A reproduce script includes a logline that may resemble:
> using these flags: --arg nixpkgs { outPath = /tmp/build-137689173/nixpkgs/source; rev = "fdc872fa200a32456f12cc849d33b1fdbd6a933c"; shortRev = "fdc872f"; revCount = 273100; } -I nixpkgs=/tmp/build-137689173/nixpkgs/source --arg officialRelease false --option extra-binary-caches https://hydra.nixos.org/ --option system x86_64-linux /tmp/build-137689173/nixpkgs/source/pkgs/top-level/release.nix -A
These are passed along to nix-build and that's fine and dandy, but you can't just copy-paste this as is, as the `{}` introduces a syntax error and the value accompanying `-A` is `''`.
A very naive approach is to just `printf "%q"` the individual args, which makes them safe to copy-paste. Unfortunately, this looks awful due to the liberal usage of slashes:
```
$ printf "%q" '{ outPath = /tmp/build-137689173/nixpkgs/source; rev = "fdc872fa200a32456f12cc849d33b1fdbd6a933c"; shortRev = "fdc872f"; revCount = 273100; }'
\{\ outPath\ =\ /tmp/build-137689173/nixpkgs/source\;\ rev\ =\ \"fdc872fa200a32456f12cc849d33b1fdbd6a933c\"\;\ shortRev\ =\ \"fdc872f\"\;\ revCount\ =\ 273100\;\ \}
```
Alternatively, if we just use `set -x` before we execute nix-build, we'll get the whole invocation in a friendly, copy-pastable format that nicely displays `{}`-enclosed content and preserves the empty arg following `-A`:
```
running nix-build...
using this invocation:
+ nix-build --arg nixpkgs '{ outPath = /tmp/build-138165173/nixpkgs/source; rev = "e0e4484f2c028d2269f5ebad0660a51bbe46caa4"; shortRev = "e0e4484"; revCount = 274008; }' -I nixpkgs=/tmp/build-138165173/nixpkgs/source --arg officialRelease false --option extra-binary-caches https://hydra.nixos.org/ --option system x86_64-linux /tmp/build-138165173/nixpkgs/source/pkgs/top-level/release.nix -A ''
```
Duplicating this data on every record of the builds table cost
approximately 4G of duplication.
Note that the database migration included took about 4h45m on an
untuned server which uses very slow rotational disks in a RAID5 setup,
with not a lot of RAM. I imagine in production it might take an hour
or two, but not 4. If this should become a chunked migration, I can do
that.
Note: Because of the question about chunked migrations, I have NOT
YET tested this migration thoroughly enough for merge.
For some reason, hg clone from a local (path-based) repo will fail if
the parent directory of the destination directory doesn't exist (though
it succeeds when cloning from an http repo).
Signed-off-by: Shea Levy <shea@shealevy.com>
The revision counting changes depending on which revision is cloned
initially, so clone the default branch first and then checkout the
required revision to match hydra's revCount.
Signed-off-by: Shea Levy <shea@shealevy.com>
You can now do:
bash <(curl http://hydra-server/build/1238757/reproduce)
to download and execute a script that reproduces a Hydra build
locally. This script fetches all inputs (e.g. Git repositories) and
then invokes nix-build.
The downloaded sources are stored in /tmp/build-<buildid> and reused
between invocations of the script.
Any additional command line options are passed to nix-build. So
bash <(curl http://hydra-server/build/1238757/reproduce) --run-env
will drop you in a shell where you can interactively hack on the
build, e.g.
$ source $stdenv/setup
$ set +e
$ unpackPhase
$ cd $sourceRoot
$ configurePhase
$ emacs foo.c &
$ make
and so on.
