Initialize Hound package / module

[grahamc]

Motivation for this change

https://search.nix.gsc.io is powered by Hound, and I figured it couldn't hurt to upstream the code for it.

Things done

• Tested using sandboxing
  (nix.useSandbox on NixOS,
  or option build-use-sandbox in nix.conf
  on non-NixOS)
• Built on platform(s)
  • NixOS
  • OS X
  • Linux
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Fits CONTRIBUTING.md.

---

[mention-bot]

@grahamc, thanks for your PR! By analyzing the history of the files in this pull request, we identified @edolstra, @joachifm and @offlinehacker to be potential reviewers.

[joachifm]

What sort of data does hound generate? Is it not sufficient to ensure eventually consistent ownership via preStart or similar mechanisms?

[grahamc]

I'm really not sold on using preStart's to chmod a bunch of data. One of my hound installs has 700GB of owned data. I definitely don't want to be running chmod during a restart.

[Mic92]

sounds reasonable.

[Mic92]

obsolete.

[Mic92]

this adds a new line per start.
I would prefer the following instead:

ExecStartPre = "${pkgs.git}/bin/git config --global --replace-all http.sslCAinfo /etc/ssl/certs/ca-certificates.crt";

[Mic92]

I think Hound Code Search is enough. On startup it will then show:

Started Hound Code Search.

[Mic92]

what is the use case for this option?

[Mic92]

Last but not least the test should be also added to release.nix:

diff --git a/nixos/release.nix b/nixos/release.nix
index 10c624a..fbd3efd 100644
--- a/nixos/release.nix
+++ b/nixos/release.nix
@@ -245,6 +245,7 @@ in rec {
   tests.gnome3-gdm = callTest tests/gnome3-gdm.nix {};
   tests.grsecurity = callTest tests/grsecurity.nix {};
   tests.hibernate = callTest tests/hibernate.nix {};
+  tests.hound = callTest tests/hound.nix {};
   tests.i3wm = callTest tests/i3wm.nix {};
   tests.installer = callSubTests tests/installer.nix {};
   tests.influxdb = callTest tests/influxdb.nix {};

[grahamc]

@Mic92 I addressed the feedback, other than adding it to the release. I don't really want it to block the tested job. Will this?

[Mic92]

@grahamc well, otherwise this tests is never evaluated by hydra. What do you mean by block?

[grahamc]

Fixed. :) Thanks for the review!

[ttuegel]

This breaks nixos-rebuild with

Option `services.hound.config' has no description.

even for configurations that don't have Hound enabled.

[grahamc]

D'oh, thank you for the heads up. Curious that it errors there, but didn't error in my local usage. Preparing a fix.

[grahamc]

Fixed up. Sorry about that. Is this a new check not in 16.09? I've used this module in 16.09.

[bjornfor]

$ nix-env -f . -qa '*' --meta --xml --drv-path --show-trace
[...]
error: while querying the derivation named ‘go1.7-hound-unstable-20160919-f95e9a9’:
attribute ‘homepage’ missing, at /home/bfo/proj/code/forks/nixpkgs3/pkgs/development/tools/misc/hound/default.nix:19:28

[grahamc]

@bjornfor guh, sorry. 😳

I fixed hound in 104d696

and in testing found another PR broke it as well, which I fixed in 33ac1e1 (/cc @Profpatsch, @Mic92 to learn what I just learned, too :) )

is this the best way to find these sorts of errors in the future?

This seems like a really good test to have in Travis-CI -- which shouldn't be so hard to run as to fail regularly.

[bjornfor]

I'm surprised travis doesn't run that check. I have put that command in a script, for my own use. It catches a lot of those eval issues:

$ cat ~/bin/nix-check-before-push.sh 
#!/bin/sh
# This checks for evaluation errors in nixpkgs (and nixos?) git repositories.
# Run it before commit/push.

set -x
nix-env -f . -qa \* --meta --xml --drv-path --show-trace >/dev/null || { echo FAILED; exit 1; }
nix-build pkgs/top-level/release.nix -A tarball || { echo FAILED; exit 1; }