Deploy app on Heroku using Poetry

[karantan]

• I have searched the issues of this repo and believe that this is not a duplicate.
• I have searched the documentation and believe that my question is not covered.

Question

Let say you have a simple Flask web app but instead of using pipenv (or regular pip + requirements.txt) I want to use poetry. How do I deploy this app on heroku?

With pipenv it is easy because there already exists a buildpack for pipenv but it does not for poetry.

[jacebrowning]

IMO, the best solution would be to update the Python buildpack to key off poetry.lock then run poetry commands. I'll see if I can put something together.

[yunti]

This would work too #100

[nmunro]

I have a more general solution to this, if I may, I had begun working on a patch, but I'm still familiarising myself with the poetry package.

We need to use pip directly on EC2 instances and I threw together a solution to generate a traditional requirements.txt file, but using a make rule, ideally a command to regenerate a standard requirements.txt file for use with heroku/aws etc would be a good way to integrate quickly and easily with existing services etc, I wrote up kinda what we're doing here: http://neilmunro.herokuapp.com/blog/python_development_and_production_workflow

Something like:

poetry export-requirements --no-deps

[zyv]

Yet another pipenv refugee here... Would be great to have an analog to pipenv lock -r in poetry. This is what we are currently using for our Heroku deployments.

In the meantime, we are thinking of running pip freeze in poetry shell and filtering out the current project with grep, but native support for pipenv lock -r would be much appreciated. Thanks!

[sdispater]

An export command is currently being worked on which will make exporting the lock file to other formats (requirements.txt being the only one for now) possible.

[zyv]

@sdispater sounds awesome! Would be great if that export command supported filtering dependencies by type (i.e. to be able to automatically filter out dev dependencies), and custom index sources. These are both pipenv features that we are currently using to generate our requirements.txt for Heroku.

[zyv]

Merged in develop in #675, yay! 👍 Will be testing when it hits the next release.

[woile]

Hey folks, could someone summarize the steps to deploy using poetry?
Thanks!

[zyv]

@woile the feature has been merged in develop, but, unfortunately, still not released :(

In the meantime, we use an internal tool that we have written to the same effect, which parses the lock-file and outputs requirements.txt for Heroku...

[jacebrowning]

@woile If you don't care about leveraging Heroku's dependency cache, the following works for a Django project using the default Python buildpack:

requirements.txt

poetry==1.0.2

bin/post_compile

#!/usr/bin/env bash

set -eo pipefail

indent() {
  sed "s/^/       /"
}

puts-step() {
  echo "-----> $@"
}

puts-step "Installing dependencies with poetry..."
poetry config virtualenvs.create false 2>&1 | indent
poetry install --no-dev 2>&1 | indent

puts-step "Collecting static files..."
python manage.py collectstatic --no-input 2>&1 | indent

[sdispater]

The export command is available in the 1.0.0 latest pre release

[joshfriend]

@jacebrowning i disagree with how heroku's dependency cache works anyways, so this is actually OK with me 😆

[CptSpaceToaster]

Using Poetry 0.12.17, my install would fail, mentioning something about pip._vendor.urllib3.packages.rfc3986 when specifying a python-3.7.3 runtime.

I modified my install for a flask-app to allow poetry to keep its virtual env, but just in the repo

requirements.txt

poetry==0.12.17

bin/post_compile

#!/usr/bin/env bash

set -eo pipefail

indent() {
  sed "s/^/       /"
}

puts-step() {
  echo "-----> $@"
}

puts-step "Installing dependencies with poetry..."
# Use a venv, but install locally
poetry config settings.virtualenvs.in-project true 2>&1 | indent
poetry install --no-dev 2>&1 | indent

# Not using Django
# puts-step "Collecting static files..."
# python manage.py collectstatic --no-input 2>&1 | indent

This requires the Procfile to be mangled, as the script to launch gunicorn (.venv/bin/gunicorn) I needed wasn't receiving a functional hashbang

Procfile

web: .venv/bin/python3 .venv/bin/gunicorn package:flask_app

[herrbenesch]

I got it working (for poetry 1.0.0) by adding bin/pre_compile with the content

# Get poetry from source
curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python
# Make poetry available to $PATH
source $HOME/.poetry/env
# Export poetry packages to requirements.txt to be used for installing the pipy packages
poetry export -f requirements.txt -o requirements.txt

pre_compile will be made executable by the buildpack:

[CptSpaceToaster]

Now that poetry 1.0.0 is out, you can run poetry export. If you you have a pre-1.0.0 release, you'll still need a work around.

[laike9m]

poetry config settings.virtualenvs.create false 2>&1 | indent

@jacebrowning

As of Poetry 1.0,

poetry config settings.virtualenvs.create false

has changed to

poetry config virtualenvs.create false

Could you help update it to help future readers? Also, it's better to use --local because you don't want to affect other projects.

[zyv]

FYI, we've eventually created a buildpack and moved to Poetry also on Heroku:

https://github.com/moneymeets/python-poetry-buildpack

/cc @marns93

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