Integrating Python Poetry with Docker

Can you give me an example of a Dockerfile in which I can install all the packages I need from poetry.lock and pyproject.toml into my image/container from Docker?

There are several things to keep in mind when using poetry together with docker.

Installation

Official way to install poetry is via:

curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python -

This way allows poetry and its dependencies to be isolated from your dependencies. But, in my point of view, it is not a very good thing for two reasons:

1. poetry version might get an update and it will break your build. In this case you can specify POETRY_VERSION environment variable. Installer will respect it
2. I do not like the idea to pipe things from the internet into my containers without any protection from possible file modifications

So, I use pip install 'poetry==$POETRY_VERSION'. As you can see, I still recommend to pin your version.

Also, pin this version in your pyproject.toml as well:

[build-system]
# Should be the same as `$POETRY_VERSION`:
requires = ["poetry>=1.0"]
build-backend = "poetry.masonry.api"

It will protect you from version mismatch between your local and docker environments.

Caching dependencies

We want to cache our requirements and only reinstall them when pyproject.toml or poetry.lock files change. Otherwise builds will be slow. To achieve working cache layer we should put:

COPY poetry.lock pyproject.toml /code/

After the poetry is installed, but before any other files are added.

Virtualenv

The next thing to keep in mind is virtualenv creation. We do not need it in docker. It is already isolated. So, we use poetry config virtualenvs.create false setting to turn it off.

Development vs Production

If you use the same Dockerfile for both development and production as I do, you will need to install different sets of dependencies based on some environment variable:

poetry install $(test "$YOUR_ENV" == production && echo "--no-dev")

This way $YOUR_ENV will control which dependencies set will be installed: all (default) or production only with --no-dev flag.

You may also want to add some more options for better experience:

1. --no-interaction not to ask any interactive questions
2. --no-ansi flag to make your output more log friendly

Result

You will end up with something similar to:

FROM python:3.6.6-alpine3.7

ARG YOUR_ENV

ENV YOUR_ENV=${YOUR_ENV} \
  PYTHONFAULTHANDLER=1 \
  PYTHONUNBUFFERED=1 \
  PYTHONHASHSEED=random \
  PIP_NO_CACHE_DIR=off \
  PIP_DISABLE_PIP_VERSION_CHECK=on \
  PIP_DEFAULT_TIMEOUT=100 \
  POETRY_VERSION=1.0.0

# System deps:
RUN pip install "poetry==$POETRY_VERSION"

# Copy only requirements to cache them in docker layer
WORKDIR /code
COPY poetry.lock pyproject.toml /code/

# Project initialization:
RUN poetry config virtualenvs.create false \
  && poetry install $(test "$YOUR_ENV" == production && echo "--no-dev") --no-interaction --no-ansi

# Creating folders, and files for a project:
COPY . /code

You can find a fully working real-life example here: wemake-django-template

Update on 2019-12-17

• Update poetry to 1.0

Multi-stage Docker build with Poetry and venv

Do not disable virtualenv creation. Virtualenvs serve a purpose in Docker builds, because they provide an elegant way to leverage multi-stage builds. In a nutshell, your build stage installs everything into the virtualenv, and the final stage just copies the virtualenv over into a small image.

Use poetry export and install your pinned requirements first, before copying your code. This will allow you to use the Docker build cache, and never reinstall dependencies just because you changed a line in your code.

Do not use poetry install to install your code, because it will perform an editable install. Instead, use poetry build to build a wheel, and then pip-install that into your virtualenv. (Thanks to PEP 517, this whole process could also be performed with a simple pip install ., but due to build isolation you would end up installing another copy of Poetry.)

Here's an example Dockerfile installing a Flask app into an Alpine image, with a dependency on Postgres. This example uses an entrypoint script to activate the virtualenv. But generally, you should be fine without an entrypoint script because you can simply reference the Python binary at /venv/bin/python in your CMD instruction.

