[Asterisk-Users] call-back example

[Peter Svensson]

On Thu, 19 Aug 2004, Tobias Jönsson wrote:

> exten => h,2,System(echo "Channel: SIP/0${callbacknr}@rix1" > /tmp/${UNIQUEID}.call)
> exten => h,3,System(echo "MaxRetries: 2" >> /tmp/${UNIQUEID}.call)
> exten => h,4,System(echo "RetryTime: 60" >> /tmp/${UNIQUEID}.call)
> exten => h,5,System(echo "WaitTime: 30" >> /tmp/${UNIQUEID}.call)
> exten => h,6,System(echo "Context: intern" >> /tmp/${UNIQUEID}.call)
> exten => h,7,System(echo "Extension: 0" >> /tmp/${UNIQUEID}.call)
> exten => h,8,System(echo "Priority: 1" >> /tmp/${UNIQUEID}.call)
> exten => h,9,System(mv /tmp/${UNIQUEID}.call /var/spool/asterisk/outgoing)

There is a race in this solution of /tmp and /var/spool/asterisk/outgoing 
are on different file systems. Then the rename operation (mv) is not 
atomic but rather a copy. Asterisk can then read half a file. Just 
something to think about when choosing the location of the temporary file.

Peter