t* Pushes 10 objects into the memory cache\n"
+			"\t* Waits (up to) 10 seconds for expiration to occur\n"
+			"\t* Confirms that the objects have been removed from the cache\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	cache = sorcery_memory_cache_open("object_lifetime_maximum=5");
+	if (!cache) {
+		ast_test_status_update(test, "Failed to create a sorcery memory cache using default options\n");
+		goto cleanup;
+	}
+
+	sorcery = alloc_and_initialize_sorcery();
+	if (!sorcery) {
+		ast_test_status_update(test, "Failed to create a test sorcery instance\n");
+		goto cleanup;
+	}
+
+	cache->cache_notify = 1;
+	ast_mutex_init(&cache->lock);
+	ast_cond_init(&cache->cond, NULL);
+
+	for (i = 0; i < 5; ++i) {
+		char uuid[AST_UUID_STR_LEN];
+		void *object;
+
+		object = ast_sorcery_alloc(sorcery, "test", ast_uuid_generate_str(uuid, sizeof(uuid)));
+		if (!object) {
+			ast_test_status_update(test, "Failed to allocate test object for expiration\n");
+			goto cleanup;
+		}
+
+		sorcery_memory_cache_create(sorcery, cache, object);
+
+		ao2_ref(object, -1);
+	}
+
+	ast_mutex_lock(&cache->lock);
+	while (!cache->cache_completed) {
+		struct timeval start = ast_tvnow();
+		struct timespec end = {
+			.tv_sec = start.tv_sec + 10,
+			.tv_nsec = start.tv_usec * 1000,
+		};
+
+		if (ast_cond_timedwait(&cache->cond, &cache->lock, &end) == ETIMEDOUT) {
+			break;
+		}
+	}
+	ast_mutex_unlock(&cache->lock);
+
+	if (ao2_container_count(cache->objects)) {
+		ast_test_status_update(test, "Objects placed into the memory cache did not expire and get removed\n");
+		goto cleanup;
+	}
+
+	res = AST_TEST_PASS;
+
+cleanup:
+	if (cache) {
+		if (cache->cache_notify) {
+			ast_cond_destroy(&cache->cond);
+			ast_mutex_destroy(&cache->lock);
+		}
+		sorcery_memory_cache_close(cache);
+	}
+	if (sorcery) {
+		ast_sorcery_unref(sorcery);
+	}
+
+	return res;
+}
+
+/*!
+ * \brief Backend data that the mock sorcery wizard uses to create objects
+ */
+static struct backend_data {
+	/*! An arbitrary data field */
+	int salt;
+	/*! Another arbitrary data field */
+	int pepper;
+	/*! Indicates whether the backend has data */
+	int exists;
+} *real_backend_data;
+
+/*!
+ * \brief Sorcery object created based on backend data
+ */
+struct test_data {
+	SORCERY_OBJECT(details);
+	/*! Mirrors the backend data's salt field */
+	int salt;
+	/*! Mirrors the backend data's pepper field */
+	int pepper;
+};
+
+/*!
+ * \brief Allocation callback for test_data sorcery object
+ */
+static void *test_data_alloc(const char *id) {
+	return ast_sorcery_generic_alloc(sizeof(struct test_data), NULL);
+}
+
+/*!
+ * \brief Callback for retrieving sorcery object by ID
+ *
+ * The mock wizard uses the \ref real_backend_data in order to construct
+ * objects. If the backend data is "nonexisent" then no object is returned.
+ * Otherwise, an object is created that has the backend data's salt and
+ * pepper values copied.
+ *
+ * \param sorcery The sorcery instance
+ * \param data Unused
+ * \param type The object type. Will always be "test".
+ * \param id The object id. Will always be "test".
+ *
+ * \retval NULL Backend data does not exist
+ * \retval non-NULL An object representing the backend data
+ */
+static void *mock_retrieve_id(const struct ast_sorcery *sorcery, void *data,
+		const char *type, const char *id)
+{
+	struct test_data *b_data;
+
+	if (!real_backend_data->exists) {
+		return NULL;
+	}
+
+	b_data = ast_sorcery_alloc(sorcery, type, id);
+	if (!b_data) {
+		return NULL;
+	}
+
+	b_data->salt = real_backend_data->salt;
+	b_data->pepper = real_backend_data->pepper;
+	return b_data;
+}
+
+/*!
+ * \brief A mock sorcery wizard used for the stale test
+ */
+static struct ast_sorcery_wizard mock_wizard = {
+	.name = "mock",
+	.retrieve_id = mock_retrieve_id,
+};
+
+/*!
+ * \brief Wait for the cache to be updated after a stale object is retrieved.
+ *
+ * Since the cache does not know what type of objects it is dealing with, and
+ * since we do not have the internals of the cache, the only way to make this
+ * determination is to continuously retrieve an object from the cache until
+ * we retrieve a different object than we had previously retrieved.
