RelEng: Refactor travis configuration

[hairmare]

Travis is currently using dist: trusty and I'd like to switch to services: docker. docker is a good match for our current workload and makes extending the CI pipeline easier. Once done I hope for this to help with #15 and my translation integration efforts in #301. It will also open it up for things like linting liquidsoap scripts.
The end goal of my travis refactor is to use docker support so we can test on different distributions. I'd also like to take care of smoke-testing the install script somehow. This seems easier if we can control our own docker containers vs. using single container we are currently using. I plan on keeping the changes to things that aren't .travis.yml or .travis/ as minimal as possible by relying on official library or upstream images everywhere.

• Refactor current pipeline to service: docker
• Fully migrate services to our own services
• Update PHP support matrix (dump oldies)
• Update PHP support matrix (add 7.2)
• Update Python support matrix (update py2, add allowed to fail py3)
• Add installer smoke screen tests

I might opt into the build stages beta on travis if performance issues arise.

[Robbt]

This sounds good to me. I have little experience in working with Travis and Docker and trust you to get it setup. Are we using a hosted travis service right now and will this change mean we are running our own infrastructure. If so will there be a hosting cost etc ? Just curious so I can get a better grasp on how this is all going to be setup.

[hairmare]

We'll be using the same free for opensource travis service as before. This would mainly change that we use a full virtual machine with it's own docker server rather than using a provided container. Starting the first build might be a bit slower on the new platform but the added flexibility should outweigh this.

There won't be any costs for this as it's really only a configuration change. I plan on taking care of the low hanging fruit (like php python version bumping first) so the actual change to docker will be done once everything works with newer php and py3.

As I have already run into some php 7.2 compat issues regarding deprecation warnings it might take a bit to finalize this.

[hairmare]

ZF1 isn't compatible with PHP 7.2, I'm investigating if there are any serious forks that might make sense for us. Magento has https://github.com/magento/zf1 but their might be others that are also well maintained and could help the PHP MVC stay viable a bit longer.

[Robbt]

Just a quick question, is there a login for our free travis setup that is needed to make some of these backend changes etc?

[hairmare]

Everything is in .travis.yml.

[Robbt]

Cool thanks, I was thinking of lending a hand on some of this stuff but I still haven't read the docs on how travis works exactly.

[paddatrapper]

@Robbt how much of this changed when you were re-working travis for the docs?

[Robbt]

None. I didn't really touch the travis file at all, just discovered a bit more about how it worked, all of this is probably still valid. We can see if we can tweak it to fix the mkdocs build at this point because I just checked and it is still not generating the howto links etc.

[jooola]

Seems like libretime don't use travis anymore, should this be closed ?