Local AWS with LocalStack using Docker Compose

Running LocalStack with Docker Compose

version: '3.8'

services:
  localstack:
    image: localstack/localstack:2.0
    ports:
      - '4566:4566' # LocalStack endpoint
      - '4510-4559:4510-4559' # external services port range
    environment:
      - DOCKER_HOST=unix:///var/run/docker.sock
    volumes:
      - ./localstack-script.sh:/etc/localstack/init/ready.d/script.sh
      - '/var/run/docker.sock:/var/run/docker.sock'

With this docker-compose file, we can start LocalStack and make queries using the AWS CLI.

As part of starting LocalStack, we will also mount a directory that will contain scripts to create some resources.

LocalStack provide a CLI called awslocal which is a wrapper around the AWS CLI.

So we will use this CLI to create an S3 bucket on startup.

Creating an S3 bucket in LocalStack

Let’s add a command to create an S3 bucket using the LocalStack CLI.

=> localstack-script.sh

#!/bin/bash

awslocal s3api \
create-bucket --bucket my-bucket \
--create-bucket-configuration LocationConstraint=eu-central-1 \
--region eu-central-1

Once you create the script file, you need to give it executable permissions. This is required or else it will fail on startup.

Now with this let's start the docker-compose file using docker compose up

=> Logs


LocalStack version: 2.0.2
LocalStack Docker container id: b67f7bb6252b
LocalStack build date: 2023-04-17
LocalStack build git hash: 6b436786

2023-04-20T21:57:50.954 WARN --- [-functhread5] hypercorn.error            : ASGI Framework Lifespan error, continuing without Lifespan support
2023-04-20T21:57:50.954 WARN --- [-functhread5] hypercorn.error            : ASGI Framework Lifespan error, continuing without Lifespan support
2023-04-20T21:57:50.955 INFO --- [-functhread5] hypercorn.error            : Running on https://0.0.0.0:4566 (CTRL + C to quit)
2023-04-20T21:57:50.955 INFO --- [-functhread5] hypercorn.error            : Running on https://0.0.0.0:4566 (CTRL + C to quit)
Ready.
2023-04-20T21:57:52.267 INFO --- [   asgi_gw_0] localstack.request.aws     : AWS s3.CreateBucket => 200
{
    "Location": "http://my-bucket.s3.localhost.localstack.cloud:4566/"
}

With this, we started LocalStack and created a new S3 bucket.

Now, let's copy a sample file to the S3 bucket using the AWS CLI from our machine.

If you have not set up the AWS CLI, you can set it up using this link.

Once you do that, run aws configure and provide any random value for "secret-key" and "access-key" as the credentials are not required to communicate with LocalStack.

In my opinion, it would be good to specify a profile name while configuring the credential using aws configure --profile profile_name

aws s3 cp samplefile.txt s3://my-bucket \
--endpoint-url http://localhost:4566

Here while using the AWS CLI, we specify the LocalStack URL so we interact with LocalStack rather than the actual AWS services.

With this, we just communicated with LocalStack using AWS CLI.

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