There are 2 services in this repository, clone it and follow the instructions on how to run it below.

Before you run either Workshop/Sub Workshop services it is advised to run docker-compose first.

Open a shell, change directory to mortar-demo/docker now run the following

docker-compose up

This should bring up the following services

• Prometheus
• Jaeger
• Grafana

• Workshop

  Open a shell, change your directory to mortar-demo/workshop and run the following

  make run

• Sub Workshop

  Open a shell, change your directory to mortar-demo/subworkshop and run the following

  make run

Now you should have Workshop and Sub Workshop services running. It's time to execute different HTTP calls.

• Register a new car

  curl -X "POST" "http://localhost:5381/v1/workshop/cars" \
    -H 'Content-Type: application/json; charset=utf-8' \
    -d $'{
  "number": "ABCD4248",
  "owner": "Mr. Smith",
  "body_style": "SEDAN",
  "color": "red"
  }'

• Paint ABCD4248 Car

  curl -X "PUT" "http://localhost:5381/v1/workshop/cars/ABCD4248/paint" \
       -H 'Content-Type: application/json; charset=utf-8' \
       -d $'{
    "desired_color": "green"
  }'

• You can see the logs of each service [Workshop/Sub Workshop] in their respective shells.

  A lot of implicit information injected to the log entry [error, git-hash, trace-info, app, host]

  w.deps.Logger.WithError(err).Debug(ctx, "sending car to be painted") // Line 56

  

• Jaeger can show you all the requests you've made including how they traveled if any to a remote services.

  

• Prometheus/Grafana can be used to visualise different metrics that are recorded implicitly or explicitly.

  counter := w.deps.Metrics.WithTags(monitor.Tags{
          "color": request.GetDesiredColor(),
          "success" : fmt.Sprintf("%t", err == nil),
         }).Counter("paint_desired_color", "New paint color for car")
  
  counter.Inc()

  

There is one special request which is actually a proxy to Sub Workshop service. In this case we are calling Sub Workshop using *http.Client a.k.a REST. This request really shows how different middleware/interceptors help you achieve great visibility.

• Open-Tracing is used to report how request is traveling between different services
• Logs implicitly inject Trace information, so you can later aggregate all the logs from different services related to a particular request.
• Metrics used to count different application insights (What 'color' is most popular)

All this is achieved mostly implicitly by using multiple middleware/interceptors.

This service only accepts one request - SubPaintCarRequest.

rpc PaintCar(SubPaintCarRequest) returns (google.protobuf.Empty) {
    option (google.api.http) = {
      post: "/v1/subworkshop/paint"
      body: "*"
    };
}

As part of its logic it will callback our Workshop service using gRPC.

This will complete our request cycle. You can see the entire Trace using Jaeger UI.