Buildbot now building Python modules

[Ryan Schmidt]

In the interest of getting more packages built on our "new" builders, without trying to build all ports just yet, I started builds of all the Python modules we hadn't built yet on the 10.12_x86_64, 10.7_x86_64_legacy, 10.6_i386_legacy and 10.5_ppc_legacy builders.

Since each Python module port has subports, and since we start a separate build for each subport now, over 3000 builds have been scheduled on each builder. Just listing the subports to schedule the builds took 25 minutes. Triggering the >3000 builds made the web interface unresponsive for several minutes, during which time I got a "502 Bad Gateway" error from Nginx. I'm not sure what we can optimize here, but we should optimize whatever we can to make this go faster and to be less disruptive, before we try a build of all 21,325 ports. We also still need to bring over the "successcache" from the old macports-autobuild, so that we don't trigger builds of ports that have already been built; this should be easy; Josh already pointed out the relevant script we need to bring over.

Email notifications are turned on now so if you maintain a python module or a port it depends on, and it fails to build, you'll get an email about it. Thanks to Mojca for making the email notifications possible again. The email notifications are still a bit noisy (and this 3000-port build may produce an extremely noisy email...)--we intend to refine them further to make it easier to see what ports failed and to get to their logs--but we wanted to turn email notifications on now so that you at least get some sort of notification when a build fails. It may take the builders a day or several days to get through all these builds, so it may be awhile before you see the huge notification email, though you may get smaller emails about other builds from the other builders in the mean time.

-Ryan