Fix 122 superlance path py3

[stevepiercy]

This PR addresses https://github.com/plone/ansible-playbook/issues/122

If plone_python_version == '3', then append an argument to install superlance that specifies the path to pip3.

[smcmahon]

The CI framework is now working, and we've got a failing test. Can we also make sure that the tests in test.yml cover superlance with python 3?

[stevepiercy]

Can the tests be run locally?

I thought that it would be possible to use Jinja2 syntax in a .yml file, but apparently logic is not supported here. Should I fall back to using a when condition?

I'm not sure how to proceed. My guess failed. Any hint appreciated.

[smcmahon]

Regarding testing: if you've got vagrant available, the easiest thing to do is to run "vagrant up". That will run the tests against bionic. After "up", use "vagrant provision" to run again against the same box instance.

[stevepiercy]

Thanks for the tip for running the tests. I had to fallback to using when and duplicate the blocks. It's not as pretty, but, meh, whatever.

Travis-CI build succeeds now.

[smcmahon]

In trying to add a test for superlance under Python 3, I ran into some issues.

If supervisor is being added as a system package (which it is), it seems to me that we want to add superlance using the same version of pip/python as is in use for the system package.

And, if that's python3, we want to use the system pip3 -- not the one in the virtualenv. If it gets added in the virtualenv, it will not be found by the system install of supervisor.

(Separate issue: mightn't we want to simply drop the superlance version of the hot_monitor in favor of the cron version. Because the latter knows how to work with haproxy and warm zodb caches, it seems superior to me. This was never spelled out, but I've long regarded the superlance mechanism as a legacy.)

[stevepiercy]

What issues did you run into?

What is the variable to use for a system path? I assumed that removing the executable parameter would use the system $PATH, but without an executable parameter I get the error message:

fatal: [bionic]: FAILED! => {"changed": false, "msg": "Unable to find any of pip2, pip to use. pip needs to be installed."}

Here's $PATH from the return of a debug statement:

"PATH": "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin",

When I hard-code executable=/usr/bin/pip3, pip is found and the playbook proceeds. That's fine for Debian/Ubuntu, but what should I use for other OSes?

[smcmahon]

Issue resolved! Thanks for getting this going.