AWS Lambda containers

POC project for running AWS Lambda functions based on containers.

• We will create an API Gateway with one endpoint (GET /hello).
• This endpoint will proxy the request to a lambda function.
• The lambda function is deployed as container image.
• We're using an AWS provided base image (see /lambda-image/Dockerfile)
• Lambda function code is in /lambda-image/hello.py (this is what is copied to the container image)

Instructions

We'll be using CDK for creating our infrastructure.

First, make sure you clone this project

$git clone https://github.com/gmansilla/aws-lambda-container-images.git && cd aws-lambda-container-images

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.

$ pip install -r requirements.txt

Prior to deploying, we need to bootstrap CDK

$cdk bootstrap

And we're ready to deploy!

$cdk deploy

Pay attention to the Output of this command as this will tell you the URL we're going to use to test our API.

Testing

Now that the infrastructure has been deployed, you can start sending GET requests to the URL printed in the previous step

Testing Locally

Since your lambda function is using a container image, and this image comes with the Lambda Runtime Interface Emulator, you can test your function locally!

Let's use the Docker CLI to build our image locally:

$cd lambda-image
$docker build -t demo .

Now, let's start the container image locally using the Lambda Runtime Interface Emulator

$docker run -p 9000:8080 demo:latest

Finally, we can start testing function invocation with cURL by opening a new terminal and sending a request.

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

You'll see in your logs something like

START RequestId: aa505f95-1bed-4fd2-adb2-2405effee01b Version: $LATEST
END RequestId: aa505f95-1bed-4fd2-adb2-2405effee01b
REPORT RequestId: aa505f95-1bed-4fd2-adb2-2405effee01b  Init Duration: 1.61 ms  Duration: 80.78 ms      Billed Duration: 100 ms Memory Size: 3008 MB     Max Memory Used: 3008 MB

Just like you would see in AWS Lambda Console!

Pushing changes

Since we're using CDK, we can just run $cdk deploy and the new image will be uploaded to ECR. As mentioned before, look at the output as it will print the URL you're going to use to make api calls.

Destroying the stack

After you experiment with this project you should run $cdk destroy to destroy all the infrastructure we created and avoid incurring in extra charges

Enjoy!

Further Reading

• New for AWS Lambda – Container Image Support Blog Post
• Testing AWS Lambda container images locally
• Create an image from an AWS base image for Lambda
• Create an image from an alternative base image