charm fails to install on Ubuntu 18.04

[Brian Murray]

The install hook is failing:

2021-08-09 18:02:26 INFO juju.worker.uniter resolver.go:148 found queued "install" hook
2021-08-09 18:03:57 WARNING unit.cassandra/7.install logger.go:60 Command "/var/lib/juju/agents/unit-cassandra-7/.venv/bin/python3 -m pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-xbp4ysnr --no-warn-script-location --no-binary :none: --only-binary :none: --no-index --find-links wheelhouse -- setuptools>=42 wheel setuptools_scm[toml]>=3.4.1" failed with error code 1 in None
2021-08-09 18:03:57 WARNING unit.cassandra/7.install logger.go:60 Injecting environment variables (in lib/charms/__init__.py)
2021-08-09 18:03:57 WARNING unit.cassandra/7.install logger.go:60 Traceback (most recent call last):
2021-08-09 18:03:57 WARNING unit.cassandra/7.install logger.go:60 File "/var/lib/juju/agents/unit-cassandra-7/charm/hooks/install", line 8, in <module>
2021-08-09 18:03:57 WARNING unit.cassandra/7.install logger.go:60 basic.bootstrap_charm_deps()
2021-08-09 18:03:57 WARNING unit.cassandra/7.install logger.go:60 File "lib/charms/layer/basic.py", line 214, in bootstrap_charm_deps
2021-08-09 18:03:57 WARNING unit.cassandra/7.install logger.go:60 env=_get_subprocess_env())
2021-08-09 18:03:57 WARNING unit.cassandra/7.install logger.go:60 File "/usr/lib/python3.6/subprocess.py", line 311, in check_call
2021-08-09 18:03:57 WARNING unit.cassandra/7.install logger.go:60 raise CalledProcessError(retcode, cmd)
2021-08-09 18:03:57 WARNING unit.cassandra/7.install logger.go:60 subprocess.CalledProcessError: Command '['/var/lib/juju/agents/unit-cassandra-7/.venv/bin/pip', 'install', '-U', '--force-reinstall', '--no-index', '--no-cache-dir', '-f', 'wheelhouse', 'netaddr==0.7.19', 'six==1.16.0', 'Jinja2==2.10.1', 'wheel==0.33.6', 'MarkupSafe==1.1.1', 'zipp==3.5.0', 'cassandra-driver==3.25.0', 'typing-extensions==3.10.0.0', 'geomet==0.2.1.post1', 'charms.reactive==1.4.1', 'tenacity==5.0.3', 'importlib-metadata==4.6.3', 'pbr==5.6.0', 'PyYAML==5.2', 'charmhelpers==0.20.22', 'click==8.0.1', 'pyaml==20.4.0', 'Tempita==0.5.2']' returned non-zero exit status 1.

Running the same pip install command the following error is returned:

ubuntu@juju-b7a87c-stg-error-tracker-83:~$ /var/lib/juju/agents/unit-cassandra-7/.venv/bin/pip install -U --force-reinstall --no-index --no-
cache-dir -f /var/lib/juju/agents/unit-cassandra-7/charm/wheelhouse geomet==0.2.1.post1 six==1.16.0 click==8.0.1 charms.reactive==1.4.1 MarkupSafe==1.1.1 charmhelpers==0.20.22 pyaml==20.4.0 Tempita==0.5.2 PyYAML==5.2 wheel==0.33.6 typing-extensions==3.10.0.0 pbr==5.6.0 cassandra-driver==3.25.0 Jinja2==2.10.1 zipp==3.5.0 tenacity==5.0.3 netaddr==0.7.19 import-metadata==4.6.3
Looking in links: /var/lib/juju/agents/unit-cassandra-7/charm/wheelhouse
Collecting geomet==0.2.1.post1
Collecting six==1.16.0
Collecting click==8.0.1
Collecting charms.reactive==1.4.1
Collecting MarkupSafe==1.1.1
Collecting charmhelpers==0.20.22
Collecting pyaml==20.4.0
Collecting Tempita==0.5.2
Collecting PyYAML==5.2
Collecting wheel==0.33.6
Collecting typing-extensions==3.10.0.0
Collecting pbr==5.6.0
Collecting cassandra-driver==3.25.0
Collecting Jinja2==2.10.1
Collecting zipp==3.5.0
  Installing build dependencies ... error
  Complete output from command /var/lib/juju/agents/unit-cassandra-7/.venv/bin/python3 -m pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-_5z9khyy --no-warn-script-location --no-binary :none: --only-binary :none: --no-index --find-links /var/lib/juju/agents/unit-cassandra-7/charm/wheelhouse -- setuptools>=42 wheel setuptools_scm[toml]>=3.4.1:
  Looking in links: /var/lib/juju/agents/unit-cassandra-7/charm/wheelhouse
  Collecting setuptools>=42
    Could not find a version that satisfies the requirement setuptools>=42 (from versions: scm-1.17.0, 41.6.0)
  No matching distribution found for setuptools>=42

  ----------------------------------------
Command "/var/lib/juju/agents/unit-cassandra-7/.venv/bin/python3 -m pip install --ignore-installed --no-user --prefix /tmp/pip-build-env-_5z9khyy --no-warn-script-location --no-binary :none: --only-binary :none: --no-index --find-links /var/lib/juju/agents/unit-cassandra-7/charm/wheelhouse -- setuptools>=42 wheel setuptools_scm[toml]>=3.4.1" failed with error code 1 in None

I guess something is dependent upon a later version of setuptools than is included in the wheelhouse directory.

[Tom Haddon (mthaddon)]

In a "built" version of the charm I see the following in `wheelhouse.txt`:
```
# layer:basic
# pip is pinned to <19.0 to avoid https://github.com/pypa/pip/issues/6164
# even with installing setuptools before upgrading pip ends up with pip seeing
# the older setuptools at the system level if include_system_packages is true
pip>=18.1,<19.0
# pin Jinja2, PyYAML and MarkupSafe to the last versions supporting python 3.5
# for trusty
Jinja2<=2.10.1
PyYAML<=5.2
MarkupSafe<2.0.0
setuptools<42
setuptools-scm<=1.17.0
charmhelpers>=0.4.0,<1.0.0
charms.reactive>=0.1.0,<2.0.0
wheel<0.34
# pin netaddr to avoid pulling importlib-resources
netaddr<=0.7.19

# layer:snap
# Newer versions of tenacity rely on `typing` which is in stdlib in
# python3.5 but not python3.4. We want to continue to support
# python3.4 (Trusty)
tenacity<5.0.4

# cassandra
cassandra-driver
```
So it looks like this is coming from layer:basic. I'm not very familiar with this but will see who I can chat with about this and what I can figure out about where to go from here.

[Tom Haddon (mthaddon)]

I've downloaded cs:cassandra-57 locally, added the `lib/apache.key` from the latest commit to the code, and then done a deployment of that on LXD and it seems to work fine on bionic.

This points further to an issue with one of the layers, will need to follow up.

[Tom Haddon (mthaddon)]

This has now been fixed in cs:cassandra-59

[Brian Murray (brian-murray)]

The fix worked for me, thanks!