Dockerfile

FROM python:3.7.6-alpine3.11 as base

ENV PYTHONFAULTHANDLER=1 \
    PYTHONHASHSEED=random \
    PYTHONUNBUFFERED=1

WORKDIR /app

FROM base as builder

ENV PIP_DEFAULT_TIMEOUT=100 \
    PIP_DISABLE_PIP_VERSION_CHECK=1 \
    PIP_NO_CACHE_DIR=1 \
    POETRY_VERSION=1.0.5

RUN apk add --no-cache gcc libffi-dev musl-dev postgresql-dev
RUN pip install "poetry==$POETRY_VERSION"
RUN python -m venv /venv

COPY pyproject.toml poetry.lock ./
RUN poetry export -f requirements.txt | /venv/bin/pip install -r /dev/stdin

COPY . .
RUN poetry build && /venv/bin/pip install dist/*.whl

FROM base as final

RUN apk add --no-cache libffi libpq
COPY --from=builder /venv /venv
COPY docker-entrypoint.sh wsgi.py ./
CMD ["./docker-entrypoint.sh"]

docker-entrypoint.sh

#!/bin/sh

set -e

. /venv/bin/activate

while ! flask db upgrade
do
     echo "Retry..."
     sleep 1
done

exec gunicorn --bind 0.0.0.0:5000 --forwarded-allow-ips='*' wsgi:app

wsgi.py

import your_app

app = your_app.create_app()

TL;DR

I have been able to set up poetry for a Django project using postgres. After doing some research, I ended up with the following Dockerfile:

FROM python:slim

# Keeps Python from generating .pyc files in the container
ENV PYTHONDONTWRITEBYTECODE 1
# Turns off buffering for easier container logging
ENV PYTHONUNBUFFERED 1

# Install and setup poetry
RUN pip install -U pip \
    && apt-get update \
    && apt install -y curl netcat \
    && curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python -
ENV PATH="${PATH}:/root/.poetry/bin"

WORKDIR /usr/src/app
COPY . .
RUN poetry config virtualenvs.create false \
  && poetry install --no-interaction --no-ansi

# run entrypoint.sh
ENTRYPOINT ["/usr/src/app/entrypoint.sh"]

This is the content of entrypoint.sh:

#!/bin/sh

if [ "$DATABASE" = "postgres" ]
then
    echo "Waiting for postgres..."

    while ! nc -z $SQL_HOST $SQL_PORT; do
      sleep 0.1
    done

    echo "PostgreSQL started"
fi

python manage.py migrate

exec "$@"

Detailed Explanation

Some points to notice:

• I have decide to use slim instead of alpine as tag for the python image because even though alpine images are supposed to reduce the size of Docker images and speed up the build, with Python, you can actually end up with a bit larger image and that takes a while to build (read this article for more info).

• Using this configuration builds containers faster than using the alpine image because I do not need to add some extra packages to install Python packages properly.

• I am installing poetry directly from the URL provided in the documentation. I am aware of the warnings provided by sobolevn. However, I consider that it is better in the long term to use the lates version of poetry by default than relying on an environment variable that I should update periodically.

• Updating the environment variable PATH is crucial. Otherwise, you will get an error saying that poetry was not found.

• Dependencies are installed directly in the python interpreter of the container. It does not create poetry to create a virtual environment before installing the dependencies.

In case you need the alpine version of this Dockerfile:

FROM python:alpine

# Keeps Python from generating .pyc files in the container
ENV PYTHONDONTWRITEBYTECODE 1
# Turns off buffering for easier container logging
ENV PYTHONUNBUFFERED 1

# Install dev dependencies
RUN apk update \
    && apk add curl postgresql-dev gcc python3-dev musl-dev openssl-dev libffi-dev

# Install poetry
RUN pip install -U pip \
    && curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python -
ENV PATH="${PATH}:/root/.poetry/bin"

WORKDIR /usr/src/app
COPY . .
RUN poetry config virtualenvs.create false \
  && poetry install --no-interaction --no-ansi

# run entrypoint.sh
ENTRYPOINT ["/usr/src/app/entrypoint.sh"]

Notice that the alpine version needs some dependencies postgresql-dev gcc python3-dev musl-dev openssl-dev libffi-dev to work properly.

