Builtbot: Don't keep huge ports installed

[ryandesign (Ryan Carsten Schmidt)]

Our buildbot setup currently keeps all built ports installed on each worker. This is supposed to speed up builds so that we don't waste time constantly downloading and installing ports that are dependencies of a lot of other ports.

But there are also some inordinately large ports, such as some games, which aren't commonly used as dependencies. Here are some of the larger ports installed on the highsierra buildbot worker:

$ cd /opt/local/var/macports/software
$ du -sch alienarena-data/* geant*-data/* knp/* supertuxkart/* texlive-{fonts,latex}-extra/* typesafe-activator/* wesnoth/*
551M	alienarena-data/alienarena-data-7.66-20130827_0.darwin_17.noarch.tbz2
427M	geant4.10.0-data/geant4.10.0-data-4.10.0_0.darwin_17.noarch.tbz2
428M	geant4.10.1-data/geant4.10.1-data-4.10.1_0.darwin_17.noarch.tbz2
432M	geant4.10.2-data/geant4.10.2-data-4.10.2_1.darwin_17.noarch.tbz2
1005M	geant4.10.3-data/geant4.10.3-data-4.10.3_0.darwin_17.noarch.tbz2
1.1G	geant4.10.4-data/geant4.10.4-data-4.10.4_0.darwin_17.noarch.tbz2
266M	geant4.9.6-data/geant4.9.6-data-4.9.6_0.darwin_17.noarch.tbz2
1.0G	knp/knp-4.14_0.darwin_17.x86_64.tbz2
512M	supertuxkart/supertuxkart-0.9.3_0.darwin_17.x86_64.tbz2
534M	texlive-fonts-extra/texlive-fonts-extra-47288_0+doc.darwin_17.noarch.tbz2
453M	texlive-latex-extra/texlive-latex-extra-47410_0+doc.darwin_17.noarch.tbz2
663M	typesafe-activator/typesafe-activator-1.3.12_0.darwin_17.noarch.tbz2
365M	wesnoth/wesnoth-1.12.6_2.darwin_17.x86_64.tbz2
7.7G	total

It's getting to the point where builds are failing because there's not enough free disk space, and I am manually uninstalling some of these ports on the buildbot workers to free up space. If we could have mpbb automatically uninstall large ports, it would free up a good deal of disk space.

I'm not sure what do about dependencies. For example, geant4.10.4 is not large, but it depends on geant4.10.4-data which is.

Do we force the uninstallation of the large ports, leaving the ports depending on them broken, on the assumption that when the buildbot asks to install them again it will reinstall the dependencies and fix them?

Or do we have the buildbot uninstall not only the large ports but also all ports depending on them? That might be ok for geant, but would be bad for texlive-latex-extra, on which lots of things depend. We could base the decision of whether to uninstall on how many ports would be uninstalled. (If it's, say, 5 or fewer ports, uninstall them, otherwise leave them installed.)

Or do we instead make a general rule (not based on size) that we don't keep a port installed if nothing depends on it?

Some of these ports might not be distributable. Once we have nondistributable archives available on a private server that won't be a big problem anymore. We can wait until we resolve that ticket before deploying an implementation for this one.

[mojca (Mojca Miklavec)]

Just a short note. I'm a maintainer of geant4 and the data files are nothing else but "fetch that gigabyte of data & extract it". There's basically no penalty in building them (there are no build steps) and the files are exactly the same for all OS versions. After you bought this up ... maybe I should also add some restrictive licence just for the sake of decreasing the space we use on our mirror for binaries. This wouldn't solve the issue with storing them on the builder, but it would at least help a tiny tiny bit somewhere else. I would be totally in favour of simply always deleting geant4 data files from the builders, even if I'm not sure about the best way. If you run some kind of a cleanup job ... simply put the geant-data files uncoditionally there.

The only dependent port (Gate) is broken as I'm stuck in the upgrade process (the last few times when I tried it failed to build and I didn't spend enough time trying to come up with a proper fix; that said, I'm not aware of anyone else offering Gate as a dmg, so it would be cool to fix it rather than deleting it).

[mojca (Mojca Miklavec)]

Btw: a rule that says "uninstall the port unless something depends on it" won't help you a tiny bit in case of Geant since:

• geant4.x depends on geant4.x-data
• gate depends on geant4.x

So in case of geant: feel free to delete both (times different versions of geant, so probably 12 ports). We should keep geant4.x on the binary package server, but it does absolutely nothing useful on the builder. I may also remove the older versions one day.

[ryandesign (Ryan Carsten Schmidt)]

Replying to mojca:

Btw: a rule that says "uninstall the port unless something depends on it" won't help you a tiny bit in case of Geant

I understand, I'm just trying to come up with multiple ideas for saving space on the workers. One idea is to uninstall huge ports. Another idea is to uninstall ports that nothing in MacPorts depends on. I'm not sure which would save more space. We could implement one or the other or both. We're already saving some space by using hfsCompression on the tools prefix. We could save a bit more space by using it on the main prefix as well, though that would probably impact performance.

What would be a good way to identify whether anything in MacPorts depends on a port? I would want "anything" to include ports that are not yet installed. Do we do something like this?

port=wine-crossover
if [ -z "$(/opt/local/bin/port echo depends:":$port(\s|$)")" ]; then
    echo uninstall it
fi