AWS ECS

Interact with Elastic Container Service, executing one-off sessions into ECS tasks/containers.

Prerequisites

To get the most out of this guide, you will need to:

• Either create an account in our managed instance or deploy your own hoop.dev instance
• You must be your account administrator to perform the following commands

Overview

This connection uses a wrapper script available in the hoophq/hoopdev image called ecs-exec.sh. This script requires the following permissions to work:

• ecs:ListTasks
• ecs:DescribeTasks
• ecs:ExecuteCommand

It’s important to configure the ECS tasks before trying this feature. Please refer to the AWS documentation first

Connection Configuration

Name	Type	Description
CLUSTER_NAME	env-var	The name or arn of the ECS Cluster
SERVICE_NAME	env-var	The name of the service on ECS
CONTAINER	env-var	The name of the container defaults to the first one.
AWS_ACCESS_KEY_ID	env-var	The access key credential
AWS_SECRET_ACCESS_KEY	env-var	The secret key credential
AWS_DEFAULT_REGION	env-var	The AWS region

Connection Configuration (Assume Role)

Name	Type	Value	Description
CLUSTER_NAME	env-var	-	The name or arn of the ECS Cluster
SERVICE_NAME	env-var	-	The name of the service on ECS
CONTAINER	env-var	-	The name of the container defaults to the first one.
ECS_AGENT_URI	env-var	system.agent.envs	The access key credential
AWS_EXECUTION_ENV	env-var	system.agent.envs	ECS launch type
AWS_CONTAINER_CREDENTIALS_RELATIVE_URI	env-var	system.agent.envs	full HTTP URL endpoint when making a request for credentials
ECS_CONTAINER_METADATA_URI_V4	env-var	system.agent.envs	This path returns metadata for the container.
AWS_DEFAULT_REGION	env-var	system.agent.envs	The default AWS region

The value system.agent.envs will expose the upstream environment variable from the agent to the connection, allowing the wrapper script to use the IAM task role.

AWS ECS - Interactive Sessions

The AWS Elastic Container Service allows users to connect to tasks and start interactive sessions. These commands can be mapped to Hoop to obtain interactive sessions by allocating a pseudo TTY.

Before attempting to use this feature, it’s essential to configure the ECS tasks. Please refer to the AWS documentation for guidance.

Connection Command

ecs-exec.sh --interactive --cluster=$CLUSTER_NAME --service-name=$SERVICE_NAME

How to Use

Start an interactive session.

hoop connect my-ecs -- --interactive --pipe /bin/bash
hoop connect my-ecs -- --interactive --pipe 'rails console'
hoop connect my-ecs -- --interactive --pipe clojure

AWS ECS - Execute one-off commands

Connection Command

ecs-exec.sh --cluster=$CLUSTER_NAME --service-name=$SERVICE_NAME

How to Use

Now it’s possible to execute the Ruby script straight from Hoop.dev

hoop exec ecs-exec -- --pipe 'rails runner -' <<EOF
myvar='Hello from Rails'
puts myvar
EOF
hoop exec ecs-exec -i 'puts Rails.env' -- --pipe 'rails runner -'

The --pipe option necessitates the availability of the base64 command in the image. This command decodes the input content, preventing leakage of shell content such as single or double quotes. This helps address a limitation of the aws ecs execute-command.

It’s possible to pipe any command.

hoop exec ecs-exec -i '(println "Clojure REPL")' -- --pipe 'clojure'
hoop exec ecs-exec -- --pipe 'python3' <<EOF
import os
print(os.environ.get("CLUSTER_NAME"))
EOF
# defaults to /bin/bash
hoop exec ecs-exec --input 'echo "hello world from bash"'

Easily call the scripts.

hoop exec ecs-exec -i '/path/to/my/script.sh'
# override the ecs task-id
hoop exec ecs-exec -i '/path/to/my/script.sh' -- --task mytaskid
# execute a rails script
hoop exec ecs-exec -i 'rails runner /path/to/script.rb'