Sunday, February 19, 2012

Hot deployment of CEP query configuration in WSO2 CEP

WSO2 CEP is an open source CEP server released under Apache License v2.0

WSO2 CEP has an added advantage of flexible integration, such as enabling it to integration with Enterprise Service Buses like WSO2 ESB which can send events across transports into various streams. WSO2 CEP can also be used with Message Brokers (E.g. WSO2 MB) to process messages of the topics CEP has subscribed and publishing back the matching occurrences in MB. Further this can also be used with WSO2 Business Activity Monitor to monitor actionable events on the fly and report them.

WSO2 CEP is designed to support multiple open source CEP engines, with out-of-the-box support for Drools Fusion and EsperTM.

WSO2 CEP's back-end CEP engine, query configuration, and all input and output mappings are represented as buckets. Here we create buckets for each of our use-cases.

In earlier versions of WSO2 CEP cep-config.xml file is the only mean of deploying cep buckets via configuration. Here the configurations will be added only at server start up. From WSO2 CEP 4.0.0 release writing buckets and deploying them in the Server has become very easy via the Axis2 hot deployment.

For hot deployment we just need to write an xml containing the bucket configuration and drop that in the CARBON_HOME/repository/deployment/server/cepbuckets/

Here each bucket configuration file can contain configuration of a single CEP bucket.
This file need to have a .xml extension and follow the cep-config.xsd.

E.g.

<bucket xmlns="http://wso2.org/carbon/cep" .... >
         .... configuration....
</bucket >


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