Just a way to put data in the messages on the BUILD.TASKS queue and have them echoed back in the message that goes on the BUILD.RESULTS topic.
It's more or less a generic bucket used for adding any kind of metadata to the message. You configure the HeaderIncludeExtention with a regex it will use to find headers that should be echoed. When a header is found it will be copied as is to the result message.
Useful for when the agent producing the build and placing it on the queue wants some data about the build sent back to it when with the results. This could perhaps be a session id or some other info that helps the build producer aggregate or track results.
<component> <role>org.apache.geronimo.gbuild.agent.BuildAgentExtension</role> <role-hint>general-headers</role-hint> <implementation>org.apache.geronimo.gbuild.agent.HeaderIncludeExtension</implementation> <configuration> <pattern>^(project|build|header).*</pattern> </configuration> </component>
In the above xml the <pattern> element is the regex that will be matched on the headers in the messages on BUILD.TASKS. This particular regex matches any header that starts with "project", "build" or "header". This headers plus their values will be copied into the results map sent to the BUILD.RESULTS topic.
You can declare as many HeaderIncludeExtensions as you like.