+ *
+ * \param sorcery The sorcery instance
+ * \param previous_object The object we had previously retrieved from the cache
+ * \param[out] new_object The new object we retrieve from the cache
+ *
+ * \retval 0 Successfully retrieved a new object from the cache
+ * \retval non-zero Failed to retrieve a new object from the cache
+ */
+static int wait_for_cache_update(const struct ast_sorcery *sorcery,
+		void *previous_object, struct test_data **new_object)
+{
+	struct timeval start = ast_tvnow();
+
+	while (ast_remaining_ms(start, 5000) > 0) {
+		void *object;
+
+		object = ast_sorcery_retrieve_by_id(sorcery, "test", "test");
+		if (object != previous_object) {
+			*new_object = object;
+			return 0;
+		}
+		ao2_cleanup(object);
+	}
+
+	return -1;
+}
+
+AST_TEST_DEFINE(stale)
+{
+	int res = AST_TEST_FAIL;
+	struct ast_sorcery *sorcery = NULL;
+	struct test_data *backend_object;
+	struct backend_data iterations[] = {
+		{ .salt = 1,      .pepper = 2,       .exists = 1 },
+		{ .salt = 568729, .pepper = -234123, .exists = 1 },
+		{ .salt = 0,      .pepper = 0,       .exists = 0 },
+	};
+	struct backend_data initial = {
+		.salt = 0,
+		.pepper = 0,
+		.exists = 1,
+	};
+	int i;
+
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "stale";
+		info->category = "/res/res_sorcery_memory_cache/";
+		info->summary = "Ensure that stale objects are replaced with updated objects";
+		info->description = "This test performs the following:\n"
+			"\t* Create a sorcery instance with two wizards"
+			"\t\t* The first is a memory cache that marks items stale after 3 seconds\n"
+			"\t\t* The second is a mock of a back-end\n"
+			"\t* Pre-populates the cache by retrieving some initial data from the backend.\n"
+			"\t* Performs iterations of the following:\n"
+			"\t\t* Update backend data with new values\n"
+			"\t\t* Retrieve item from the cache\n"
+			"\t\t* Ensure the retrieved item does not have the new backend values\n"
+			"\t\t* Wait for cached object to become stale\n"
+			"\t\t* Retrieve the stale cached object\n"
+			"\t\t* Ensure that the stale object retrieved is the same as the fresh one from earlier\n"
+			"\t\t* Wait for the cache to update with new data\n"
+			"\t\t* Ensure that new data in the cache matches backend data\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	ast_sorcery_wizard_register(&mock_wizard);
+
+	sorcery = ast_sorcery_open();
+	if (!sorcery) {
+		ast_test_status_update(test, "Failed to create sorcery instance\n");
+		goto cleanup;
+	}
+
+	ast_sorcery_apply_wizard_mapping(sorcery, "test", "memory_cache",
+			"object_lifetime_stale=3", 1);
+	ast_sorcery_apply_wizard_mapping(sorcery, "test", "mock", NULL, 0);
+	ast_sorcery_internal_object_register(sorcery, "test", test_data_alloc, NULL, NULL);
+
+	/* Prepopulate the cache */
+	real_backend_data = &initial;
+
+	backend_object = ast_sorcery_retrieve_by_id(sorcery, "test", "test");
+	if (!backend_object) {
+		ast_test_status_update(test, "Unable to retrieve backend data and populate the cache\n");
+		goto cleanup;
+	}
+	ao2_ref(backend_object, -1);
+
+	for (i = 0; i < ARRAY_LEN(iterations); ++i) {
+		RAII_VAR(struct test_data *, cache_fresh, NULL, ao2_cleanup);
+		RAII_VAR(struct test_data *, cache_stale, NULL, ao2_cleanup);
+		RAII_VAR(struct test_data *, cache_new, NULL, ao2_cleanup);
+
+		real_backend_data = &iterations[i];
+
+		ast_test_status_update(test, "Begininning iteration %d\n", i);
+
+		cache_fresh = ast_sorcery_retrieve_by_id(sorcery, "test", "test");
+		if (!cache_fresh) {
+			ast_test_status_update(test, "Unable to retrieve fresh cached object\n");
+			goto cleanup;
+		}
+
+		if (cache_fresh->salt == iterations[i].salt || cache_fresh->pepper == iterations[i].pepper) {
+			ast_test_status_update(test, "Fresh cached object has unexpected values. Did we hit the backend?\n");
+			goto cleanup;
+		}
+
+		sleep(5);
+
+		cache_stale = ast_sorcery_retrieve_by_id(sorcery, "test", "test");
+		if (!cache_stale) {
+			ast_test_status_update(test, "Unable to retrieve stale cached object\n");
+			goto cleanup;
+		}
+
+		if (cache_stale != cache_fresh) {
+			ast_test_status_update(test, "Stale cache hit retrieved different object than fresh cache hit\n");
+			goto cleanup;
+		}
+
