Package nl.nlighten.prometheus.tomcat

Class TomcatServletMetricsFilter

java.lang.Object

nl.nlighten.prometheus.tomcat.TomcatServletMetricsFilter

All Implemented Interfaces:

javax.servlet.Filter

public class TomcatServletMetricsFilter
extends Object
implements javax.servlet.Filter

A servlet filter that can be configured in Tomcat's global web.xml and that provides the following metrics: - A Histogram with response time distribution per context - A Gauge with the number of concurrent request per context - A Gauge with a the number of responses per context and status code

If you are running Tomcat in the conventional non-embedded way you should add the client_tomcat jar and all its dependencies (see POM.XML) to the $CATALINA_BASE/lib directory or another directory on the common.loader path. Next, add this filter to the $CATALINA_BASE/lib/web.xml, e.g.:

 
 <filter>
   <filter-name>ServletMetricsFilter</filter-name>
   <filter-class>nl.nlighten.prometheus.TomcatServletMetricsFilter</filter-class>
   <async-supported>true</async-supported>
   <init-param>
     <param-name>buckets</param-name>
     <param-value>.01, .05, .1, .25, .5, 1, 2.5, 5, 10, 30</param-value>
   </init-param>
 </filter>
 
 

If you running Tomcat embedded, please check AbstractTomcatMetricsTest for example configuration. Example metrics being exported:

     servlet_request_seconds_bucket{"/foo", "GET", "0.1",} 1.0
     ....
     servlet_request_seconds_bucket{"/foo", "GET", "+Inf",} 1.0
     servlet_request_concurrent_total{"/foo",} 1.0
     servlet_response_status_total{"/foo", "200",} 1.0
  

Constructor Summary

Constructors

Constructor	Description
TomcatServletMetricsFilter()

Method Summary

Modifier and Type	Method	Description
void	destroy()
void	doFilter(javax.servlet.ServletRequest servletRequest, javax.servlet.ServletResponse servletResponse, javax.servlet.FilterChain filterChain)
void	init(javax.servlet.FilterConfig filterConfig)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TomcatServletMetricsFilter

public TomcatServletMetricsFilter()

Method Detail

init

public void init(javax.servlet.FilterConfig filterConfig)
          throws javax.servlet.ServletException

Specified by:

init in interface javax.servlet.Filter

Throws:

javax.servlet.ServletException

doFilter

public void doFilter(javax.servlet.ServletRequest servletRequest,
                     javax.servlet.ServletResponse servletResponse,
                     javax.servlet.FilterChain filterChain)
              throws IOException,
                     javax.servlet.ServletException

Specified by:

doFilter in interface javax.servlet.Filter

Throws:

IOException

javax.servlet.ServletException

destroy

public void destroy()

Specified by:

destroy in interface javax.servlet.Filter