We have open-sourced a set of software packages, Runtime Interface Clients (RIC), that implement the Lambda Runtime API, allowing you to seamlessly extend your preferred base images to be Lambda compatible. The Lambda Runtime Interface Client is a lightweight interface that allows your runtime to receive requests from and send requests to the Lambda service.

The Lambda Python Runtime Interface Client is vended through pip. You can include this package in your preferred base image to make that base image Lambda compatible.

The Python Runtime Interface Client package currently supports Python versions:

• 3.9.x up to and including 3.13.x

For development or when you need to build awslambdaric from source, you can use container-based builds to ensure consistent compilation across different platforms, and native dependencies linking.

# Build awslambdaric wheel in a Linux container
make build-container
# Or with poetry (run 'poetry install' first):
poetry run build-container

# Test with RIE using the built wheel
make test-rie
# Or with poetry:
poetry run test-rie

This approach builds the C++ extensions in a Linux environment, ensuring compatibility with Lambda's runtime environment regardless of your host OS.

Note: Running make build (or poetry run build) on non-Linux machines will not properly link the native C++ dependencies, resulting in a non-functional runtime client. Always use container-based builds for development.

First step is to choose the base image to be used. The supported Linux OS distributions are:

• Amazon Linux 2
• Alpine
• Debian
• Ubuntu

Then, the Runtime Interface Client needs to be installed. We provide both wheel and source distribution. If the OS/pip version used does not support manylinux2014 wheels, you will also need to install the required build dependencies. Also, your Lambda function code needs to be copied into the image.

# Include global arg in this stage of the build
ARG FUNCTION_DIR

# Install aws-lambda-cpp build dependencies
RUN apt-get update && \
  apt-get install -y \
  g++ \
  make \
  cmake \
  unzip \
  libcurl4-openssl-dev

# Copy function code
RUN mkdir -p ${FUNCTION_DIR}
COPY app/* ${FUNCTION_DIR}

# Install the function's dependencies
RUN pip install \
    --target ${FUNCTION_DIR} \
        awslambdaric

The next step would be to set the ENTRYPOINT property of the Docker image to invoke the Runtime Interface Client and then set the CMD argument to specify the desired handler.

Example Dockerfile (to keep the image light we use a multi-stage build):

# Define custom function directory
ARG FUNCTION_DIR="/function"

FROM public.ecr.aws/docker/library/python:buster as build-image

# Include global arg in this stage of the build
ARG FUNCTION_DIR

# Install aws-lambda-cpp build dependencies
RUN apt-get update && \
  apt-get install -y \
  g++ \
  make \
  cmake \
  unzip \
  libcurl4-openssl-dev

# Copy function code
RUN mkdir -p ${FUNCTION_DIR}
COPY app/* ${FUNCTION_DIR}

# Install the function's dependencies
RUN pip install \
    --target ${FUNCTION_DIR} \
        awslambdaric


FROM public.ecr.aws/docker/library/python:buster

# Include global arg in this stage of the build
ARG FUNCTION_DIR
# Set working directory to function root directory
WORKDIR ${FUNCTION_DIR}

# Copy in the built dependencies
COPY --from=build-image ${FUNCTION_DIR} ${FUNCTION_DIR}

ENTRYPOINT [ "/usr/local/bin/python", "-m", "awslambdaric" ]
CMD [ "app.handler" ]

Example Python handler app.py:

def handler(event, context):
    return "Hello World!"

To test Lambda functions with the Runtime Interface Client, use the AWS Lambda Runtime Interface Emulator (RIE). To test your local changes with RIE (Runtime Interface Emulator):

# Build your current code (do this when you make changes) 
# We build on a linux machine to ensure native build dependencies are met
make build-container
# Or with poetry:
poetry run build-container

# Test with RIE (fast, repeatable)
make test-rie
# Or with poetry:
poetry run test-rie

# Test the function
curl -XPOST "http://localhost:9000/2015-03-31/functions/function/invocations" -d '{"message":"test"}'

Clone this repository and run:

make init
make build

Make sure the project is built:

make init build

Then,

• to run unit tests: make test
• to run integration tests: make test-integ
• to run smoke tests: make test-smoke

While running integration tests, you might encounter the Docker Hub rate limit error with the following body:

You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limits

To fix the above issue, consider authenticating to a Docker Hub account by setting the Docker Hub credentials as below CodeBuild environment variables.

DOCKERHUB_USERNAME=<dockerhub username>
DOCKERHUB_PASSWORD=<dockerhub password>

Recommended way is to set the Docker Hub credentials in CodeBuild job by retrieving them from AWS Secrets Manager.

If you discover a potential security issue in this project we ask that you notify AWS/Amazon Security via our vulnerability reporting page. Please do not create a public github issue.

This project is licensed under the Apache-2.0 License.