+		if (wait_for_cache_update(sorcery, cache_stale, &cache_new)) {
+			ast_test_status_update(test, "Cache was not updated\n");
+			goto cleanup;
+		}
+
+		if (iterations[i].exists) {
+			if (!cache_new) {
+				ast_test_status_update(test, "Failed to retrieve item from cache when there should be one present\n");
+				goto cleanup;
+			} else if (cache_new->salt != iterations[i].salt ||
+					cache_new->pepper != iterations[i].pepper) {
+				ast_test_status_update(test, "New cached item has unexpected values\n");
+				goto cleanup;
+			}
+		} else if (cache_new) {
+			ast_test_status_update(test, "Retrieved a cached item when there should not have been one present\n");
+			goto cleanup;
+		}
+	}
+
+	res = AST_TEST_PASS;
+
+cleanup:
+	if (sorcery) {
+		ast_sorcery_unref(sorcery);
+	}
+	ast_sorcery_wizard_unregister(&mock_wizard);
+	return res;
+}
+
+#endif
+
+static int unload_module(void)
+{
+	if (sched) {
+		ast_sched_context_destroy(sched);
+		sched = NULL;
+	}
+
+	ao2_cleanup(caches);
+
+	ast_sorcery_wizard_unregister(&memory_cache_object_wizard);
+
+	ast_cli_unregister_multiple(cli_memory_cache, ARRAY_LEN(cli_memory_cache));
+
+	ast_manager_unregister("SorceryMemoryCacheExpireObject");
+	ast_manager_unregister("SorceryMemoryCacheExpire");
+	ast_manager_unregister("SorceryMemoryCacheStaleObject");
+	ast_manager_unregister("SorceryMemoryCacheStale");
+
+	AST_TEST_UNREGISTER(open_with_valid_options);
+	AST_TEST_UNREGISTER(open_with_invalid_options);
+	AST_TEST_UNREGISTER(create_and_retrieve);
+	AST_TEST_UNREGISTER(update);
+	AST_TEST_UNREGISTER(delete);
+	AST_TEST_UNREGISTER(maximum_objects);
+	AST_TEST_UNREGISTER(expiration);
+	AST_TEST_UNREGISTER(stale);
+
+	return 0;
+}
+
+static int load_module(void)
+{
+	int res;
+
+	sched = ast_sched_context_create();
+	if (!sched) {
+		ast_log(LOG_ERROR, "Failed to create scheduler for cache management\n");
+		unload_module();
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	if (ast_sched_start_thread(sched)) {
+		ast_log(LOG_ERROR, "Failed to create scheduler thread for cache management\n");
+		unload_module();
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	caches = ao2_container_alloc(CACHES_CONTAINER_BUCKET_SIZE, sorcery_memory_cache_hash,
+		sorcery_memory_cache_cmp);
+	if (!caches) {
+		ast_log(LOG_ERROR, "Failed to create container for configured caches\n");
+		unload_module();
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	if (ast_sorcery_wizard_register(&memory_cache_object_wizard)) {
+		unload_module();
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	res = ast_cli_register_multiple(cli_memory_cache, ARRAY_LEN(cli_memory_cache));
+	res |= ast_manager_register_xml("SorceryMemoryCacheExpireObject", EVENT_FLAG_SYSTEM, sorcery_memory_cache_ami_expire_object);
+	res |= ast_manager_register_xml("SorceryMemoryCacheExpire", EVENT_FLAG_SYSTEM, sorcery_memory_cache_ami_expire);
+	res |= ast_manager_register_xml("SorceryMemoryCacheStaleObject", EVENT_FLAG_SYSTEM, sorcery_memory_cache_ami_stale_object);
+	res |= ast_manager_register_xml("SorceryMemoryCacheStale", EVENT_FLAG_SYSTEM, sorcery_memory_cache_ami_stale);
+
+	if (res) {
+		unload_module();
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	/* This causes the stale unit test to execute last, so if a sorcery instance persists
+	 * longer than expected subsequent unit tests don't fail when setting it up.
+	 */
+	AST_TEST_REGISTER(stale);
+	AST_TEST_REGISTER(open_with_valid_options);
+	AST_TEST_REGISTER(open_with_invalid_options);
+	AST_TEST_REGISTER(create_and_retrieve);
+	AST_TEST_REGISTER(update);
+	AST_TEST_REGISTER(delete);
+	AST_TEST_REGISTER(maximum_objects);
+	AST_TEST_REGISTER(expiration);
+
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+AST_MODULE_INFO(ASTERISK_GPL_KEY, AST_MODFLAG_GLOBAL_SYMBOLS | AST_MODFLAG_LOAD_ORDER, "Sorcery Memory Cache Object Wizard",
+	.support_level = AST_MODULE_SUPPORT_CORE,
+	.load = load_module,
+	.unload = unload_module,
+	.load_pri = AST_MODPRI_REALTIME_DRIVER,
+);
diff --git a/tests/test_sorcery_memory_cache_thrash.c b/tests/test_sorcery_memory_cache_thrash.c
new file mode 100644
index 0000000..8bf63a6
--- /dev/null
+++ b/tests/test_sorcery_memory_cache_thrash.c
@@ -0,0 +1,618 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2015, Digium, Inc.
