Package 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>

  • Field Details

  • Constructor Details

    • MetricsFilter

      public MetricsFilter()

    • MetricsFilter

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

  • Method Details

    • isEmpty

      private boolean isEmpty(String s)

    • getComponents

      private String getComponents(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 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