[fix] Update apt-cache before installing dependencies

[obitech]

Updates the apt cache before installing Grafana dependencies
through the package manager. This resolves a bug where old dependencies,
or those with a changed name, would not be installed due to
the package manager not being able to find them.

Fixes #200
Ref #201

[paulfantom]

LGTM, but let's see if CI catches anything.

[obitech]

Hmm it seems to fail at the pre-validate stage but I have trouble parsing the output. Any pointers?

Edit: maybe it's linting, I'm checking

Edit2: Seems to be linting but I'm not sure where exactly it fails:

ERROR: Failed to pre-validate.
{'lint': ['must be of string type']}
ERROR: InvocationError for command /home/travis/build/cloudalchemy/ansible-grafana/.tox/py37-ansible27/bin/molecule test -s default --destroy always (exited with code 1)

I've ran ansible-lint and yamlint on the changed file but nothing came up. Any ideas?

[paulfantom]

The issue is with molecule itself. More in cloudalchemy/skeleton#5. You can port that fix here and it should work.

[obitech]

I've migrated the changes but now there are a lot of warnings and errors from yamlint in different files. Let's see what CI says

Edit: I'd be happy to fix them but let me know how to handle the docker module exception

[paulfantom]

Seems like migration to molecule v3 might take more time than I though :(

Can you revert previous change and just pin molecule to version v2 in test-requirements.txt?
This would need just a change of one line to be like this one:

molecule>=2.15.0,<3.0.0

Sorry for those problems. I'll try to tackle it during weekend.

[obitech]

I've reverted and squashed commits.

Sorry for those problems. I'll try to tackle it during weekend.

No worries! Let me know if I can help with anything 🙂

[paulfantom]

Seems like tests don't like refreshing apt cache:

ERROR: Idempotence test failed because of the following tasks:

• [xenial] => ansible-grafana : Update apt cache
• [bionic] => ansible-grafana : Update apt cache

from https://travis-ci.com/cloudalchemy/ansible-grafana/jobs/291642777#L907

If this is necessary we might need to use apt module for installing grafana on debiand-based or apt-based systems and package module on others. However IMHO this is very "dirty" solution and should be avoided if possible.

Maybe we can move refreshing cache to block in which we set up GPG keys for repository?

[obitech]

If this is necessary we might need to use apt module for installing grafana on debiand-based or apt-based systems and package module on others. However IMHO this is very "dirty" solution and should be avoided if possible.

I agree, this is not something I'd want to do either.

Maybe we can move refreshing cache to block in which we set up GPG keys for repository?

If you mean the block later in the task, I don't think it works because apt cache needs to be refreshed before the dependencies are installed, right at the beginning. I've tried encapsulating the whole Install dependencies step as a block, let's see if that works.

Edit: looks good 🙂