+ *
+ * Joshua Colp <jcolp at digium.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*!
+ * \file
+ * \brief Sorcery Unit Tests
+ *
+ * \author Joshua Colp <jcolp at digium.com>
+ *
+ */
+
+/*** MODULEINFO
+	<depend>TEST_FRAMEWORK</depend>
+	<support_level>core</support_level>
+ ***/
+
+#include "asterisk.h"
+
+#include "asterisk/test.h"
+#include "asterisk/module.h"
+#include "asterisk/sorcery.h"
+#include "asterisk/logger.h"
+#include "asterisk/vector.h"
+#include "asterisk/cli.h"
+
+/*! \brief The default amount of time (in seconds) that thrash unit tests execute for */
+#define TEST_THRASH_TIME 3
+
+/*! \brief The number of threads to use for retrieving for applicable tests */
+#define TEST_THRASH_RETRIEVERS 25
+
+/*! \brief The number of threads to use for updating for applicable tests*/
+#define TEST_THRASH_UPDATERS 25
+
+/*! \brief Structure for a memory cache thras thread */
+struct sorcery_memory_cache_thrash_thread {
+	/*! \brief The thread thrashing the cache */
+	pthread_t thread;
+	/*! \brief Sorcery instance being tested */
+	struct ast_sorcery *sorcery;
+	/*! \brief The number of unique objects we should restrict ourself to */
+	unsigned int unique_objects;
+	/*! \brief Set when the thread should stop */
+	unsigned int stop;
+	/*! \brief Average time spent executing sorcery operation in this thread */
+	unsigned int average_execution_time;
+};
+
+/*! \brief Structure for memory cache thrasing */
+struct sorcery_memory_cache_thrash {
+	/*! \brief The sorcery instance being tested */
+	struct ast_sorcery *sorcery;
+	/*! \brief The number of threads which are updating */
+	unsigned int update_threads;
+	/*! \brief The average execution time of sorcery update operations */
+	unsigned int average_update_execution_time;
+	/*! \brief The number of threads which are retrieving */
+	unsigned int retrieve_threads;
+	/*! \brief The average execution time of sorcery retrieve operations */
+	unsigned int average_retrieve_execution_time;
+	/*! \brief Threads which are updating or reading from the cache */
+	AST_VECTOR(, struct sorcery_memory_cache_thrash_thread *) threads;
+};
+
+/*!
+ * \brief Sorcery object created based on backend data
+ */
+struct test_data {
+	SORCERY_OBJECT(details);
+};
+
+/*!
+ * \brief Allocation callback for test_data sorcery object
+ */
+static void *test_data_alloc(const char *id)
+{
+	return ast_sorcery_generic_alloc(sizeof(struct test_data), NULL);
+}
+
+/*!
+ * \brief Callback for retrieving sorcery object by ID
+ *
+ * \param sorcery The sorcery instance
+ * \param data Unused
+ * \param type The object type. Will always be "test".
+ * \param id The object id. Will always be "test".
+ *
+ * \retval NULL Backend data successfully allocated
+ * \retval non-NULL Backend data could not be successfully allocated
+ */
+static void *mock_retrieve_id(const struct ast_sorcery *sorcery, void *data,
+		const char *type, const char *id)
+{
+	return ast_sorcery_alloc(sorcery, type, id);
+}
+
+/*!
+ * \brief Callback for updating a sorcery object
+ *
+ * \param sorcery The sorcery instance
+ * \param data Unused
+ * \param object The object to update.
+ *
+ */
+static int mock_update(const struct ast_sorcery *sorcery, void *data,
+	void *object)
+{
+	return 0;
+}
+
+/*!
+ * \brief A mock sorcery wizard used for the stale test
+ */
+static struct ast_sorcery_wizard mock_wizard = {
+	.name = "mock",
+	.retrieve_id = mock_retrieve_id,
+	.update = mock_update,
+};
+
+/*!
+ * \internal
+ * \brief Destructor for sorcery memory cache thrasher
+ *
+ * \param obj The sorcery memory cache thrash structure
+ */
+static void sorcery_memory_cache_thrash_destroy(void *obj)
+{
+	struct sorcery_memory_cache_thrash *thrash = obj;
+	int idx;
+
+	if (thrash->sorcery) {
+		ast_sorcery_unref(thrash->sorcery);
+	}
+
+	for (idx = 0; idx < AST_VECTOR_SIZE(&thrash->threads); ++idx) {
+		struct sorcery_memory_cache_thrash_thread *thread;
+
+		thread = AST_VECTOR_GET(&thrash->threads, idx);
+		ast_free(thread);
+	}
+	AST_VECTOR_FREE(&thrash->threads);
+
+	ast_sorcery_wizard_unregister(&mock_wizard);
+}
+
+/*!
