Configure routes between ECS tasks

This topic describes how to configure routes between tasks after registering the tasks to Consul service mesh.

Overview

To enable tasks to call through the service mesh, complete the following steps:

Configure the sidecar proxy to listen on a different port for each upstream service your application needs to call.
Modify your application to make requests to the sidecar proxy on the specified port.

Requirements

Consul service mesh must be deployed to ECS before you can bind a network address. For more information, refer to the following topics:

Configure the sidecar proxy

Add the upstreams block to your application configuration and specify the following fields:

destinationName: Specifies the name of the upstream service as it is registered in the Consul service catalog.
localBindPort: Specifies the port that the proxy forwards requests to. You must specify an unused port but it does not need to match the upstream service port.

In the following example, the route from an application named web to an application named backend goes through port 8080:

module "web" {
  family = "web"
  upstreams = [
    {
      destinationName = "backend"
      localBindPort = 8080
    }
  ]
}

You must include all upstream services in the upstream configuration.

Configure your application

Use an appropriate environment variable in your container definition to configure your application to call the upstream service at the loopback address.

In the following example, the web application calls the backend service by sending requests to the BACKEND_URL environment variable:

module "web" {
  family = "web"
  upstreams = [
    {
      destinationName = "backend"
      localBindPort = 8080
    }
  ]
  container_definitions = [
    {
      name        = "web"
      environment = [
        {
          name  = "BACKEND_URL"
          value = "http://localhost:8080"
        }
      ]
      ...
    }
  ]
  ...
}