Meinheld 1.0.2 is incompatible with greenlet 1.0

[bburtin]

A pip install of SQLAlchemy 1.4 causes greenlet 1.0 to be installed. As a result, we started getting the error below during Meinheld startup. We were able to avoid the problem in the short term by pinning SQLAlchemy to 1.3.x. It would be good if Meinheld supported later versions of greenlet. This will allow us to upgrade SQLAlchemy in the future.

Error: class uri 'egg:meinheld#gunicorn_worker' invalid or not found: [Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/gunicorn/util.py", line 72, in load_class
    return pkg_resources.load_entry_point(dist, section, name)
  File "/usr/local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 474, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/usr/local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2846, in load_entry_point
    return ep.load()
  File "/usr/local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2449, in load
    self.require(*args, **kwargs)
  File "/usr/local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 2472, in require
    items = working_set.resolve(reqs, env, installer, extras=self.extras)
  File "/usr/local/lib/python3.6/site-packages/pkg_resources/__init__.py", line 777, in resolve
    raise VersionConflict(dist, req).with_context(dependent_req)
pkg_resources.VersionConflict: (greenlet 1.0.0 (/usr/local/lib/python3.6/site-packages), Requirement.parse('greenlet<0.5,>=0.4.5'))

[idot]

created pull request:
#123

[mdantonio]

Hello,
sorry to urge this issue, but it's more then 1 year that it is open with a PR waiting for the merge... Is there any plan to fix this problem? I would like to upgrade my environment to python 3.10 but I can't because greenlet 0.4.17 is not compatible

[luckydonald]

The easiest workaround seems to be to install greenlet in a correct version first, and then meinheld while ignoring it's dependencies (greenlet):

# python:3.10

pip install "greenlet>=0.4.5,<2.0.0"
pip install --no-dependencies meinheld

---

Edit 1: Never mind, that results in a pkg_resources.VersionConflict. Apparently it does check that version on runtime.

[Traceback (most recent call last):
  File "/env/lib/python3.10/site-packages/gunicorn/util.py", line 71, in load_class
    return pkg_resources.load_entry_point(dist, section, name)
  File "/env/lib/python3.10/site-packages/pkg_resources/__init__.py", line 474, in load_entry_point
    return get_distribution(dist).load_entry_point(group, name)
  File "/env/lib/python3.10/site-packages/pkg_resources/__init__.py", line 2846, in load_entry_point
    return ep.load()
  File "/env/lib/python3.10/site-packages/pkg_resources/__init__.py", line 2449, in load
    self.require(*args, **kwargs)
  File "/env/lib/python3.10/site-packages/pkg_resources/__init__.py", line 2472, in require
    items = working_set.resolve(reqs, env, installer, extras=self.extras)
  File "/env/lib/python3.10/site-packages/pkg_resources/__init__.py", line 777, in resolve
    raise VersionConflict(dist, req).with_context(dependent_req)
pkg_resources.VersionConflict: (greenlet 1.1.3.post0 (/env/lib/python3.10/site-packages), Requirement.parse('greenlet<0.5,>=0.4.5'))

---

Edit 2:
You can install the patch at:

pip3 install git+https://github.com/idot/meinheld.git@2bfe452d6608c92688d92337c87b1dd6448f4ccb