This is a minor revision to the answer provided by @Claudio, which uses the new poetry install --no-root feature as described by @sobolevn in his answer.

In order to force poetry to install dependencies into a specific virtualenv, one needs to first enable it.

. /path/to/virtualenv/bin/activate && poetry install

Therefore adding these into @Claudio's answer we have

FROM python:3.9-slim as base

ENV PYTHONFAULTHANDLER=1 \
    PYTHONHASHSEED=random \
    PYTHONUNBUFFERED=1

RUN apt-get update && apt-get install -y gcc libffi-dev g++
WORKDIR /app

FROM base as builder

ENV PIP_DEFAULT_TIMEOUT=100 \
    PIP_DISABLE_PIP_VERSION_CHECK=1 \
    PIP_NO_CACHE_DIR=1 \
    POETRY_VERSION=1.1.3

RUN pip install "poetry==$POETRY_VERSION"
RUN python -m venv /venv

COPY pyproject.toml poetry.lock ./
RUN . /venv/bin/activate && poetry install --no-dev --no-root

COPY . .
RUN . /venv/bin/activate && poetry build

FROM base as final

COPY --from=builder /venv /venv
COPY --from=builder /app/dist .
COPY docker-entrypoint.sh ./

RUN . /venv/bin/activate && pip install *.whl
CMD ["./docker-entrypoint.sh"]

If you need to use this for development purpose, you add or remove the --no-dev by replacing this line

RUN . /venv/bin/activate && poetry install --no-dev --no-root

to something like this as shown in @sobolevn's answer

RUN . /venv/bin/activate && poetry install --no-root $(test "$YOUR_ENV" == production && echo "--no-dev")

after adding the appropriate environment variable declaration.

The example uses debian-slim's as base, however, adapting this to alpine-based image should be a trivial task.

That's minimal configuration that works for me:

FROM python:3.7

ENV PIP_DISABLE_PIP_VERSION_CHECK=on

RUN pip install poetry

WORKDIR /app
COPY poetry.lock pyproject.toml /app/

RUN poetry config virtualenvs.create false
RUN poetry install --no-interaction

COPY . /app

Note that it is not as safe as @sobolevn's configuration.

As a trivia I'll add that if editable installs will be possible for pyproject.toml projects, a line or two could be deleted:

FROM python:3.7

ENV PIP_DISABLE_PIP_VERSION_CHECK=on

WORKDIR /app
COPY poetry.lock pyproject.toml /app/

RUN pip install -e .

COPY . /app

Here's a stripped example where first a layer with the dependencies (that is only build when these changed) and then one with the full source code is added to an image. Setting poetry to install into the global site-packages leaves a configuration artifact that could also be removed.

FROM python:alpine

WORKDIR /app

COPY poetry.lock pyproject.toml ./
RUN pip install --no-cache-dir --upgrade pip \
 && pip install --no-cache-dir poetry \
 \
 && poetry config settings.virtualenvs.create false \
 && poetry install --no-dev \
 \
 && pip uninstall --yes poetry \

COPY . ./

I've created a solution using a lock package (package which depends on all versions in the lock file). This results in a clean pip-only install without requirements files.

Steps are: build the package, build the lock package, copy both wheels into your container, install both wheels with pip.

Installation is: poetry add --dev poetry-lock-package

Steps outside of docker build are:

poetry build
poetry run poetry-lock-package --build

Then your Dockerfile should contain:

FROM python:3-slim

COPY dist/*.whl /

RUN pip install --no-cache-dir /*.whl \
    && rm -rf /*.whl

CMD ["python", "-m", "entry_module"]

I see all the answers here are using the pip way to install Poetry to avoid version issue. The official way to install poetry read POETRY_VERSION env variable if defined to install the most appropriate version.

