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Enable Metrics

Metrics are disable by default. The gathering of metrics as well as exposing them via HTTP for analysis needs to be enabled first.

Enable HTTP and WebService calls enable the Servlet Filter

Comment in the following block in the openmeetings/WEB-INF/web.xml

<!-- Start Prometheus Filter HTTP Servlet metrics
	<filter>
		<filter-name>prometheusFilter</filter-name>
		<filter-class>io.prometheus.client.filter.MetricsFilter</filter-class>
		<init-param>
			<param-name>metric-name</param-name>
			<param-value>webapp_metrics_filter</param-value>
		</init-param>
		<init-param>
			<param-name>help</param-name>
			<param-value>This is the help for your metrics filter</param-value>
		</init-param>
		<init-param>
			<param-name>buckets</param-name>
			<param-value>0.005,0.01,0.025,0.05,0.075,0.1,0.25,0.5,0.75,1,2.5,5,7.5,10</param-value>
		</init-param>
		<init-param>
			<param-name>path-components</param-name>
			<param-value>0</param-value>
		</init-param>
	</filter>

	<filter-mapping>
		<filter-name>prometheusFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	End Prometheus -->

Enable Exposing the metrics and enable Tomcat generic metrics

To enable the export of the metrics as well as some generic Tomcat export (for example around active threads) you need to comment in the following block in openmeetings/WEB-INF/In order to enable the metrics to be published as endpoint comment in the servlet in the web.xml

<!-- Start Prometheus export metrics HTTP
	<servlet>
  		<servlet-name>metrics</servlet-name>
  		<servlet-class>io.prometheus.client.exporter.MetricsServlet<class>org.apache.openmeetings.web.util.logging.OpenMeetingsMetricsServlet</servlet-class>
	</servlet>
	<servlet-mapping>
  		<servlet-name>metrics</servlet-name>
  		<url-pattern>/services/metrics/</url-pattern>
	</servlet-mapping>
	End Prometheus -->

This will expose the metrics at: http://$HOST:$PORT/openmeetings/services/metrics/ (be aware of the trailing "/" !)See: /openmeetings-web/src/main/webapp/WEB-INF/web.xml#L110

Enable metrics for streaming and other application relevant metrics

In order to get insights on the application specific logic and streaming relevant components you need to additionally enable certain annotations by commenting in openmeetings/WEB-INF/classes/applicationContext.xml

<!-- Start annotation Prometheus metrics
	<aop:aspectj-autoproxy/>
	End annotation -->

View your metrics in Prometheus

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Application metrics based on manual metric

Unfortunate not all places in the code are spring beans. Also sometimes we have inner classes or similar issues.

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