Discussion on: Deploy Python Lambda Functions With Container Image

[Jason Yuen]

I am trying to follow step 1 but getting this os.environ error. Any help would be greatly appreciated.

File "/usr/local/lib/python3.8/runpy.py", line 194, in run_module_as_main
return _run_code(code, main_globals, None,
File "/usr/local/lib/python3.8/runpy.py", line 87, in _run_code
exec(code, run_globals)
File "/usr/local/lib/python3.8/site-packages/awslambdaric/main.py", line 21, in
main(sys.argv)
File "/usr/local/lib/python3.8/site-packages/awslambdaric/main.py", line 14, in main
lambda_runtime_api_addr = os.environ["AWS_LAMBDA_RUNTIME_API"]
File "/usr/local/lib/python3.8/os.py", line 675, in __getitem_
raise KeyError(key) from None
KeyError: 'AWS_LAMBDA_RUNTIME_API'

[🚀 Vu Dao 🚀]

Hi Jason,

I guess you're trying to build lambda image from alternative base image but I recommend to use image base from AWS such as public.ecr.aws/lambda/python:3.8 or amazon/aws-lambda-python:3.8

For your issue, you're missing setting ENV AWS_LAMBDA_RUNTIME_API=, this variable env must be defined but you will still get following error after that

  File "/function/awslambdaric/lambda_runtime_client.py", line 76, in wait_next_invocation
    response_body, headers = runtime_client.next()
RuntimeError: Failed to get next

[Cherny]

you should use aws-lambda-rie (emulator) instead of aws-lambda-ric - docs.aws.amazon.com/lambda/latest/.... I believe that environment variable is set by AWS, so if it's not present that script will execute the emulator. This is an example

entry_script.sh

#!/bin/sh

if [ -z "${AWS_LAMBDA_RUNTIME_API}" ]; then
    exec /usr/local/bin/aws-lambda-rie /usr/local/bin/python -m awslambdaric $@
else
    exec /usr/local/bin/python -m awslambdaric $@
fi

Dockerfile

FROM python:3.9-bullseye

ARG FUNCTION_DIR="/function"
WORKDIR ${FUNCTION_DIR}

RUN curl -Lo /usr/local/bin/aws-lambda-rie \
    https://github.com/aws/aws-lambda-runtime-interface-emulator/releases/latest/download/aws-lambda-rie && \
    chmod +x /usr/local/bin/aws-lambda-rie

COPY entry_script.sh ${FUNCTION_DIR}

# Install dependencies
RUN pip install \
    --target ${FUNCTION_DIR} \
    awslambdaric

# Copy function code
COPY src/* ${FUNCTION_DIR}

ENTRYPOINT [ "sh", "entry_script.sh" ]
CMD [ "app.handler" ]