Poetry can't install opencv but pip can (RPI)

[A-Telfer]

• I am on the latest Poetry version.
• I have searched the issues of this repo and believe that this is not a duplicate. NOTE: there are some similar mac os ones, but some of the solutions are targeted at macs and none worked for me.
• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: Raspbian, release 10
• Poetry version: 1.16

Issue

poetry add opencv-python-headless fails, but pip install opencv-python-headless works.

This is my first time using poetry and it's not going very well. I've spent a few hours searching around for solutions but no luck, the closest I've come is #3621 (I tried many of the solutions in the linked issues), I've tried installing different versions of opencv, upgrading pip, reinstalling poetry... nothing has worked so far.

[clintonroy]

What error do you get?

[A-Telfer]

Unable to find installation candidates for opencv-python-headless (4.5.2.52)

[epower]

I've found adding

[[tool.poetry.source]]
name = "piwheels"
url = "https://www.piwheels.org/simple/"

to the pyproject.toml file allows the correct candidate to be installed provided the relevant system dependencies are present.

[LorhanSohaky]

That happened to me

[jimmywan]

@A-Telfer Might want to try increasing the verbosity. Might give you more insight into what's going on.

poetry add -vvv opencv-python-headless

[A-Telfer]

Thanks for the suggestions, I got it working

1. Following @epower, I added piwheels to the pyproject.toml file

[[tool.poetry.source]]
name = "piwheels"
url = "https://www.piwheels.org/simple/"

2. Look on piwheels to find which opencv versions are supported, then explicitly add it. eg poetry add opencv-python-headless==4.5.1.48

[A-Telfer]

Without specifying the version it tries to install the latest pip version (4.5.2.52) and fails. The reason pip works on the RPI without specifying the version is that it seems to search piwheels first and install 4.5.1.48.

It would be nice if poetry could be configured to have the same behavior as pip

[JexPY]

Same problem with PyJSON5 https://pyjson5.readthedocs.io/en/latest/index.html,

I tried poetry add pyjson5 but getting:

• Installing pyjson5 (1.6.0.post1): Failed

  RuntimeError

  Unable to find installation candidates for pyjson5 (1.6.0.post1)

But specifying version solves the problem.

[clintonroy]

Same problem with PyJSON5 https://pyjson5.readthedocs.io/en/latest/index.html,

I tried poetry add pyjson5 but getting:

• Installing pyjson5 (1.6.0.post1): Failed

  RuntimeError

  Unable to find installation candidates for pyjson5 (1.6.0.post1)

The error's not great, but the problem is that there's no sdist for pyjson5, and only windows builds, check out pypi. Poetry should probably do better here, and take that into account when doing resolving. PyJson5 should definitely upload an sdist though.

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.