docker sam-cli min size

container_size_and_output.md

Solution heavily inspired from this EuroPython Conference talk: Dmitry Figol - Optimizing Docker builds for Python applications

$ docker run sam-cli
Usage: sam [OPTIONS] COMMAND [ARGS]...

  AWS Serverless Application Model (SAM) CLI

  The AWS Serverless Application Model extends AWS CloudFormation to provide
  a simplified way of defining the Amazon API Gateway APIs, AWS Lambda
  functions, and Amazon DynamoDB tables needed by your serverless
  application. You can find more in-depth guide about the SAM specification
  here: https://github.com/awslabs/serverless-application-model.

Options:
  --debug    Turn on debug logging to print debug message generated by SAM
             CLI.
  --version  Show the version and exit.
  --info
  --help     Show this message and exit.

Commands:
  init      Init an AWS SAM application.
  validate  Validate an AWS SAM template.
  build     Build your Lambda function code
  local     Run your Serverless application locally for quick development &...
  package   Package an AWS SAM application.
  deploy    Deploy an AWS SAM application.
  logs      Fetch logs for a function
  publish   Publish a packaged AWS SAM template to the AWS Serverless
            Application Repository.

$ docker run sam-cli --version
SAM CLI, version 0.41.0

docker-inspect-sam-cli.json

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Dockerfile

FROM python:3.8-alpine AS builder

WORKDIR /app
ARG BUILD_DEPS="build-base gcc libffi-dev openssl-dev"

RUN apk add --no-cache ${BUILD_DEPS} \
	&& python -m venv .venv \
	&& .venv/bin/pip install --no-cache-dir -U pip setuptools

RUN .venv/bin/pip install --no-cache-dir aws-sam-cli \
	&& find /app/.venv \( -type d -a -name test -o -name tests \) \
	-o \( -type f -a -name '*.pyc' -o -name '*.pyo' \) -delete


FROM python:3.8-alpine
WORKDIR /app
COPY --from=builder /app /app

ENV PATH="/app/.venv/bin:$PATH"
ENV PYTHONWARNINGS="ignore" #removing *.pyo files seems to throw some syntax warnings from a dep to stdout

ENTRYPOINT ["sam"]