+ * \internal
+ * \brief Set up thrasing against a memory cache on a sorcery instance
+ *
+ * \param cache_configuration The sorcery memory cache configuration to use
+ * \param update_threads The number of threads which should be constantly updating sorcery
+ * \param retrieve_threads The number of threads which should be constantly retrieving from sorcery
+ * \param unique_objects The number of unique objects that can exist
+ *
+ * \retval non-NULL success
+ * \retval NULL failure
+ */
+static struct sorcery_memory_cache_thrash *sorcery_memory_cache_thrash_create(const char *cache_configuration,
+	unsigned int update_threads, unsigned int retrieve_threads, unsigned int unique_objects)
+{
+	struct sorcery_memory_cache_thrash *thrash;
+	struct sorcery_memory_cache_thrash_thread *thread;
+	unsigned int total_threads = update_threads + retrieve_threads;
+
+	thrash = ao2_alloc_options(sizeof(*thrash), sorcery_memory_cache_thrash_destroy,
+		AO2_ALLOC_OPT_LOCK_NOLOCK);
+	if (!thrash) {
+		return NULL;
+	}
+
+	thrash->update_threads = update_threads;
+	thrash->retrieve_threads = retrieve_threads;
+
+	ast_sorcery_wizard_register(&mock_wizard);
+
+	thrash->sorcery = ast_sorcery_open();
+	if (!thrash->sorcery) {
+		ao2_ref(thrash, -1);
+		return NULL;
+	}
+
+	ast_sorcery_apply_wizard_mapping(thrash->sorcery, "test", "memory_cache",
+			!strcmp(cache_configuration, "default") ? "" : cache_configuration, 1);
+	ast_sorcery_apply_wizard_mapping(thrash->sorcery, "test", "mock", NULL, 0);
+	ast_sorcery_internal_object_register(thrash->sorcery, "test", test_data_alloc, NULL, NULL);
+
+	if (AST_VECTOR_INIT(&thrash->threads, update_threads + retrieve_threads)) {
+		ao2_ref(thrash, -1);
+		return NULL;
+	}
+
+	while (AST_VECTOR_SIZE(&thrash->threads) != total_threads) {
+		thread = ast_calloc(1, sizeof(*thread));
+
+		if (!thread) {
+			ao2_ref(thrash, -1);
+			return NULL;
+		}
+
+		thread->thread = AST_PTHREADT_NULL;
+		thread->unique_objects = unique_objects;
+
+		/* This purposely holds no ref as the main thrash structure does */
+		thread->sorcery = thrash->sorcery;
+
+		AST_VECTOR_APPEND(&thrash->threads, thread);
+	}
+
+	return thrash;
+}
+
+/*!
+ * \internal
+ * \brief Thrashing cache update thread
+ *
+ * \param data The sorcery memory cache thrash thread
+ */
+static void *sorcery_memory_cache_thrash_update(void *data)
+{
+	struct sorcery_memory_cache_thrash_thread *thread = data;
+	struct timeval start;
+	unsigned int object_id;
+	char object_id_str[AST_UUID_STR_LEN];
+	void *object;
+
+	while (!thread->stop) {
+		object_id = ast_random() % thread->unique_objects;
+		snprintf(object_id_str, sizeof(object_id_str), "%u", object_id);
+
+		object = ast_sorcery_alloc(thread->sorcery, "test", object_id_str);
+		ast_assert(object != NULL);
+
+		start = ast_tvnow();
+		ast_sorcery_update(thread->sorcery, object);
+		thread->average_execution_time = (thread->average_execution_time + ast_tvdiff_ms(ast_tvnow(), start)) / 2;
+		ao2_ref(object, -1);
+	}
+
+	return NULL;
+}
+
+/*!
+ * \internal
+ * \brief Thrashing cache retrieve thread
+ *
+ * \param data The sorcery memory cache thrash thread
+ */
+static void *sorcery_memory_cache_thrash_retrieve(void *data)
+{
+	struct sorcery_memory_cache_thrash_thread *thread = data;
+	struct timeval start;
+	unsigned int object_id;
+	char object_id_str[AST_UUID_STR_LEN];
+	void *object;
+
+	while (!thread->stop) {
+		object_id = ast_random() % thread->unique_objects;
+		snprintf(object_id_str, sizeof(object_id_str), "%u", object_id);
+
+		start = ast_tvnow();
+		object = ast_sorcery_retrieve_by_id(thread->sorcery, "test", object_id_str);
+		thread->average_execution_time = (thread->average_execution_time + ast_tvdiff_ms(ast_tvnow(), start)) / 2;
+		ast_assert(object != NULL);
+
+		ao2_ref(object, -1);
+	}
+
+	return NULL;
+}
+
+/*!
