Install & Compatibility
Where this runs
tested against v4.0.2 · pip install
no network on importno background threads
Install × environment matrix
Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux
muslpy 3.10–3.95 runs
installs and imports cleanly · install 0.0s · import 0.000s · 23.6MB
glibcpy 3.10–3.95 runs
installs and imports cleanly · install 1.9s · import 0.000s · 20MB
20MB installed
● package 20MB
Code
Verified usage
Verified import paths — ran on the pinned version, not inferred.
LambdaRuntimeException
✓ from awslambdaric.lambda_runtime_exception import LambdaRuntimeException
✗ from awslambdaric import LambdaRuntimeException
This quickstart demonstrates how to create a Python Lambda function using a custom container image with `awslambdaric`. You define your Lambda handler in `app.py` and then create a `Dockerfile` that installs `awslambdaric` and sets it as the container's entrypoint, with your function handler as the command. This allows the Lambda service to properly invoke your Python code within the custom runtime environment.
# app.py
def handler(event, context):
print(f"Received event: {event}")
print(f"Context: {context.aws_request_id}")
return {"statusCode": 200, "body": "Hello from Lambda!"}
# Dockerfile
FROM python:3.9-slim-buster
# Set working directory
WORKDIR /var/task
# Copy function code
COPY app.py .
# Install awslambdaric and any other dependencies
RUN pip install --no-cache-dir awslambdaric
# Set the ENTRYPOINT to the AWS Lambda Runtime Interface Client
ENTRYPOINT ["/usr/local/bin/python", "-m", "awslambdaric"]
# Set the CMD to your Lambda handler
CMD ["app.handler"]
aws-lambda-ric --version
Debug
Known issues
breakingVersion 3.0.0 of `awslambdaric` dropped support for Python runtimes older than 3.9. Functions using Python versions 3.8 or earlier will no longer work with `awslambdaric` v3.0.0 and newer.fixUpgrade your Python runtime to 3.9 or newer (e.g., Python 3.13 support was added in v3.0.0) and ensure your `awslambdaric` dependency is compatible.
affects: >=3.0.0
deprecatedAWS Lambda will deprecate Python 3.9 runtime. New functions using Python 3.9 will be blocked from creation after January 15, 2026, and existing functions cannot be updated with Python 3.9 after February 15, 2026.fixPlan to upgrade your Lambda functions to Python 3.10 or later versions. While `awslambdaric` itself supports Python 3.9+, the underlying Lambda service is deprecating the 3.9 runtime.
affects: All (affects Python 3.9 runtime environment)
gotchaWhen upgrading Python runtime versions for Lambda functions (e.g., from 3.7 to 3.9), ensure that external dependencies are correctly packaged at the root level of your deployment, not within a 'packages' folder, as the underlying Python runtime search path changed.fixAdjust your packaging script or `Dockerfile` to install dependencies directly into the root of your function's deployment directory (e.g., `/var/task`) or ensure they are properly accessible on the `PYTHONPATH`.
affects: All versions, specifically during Python runtime upgrades.
gotchaIncorrect configuration of `ENTRYPOINT` and `CMD` in Dockerfiles for custom runtimes is a common error. The `awslambdaric` module must be the `ENTRYPOINT`, and your function's handler path the `CMD`.fixEnsure your Dockerfile correctly sets `ENTRYPOINT ["/usr/local/bin/python", "-m", "awslambdaric"]` and `CMD ["your_module.your_handler_function"]`.
affects: All versions when using container images.
gotchaHistorical compatibility issues with the `simplejson` dependency (e.g., lack of Python 3.9 wheels for older `simplejson` versions) could lead to installation failures.fix`awslambdaric` versions 2.0.11 and newer (including 3.x and 4.x) have updated `simplejson` dependencies to be compatible with newer Python versions. Ensure you are using a recent `awslambdaric` version.
affects: <=2.0.11 (addressed in 2.0.11 and later)
gotchaVersion 3.0.0 introduced support for SnapStart runtime hooks. If you are leveraging AWS Lambda SnapStart, be aware of the new hooks and how they might affect your function's initialization lifecycle.fixReview the AWS Lambda documentation on SnapStart runtime hooks for Python to understand how to implement `after_restore` and `before_checkpoint` if your function uses SnapStart.
affects: >=3.0.0
Upgrade
Version history
4.0.2latest on PyPI · released Jul 30, 2026
Audit
Dependencies
simplejsonrequiredUsed for JSON serialization/deserialization; historically had compatibility issues with specific Python versions which have since been addressed.