poetry: Unable to install using python 3 on clean Ubuntu 18.04 image

@finswimmer thanks for double-checking; I already knew that python 2 worked to install it. The documentation is clear that it doesn’t matter which version of python is used to install poetry, so the scenario outlined in my original post (with python 3) is clearly an issue.

Using python 2 is not acceptable in my case; it’s simply not available on our production images and our python executable launches py3. Poetry absolutely have to be able to work in a python2-less environment.

Hello,

I try to reproduce the problems mentioned here, by installing a fresh ubuntu 18.04 in a virtual machine. After doing this (installing the “minimal” variant), I ended up with a system where a python3 exists but no python. At the moment, poetry expects that there is a python within the path. It doesn’t matter if it links to a python2 or python3. So I install python2 by sudo apt-get install python. After that it looks like this

$ which python
/usr/bin/python

$ python --version
Python 2.7.17

$ which python2
/usr/bin/python2

$ python2 --version
Python 2.7.17

$ which python3
/usr/bin/python3

$ python3 --version
Python 3.6.9

For installing poetry, curl is needed:

sudo apt-get install curl

Then:

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

Now let’s create two poetry projects. One that should use python2 and one python3.

mkdir project_python2
cd project_python2
poetry init --no-interaction

The pyproject.toml looks like this:

[tool.poetry]
name = "project_python2"
version = "0.1.0"
description = ""
authors = ["Your Name <you@example.com>"]

[tool.poetry.dependencies]
python = "^2.7"

[tool.poetry.dev-dependencies]

[build-system]
requires = ["poetry>=0.12"]
build-backend = "poetry.masonry.api"

Now install the project:

$ poetry install

And you’re done. Whenever running a poetry command you will receive a warning like this:

/home/finswimmer/.poetry/lib/poetry/_vendor/py2.7/subprocess32.py:149: RuntimeWarning: The _posixsubprocess module is not being used. Child process reliability may suffer if your program uses threads.  "program uses threads.", RuntimeWarning)

It’s a warning and AFAIK you can ignore it.

Now let’s see what happens for a project uses python3. Copy the above pyproject.toml to a new folder called project_python3. Change the name in this file to match the folder name and change python = "^2.7" to python = "^3.6".

Run poetry install and you may receive an error message that you need to install python3-venv. Ok, let’s do it:

$ sudo apt-get install python3-venv

Unfortunately poetry left a broken venv behind, we had to remove before trying again.

$ poetry env remove python3

and

$ poetry install
$ poetry run python --version
Python 3.6.9

To summarize:

• make sure there is a python
• it doesn’t matter if python links to python2 or python3
• in addition to python there should be python2 and python3 in your path, if you like to use different python3 versions in different project. Because poetry tries the one or the other if the version of python doesn’t match the project’s python version
• You may need to install python3-venv. But poetry will complain about it if needed.

fin swimmer

Get the same error when installing poetry using pip3 as well. Doesn’t seem to be a way to get 1.0.0 to use python3 at all, at least on ubuntu.

@jonapich this works for me at the moment; can you confirm please?

docker run --rm -it ubuntu:18.04 bash -c "apt -y update; apt install -y python3 python3-pip curl; curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python3; source \$HOME/.poetry/env; export PYTHONIOENCODING=utf-8; poetry --version; poetry --help"

Note that that the ascii encoding error is an issuew ith the ubuntu docker image locale. In the above command I make use of export PYTHONIOENCODING=utf-8 to make that work. See https://github.com/python-poetry/poetry/issues/1719#issuecomment-565391165.

And the distutils requirement is expected to be available in a python install. I am not sure how Ubuntu is building their python package to comment on why it does not exist there.

@pcgeek86 regarding keyring.alt issue, see https://github.com/python-poetry/poetry/issues/1719#issuecomment-565846793. The package is not required by poetry and hence should not be indicated as a dependency. This is a distro issue unfortunately and there is not clean fix that can be done from the poetry side for this one.

See also: #1719

This issue also happens to Ubuntu 20.04

I’m not sure if this is the correct long-term fix for poetry, but do we need to add keyrings.alt to the list of poetry dependencies in this file? I can confirm that installing this package causes poetry to start working.

https://github.com/python-poetry/poetry/blob/master/pyproject.toml#L52

I think I may have added a misstep in my original post… I tried my first scenario again and get a different result:

root@7ebac430ec14:~# poetry
  File "/root/.poetry/lib/poetry/console/commands/shell.py", line 3, in <module>
    from distutils.util import strtobool
ModuleNotFoundError: No module named 'distutils.util'

So I went ahead and apt install python3-pip. It’s a 110mb download with all its dependencies. Only then, I can reproduce the issue from my original post. (EDIT: you can also get python3-distutils which is a much smaller package; in both cases, we end up with the keyring callstack)

I tried updating keyrings.alt as suggested. It seems to fix it, and then it breaks again later on:

Successfully installed keyrings.alt-3.4.0
root@7ebac430ec14:~# poetry
Poetry version 1.0.0

USAGE

[UnicodeEncodeError]
'ascii' codec can't encode character '\xa0' in position 30: ordinal not in range(128)

I tried the same steps using python2 instead of python3. I get a different outcome:

root@af0c0fe8f81c:~/.poetry/bin# ./poetry --version
/root/.poetry/lib/poetry/_vendor/py2.7/subprocess32.py:149: RuntimeWarning: The _posixsubprocess module is not being used. Child process reliability may suffer if your program uses threads.
  "program uses threads.", RuntimeWarning)
Poetry version 1.0.0
root@af0c0fe8f81c:~/.poetry/bin#