localstack docker-compose - The AWS Access Key Id you provided does not exist in our records

Question

Running localstack and app via docker-compose to dummy a s3 bucket, but getting the error:

"msg":"Failed to upload file /test-data/test.txt: The AWS Access Key Id you provided does not exist in our records."

If i run the app via docker run using valid AWS credentials, it will run successfully and connect. Any ideas what ive done wrong?

version: '3.8'

services:
  postbox:
    build: .
    ports: 
      - "8000:8000"
    environment:
      - S3_BUCKET=localstack-postbox-s3
      - MESSAGE_BUS_ENDPOINT=http://localhost
      - AWS_REGION=eu-west-2
      - AWS_ACCESS_KEY_ID=xyz
      - AWS_SECRET_ACCESS_KEY=aaa
      - NODE_ENV=test
    depends_on:
      - localstack
    
  localstack:
    container_name: localstack
    image: localstack/localstack:0.14.2
    ports:
      - "4566-4599:4566-4599"
    environment:
      - SERVICES=s3
    volumes:
      - ./infra/localstack:/docker-entrypoint-initaws.d

  aws:
    container_name: aws-cli
    image: amazon/aws-cli:latest
    environment:
      - AWS_REGION=eu-west-2
      - AWS_ACCESS_KEY_ID=xyz
      - AWS_SECRET_ACCESS_KEY=aaa
    entrypoint: tail -f /dev/null
    depends_on:
      - localstack
      - postbox

Answer 1

Got this all working!

First ensure that endpoint_url is added for any localstack calls

Second, in the docker app ensure that any localhost calls are updated to host.docker.internal