There is an issue in github here and I think the solution from this ticket is quite interesting:

# `python-base` sets up all our shared environment variables
FROM python:3.8.1-slim as python-base

    # python
ENV PYTHONUNBUFFERED=1 \
    # prevents python creating .pyc files
    PYTHONDONTWRITEBYTECODE=1 \
    \
    # pip
    PIP_NO_CACHE_DIR=off \
    PIP_DISABLE_PIP_VERSION_CHECK=on \
    PIP_DEFAULT_TIMEOUT=100 \
    \
    # poetry
    # https://python-poetry.org/docs/configuration/#using-environment-variables
    POETRY_VERSION=1.0.3 \
    # make poetry install to this location
    POETRY_HOME="/opt/poetry" \
    # make poetry create the virtual environment in the project's root
    # it gets named `.venv`
    POETRY_VIRTUALENVS_IN_PROJECT=true \
    # do not ask any interactive question
    POETRY_NO_INTERACTION=1 \
    \
    # paths
    # this is where our requirements + virtual environment will live
    PYSETUP_PATH="/opt/pysetup" \
    VENV_PATH="/opt/pysetup/.venv"


# prepend poetry and venv to path
ENV PATH="$POETRY_HOME/bin:$VENV_PATH/bin:$PATH"


# `builder-base` stage is used to build deps + create our virtual environment
FROM python-base as builder-base
RUN apt-get update \
    && apt-get install --no-install-recommends -y \
        # deps for installing poetry
        curl \
        # deps for building python deps
        build-essential

# install poetry - respects $POETRY_VERSION & $POETRY_HOME
RUN curl -sSL https://raw.githubusercontent.com/sdispater/poetry/master/get-poetry.py | python

# copy project requirement files here to ensure they will be cached.
WORKDIR $PYSETUP_PATH
COPY poetry.lock pyproject.toml ./

# install runtime deps - uses $POETRY_VIRTUALENVS_IN_PROJECT internally
RUN poetry install --no-dev


# `development` image is used during development / testing
FROM python-base as development
ENV FASTAPI_ENV=development
WORKDIR $PYSETUP_PATH

# copy in our built poetry + venv
COPY --from=builder-base $POETRY_HOME $POETRY_HOME
COPY --from=builder-base $PYSETUP_PATH $PYSETUP_PATH

# quicker install as runtime deps are already installed
RUN poetry install

# will become mountpoint of our code
WORKDIR /app

EXPOSE 8000
CMD ["uvicorn", "--reload", "main:app"]


# `production` image used for runtime
FROM python-base as production
ENV FASTAPI_ENV=production
COPY --from=builder-base $PYSETUP_PATH $PYSETUP_PATH
COPY ./app /app/
WORKDIR /app
CMD ["gunicorn", "-k", "uvicorn.workers.UvicornWorker", "main:app"]

There are two projects where you can see how to do it properly, or you can use these ones to build your own images upon as they are just base images:

• https://github.com/max-pfeiffer/uvicorn-poetry
• https://github.com/max-pfeiffer/uvicorn-gunicorn-poetry

Dockerfile of base image: https://github.com/max-pfeiffer/uvicorn-poetry/blob/main/build/Dockerfile

ARG OFFICIAL_PYTHON_IMAGE
FROM ${OFFICIAL_PYTHON_IMAGE}

ENV PYTHONUNBUFFERED=1 \
    PYTHONDONTWRITEBYTECODE=1 \
    PIP_NO_CACHE_DIR=off \
    PIP_DISABLE_PIP_VERSION_CHECK=on \
    PIP_DEFAULT_TIMEOUT=100 \
    POETRY_VERSION=1.1.11 \
    POETRY_HOME="/opt/poetry" \
    POETRY_VIRTUALENVS_IN_PROJECT=true \
    PYTHONPATH=/application_root \
    VIRTUAL_ENVIRONMENT_PATH="/application_root/.venv"

