Detect missing Java when validating mustache template

[paulholden]

@stronk7 points to this line https://github.com/stronk7/moodle-local_ci/blob/master/mustache_lint/mustache_lint.php#L297

Example error in moodle-plugin-ci when Java is apparently not present

$ ./bin/moodle-plugin-ci mustache --moodle=/opt/moodle/master/src /opt/moodle/master/src/mod/forum
 RUN  Mustache Lint on mod_forum
/mnt/export/moodle/master/src/mod/forum/report/summary/templates/filter_dates.mustache - WARNING: Problem calling HTML validator - please report bug to integration team.

We can

1. Detect missing Java;
2. Switch to online

[stronk7]

I've been thinking about this and, honestly, think that sutomatically switching to the online alternative is not a good idea. We can start flooding by default https://html5.validator.nu or any other service providing that.

So, maybe, a better alternative could be something like:

• When the jar is passed and java is missing. Exit with error.
• Of course, suggest to install java, how not.
• Alternatively, suggest to use the "vnu" binary instead (AFAIK it can be installed on all OSs and includes an embedded JRE, but at all effects it's a self-contained binary).
• Also, suggest to use a local vnu docker container and point to it (http://localhost:8888 or whatever).

And then, in moodle-plugin-ci... that always tries the vnu.jar alternative...

• try also the vnu (binary) alternative, just in case it's installed in the system.
• allow to specify a URL with the service running. It can be the locally running docker image or, less desirable, the public html5 validator.

The point that I want to avoid here is to start "abusing" the public html5 validator without control, that's the reason I think we only should use it if explicitly said.

How does that sound?

[paulholden]

That sounds good to me!

[andrewnicols]

Maybe we also document more clearly how to run the docker validator image and include it in our Moodle-docker toolchain https://validator.github.io/validator/ Moodle could also run a public validator too but that’s likely to get abused too