MessageQueue
The MessageQueues is a mechanism for organizing YATE's messages in different queues, identified by message name and some specified filters.
This article explains how to create and use a MessageQueue in Javascript.
The purpose of messageQueue mechanism is to streamline the message processing in Yate.
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How to create MessageQueue in Javascript
In JavaScript a MessageQueue can be created by calling Message.installHook() method.
Read the description of MessageQueue behaviour in messages page .
installHook parameters
- processCallback - function, optional. The method that should process the messages skipping the engine handlers list.
- msgName - string, mandatory. The message name for the queue filtering.
- workers - integer, mandatory. The number of workers that should be used for message processing.
- trapCallback - function, optional. The method that should be called when a queue overload is detected.
- trapCount - integer, mandatory if trapCallback is present. The number of messages in the queue when we should be alerted.
- filter - string, optional, can be repeated. Optional message filter. Should be in form 'name=value'.
Examples
1. Creates a MessageQueue for engine.timer message with one processing thread.
installHook("engine.timer",1);
2. Creates a MessageQueue for call.route message, who has called=123. Two processing threads will be created. When a message needs to be processed the callback method will be called.
installHook(callback,"call.route",2,"called=123");
3. The same behaviour as above only that the trapCallback method will be called when in the queue exists more than 50 unprocessed messages
installHook(callback,"call.route",2,trapCallback,50,"called=123");
When to use?
MessageQueue can be used:
- when you have a high number of a specific message that needs to be handled
- when handling a message implies sending more messages that need to be processed
- when you want to avoid using Yate's message queue
If you need to handle a specific message frequently or see that processing this message takes too long you might need to use a custom MessageQueue for that message.
See also
