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lambda-custom-container

README.md

AWS Lambda function with Custom Container

This is a CDK Python project to show how to deploy AWS Lambda function with a custom container.

aws-lambda-custom-container

It is useful to use the custom container when you need to more than two different run time enviroments for AWS Lambda function. For example, if you try to use a python package wrapping Java package (e.g., KoNLpy) in the AWS Lambda function, you would need both Python and Java run time.

The cdk.json file tells the CDK Toolkit how to execute your app.

This project is set up like a standard Python project. The initialization process also creates a virtualenv within this project, stored under the .venv directory. To create the virtualenv it assumes that there is a python3 (or python for Windows) executable in your path with access to the venv package. If for any reason the automatic creation of the virtualenv fails, you can create the virtualenv manually.

To manually create a virtualenv on MacOS and Linux:

$ python3 -m venv .venv

After the init process completes and the virtualenv is created, you can use the following step to activate your virtualenv.

$ source .venv/bin/activate

If you are a Windows platform, you would activate the virtualenv like this:

% .venv\Scripts\activate.bat

Once the virtualenv is activated, you can install the required dependencies.

(.venv) $ pip install -r requirements.txt

Deploy

At this point you can now synthesize the CloudFormation template for this code.

(.venv) $ export CDK_DEFAULT_ACCOUNT=$(aws sts get-caller-identity --query Account --output text)
(.venv) $ export CDK_DEFAULT_REGION=$(aws configure get region)
(.venv) $ cdk synth

Use cdk deploy command to create the stack shown above.

(.venv) $ cdk deploy

To add additional dependencies, for example other CDK libraries, just add them to your setup.py file and rerun the pip install -r requirements.txt command.

Clean Up

Delete the CloudFormation stack by running the below command.

(.venv) $ cdk destroy

Useful commands

  • cdk ls list all stacks in the app
  • cdk synth emits the synthesized CloudFormation template
  • cdk deploy deploy this stack to your default AWS account/region
  • cdk diff compare deployed stack with current state
  • cdk docs open CDK documentation

Enjoy!

Run Test

When you run Test in the lambda function, you can see the result like this:

aws-lambda-custom-container-test-run-result

How to create and upload Docker image to the Amazon ECR repository

Create an image from an AWS base image for Lambda

You can create the container image with an AWS base image for Lambda by following the instructions.

  1. On your local machine, create a project directory for your new function.

  2. Create a directory named app in the project directory, and then add your function handler code to the app directory.

  3. Use a text editor to create a new Dockerfile.
    In this project, you can find the examplary application in the custom_container/app directory.

    $ cd custom_container/app
$ tree ./
./
├── app.py
├── Dockerfile
└── requirements.txt

0 directories, 3 files

  4. Build your Docker image with the docker build command. Enter a name for the image. The following example names the image hello-world.

    docker build -t hello-world .

  5. Start the Docker image with the docker run command. For this example, enter hello-world as the image name.

    docker run -p 9000:8080 hello-world

  6. (Optional) Test your application locally using the runtime interface emulator. From a new terminal window, post an event to the following endpoint using a curl command:

    curl -XPOST "http://localhost:9000/2015-03-31/functions/function/invocations" -d '{}'

Upload the image to the Amazon ECR repository

In the following commands, replace 123456789012 with your AWS account ID and set the region value to the region where you want to create the Amazon ECR repository.

  1. Authenticate the Docker CLI to your Amazon ECR registry. 
    aws ecr get-login-password --region us-east-1 | docker login --username AWS --password-stdin 123456789012.dkr.ecr.us-east-1.amazonaws.com
  2. Create a repository in Amazon ECR using the create-repository command. 
    aws ecr create-repository --repository-name hello-world --image-scanning-configuration scanOnPush=true --image-tag-mutability MUTABLE
  3. Tag your image to match your repository name, and deploy the image to Amazon ECR using the docker push command. 
    docker tag hello-world:latest 123456789012.dkr.ecr.us-east-1.amazonaws.com/hello-world:latest
docker push 123456789012.dkr.ecr.us-east-1.amazonaws.com/hello-world:latest

References