Add rest service to microservices demo

.signadot/sandbox-rest.yaml

@@ -0,0 +1,20 @@
+name: "@{name}"
+spec:
+  description: Adds REST API to the baseline sandbox
+  cluster: ms-cluster
+  labels:
+    branch: "rest"
+  forks:
+    - forkOf:
+        kind: Deployment
+        name: restservice
+        namespace: default
+      customizations:
+        images:
+          - image: {docker_username}/{docker_repo}:@{rest-tag}
+  defaultRouteGroup: # CLI v0.3.7+ required (see sandbox specification for details)
+    endpoints:
+      - name: rest-endpoint
+        target: http://restservice.default.svc:5051
+      - name: frontend-endpoint
+        target: http://frontend.default.svc:80

kubernetes-manifests/restservice.yaml

@@ -0,0 +1,68 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: restservice
+spec:
+  selector:
+    matchLabels:
+      app: restservice
+  template:
+    metadata:
+      labels:
+        app: restservice
+      annotations:
+        sidecar.signadot.com/inject: rest
+    spec:
+      serviceAccountName: default
+      containers:
+        - name: server
+          image: restservice
+          ports:
+            - containerPort: 5051
+          # readinessProbe:
+          #   exec:
+          #     command: ["/bin/grpc_health_probe", "-addr=:5050"]
+          # livenessProbe:
+          #   exec:
+          #     command: ["/bin/grpc_health_probe", "-addr=:5050"]
+          env:
+            - name: PORT
+              value: "5051"
+            - name: PRODUCT_CATALOG_SERVICE_ADDR
+              value: "productcatalogservice:3550"
+            - name: SHIPPING_SERVICE_ADDR
+              value: "shippingservice:50051"
+            - name: PAYMENT_SERVICE_ADDR
+              value: "paymentservice:50051"
+            - name: EMAIL_SERVICE_ADDR
+              value: "emailservice:5000"
+            - name: CURRENCY_SERVICE_ADDR
+              value: "currencyservice:7000"
+            - name: CART_SERVICE_ADDR
+              value: "cartservice:7070"
+            - name: POD_IP
+              valueFrom:
+                fieldRef:
+                  fieldPath: status.podIP
+            - name: CACHE_USER_THRESHOLD
+              value: "35000"
+          resources:
+            requests:
+              cpu: 100m
+              memory: 32Mi
+            limits:
+              cpu: 200m
+              memory: 32Mi
+---
+apiVersion: v1
+kind: Service
+metadata:
+  name: restservice
+spec:
+  type: ClusterIP
+  selector:
+    app: restservice
+  ports:
+    - name: rest
+      port: 5051
+      targetPort: 5051

skaffold.yaml

@@ -2,10 +2,10 @@ apiVersion: skaffold/v1beta2
 kind: Config
 build:
   artifacts:
-  # image tags are relative; to specify an image repo (e.g. GCR), you
-  # must provide a "default repo" using one of the methods described
-  # here:
-  # https://skaffold.dev/docs/concepts/#image-repository-handling
+    # image tags are relative; to specify an image repo (e.g. GCR), you
+    # must provide a "default repo" using one of the methods described
+    # here:
+    # https://skaffold.dev/docs/concepts/#image-repository-handling
     - image: adservice
       context: src/adservice
     - image: cartservice
@@ -28,6 +28,8 @@ build:
       context: src/recommendationservice
     - image: shippingservice
       context: src/shippingservice
+    - image: restservice
+      context: src/restservice
   tagPolicy:
     gitCommit: {}
   local:
@@ -36,4 +38,3 @@ deploy:
   kubectl:
     manifests:
       - ./kubernetes-manifests/**.yaml
-

src/restservice/.dockerignore

@@ -0,0 +1 @@
+vendor/

src/restservice/Dockerfile

@@ -0,0 +1,19 @@
+FROM golang:1.17-alpine as builder
+RUN apk add --no-cache ca-certificates git
+WORKDIR /src
+
+# restore dependencies
+COPY go.mod go.sum ./
+RUN go mod download
+
+COPY . .
+RUN go build -gcflags='-N -l' -o /restservice .
+
+FROM alpine as release
+RUN apk add --no-cache ca-certificates
+#RUN GRPC_HEALTH_PROBE_VERSION=v0.3.6 && \
+#    wget -qO/bin/grpc_health_probe https://github.com/grpc-ecosystem/grpc-health-probe/releases/download/${GRPC_HEALTH_PROBE_VERSION}/grpc_health_probe-linux-amd64 && \
+#    chmod +x /bin/grpc_health_probe
+COPY --from=builder /restservice /restservice
+EXPOSE 5051
+ENTRYPOINT ["/restservice"]

