Setup Gentoo+Meson CI

[DarthGandalf]

The goal was to add a CI with Meson, and without access to internet, because Gentoo emerge runs tests in sandbox, skipping tests which are explicitly marked as online.
But on github-hosted runners, there's no good way to disable network, emulate that by emptying resolv.conf

With such workaround the "Gentoo" part is not really relevant anymore, the same meson+resolv.conf can be done in Ubuntu. But this does increase coverage a bit, so why not.

[yhirose]

I made #2358 which handles the offline test with openssl, mbedtls, no_tls on ubuntu.

[DarthGandalf]

Do I understand correctly that you just filtered which tests to run?

The point here is to ensure that tests which require network, all have the suffix. I don't see you disabling network in any way?

[yhirose]

You’re right. I forgot to disable the network. Do you notice any missing pieces? Thanks!

      - name: disable network
        run: sudo sh -c 'echo > /etc/resolv.conf'

[DarthGandalf]

I suppose that should work, thanks. Not sure what's the value of the matrix [openssl, mbedtls, no-tls] though: if the purpose of the test is to check names of tests, running one of them should probably be enough; the rest is just subset of tests running in the other ubuntu CI

What about having meson in one of jobs? That one would benefit from a matrix actually

[yhirose]

There are non _Online tests for both CPPHTTPLIB_SSL_ENABLED and when CPPHTTPLIB_SSL_ENABLED is not defined. So we need to test with both no-tls and either openssl or mbedtls. Since mbedtls was just introduced and openssl is more widely used, I'll stick with openssl and no-tls. Thanks for your insight!

[yhirose]

The only issue is that this test_offline adds 10 more minutes to the GitHub CI. The CI tests already take quite a long time, so I'm wondering if it's really worth including this check in this way. If there's a more efficient approach, I'd prefer to use that instead.