From 3f7b6eade8d7aaa1103733fb9677042e85fd46ee 2020-12-25 17:51:40
From: Branko Majic <branko@majic.rs>
Date: 2020-12-25 17:51:40
Subject: [PATCH] MAR-177: Do not pin pip/setuptools to specific versions when setting up Python virtual environment:

- Provided more details for the pkg-resources workaround.
- Skip installing latest version of pip - it will get installed
  automatically via the virtualenv command already.
- Do not pin the setuptools package when installing.
- Updated release notes.

---

diff --git a/docs/releasenotes.rst b/docs/releasenotes.rst
index 07d19cd7410a8a5169f9b06f7f886453def52502..000e051dc88c32af2603f9ed6e8497f2e143d2ae 100644
--- a/docs/releasenotes.rst
+++ b/docs/releasenotes.rst
@@ -2,6 +2,20 @@ Release notes
 =============
 
 
+NEXT RELEASE
+------------
+
+**Bug fixes:**
+
+* ``wsgi_website_`` role
+
+  * When the virtual environment is created, the ``setuptools`` and
+    ``pip`` packages will not get pinned to any specific version,
+    allowing roles that are based on ``wsgi_website`` to easily
+    install preferred versions, and avoid idempotence problems in the
+    process.
+
+
 5.0.0
 -----
 
diff --git a/roles/wsgi_website/tasks/main.yml b/roles/wsgi_website/tasks/main.yml
index c74b3ce06c3ab61098b24ddb84e0988432745dcb..ab2256d2547132ba2a3e7615c0d5f77bdd50db3f 100644
--- a/roles/wsgi_website/tasks/main.yml
+++ b/roles/wsgi_website/tasks/main.yml
@@ -113,8 +113,24 @@
     group: "{{ user }}"
     mode: 02750
 
-# setuptools is excluded on Stretch, because it would pull-in the
-# pkg-resources package that then messes with pip freeze etc.
+# @TODO: Get rid of this if possible in Debian Buster.
+# Do not install setuptools when creating the virtual environment -
+# otherwise it will also install Debian-specific pkg-resources
+# package. The pkg-resources package can be removed, but this breaks
+# the package downloading via pip.
+#
+# Install setuptools later on via separate pip invocation.
+#
+# The pkg-resources package is also annoying because it shows-up in
+# the output of the pip freeze command, and also interferes with the
+# virtual environment management using pip-tools.
+#
+# For more details, see:
+#
+# - https://github.com/pypa/pip/issues/4022
+# - https://bugs.launchpad.net/ubuntu/+source/python-pip/+bug/1635463
+# - https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=871790
+
 - name: Create Python virtual environment
   command: '/usr/bin/virtualenv --no-setuptools --python "{{ python_interpreter }}" --prompt "({{ fqdn }})" "{{ home }}/virtualenv"'
   args:
@@ -127,20 +143,16 @@
     #   created (thanks to 'creates' parameter).
     - skip_ansible_lint
 
-- name: Install latest pip and setuptools in virtual environment
+# @TODO: Park of the pkg-resources described above.
+- name: Install setuptools in virtual environment
   pip:
     name:
-      - "pip>=18.0.0,<19.0.0"
-      - "setuptools>=40.0.0,<41.0.0"
+      - "setuptools"
     virtualenv: "{{ home }}/virtualenv"
   become: true
   become_user: "{{ admin }}"
 
-# Workaround for:
-#
-# - https://github.com/pypa/pip/issues/4022
-# - https://bugs.launchpad.net/ubuntu/+source/python-pip/+bug/1635463
-# - https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=871790
+# @TODO: Park of the pkg-resources described above.
 - name: Remove the pkg-resources package from virtual environment (see comments above for details)
   pip:
     name: pkg-resources