ENV PATH="$POETRY_HOME/bin:$VIRTUAL_ENVIRONMENT_PATH/bin:$PATH"

# https://python-poetry.org/docs/#osx--linux--bashonwindows-install-instructions
RUN apt-get update \
    && apt-get install --no-install-recommends -y \
        build-essential \
        curl \
    && curl -sSL https://raw.githubusercontent.com/sdispater/poetry/master/get-poetry.py | python - \
    && apt-get purge --auto-remove -y \
      build-essential \
      curl

COPY ./scripts/start_uvicorn.sh /application_server/
RUN chmod +x /application_server/start_uvicorn.sh

COPY ./scripts/pytest_entrypoint.sh ./scripts/black_entrypoint.sh /entrypoints/
RUN chmod +x /entrypoints/pytest_entrypoint.sh
RUN chmod +x /entrypoints/black_entrypoint.sh

EXPOSE 80

CMD ["/application_server/start_uvicorn.sh"]

Dockerfile of sample project image: https://github.com/max-pfeiffer/uvicorn-poetry/blob/main/examples/fast_api_multistage_build/Dockerfile

ARG BASE_IMAGE_NAME_AND_TAG=pfeiffermax/uvicorn-poetry:1.0.1-python3.9.8-slim-bullseye
FROM ${BASE_IMAGE_NAME_AND_TAG} as base-image

WORKDIR /application_root

# install [tool.poetry.dependencies]
# this will install virtual environment into /.venv because of POETRY_VIRTUALENVS_IN_PROJECT=true
# see: https://python-poetry.org/docs/configuration/#virtualenvsin-project
COPY ./poetry.lock ./pyproject.toml /application_root/
RUN poetry install --no-interaction --no-root --no-dev

FROM base-image as test-base-image
ENV LOG_LEVEL="debug"

COPY --from=base-image $VIRTUAL_ENVIRONMENT_PATH $VIRTUAL_ENVIRONMENT_PATH

# install [tool.poetry.dev-dependencies]
RUN poetry install --no-interaction --no-root

COPY /app /application_root/app/
COPY /tests /application_root/tests/

# image for running pep8 checks
FROM test-base-image as black-test-image

ENTRYPOINT /entrypoints/black_entrypoint.sh $0 $@

CMD ["--target-version py39", "--check", " --line-length 80", "app"]

# image for running unit tests
FROM test-base-image as unit-test-image

ENTRYPOINT /entrypoints/pytest_entrypoint.sh $0 $@

# You need to use pytest-cov as pytest plugin. Makes life very simple.
# tests directory is configured in pyproject.toml
# https://github.com/pytest-dev/pytest-cov
CMD ["--cov=app", "--cov-report=xml:/test_coverage_reports/unit_tests_coverage.xml"]

FROM base-image as development-image
ENV RELOAD="true" \
    LOG_LEVEL="debug"

COPY --from=base-image $VIRTUAL_ENVIRONMENT_PATH $VIRTUAL_ENVIRONMENT_PATH

# install [tool.poetry.dev-dependencies]
RUN poetry install --no-interaction --no-root

COPY . /application_root/

FROM base-image as production-image

COPY --from=base-image $VIRTUAL_ENVIRONMENT_PATH $VIRTUAL_ENVIRONMENT_PATH

# This RUN statement fixes an issue while running the tests with GitHub Actions.
# Tests work reliable locally on my machine or running GitHub Actions using act.
# There is a bug with multistage builds in GitHub Actions which I can also reliable reproduce
# see: https://github.com/moby/moby/issues/37965
# Will also check if I can fix that annoying issue with some tweaks to docker build args
# see: https://gist.github.com/UrsaDK/f90c9632997a70cfe2a6df2797731ac8
RUN true

COPY /app /application_root/app/

Use docker multiple stage build and python slim image, export poetry lock to requirements.txt, then install via pip inside virtualenv.

