‘guix weather’ reports CI stats

[ludo@gnu.org (Ludovic Courtès)]

Hello Guix!

With commit 183445a6ed1cbac929ecb65303246945c8ccf39d, ‘guix weather’ can
now report continuous integration (CI) stats using the Hydra/Cuirass
HTTP interface:

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guix weather --substitute-urls='https://berlin.guixsd.org https://hydra.gnu.org' -m ~/src/configuration/user-profile.scm
computing 352 package derivations for x86_64-linux...
looking for 421 store items on https://berlin.guixsd.org...
https://berlin.guixsd.org
  76.7% substitutes available (323 out of 421)
  753.4 MiB of nars (compressed)
  1,805.7 MiB on disk (uncompressed)
  0.000 seconds per request (0.2 seconds in total)
  2,740.3 requests per second

  0.0% (0 out of 98) of the missing items are queued
  965 queued builds
      aarch64-linux: 965 (100.0%)
  build rate: 23.41 builds per hour
      x86_64-linux: 11.16 builds per hour
      i686-linux: 6.03 builds per hour
      aarch64-linux: 6.41 builds per hour
looking for 421 store items on https://hydra.gnu.org...
https://hydra.gnu.org
  96.7% substitutes available (407 out of 421)
  1,296.8 MiB of nars (compressed)
  3,158.4 MiB on disk (uncompressed)
  0.001 seconds per request (0.5 seconds in total)
  808.5 requests per second

  867 queued builds
      x86_64-linux: 518 (59.7%)
      i686-linux: 221 (25.5%)
      armhf-linux: 128 (14.8%)
  build rate: 20.93 builds per hour
      i686-linux: 9.23 builds per hour
      armhf-linux: 8.75 builds per hour
      x86_64-linux: 2.95 builds per hour
--8<---------------cut here---------------end--------------->8---

In a way, this adds a forecasting capability to ‘guix weather’.

In this example we can also see that /api/queue?nr=10 returns
non-sensical data in the current Cuirass snapshot (the actual queue
contains lots of builds, and not only for aarch64!).

The build rates are also interesting and surprising.  On hydra, the low
x86_64 build rate is probably because x86_64 builds completed earlier,
so nothing happened lately.  On berlin, we have 20 Intel machines and
only 1 aarch64 machine, yet the Intel build rate is not 20 times that of
aarch64; I’m guessing we could do better.  :-)

Comments welcome!

Ludo’.