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Integrating Amazon ECR with Docker Compose

Objective​

This lab shows to streamline the process of uploading Docker images to Amazon ECR and employing them within Docker Compose. By shifting the Docker image storage to Amazon ECR and harnessing them in Docker Compose, we aim to enhance deployment smoothness and the scalability of your microservices application.

Prerequisites​

Initial Setup​

Navigate to the root directory of the python-fastapi-demo-docker project where your environment variables are sourced:

cd ~/environment/python-fastapi-demo-docker

1. Adjustments to the Dockerfile​

After the successful upload of Docker images to Amazon ECR, no changes are required in the Dockerfile, which serves as a consistent blueprint for defining the environment, dependencies, and image creation steps.

2. Updating Docker Compose Configuration​

To ensure consistent deployments and resource efficiency, update the docker-compose.yml file to use images from your Amazon ECR repository, rather than building them locally.

Replace the local build directive in your docker-compose.yml:

  web:
    build: .
    image: fastapi-microservices:${IMAGE_VERSION}

Instead, use the pre-built Docker image hosted on Amazon ECR:

  web:
    build: .
    image: ${AWS_ACCOUNT_ID}.dkr.ecr.${AWS_REGION}.amazonaws.com/fastapi-microservices:${IMAGE_VERSION}

3. Running Docker Compose​

Authenticate your Docker CLI to your Amazon ECR registry before running Docker Compose:

aws ecr get-login-password --region ${AWS_REGION} | docker login --username AWS --password-stdin ${AWS_ACCOUNT_ID}.dkr.ecr.${AWS_REGION}.amazonaws.com

Alternatively, if you're using Finch, run the following command to login to Amazon ECR:

aws ecr get-login-password --region ${AWS_REGION} | finch login --username AWS --password-stdin ${AWS_ACCOUNT_ID}.dkr.ecr.${AWS_REGION}.amazonaws.com

Now, initiate the services with Docker Compose, pulling the image from Amazon ECR:

docker-compose up

Alternatively, if you're using Finch, run the following command to compose and pull the image from Amazon ECR:

finch compose up

This command will now pull the image from the Amazon ECR repository, as specified in the docker-compose.yml file, and start your services.

Press Ctrl+C to stop the services.

4. Updating Docker Images​

If you're working with a team and sharing the Docker image for the FastAPI application on Amazon ECR, you might find yourself pulling updates from ECR, making changes, and then pushing updates back to ECR. Here's the typical workflow.

To pull the latest image, run:

docker-compose pull web

Alternatively, if you're using Finch, run the following command to pull the latest image:

finch compose pull web

To start your services, run:

docker-compose up

Alternatively, if you're using Finch, run the following command:

finch compose up

After making changes to your application, stop the running services with Ctrl+C. Then update the image version value in your environment variable:

export IMAGE_VERSION=1.1

Verify that IMAGE_VERSION is updated by executing the following command:

echo $IMAGE_VERSION
1.1

To build a new image for your application, run:

docker-compose build web

Alternatively, if you're using Finch, run the following command:

finch compose build web

Above command will build image with ECR tag to verify please run following command:

docker image ls | grep amazonaws.com/fastapi-microservices
AWS_ACCOUNT_ID.dkr.ecr.AWS_REGION.amazonaws.com/fastapi-microservices   1.1                             defd60e3e376   6 minutes ago   233MB
AWS_ACCOUNT_ID.dkr.ecr.AWS_REGION.amazonaws.com/fastapi-microservices   1.0                             abc11f568055   2 hours ago     233MB

Alternatively, if you're using Finch, run the following command:

finch image ls | grep amazonaws.com/fastapi-microservices

The expected output should look like this:

AWS_ACCOUNT_ID.dkr.ecr.AWS_REGION.amazonaws.com/fastapi-microservices   1.1                             defd60e3e376   6 minutes ago   233MB
AWS_ACCOUNT_ID.dkr.ecr.AWS_REGION.amazonaws.com/fastapi-microservices   1.0                             abc11f568055   2 hours ago     233MB

To push the new image to your ECR repository, run:

docker push ${AWS_ACCOUNT_ID}.dkr.ecr.${AWS_REGION}.amazonaws.com/fastapi-microservices:${IMAGE_VERSION}

Alternatively, if you're using Finch, run the following command to push the new image:

finch push ${AWS_ACCOUNT_ID}.dkr.ecr.${AWS_REGION}.amazonaws.com/fastapi-microservices:${IMAGE_VERSION}

Cleanup​

To clean up created images run the following command:

docker rmi -f $(docker images "${AWS_ACCOUNT_ID}.dkr.ecr.${AWS_REGION}.amazonaws.com/*" -q)

Alternatively, if you're using Finch, run the following command:

finch rmi -f $(finch images --filter reference=${AWS_ACCOUNT_ID}.dkr.ecr.${AWS_REGION}.amazonaws.com -q)

Stop and remove the containers of both services by running the following command:

docker-compose down --volumes

Alternatively, if you're using Finch, run the following command to stop and remove the containers:

finch compose down

Conclusion​

Through this lab, we've achieved seamless integration of Docker images with Docker Compose by uploading them to Amazon ECR. This approach has increased the portability of our FastAPI application and PostgreSQL database, allowing any Docker-equipped environment to pull images, create containers, and run the application with minimal fuss.