opentracing-servlet-extension

OpenTracing: Servlet Extension

• Technology stack: Java 8+, OpenTracing, Servlet
• Status: Under development and used in production

Example

TracingFilter filter = new TracingFilter(
        tracer, singletonList(new StandardSpanDecorator()), null);
servletContext.addFilter("tracingFilter", filter);

Features

• applies Zalando's standard tags/logs to each request
• builds on top of an existing instrumentation (see dependencies)

Dependencies

• Java 8 or higher
• OpenTracing
• OpenTracing Java Web Servlet Filter Instrumentation

Installation

Add the following dependency to your project:

<dependency>
    <groupId>org.zalando</groupId>
    <artifactId>opentracing-servlet-extension</artifactId>
    <version>${opentracing-servlet-extension.version}</version>
</dependency>

A new span will be started for each request/response.

The following tags/logs are supported out of the box:

Tag/Log Field	Decorator	Example
component	ComponentSpanDecorator	Servlet
http.method_override	HttpMethodSpanDecorator	GET
http.method	HttpMethodSpanDecorator	POST
http.prefer	HttpPreferSpanDecorator	respond=async
http.retry_after	HttpRetryAfterSpanDecorator	60
http.status_code	HttpStatusCodeSpanDecorator	200
http.url¹	HttpUrlSpanDecorator	http://localhost/users?q=me
peer.address	PeerAddressSpanDecorator	localhost:80
peer.hostname	PeerSpanDecorator	localhost
peer.ipv4	PeerSpanDecorator	127.0.0.1
peer.ipv6	PeerSpanDecorator	::1
peer.port	PeerSpanDecorator	80
error	ErrorSpanDecorator	true
error.kind (log)	ErrorSpanDecorator	SocketTimeoutException
error.object (log)	ErrorSpanDecorator	(exception instance)
message (log)	ErrorMessageSpanDecorator	Connection timed out
stack (log)	ErrorStackSpanDecorator	SocketTimeoutException at [...]

¹ Disabled by default due to security concerns (may expose passwords)

Custom SpanDecorator implementations that are registered using Java's Service Provider Interface mechanism will be picked up automatically by default.

Getting Help

If you have questions, concerns, bug reports, etc., please file an issue in this repository's Issue Tracker.

Getting Involved/Contributing

To contribute, simply make a pull request and add a brief description (1-2 sentences) of your addition or change. For more details, check the contribution guidelines.