This is the customer microservice, part of the Istio Tutorial demo. Even though this microservice is meant to be executed within a Container on a Pod on Kubernetes/OpenShift, it can still be executed on bare metal.
This is a regular Spring Boot application, with OpenTracing and Jaeger dependencies to provide distributed tracing capabilities.
To run this service for development purposes on your own machine, execute:
JAEGER_SERVICE_NAME=customer mvn \
spring-boot:run \
-Drun.arguments="--spring.config.location=src/main/resources/application-local.properties"
The application-local.properties contains sensible values for a setup where all services are running locally. It assumes that the preferences service is running on the port 8180. If that's not the case, adjust the property file accordingly.
The environment variable JAEGER_SERVICE_NAME is required, as the Jaeger Tracer is embedded into our application and expects a service name to be specified. The example should work, however, even when an installation of Jaeger is not available.
If you do prefer to have a local Jaeger instance running to see the traces, the easiest is to start via a Docker
container:
docker run \
--rm \
-p5775:5775/udp \
-p6831:6831/udp \
-p6832:6832/udp \
-p16686:16686 \
-p14268:14268 \
jaegertracing/all-in-one:1.3
The default configuration for the Jaeger tracer samples only a small portion of the requests. To trace every incoming request and report the spans to the log file, export the following environment variables and start the application again:
export JAEGER_REPORTER_LOG_SPANS=true
export JAEGER_SAMPLER_TYPE=const
export JAEGER_SAMPLER_PARAM=1
To test, call http://localhost:8280/
$ curl http://localhost:8280/
customer => preference => recommendation v1 from 'caju': 3
The following commands will build a Docker image containing the application, create a Kubernetes Deployment and a corresponding Service, so that other services can discover the pods via the service name.
mvn clean package
docker build -t example/customer .
docker images | grep customer
oc apply -f ../../kubernetes/Deployment.yml
oc apply -f ../../kubernetes/Service.yml
oc expose service customer
The last command will expose the service to the outside world, allowing you to make an HTTP call directly from your host machine:
curl http://customer-tutorial.127.0.0.1.nip.io/