+ * \internal
+ * \brief Stop thrashing against a sorcery memory cache
+ *
+ * \param thrash The sorcery memory cache thrash structure
+ */
+static void sorcery_memory_cache_thrash_stop(struct sorcery_memory_cache_thrash *thrash)
+{
+	int idx;
+
+	for (idx = 0; idx < AST_VECTOR_SIZE(&thrash->threads); ++idx) {
+		struct sorcery_memory_cache_thrash_thread *thread;
+
+		thread = AST_VECTOR_GET(&thrash->threads, idx);
+		if (thread->thread == AST_PTHREADT_NULL) {
+			continue;
+		}
+
+		thread->stop = 1;
+
+		pthread_join(thread->thread, NULL);
+
+		if (idx < thrash->update_threads) {
+			thrash->average_update_execution_time += thread->average_execution_time;
+		} else {
+			thrash->average_retrieve_execution_time += thread->average_execution_time;
+		}
+	}
+
+	if (thrash->update_threads) {
+		thrash->average_update_execution_time /= thrash->update_threads;
+	}
+	if (thrash->retrieve_threads) {
+		thrash->average_retrieve_execution_time /= thrash->retrieve_threads;
+	}
+}
+
+/*!
+ * \internal
+ * \brief Start thrashing against a sorcery memory cache
+ *
+ * \param thrash The sorcery memory cache thrash structure
+ *
+ * \retval 0 success
+ * \retval -1 failure
+ */
+static int sorcery_memory_cache_thrash_start(struct sorcery_memory_cache_thrash *thrash)
+{
+	int idx;
+
+	for (idx = 0; idx < AST_VECTOR_SIZE(&thrash->threads); ++idx) {
+		struct sorcery_memory_cache_thrash_thread *thread;
+
+		thread = AST_VECTOR_GET(&thrash->threads, idx);
+
+		if (ast_pthread_create(&thread->thread, NULL, idx < thrash->update_threads ?
+			sorcery_memory_cache_thrash_update : sorcery_memory_cache_thrash_retrieve, thread)) {
+			sorcery_memory_cache_thrash_stop(thrash);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
+/*!
+ * \internal
+ * \brief CLI command implementation for 'sorcery memory cache thrash'
+ */
+static char *sorcery_memory_cache_cli_thrash(struct ast_cli_entry *e, int cmd, struct ast_cli_args *a)
+{
+	struct sorcery_memory_cache_thrash *thrash;
+	unsigned int thrash_time, unique_objects, retrieve_threads, update_threads;
+
+	switch (cmd) {
+	case CLI_INIT:
+		e->command = "sorcery memory cache thrash";
+		e->usage =
+		    "Usage: sorcery memory cache thrash <cache configuration> <amount of time to thrash the cache> <number of unique objects> <number of retrieve threads> <number of update threads>\n"
+		    "       Create a sorcery instance with a memory cache using the provided configuration and thrash it.\n";
+		return NULL;
+	case CLI_GENERATE:
+		return NULL;
+	}
+
+	if (a->argc != 9) {
+		return CLI_SHOWUSAGE;
+	}
+
+	if (sscanf(a->argv[5], "%30u", &thrash_time) != 1) {
+		ast_cli(a->fd, "An invalid value of '%s' has been provided for the thrashing time\n", a->argv[5]);
+		return CLI_FAILURE;
+	} else if (sscanf(a->argv[6], "%30u", &unique_objects) != 1) {
+		ast_cli(a->fd, "An invalid value of '%s' has been provided for number of unique objects\n", a->argv[6]);
+		return CLI_FAILURE;
+	} else if (sscanf(a->argv[7], "%30u", &retrieve_threads) != 1) {
+		ast_cli(a->fd, "An invalid value of '%s' has been provided for the number of retrieve threads\n", a->argv[7]);
+		return CLI_FAILURE;
+	} else if (sscanf(a->argv[8], "%30u", &update_threads) != 1) {
+		ast_cli(a->fd, "An invalid value of '%s' has been provided for the number of update threads\n", a->argv[8]);
+		return CLI_FAILURE;
+	}
+
+	thrash = sorcery_memory_cache_thrash_create(a->argv[4], update_threads, retrieve_threads, unique_objects);
+	if (!thrash) {
+		ast_cli(a->fd, "Could not create a sorcery memory cache thrash test using the provided arguments\n");
+		return CLI_FAILURE;
+	}
+
+	ast_cli(a->fd, "Starting cache thrash test.\n");
+	ast_cli(a->fd, "Memory cache configuration: %s\n", a->argv[4]);
+	ast_cli(a->fd, "Amount of time to perform test: %u seconds\n", thrash_time);
+	ast_cli(a->fd, "Number of unique objects: %u\n", unique_objects);
+	ast_cli(a->fd, "Number of retrieve threads: %u\n", retrieve_threads);
+	ast_cli(a->fd, "Number of update threads: %u\n", update_threads);
+
+	sorcery_memory_cache_thrash_start(thrash);
+	while ((thrash_time = sleep(thrash_time)));
+	sorcery_memory_cache_thrash_stop(thrash);
+
+	ast_cli(a->fd, "Stopped cache thrash test\n");
+
+	ast_cli(a->fd, "Average retrieve execution time (in milliseconds): %u\n", thrash->average_retrieve_execution_time);
+	ast_cli(a->fd, "Average update execution time (in milliseconds): %u\n", thrash->average_update_execution_time);
+
+	ao2_ref(thrash, -1);
+
+	return CLI_SUCCESS;
+}
+
+static struct ast_cli_entry cli_memory_cache_thrash[] = {
+	AST_CLI_DEFINE(sorcery_memory_cache_cli_thrash, "Thrash a sorcery memory cache"),
+};
+
+/*!
