feat: service discovery by default

This change enables service discovery by default for
all apps. Service discovery alows apps within an
environment to communicate with each other without
having to traverse the internet (traffic is routed
internally within the VPC).

To access a service via its service discovery endpoint,
you can make a request like:

```golang
  resp, _ := http.Get(fmt.Sprintf("http://%s.%s", appName, os.Getenv("ECS_APP_DISCOVERY_ENDPOINT"))
```

Or, with only the project name:
```golang
  resp, _ := http.Get(fmt.Sprintf("http://%s.%s.local", appName, projectName))
```

Or, without the string interpolation:

```golang
  # Making a request to app `api` in project `kudos`
  resp, _ := http.Get("http://api.kudos.local")
```

The same address works across environments, since the requests
are scoped to services within one environment.

__ Why not just .local ?__

A couple of reasons to go for the `.{project}.local` scheme, rather
than just `.local` or just `.{project}`.

The reason for not using just `.local` is just to reduce the chance
of a namespace colision if another project is using the same VPC.

The reason for not just going with `.{project}` is in case the
project name matches an existing TLD. That'd be confusing behavior.
The `.local` TLD doesn't seem to exist.

__ Why make this default for every service? __

You can't add service discovery after the fact, unfortunately.
The only sensible thing is to just enable it by default. In the
future, we can offer a disable knob, but it's very cheap (less
than a dollar per month per env) - so isn't a huge burden for
customers who end up not using it.

resolves #599

Author: kohidave

e2e/multi-app-project/back-end/Dockerfile

@@ -1,6 +1,33 @@
-FROM nginx
+# We specify the base image we need for our
+# go application
+FROM golang:1.13 AS builder
+# We create an /app directory within our
+# image that will hold our application source
+# files
+RUN mkdir /app
+# We copy everything in the root directory
+# into our /app directory
+ADD . /app
+# We specify that we now wish to execute
+# any further commands inside our /app
+# directory
+WORKDIR /app
+# Avoid the GoProxy
+ENV GOPROXY=direct
+# we run go build to compile the binary
+# executable of our Go program
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64  go build -o e2e-service ./
 
-COPY nginx.conf /etc/nginx/nginx.conf
+# To make our images smaller, use alpine and copy in the service binary.
+FROM alpine:latest
+# Install certs
+RUN apk --no-cache add ca-certificates
+# Copy the binary from the builder image
+COPY --from=builder /app ./
+# Make the binary executable
+RUN chmod +x ./e2e-service
+# Start the service
+ENTRYPOINT ["./e2e-service"]
+# The service runs on port 80
+EXPOSE 80
 
-RUN mkdir -p /www/data/back-end
-COPY index.html /www/data/back-end

e2e/multi-app-project/back-end/go.mod

@@ -0,0 +1,5 @@
+module github.com/aws/amazon-ecs-cli-v2/e2e/multi-app-project/back-end
+
+go 1.13
+
+require github.com/julienschmidt/httprouter v1.3.0 // indirect

e2e/multi-app-project/back-end/go.sum

@@ -0,0 +1,2 @@
+github.com/julienschmidt/httprouter v1.3.0 h1:U0609e9tgbseu3rBINet9P48AI/D3oJs4dN7jwJOQ1U=
+github.com/julienschmidt/httprouter v1.3.0/go.mod h1:JR6WtHb+2LUe8TCKY3cZOxFyyO8IZAc4RVcycCCAKdM=

e2e/multi-app-project/back-end/index.html

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"log"
+	"net/http"
+
+	"github.com/julienschmidt/httprouter"
+)
+
+// HealthCheck just returns true if the service is up.
+func HealthCheck(w http.ResponseWriter, req *http.Request, ps httprouter.Params) {
+	log.Println("🚑 healthcheck ok!")
+	w.WriteHeader(http.StatusOK)
+}
+
+// SimpleGet just returns true no matter what
+func SimpleGet(w http.ResponseWriter, req *http.Request, ps httprouter.Params) {
+	log.Println("Get Succeeded")
+	w.WriteHeader(http.StatusOK)
+	w.Write([]byte("back-end"))
+}
+
+// ServiceDiscoveryGet just returns true no matter what
+func ServiceDiscoveryGet(w http.ResponseWriter, req *http.Request, ps httprouter.Params) {
+	log.Println("Get on ServiceDiscovery endpoint Succeeded")
+	w.WriteHeader(http.StatusOK)
+	w.Write([]byte("back-end-service-discovery"))
+}
+
+func main() {
+	router := httprouter.New()
+	router.GET("/back-end/", SimpleGet)
+	router.GET("/service-discovery/", ServiceDiscoveryGet)
+
+	// Health Check
+	router.GET("/", HealthCheck)
+
+	log.Fatal(http.ListenAndServe(":80", router))
+}

e2e/multi-app-project/back-end/main.go

@@ -1,6 +1,33 @@
-FROM nginx
+# We specify the base image we need for our
+# go application
+FROM golang:1.13 AS builder
+# We create an /app directory within our
+# image that will hold our application source
+# files
+RUN mkdir /app
+# We copy everything in the root directory
+# into our /app directory
+ADD . /app
+# We specify that we now wish to execute
+# any further commands inside our /app
+# directory
+WORKDIR /app
+# Avoid the GoProxy
+ENV GOPROXY=direct
+# we run go build to compile the binary
+# executable of our Go program
+RUN CGO_ENABLED=0 GOOS=linux GOARCH=amd64  go build -o e2e-service ./
 
-COPY nginx.conf /etc/nginx/nginx.conf
+# To make our images smaller, use alpine and copy in the service binary.
+FROM alpine:latest
+# Install certs
+RUN apk --no-cache add ca-certificates
+# Copy the binary from the builder image
+COPY --from=builder /app ./
+# Make the binary executable
+RUN chmod +x ./e2e-service
+# Start the service
+ENTRYPOINT ["./e2e-service"]
+# The service runs on port 80
+EXPOSE 80
 
-RUN mkdir -p /www/data/front-end
-COPY index.html /www/data/front-end

e2e/multi-app-project/back-end/nginx.conf

@@ -0,0 +1,5 @@
+module github.com/aws/amazon-ecs-cli-v2/e2e/multi-app-project/front-end
+
+go 1.13
+
+require github.com/julienschmidt/httprouter v1.3.0 // indirect

e2e/multi-app-project/front-end/Dockerfile

@@ -0,0 +1,2 @@
+github.com/julienschmidt/httprouter v1.3.0 h1:U0609e9tgbseu3rBINet9P48AI/D3oJs4dN7jwJOQ1U=
+github.com/julienschmidt/httprouter v1.3.0/go.mod h1:JR6WtHb+2LUe8TCKY3cZOxFyyO8IZAc4RVcycCCAKdM=