lambda-container-image

Lambda Container Images

Key	Value
Services	Lambda, ECR
Integrations	AWS CLI, Docker
Categories	Serverless; Containers

Introduction

A demo application illustrating Lambda container images with LocalStack. The Lambda image is built using Docker and pushed to a local ECR registry, then deployed and invoked as a container-based Lambda function.

Prerequisites

• A valid LocalStack for AWS license. Your license provides a LOCALSTACK_AUTH_TOKEN to activate LocalStack.
• Docker
• localstack CLI
• awslocal CLI

Check prerequisites

make check

Installation

make install

Start LocalStack

export LOCALSTACK_AUTH_TOKEN=<your-auth-token>
make start

Run the application

make run

The script:

• Creates a local ECR repository.
• Builds the Lambda Docker image and pushes it to the ECR registry.
• Deploys the Lambda function using the container image.
• Invokes the Lambda function and shows the response.

You should see output similar to:

Creating a new ECR repository locally
Building the Docker image, pushing it to ECR URL: localhost:4513/repo1
...
Deploying Lambda function from container image locally
{
    "FunctionName": "ls-lambda-image",
    ...
    "PackageType": "Image"
}
Invoking Lambda function from container image
{
    "StatusCode": 200,
    "LogResult": "",
    "ExecutedVersion": "$LATEST"
}
Done - test successfully finished.

The Lambda invocation logs are visible in the LocalStack container output (with DEBUG=1 enabled):

DEBUG:localstack_ext.services.awslambda.lambda_extended: Log output for invocation of Lambda "ls-lambda-image":
INIT: Using Lambda API Runtime target host: 'ls-lambda-image.us-east-1.localhost.localstack.cloud:4566'
INIT: Starting daemons...
INIT: Host 'ls-lambda-image.us-east-1.localhost.localstack.cloud' resolves to '172.17.0.2'
-----
Hello from LocalStack Lambda container image!

Troubleshooting

UnsupportedMediaTypeException

An error occurred (UnsupportedMediaTypeException) when calling the Invoke operation (reached max retries: 0): The payload is not JSON: b'\xb5\xeb-\xb5\xeb-'

Solution: Downgrade your awslocal CLI to version 1, or update the Lambda invocation to use --cli-binary-format raw-in-base64-out:

awslocal lambda invoke --cli-binary-format raw-in-base64-out \
    --function-name ls-lambda-image \
    --payload '{"test": "test"}' /tmp/lambda.out \
    --log-type Tail --query 'LogResult' --output text | base64 -d

License

This code is available under the Apache 2.0 license.