It has smallest size, not require poetry in runtime image, pin the versions of everything.

FROM python:3.9.7 as base
ENV PIP_DISABLE_PIP_VERSION_CHECK=1
WORKDIR /app

FROM base as poetry
RUN pip install poetry==1.1.12
COPY poetry.lock pyproject.toml /app/
RUN poetry export -o requirements.txt

FROM base as build
COPY --from=poetry /app/requirements.txt /tmp/requirements.txt
RUN python -m venv .venv && \
    .venv/bin/pip install 'wheel==0.36.2' && \
    .venv/bin/pip install -r /tmp/requirements.txt

FROM python:3.9.7-slim as runtime
ENV PIP_DISABLE_PIP_VERSION_CHECK=1
WORKDIR /app
ENV PATH=/app/.venv/bin:$PATH
COPY --from=build /app/.venv /app/.venv
COPY . /app

Here's a different approach that leaves Poetry intact so you can still use poetry add etc. This is good if you're using a VS Code devcontainer.

In short, install Poetry, let Poetry create the virtual environment, then enter the virtual environment every time you start a new shell by modifying .bashrc.

FROM ubuntu:20.04

RUN apt-get update && apt-get install -y python3 python3-pip curl

# Use Python 3 for `python`, `pip`
RUN    update-alternatives --install /usr/bin/python  python  /usr/bin/python3 1 \
    && update-alternatives --install /usr/bin/pip     pip     /usr/bin/pip3    1

# Install Poetry
RUN curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/install-poetry.py | python3 -
ENV PATH "$PATH:/root/.local/bin/"

# Install Poetry packages (maybe remove the poetry.lock line if you don't want/have a lock file)
COPY pyproject.toml ./
COPY poetry.lock ./
RUN poetry install --no-interaction

# Provide a known path for the virtual environment by creating a symlink
RUN ln -s $(poetry env info --path) /var/my-venv

# Clean up project files. You can add them with a Docker mount later.
RUN rm pyproject.toml poetry.lock

# Hide virtual env prompt
ENV VIRTUAL_ENV_DISABLE_PROMPT 1

# Start virtual env when bash starts
RUN echo 'source /var/my-venv/bin/activate' >> ~/.bashrc

Reminder that there's no need to avoid the virtualenv. It doesn't affect performance and Poetry isn't really designed to work without them.

EDIT: @Davos points out that this doesn't work unless you already have a pyproject.toml and poetry.lock file. If you need to handle that case, you might be able to use this workaround which should work whether or not those files exist.

COPY pyproject.toml* ./
COPY poetry.lock* ./
RUN poetry init --no-interaction; (exit 0) # Does nothing if pyproject.toml exists
RUN poetry install --no-interaction

My Dockerfile based on @lmiguelvargasf's answer. Do refer to his post for a more detailed explanation. The only significant changes I have are the following:

• I am now using the latest official installer install-poetry.py instead of the deprecated get-poetry.py as recommended in their official documentation. I'm also installing a specific version using the --version flag but you can alternatively use the environment variable POETRY_VERSION. More info on their official docs!

• The PATH I use is /root/.local/bin:$PATH instead of ${PATH}:/root/.poetry/bin from OP's Dockerfile

FROM python:3.10.4-slim-buster

ENV PYTHONDONTWRITEBYTECODE 1 \
    PYTHONUNBUFFERED 1

RUN apt-get update \
    && apt-get install curl -y \
    && curl -sSL https://install.python-poetry.org | python - --version 1.1.13

ENV PATH="/root/.local/bin:$PATH"

WORKDIR /usr/app

COPY pyproject.toml poetry.lock ./

RUN poetry config virtualenvs.create false \
    && poetry install --no-dev --no-interaction --no-ansi

COPY ./src ./

EXPOSE 5000

CMD [ "poetry", "run", "gunicorn", "-b", "0.0.0.0:5000", "test_poetry.app:create_app()" ]