+ * \internal
+ * \brief Perform a thrash test against a cache
+ *
+ * \param test The unit test being run
+ * \param cache_configuration The underlying cache configuration
+ * \param thrash_time How long (in seconds) to thrash the cache for
+ * \param unique_objects The number of unique objects
+ * \param retrieve_threads The number of threads constantly doing a retrieve
+ * \param update_threads The number of threads constantly doing an update
+ *
+ * \retval AST_TEST_PASS success
+ * \retval AST_TEST_FAIL failure
+ */
+static enum ast_test_result_state nominal_thrash(struct ast_test *test, const char *cache_configuration,
+	unsigned int thrash_time, unsigned int unique_objects, unsigned int retrieve_threads,
+	unsigned int update_threads)
+{
+	struct sorcery_memory_cache_thrash *thrash;
+
+	thrash = sorcery_memory_cache_thrash_create(cache_configuration, update_threads, retrieve_threads, unique_objects);
+	if (!thrash) {
+		return AST_TEST_FAIL;
+	}
+
+	sorcery_memory_cache_thrash_start(thrash);
+	while ((thrash_time = sleep(thrash_time)));
+	sorcery_memory_cache_thrash_stop(thrash);
+
+	ao2_ref(thrash, -1);
+
+	return AST_TEST_PASS;
+}
+
+AST_TEST_DEFINE(low_unique_object_count_immediately_stale)
+{
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "low_unique_object_count_immediately_stale";
+		info->category = "/res/res_sorcery_memory_cache/thrash/";
+		info->summary = "Thrash a cache with low number of unique objects that are immediately stale";
+		info->description = "This test creates a cache with objects that are stale\n"
+			"after 1 second. It also creates 25 threads which are constantly attempting\n"
+			"to retrieve the objects. This test confirms that the background refreshes\n"
+			"being done as a result of going stale do not conflict or cause problems with\n"
+			"the large number of retrieve threads.\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	return nominal_thrash(test, "object_lifetime_stale=1", TEST_THRASH_TIME, 10, TEST_THRASH_RETRIEVERS, 0);
+}
+
+AST_TEST_DEFINE(low_unique_object_count_immediately_expire)
+{
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "low_unique_object_count_immediately_expire";
+		info->category = "/res/res_sorcery_memory_cache/thrash/";
+		info->summary = "Thrash a cache with low number of unique objects that are immediately expired";
+		info->description = "This test creates a cache with objects that are expired\n"
+			"after 1 second. It also creates 25 threads which are constantly attempting\n"
+			"to retrieve the objects. This test confirms that the expiration process does\n"
+			"not cause a problem as the retrieve threads execute.\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	return nominal_thrash(test, "object_lifetime_maximum=1", TEST_THRASH_TIME, 10, TEST_THRASH_RETRIEVERS, 0);
+}
+
+AST_TEST_DEFINE(low_unique_object_count_high_concurrent_updates)
+{
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "low_unique_object_count_high_concurrent_updates";
+		info->category = "/res/res_sorcery_memory_cache/thrash/";
+		info->summary = "Thrash a cache with low number of unique objects that are updated frequently";
+		info->description = "This test creates a cache with objects that are being constantly\n"
+			"updated and retrieved at the same time. This will create contention between all\n"
+			"of the threads as the write lock is held for the updates. This test confirms that\n"
+			"no problems occur in this situation.\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	return nominal_thrash(test, "default", TEST_THRASH_TIME, 10, TEST_THRASH_RETRIEVERS, TEST_THRASH_UPDATERS);
+}
+
+AST_TEST_DEFINE(unique_objects_exceeding_maximum)
+{
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "unique_objects_exceeding_maximum";
+		info->category = "/res/res_sorcery_memory_cache/thrash/";
+		info->summary = "Thrash a cache with a fixed maximum object count";
+		info->description = "This test creates a cache with a maximum number of objects\n"
+			"allowed in it. The maximum number of unique objects, however, far exceeds the\n"
+			"the maximum number allowed in the cache. This test confirms that the cache does\n"
+			"not exceed the maximum and that the removal of older objects does not cause\n"
