https://github.com/opentracing-contrib/java-web-servlet-filter

OpenTracing Java Web Servlet Filter Instrumentation
https://github.com/opentracing-contrib/java-web-servlet-filter

filter instrumentation opentracing servlet tracing

Last synced: 6 days ago
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OpenTracing Java Web Servlet Filter Instrumentation

• Host: GitHub
• URL: https://github.com/opentracing-contrib/java-web-servlet-filter
• Owner: opentracing-contrib
• License: apache-2.0
• Created: 2017-01-12T18:50:00.000Z (about 8 years ago)
• Default Branch: master
• Last Pushed: 2022-07-07T20:59:40.000Z (over 2 years ago)
• Last Synced: 2025-01-08T01:21:05.204Z (14 days ago)
• Topics: filter, instrumentation, opentracing, servlet, tracing
• Language: Java
• Homepage:
• Size: 173 KB
• Stars: 25
• Watchers: 5
• Forks: 31
• Open Issues: 10
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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[![Build Status][ci-img]][ci] [![Released Version][maven-img]][maven]

# OpenTracing Java Web Servlet Filter Instrumentation

This library provides instrumentation for Java Web Servlet applications.

## Initialization

Tracing filter can be programmatically initialized:

```java

   TracingFilter filter = new TracingFilter(tracer);

   servletContext.addFilter("tracingFilter", filter);

```

or added to `web.xml`, however it requires to register a tracer instance: `GlobalTracer.register(tracer)`.

## Tracer override

If a tracer has been associated with the `ServletContext` as an attribute with key `io.opentracing.Tracer`,

then it will override any tracer explicitly passed to the filter or registered with the `GlobalTracer`.

This approach can be used where OpenTracing and Tracer implementation specific dependencies are configured within a

servlet container (rather than bundled with the webapp), and we don't wish to share a single `GlobalTracer` instance

across all webapps (e.g. as this may mean all webapps report their spans associated with the same service name).

In these situations, using a `ServletContextListener` to create a `Tracer` will enable it to be specific to the webapp and

managed with its lifecycle.

## Accessing Server Span

Current server span context is accessible in HttpServletRequest attributes.

```java

   SpanContext spanContext = (SpanContext)httpservletRequest.getAttribute(TracingFilter.SERVER_SPAN_CONTEXT);

   

```

## Development

```shell

./mvnw clean install

```

## Release

Follow instructions in [RELEASE](RELEASE.md)

   [ci-img]: https://travis-ci.org/opentracing-contrib/java-web-servlet-filter.svg?branch=master

   [ci]: https://travis-ci.org/opentracing-contrib/java-web-servlet-filter

   [maven-img]: https://img.shields.io/maven-central/v/io.opentracing.contrib/opentracing-web-servlet-filter.svg?maxAge=2592000

   [maven]: http://search.maven.org/#search%7Cga%7C1%7Copentracing-web-servlet-filter