[asterisk-dev] A project idea for a journeyman Asterisk developer

[Steve Murphy]

On Mon, Jun 15, 2009 at 3:11 PM, Mark Michelson <mmichelson at digium.com>wrote:

> Hi list,
>
> Before Asterisk 1.6.0 was released, Steve Murphy did quite a bit of work to
> create a new method of executing the pattern-matching for extensions in the
> dialplan.
>
> The biggest change he made was to change the structure used to store
> extensions
> from a linked list to a "trie." The use of this storage method means that
> the
> running time for looking up an extension is no longer bounded by the number
> of
> extensions in the dialplan but rather by the length of extensions in the
> dialplan. For installations with hundreds or thousands of extensions, this
> change means a remarkable improvement in lookup speed.
>
> The 'extenpatternmatchnew' option debuted in Asterisk 1.6.0, but it was
> disabled
> by default. It was disabled because it hadn't gone through all the tweaking
> and
> testing that the old pattern-matching had been through and possibly due to
> the
> knowledge of unfixed bugs.
>
> Since then, there have been several fixes to extenpatternmatchnew to
> improve its
> pattern-matching accuracy. I think it has reached a point where we should
> take
> the next logical step and consider making extenpatternmatchnew the
> standard.
>
> I think this can be accomplished through the following steps:
>
> 1. Write a module for the tests/ directory which can take a sample dialplan
> and
> sample input, and tell which extension in the dialplan was matched given
> the input.
>
> 2. Test many inputs against many dialplans, making sure that the new
> pattern
> matching algorithm results in the same pattern being matched by the old
> algorithm. Community-submitted dialplans would be great for this because
> you can
> test against patterns you may not have thought of yourself.
>
> 3. If (2) results in bugs being found, submit issue reports and get the
> problems
> fixed. When the bugs are fixed, re-run all the tests from (2) to be sure
> there
> are no regressions from the bug fixes.
>
> 4. Once it is determined that the new algorithm is matching the same
> patterns as
> the old, then change the default option in extensions.conf.sample for
> extenpatternmatchnew and change the default setting for it in the code.
> Commit
> the change.
>
> At this point, extenpatternmatchnew will be enabled by default for future
> versions of Asterisk. However, since all that testing was done to determine
> that
> the new pattern matching algorithm matches just as accurately as the old
> one,
> there's really no reason to keep the old code around.
>
> 5. Remove all code dealing with the old pattern-matching method. Remove the
> extenpatternmatchnew option since it now is the standard.
>
> 6. Re-run all the tests in 2, fixing any regressions found.
>
> 7. Commit the code changes.
>
> Now for the catch. Even though I am presenting this project to the mailing
> list
> and laying out the steps necessary to get the project done, I just don't
> have
> the time to dedicate myself to this task. The difficulty of this project is
> such
> that it can't really be called a "janitor project" but it's small enough
> that I
> don't think you'd necessarily have to be an Asterisk development guru to
> finish
> it successfully.
>
> If there are interested parties, speak up! This is a good opportunity for
> you to
> get more involved in Asterisk's development.
>
> Mark Michelson
>


I'll be happy to serve as a resource here! I can answer questions,
offer advise, and provide a shoulder to cry on. You may have to
provide the towel, tho!

murf


-- 
Steve Murphy
ParseTree Corp
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