Once upon a time, I wrote my bachelors thesis about functional
deployment mechanisms.
I had to evaluate several szenarios where package management and
deployment were relevant. One szenario was to do distributed builds
over several machines.
I told myself: Weee, nix can do this! And with nix, this is actually
save, as you do not have side effects when building!
So I started. I use a cloud to set up four virtual machines where I
wanted to do the build. A fifth machine was used as master to distribute
the builds. All was good.
I created the necessary SSH keys, made sure every machine was reachable
by the master and configured the build in my remotes.conf.
When I started to try to build weechat from source, the build failed. It
failed, telling me
error: unable to start any build; either increase ‘--max-jobs’ or enable distributed builds
And I started to dig around. I digged long and good. But I wasn't able
to find the issue.
I double and triple checked my environment variables, my settings, the
SSH key and everything.
I reached out to fellow Nixers by asking on the nixos IRC channel. And I
got help. But we weren't able to find the issue, either.
So I became frustrated. I re-did all the environment variables.
And suddenly,... it worked! What did I change? Well... I made the
environment variables which contained pathes contain absolute pathes
rather than relatives.
And because I like to share my knowledge, this should be put into the
documentation, so others do not bang their heads against the wall
because something is not documented somewhere.
Docbook XSL got updated to version 1.79.1 in NixOS/nixpkgs@fb893a8 and
we're still referring to the hardcoded previous version.
So instead of just updating this to 1.79.1 we're going to use "current"
in the hope that this won't happen again.
I have tested this by building the manual under Nix(OS) but I haven't
tested this in a non-Nix environment, so I'm not sure whether this could
have implications.
Signed-off-by: aszlig <aszlig@redmoonstudios.org>
Cc: @edolstra
The existing "nix-build" examples were failing:
error: cannot auto-call a function that has an argument without a default value (‘system’)
Thanks to @groxxda on irc for pointing out the fix!
Updated to completely remove unneeded path argument, suggested by @joachifm
Updated to remove other occurences of `all-packages.nix` from files as
suggested by @domenkozar
Some benchmarking suggested this as a good value. Running
$ benchmark -f ... -t 25 -- sh -c 'rm -f /nix/var/nix/binary-cache*; nix-store -r /nix/store/x5z8a2yvz8h6ccmhwrwrp9igg03575jg-nixos-15.09.git.5fd87e1M.drv --dry-run --option binary-caches-parallel-connections <N>'
gave the following mean elapsed times for these values of N:
N=10: 3.3541
N=20: 2.9320
N=25: 2.6690
N=30: 2.9417
N=50: 3.2021
N=100: 3.5718
N=150: 4.2079
Memory usage is also reduced (N=150 used 186 MB, N=25 only 68 MB).
Closes#708.
- rename options but leav old names as lower-priority aliases,
also "-dirs" -> "-paths" to get closer to the meaning
- update docs to reflect the new names (old aliases are not documented),
including a new file with release notes
- tests need an update after corresponding changes to nixpkgs
- __noChroot is left as it is (after discussion on the PR)
Passing "--option build-repeat <N>" will cause every build to be
repeated N times. If the build output differs between any round, the
build is rejected, and the output paths are not registered as
valid. This is primarily useful to verify build determinism. (We
already had a --check option to repeat a previously succeeded
build. However, with --check, non-deterministic builds are registered
in the DB. Preventing that is useful for Hydra to ensure that
non-deterministic builds don't end up getting published at all.)
This allows overriding the name component of the resulting Nix store
path, which is necessary if the base name of the URI contains
"illegal" characters.
This allows nix-prefetch-url to prefetch the output of fetchzip and
its wrappers (like fetchFromGitHub). For example:
$ nix-prefetch-url --unpack https://github.com/NixOS/patchelf/archive/0.8.tar.gz
or from a Nix expression:
$ nix-prefetch-url -A nix-repl.src
In the latter case, --unpack can be omitted because nix-repl.src is a
fetchFromGitHub derivation and thus has "outputHashMode" set to
"recursive".
For example,
$ nix-prefetch-url -A hello.src
will prefetch the file specified by the fetchurl call in the attribute
‘hello.src’ from the Nix expression in the current directory. This
differs from ‘nix-build -A hello.src’ in that it doesn't verify the
hash.
You can also specify a path to the Nix expression:
$ nix-prefetch-url ~/Dev/nixpkgs -A hello.src
List elements (typically used in ‘patches’ attributes) also work:
$ nix-prefetch-url -A portmidi.patches.0
This hook can be used to set system-specific per-derivation build
settings that don't fit into the derivation model and are too complex or
volatile to be hard-coded into nix. Currently, the pre-build hook can
only add chroot dirs/files through the interface, but it also has full
access to the chroot root.
The specific use case for this is systems where the operating system ABI
is more complex than just the kernel-support system calls. For example,
on OS X there is a set of system-provided frameworks that can reliably
be accessed by any program linked to them, no matter the version the
program is running on. Unfortunately, those frameworks do not
necessarily live in the same locations on each version of OS X, nor do
their dependencies, and thus nix needs to know the specific version of
OS X currently running in order to make those frameworks available. The
pre-build hook is a perfect mechanism for doing just that.
This hook can be used to set system specific per-derivation build
settings that don't fit into the derivation model and are too complex or
volatile to be hard-coded into nix. Currently, the pre-build hook can
only add chroot dirs/files.
The specific use case for this is systems where the operating system ABI
is more complex than just the kernel-supported system calls. For
example, on OS X there is a set of system-provided frameworks that can
reliably be accessed by any program linked to them, no matter the
version the program is running on. Unfortunately, those frameworks do
not necessarily live in the same locations on each version of OS X, nor
do their dependencies, and thus nix needs to know the specific version
of OS X currently running in order to make those frameworks available.
The pre-build hook is a perfect mechanism for doing just that.
If ‘build-use-chroot’ is set to ‘true’, fixed-output derivations are
now also chrooted. However, unlike normal derivations, they don't get
a private network namespace, so they can still access the
network. Also, the use of the ‘__noChroot’ derivation attribute is
no longer allowed.
Setting ‘build-use-chroot’ to ‘relaxed’ gives the old behaviour.
If ‘--option restrict-eval true’ is given, the evaluator will throw an
exception if an attempt is made to access any file outside of the Nix
search path. This is primarily intended for Hydra, where we don't want
people doing ‘builtins.readFile ~/.ssh/id_dsa’ or stuff like that.
‘--run’ is like ‘--command’, except that it runs the command in a
non-interactive shell. This is important if you do things like:
$ nix-shell --command make
Hitting Ctrl-C while make is running drops you into the interactive
Nix shell, which is probably not what you want. So you can now do
$ nix-shell --run make
instead.
'... another level of indirection not shown in the figure above ...'
but in the 'user-environments.png' figure there is '~/.nix-profile'.
the figure was updated with the commit: f982df3 on Mar 16, 2005.
Scott Olson
Bob van der Linden