Binary dependencies with AWS Lambda

When you’re developing an AWS Lambda, sometimes you’re going to need to install binary package dependencies. Today’s article will take you through the construction of a project that can be deployed into AWS Lambda including your binary dependencies.

Structure

The whole idea here is based on AWS Lambda using Docker to facilite package, deployment, and execution of your function. The standard python:3.6 image available in the standard library is compatible with what we’ll end up deploying.

The structure of your project should have a requirements.txt file holding your dependencies, a standard Dockerfile and of course, your code.

.
├── Dockerfile
├── requirements.txt
└── src
    └── __init__.py

Any depeendencies are listed out by the requirements.txt file.

Docker

We can now bundle our application up, so that it can be used by AWS Lambda.

FROM python:3.6
RUN apt-get update && apt-get install -y zip
WORKDIR /lambda

# add the requirements and perform any installations
ADD requirements.txt /tmp
RUN pip install --quiet -t /lambda -r /tmp/requirements.txt && \
    find /lambda -type d | xargs chmod ugo+rx && \
    find /lambda -type f | xargs chmod ugo+r

# the application source code is added to the container
ADD src/ /lambda/
RUN find /lambda -type d | xargs chmod ugo+rx && \
    find /lambda -type f | xargs chmod ugo+r

# pre-compilation into the container
RUN python -m compileall -q /lambda

RUN zip --quiet -9r /lambda.zip .

FROM scratch
COPY --from=0 /lambda.zip /

The docker container is then built with the following:

docker build -t my-lambda .
ID=$(docker create my-lambda /bin/true)
docker cp $ID:/ .

The retrieves the zip file that we built through the process, that’s readily deployable to AWS Lambda.