Tuesday, 6 June 2017

Spring Sleuth

Sleuth is used to trace calls in a microservices environment. It creates a trace-id over the whole interactions and a span-id between each call.  For example, there is a call from a client to a microservice to load information for a customer id.  First is the call to the customer service, then the recent orders and accounts services.  All these calls would share the same trace-id but between each one is a different span-id.  To turn on sleuth just add the following dependencies into the pom.  You'll also need to add an application name.

spring.application.name=My Server

Maven


<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-starter-sleuth</artifactId>
    <version>1.2.0.RELEASE</version>
</dependency>

The trace and span ids will now be created and can be seen in the headers.

To log this and make it useful though is one thing but there is a graphical tool which makes this very easy.

Zipkin

Zipkin can be configured so that all Sleuth output is sent there and it allows a view of the interactions so that the times and services called can be seen.  To configure and use zipkin just add another dependency,

<dependency>
    <groupId>org.springframework.cloud</groupId>
    <artifactId>spring-cloud-sleuth-zipkin</artifactId>
    <version>1.2.0.RELEASE</version>
</dependency>

By default everything is logged to localhost:9411 but this can be changed by adding a property

spring.zipkin.baseurl=http://zipkin:9411/

Docker

If you are running with docker you'll need to add a zipkin image into the compose file,

      
  zipkin:
    image: openzipkin/zipkin
    networks:
      - my-network
    hostname: zipkin
    ports:
      - "9411:9411"




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