brave

Java implementation of Zipkin.

Zipkin is based on Dapper.

dapper (dutch) = brave (english)... so that's where the name comes from.

introduction

I advise you to read the Dapper paper, but in short:

What we want to achieve is understand system behavior and performance of complex distributed systems. We want to do this with minimal impact on existing code by introducing some small common libraries that are reusable and don't interfere with the existing business logic or architecture. Besides not impacting business logic or architecute we off course also want it to have a neglectable impact on performance.

I looked into reusing zipkin 'as is' but did not find an elegant way to use the exising Scala code/api's into the Java/Spring code I want to incorporate it.

However Brave uses the Zipkin thrift generated classes as part of its api so it is easy to use existing Zipkin components with Brave (zipkin-collector, zipkin-query, zipkin-ui, cassandra store,...).

I'm very thankful to Twitter for open sourcing Zipkin! Is is by seeing their Zipkin video and presentation that I got to know Zipkin/Dapper and that I saw the potential and the simplicity of the solution.

about spans and traces

span: A single client/server request/response. Can have an optional parent span id and is part of a trace.
trace: A tree of spans.

So as you can see a single span is submitted twice:

from the client side, the initiator, with cs (client send) and cr (client received) annotations
from the server side with sr (server received) and ss (server send) annotations.

The above image shows how Brave integrates with Zipkin back-end components. This is probably what you want to do as those components have already proven themselves. However you can create new SpanCollector implementations that submit Span/Trace data to other data stores or processing engines.

Example implementation

The brave-resteasy-example is a good starting point to get you up to speed on how you can implement brave in your own apps.

Maven artifacts

Version 1.0 is available in Maven central. So you can simple add the dependencies you need to your pom.xml:

<dependency>
    <groupId>com.github.kristofa</groupId>
    <artifactId>brave-interfaces</artifactId>
    <version>1.0</version>
</dependency>
<dependency>
    <groupId>com.github.kristofa</groupId>
    <artifactId>brave-impl</artifactId>
    <version>1.0</version>
</dependency>
 <dependency>
    <groupId>com.github.kristofa</groupId>
    <artifactId>brave-resteasy-spring</artifactId>
    <version>1.0</version>
</dependency>

Version 2.0-SNAPSHOT is not available on a central Maven repo. You can deploy the jars in your local environment.

Version history

2.0-SNAPSHOT

Brave 1.0 was an alternative implementation of Dapper with Zipkin compatibility. Brave 2.0-SNAPSHOT is a Java implementation of Zipkin. The Zipkin thrift classes are part of the public api of Brave. This has as consequence that it will be easier to share components or extensions between Zipkin/Brave.

Done: Use Zipkin-core thrift generated classes as part of api.
Done: Binary annotation support.
TODO: Add TraceFilter implementations that use Zookeeper for globally adjusting sample rate or enable/disable tracing all together.
TODO: Add flume support for transporting spans.

1.0

Functional but might not be ideal for large scale production usage. Usable for development and testing.

achun2080 / brave