mqueue Module
Elena-Ramona Modroiu
asipto.com
Edited by
Elena-Ramona Modroiu
Edited by
Alex Balashov
Evariste Systems
Copyright � 2010 Elena-Ramona Modroiu (asipto.com)
__________________________________________________________________
Table of Contents
1. Admin Guide
1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Parameters
3.1. mqueue (string)
4. Functions
4.1. mq_add(queue, key, value)
4.2. mq_fetch(queue)
4.3. mq_pv_free(queue)
4.4. mq_size(queue)
5. Exported Pseudo-variables
List of Examples
1.1. Set mqueue parameter
1.2. mq_add usage
1.3. mq_fetch usage
1.4. mq_pv_free usage
1.5. mq_size usage
Chapter 1. Admin Guide
Table of Contents
1. Overview
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
3. Parameters
3.1. mqueue (string)
4. Functions
4.1. mq_add(queue, key, value)
4.2. mq_fetch(queue)
4.3. mq_pv_free(queue)
4.4. mq_size(queue)
5. Exported Pseudo-variables
1. Overview
The mqueue module offers a generic message queue system in shared
memory for inter-process communication using the config file. One
example of usage is to send time consuming operations to one or several
timer processes that consumes items in the queue, without affecting SIP
message handling in the socket-listening process.
There can be many defined queues. Access to queued values is done via
pseudo variables.
2. Dependencies
2.1. Kamailio Modules
2.2. External Libraries or Applications
2.1. Kamailio Modules
The following modules must be loaded before this module:
* None.
2.2. External Libraries or Applications
The following libraries or applications must be installed before
running Kamailio with this module loaded:
* None.
3. Parameters
3.1. mqueue (string)
3.1. mqueue (string)
Definition of a memory queue
Default value is "none".
Value must be a list of parameters: attr=value;... The attribute 'name'
is mandatory, defining the name of the queue. Optional attribute 'size'
specifies the maximum number of items in queue, if it is execeeded the
oldest one is removed.
The parameter can be set many times, each holding the definition of one
queue.
Example 1.1. Set mqueue parameter
...
modparam("mqueue", "mqueue", "name=myq;size=20;")
modparam("mqueue", "mqueue", "name=qaz")
...
4. Functions
4.1. mq_add(queue, key, value)
4.2. mq_fetch(queue)
4.3. mq_pv_free(queue)
4.4. mq_size(queue)
4.1. mq_add(queue, key, value)
Add a new item (key, value) in the queue. If max size of queue is
exceeded, the oldest one is removed.
Example 1.2. mq_add usage
...
mq_add("myq", "$rU", "call from $fU");
...
4.2. mq_fetch(queue)
Take oldest item from queue and fill $mqk(queue) and $mqv(queue) pseudo
variables.
Return: true on success (1); false on failure (-1) or no item fetched
(-2).
Example 1.3. mq_fetch usage
...
while(mq_fetch("myq"))
{
xlog("$mqk(myq) - $mqv(myq)\n");
}
...
4.3. mq_pv_free(queue)
Free the item fetched in pseudo-variables. It is optional, a new fetch
frees the previous values.
Example 1.4. mq_pv_free usage
...
mq_pv_free("myq");
...
4.4. mq_size(queue)
Returns the current number of elements in the mqueue.
If the mqueue is empty, the function returns -1. If the mqueue is not
found, the function returns -2.
Example 1.5. mq_size usage
...
$var(q_size) = mq_size("queue");
xlog("L_INFO", "Size of queue is: $var(q_size)\n");
...
5. Exported Pseudo-variables
* $mqv(mqueue) - the most recent item key fetched from the specified
mqueue
* $mqv(mqueue) - the most recent item value fetched from the
specified mqueue
* $mq_size(mqueue) - the size of the specified mqueue
Exported pseudo-variables are documented at
http://www.kamailio.org/wiki/.