+			"a problem.\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	return nominal_thrash(test, "maximum_objects=10", TEST_THRASH_TIME, 100, TEST_THRASH_RETRIEVERS, 0);
+}
+
+AST_TEST_DEFINE(unique_objects_exceeding_maximum_with_expire_and_stale)
+{
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "unique_objects_exceeding_maximum_with_expire_and_stale";
+		info->category = "/res/res_sorcery_memory_cache/thrash/";
+		info->summary = "Thrash a cache with a fixed maximum object count with objects that expire and go stale";
+		info->description = "This test creates a cache with a maximum number of objects\n"
+			"allowed in it with objects that also go stale after a period of time and expire.\n"
+			"A number of threads are created that constantly retrieve from the cache, causing\n"
+			"both stale refresh and expiration to occur. This test confirms that the combination\n"
+			"of these do not present a problem.\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	return nominal_thrash(test, "maximum_objects=10,object_lifetime_maximum=2,object_lifetime_stale=1",
+		TEST_THRASH_TIME * 2, 100, TEST_THRASH_RETRIEVERS, 0);
+}
+
+AST_TEST_DEFINE(conflicting_expire_and_stale)
+{
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "conflicting_expire_and_stale";
+		info->category = "/res/res_sorcery_memory_cache/thrash/";
+		info->summary = "Thrash a cache with a large number of objects that expire and go stale";
+		info->description = "This test creates a cache with a large number of objects that expire\n"
+			"and go stale. As there is such a large number this ensures that both operations occur.\n"
+			"This test confirms that stale refreshing and expiration do not conflict.\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	return nominal_thrash(test, "object_lifetime_maximum=2,object_lifetime_stale=1", TEST_THRASH_TIME * 2, 5000,
+		TEST_THRASH_RETRIEVERS, 0);
+}
+
+AST_TEST_DEFINE(high_object_count_without_expiration)
+{
+	switch (cmd) {
+	case TEST_INIT:
+		info->name = "high_object_count_without_expiration";
+		info->category = "/res/res_sorcery_memory_cache/thrash/";
+		info->summary = "Thrash a cache with a large number of objects";
+		info->description = "This test creates a cache with a large number of objects that persist.\n"
+			"A large number of threads are created which constantly retrieve from the cache.\n"
+			"This test confirms that the large number of retrieves do not cause a problem.\n";
+		return AST_TEST_NOT_RUN;
+	case TEST_EXECUTE:
+		break;
+	}
+
+	return nominal_thrash(test, "default", TEST_THRASH_TIME, 5000, TEST_THRASH_RETRIEVERS, 0);
+}
+
+static int unload_module(void)
+{
+	ast_cli_unregister_multiple(cli_memory_cache_thrash, ARRAY_LEN(cli_memory_cache_thrash));
+	AST_TEST_UNREGISTER(low_unique_object_count_immediately_stale);
+	AST_TEST_UNREGISTER(low_unique_object_count_immediately_expire);
+	AST_TEST_UNREGISTER(low_unique_object_count_high_concurrent_updates);
+	AST_TEST_UNREGISTER(unique_objects_exceeding_maximum);
+	AST_TEST_UNREGISTER(unique_objects_exceeding_maximum_with_expire_and_stale);
+	AST_TEST_UNREGISTER(conflicting_expire_and_stale);
+	AST_TEST_UNREGISTER(high_object_count_without_expiration);
+
+	return 0;
+}
+
+static int load_module(void)
+{
+	ast_cli_register_multiple(cli_memory_cache_thrash, ARRAY_LEN(cli_memory_cache_thrash));
+	AST_TEST_REGISTER(low_unique_object_count_immediately_stale);
+	AST_TEST_REGISTER(low_unique_object_count_immediately_expire);
+	AST_TEST_REGISTER(low_unique_object_count_high_concurrent_updates);
+	AST_TEST_REGISTER(unique_objects_exceeding_maximum);
+	AST_TEST_REGISTER(unique_objects_exceeding_maximum_with_expire_and_stale);
+	AST_TEST_REGISTER(conflicting_expire_and_stale);
+	AST_TEST_REGISTER(high_object_count_without_expiration);
+
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Sorcery Cache Thrasing test module");

-- 
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Gerrit-MessageType: newchange
Gerrit-Change-Id: I6dda90343fae24a75dc5beec84980024e8d61eb9
Gerrit-PatchSet: 1
Gerrit-Project: asterisk
Gerrit-Branch: 13
Gerrit-Owner: Mark Michelson <mmichelson at digium.com>
Gerrit-Reviewer: Joshua Colp <jcolp at digium.com>



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