src/restservice/README.md

@@ -0,0 +1,95 @@
+# checkout service
+
+The **checkout** service provides cart management, and order placement functionality.
+
+## OpenTelemetry instrumentation
+
+### Initialization
+The OpenTelemetry SDK is initialized in `main` using the `initOtelTracing` function
+```
+func initOtelTracing(ctx context.Context, log logrus.FieldLogger) *sdktrace.TracerProvider {
+	endpoint := os.Getenv("OTEL_EXPORTER_OTLP_ENDPOINT")
+	if endpoint == "" {
+		endpoint = "opentelemetry-collector:4317"
+	}
+
+	// Set GRPC options to establish an insecure connection to an OpenTelemetry Collector
+	// To establish a TLS connection to a secured endpoint use:
+	//   otlptracegrpc.WithTLSCredentials(credentials.NewClientTLSFromCert(nil, ""))
+	opts := []otlptracegrpc.Option{
+		otlptracegrpc.WithEndpoint(endpoint),
+		otlptracegrpc.WithInsecure(),
+	}
+
+	// Create the exporter
+	exporter, err := otlptrace.New(ctx, otlptracegrpc.NewClient(opts...))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Specify the TextMapPropagator to ensure spans propagate across service boundaries
+	otel.SetTextMapPropagator(propagation.NewCompositeTextMapPropagator(propagation.Baggage{}, propagation.TraceContext{}))
+
+	// Set standard attributes per semantic conventions
+	res := resource.NewWithAttributes(
+		semconv.SchemaURL,
+		semconv.ServiceNameKey.String("checkout"),
+	)
+
+	// Create and set the TraceProvider
+	tp := sdktrace.NewTracerProvider(
+		sdktrace.WithBatcher(exporter),
+		sdktrace.WithResource(res),
+	)
+	otel.SetTracerProvider(tp)
+
+	return tp
+}
+```
+
+You should call `TraceProvider.shutdown()` when your service is shutdown to ensure all spans are exported.
+This service makes that call as part of a deferred function in `main`
+```
+	// Initialize OpenTelemetry Tracing
+	ctx := context.Background()
+	tp := initOtelTracing(ctx, log)
+	defer func() { _ = tp.Shutdown(ctx) }()
+```
+
+### gRPC instrumentation
+This service receives gRPC requests, which are instrumented in the `main` function as part of the gRPC server creation.
+```
+	// create gRPC server with OpenTelemetry instrumentation on all incoming requests
+    srv := grpc.NewServer(
+        grpc.UnaryInterceptor(otelgrpc.UnaryServerInterceptor(otelgrpc.WithTracerProvider(otel.GetTracerProvider()))),
+        grpc.StreamInterceptor(otelgrpc.StreamServerInterceptor(otelgrpc.WithTracerProvider(otel.GetTracerProvider()))),
+    )
+```
+
+This service will issue several outgoing gRPC calls, which are all instrumented within their respective handlers.
+```go
+	// add OpenTelemetry instrumentation to outgoing gRPC requests
+	conn, err := grpc.DialContext(ctx, cs.shippingSvcAddr,
+		grpc.WithInsecure(),
+		grpc.WithUnaryInterceptor(otelgrpc.UnaryClientInterceptor(otelgrpc.WithTracerProvider(otel.GetTracerProvider()))),
+		grpc.WithStreamInterceptor(otelgrpc.StreamClientInterceptor(otelgrpc.WithTracerProvider(otel.GetTracerProvider()))))
+```
+
+### Baggage 
+This service makes use of information from Baggage, which originate from an upstream service (frontend).
+The `PlaceOrder` function makes use of Baggage to both read, and set Members on it.
+Reading userid and requestid from Baggage
+```go
+	// get userID and requestsID from Tracing Baggage
+	bags := baggage.FromContext(ctx)
+	userID := bags.Member("userid").Value()
+	requestID := bags.Member("requestID").Value()
+```
+
+Setting orderid into Baggage
+```go
+	// Add orderid to Tracing Baggage
+	orderIDMember, _ := baggage.NewMember("orderid", orderID.String())
+	bags, _ = bags.SetMember(orderIDMember)
+	ctx = baggage.ContextWithBaggage(ctx, bags)
+```