io.prometheus.client.filter

Class MetricsFilter

java.lang.Object

io.prometheus.client.filter.MetricsFilter

All Implemented Interfaces:

javax.servlet.Filter

public class MetricsFilter
extends Object
implements javax.servlet.Filter

The MetricsFilter class exists to provide a high-level filter that enables tunable collection of metrics for Servlet performance.

The Histogram name itself is required, and configured with a metric-name init parameter.

The help parameter, configured with the help init parameter, is not required but strongly recommended.

By default, this filter will provide metrics that distinguish only 1 level deep for the request path (including servlet context path), but can be configured with the path-components init parameter. Any number provided that is less than 1 will provide the full path granularity (warning, this may affect performance).

The Histogram buckets can be configured with a buckets init parameter whose value is a comma-separated list of valid double values.

 <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>The time taken fulfilling servlet requests</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>
 

Author:

Andrew Stuart <andrew.stuart2@gmail.com>

Constructor Summary

Constructors

Constructor and Description
MetricsFilter()
MetricsFilter(String metricName, String help, Integer pathComponents, double[] buckets)

Method Summary

Modifier and Type	Method and 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

MetricsFilter

public MetricsFilter()

MetricsFilter

public MetricsFilter(String metricName,
                     String help,
                     Integer pathComponents,
                     double[] buckets)

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