Package io.prometheus.client.filter

Class MetricsFilter

  • All Implemented Interfaces:
    javax.servlet.Filter
    public class MetricsFilter
extends java.lang.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>

    • Constructor Summary

      Constructors 
      Constructor Description
      MetricsFilter()  
      MetricsFilter​(java.lang.String metricName, java.lang.String help, java.lang.Integer pathComponents, double[] buckets)  

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void destroy()  
      void doFilter​(javax.servlet.ServletRequest servletRequest, javax.servlet.ServletResponse servletResponse, javax.servlet.FilterChain filterChain)  
      private java.lang.String getComponents​(java.lang.String str)  
      void init​(javax.servlet.FilterConfig filterConfig)  
      private boolean isEmpty​(java.lang.String s)  

      • Methods inherited from class java.lang.Object

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

    • Field Detail

      • PATH_COMPONENT_PARAM

        static final java.lang.String PATH_COMPONENT_PARAM
        See Also:
        Constant Field Values

      • pathComponents

        int pathComponents

      • metricName

        private java.lang.String metricName

      • help

        private java.lang.String help

      • buckets

        private double[] buckets

    • Constructor Detail

      • MetricsFilter

        public MetricsFilter()

      • MetricsFilter

        public MetricsFilter​(java.lang.String metricName,
                     java.lang.String help,
                     java.lang.Integer pathComponents,
                     double[] buckets)

    • Method Detail

      • isEmpty

        private boolean isEmpty​(java.lang.String s)

      • getComponents

        private java.lang.String getComponents​(java.lang.String str)

      • 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 java.io.IOException,
                     javax.servlet.ServletException
        Specified by:
        doFilter in interface javax.servlet.Filter
        Throws:
        java.io.IOException
        javax.servlet.ServletException

      • destroy

        public void destroy()
        Specified by:
        destroy in interface javax.servlet.Filter