From 7f38087f35e6f74a73bfdb28da8acd8930565d51 Mon Sep 17 00:00:00 2001 From: Eelco Dolstra Date: Mon, 19 Mar 2012 04:14:21 +0100 Subject: [PATCH] Add a command "nix-build --run-env" to reproduce the environment of a derivation This command builds or fetches all dependencies of the given derivation, then starts a shell with the environment variables from the derivation. This shell also sources $stdenv/setup to initialise the environment further. The current directory is not changed. Thus this is a convenient way to reproduce a build environment in an existing working tree. Existing environment variables are left untouched (unless the derivation overrides them). As a special hack, the original value of $PATH is appended to the $PATH produced by $stdenv/setup. Example session: $ nix-build --run-env '' -A xterm (the dependencies of xterm are built/fetched...) $ tar xf $src $ ./configure $ make $ emacs (... hack source ...) $ make $ ./xterm --- perl/lib/Nix/Store.pm | 1 + perl/lib/Nix/Store.xs | 42 ++++++++++++++++++++++++++++++++++++++++++ scripts/nix-build.in | 29 +++++++++++++++++++++++++++++ 3 files changed, 72 insertions(+) diff --git a/perl/lib/Nix/Store.pm b/perl/lib/Nix/Store.pm index 4283e77a4..1ae3b04b7 100644 --- a/perl/lib/Nix/Store.pm +++ b/perl/lib/Nix/Store.pm @@ -16,6 +16,7 @@ our @EXPORT = qw( topoSortPaths computeFSClosure followLinksToStorePath exportPaths hashPath hashFile hashString addToStore makeFixedOutputPath + derivationFromPath ); our $VERSION = '0.15'; diff --git a/perl/lib/Nix/Store.xs b/perl/lib/Nix/Store.xs index f8a577fce..8ca72b62a 100644 --- a/perl/lib/Nix/Store.xs +++ b/perl/lib/Nix/Store.xs @@ -216,3 +216,45 @@ SV * makeFixedOutputPath(int recursive, char * algo, char * hash, char * name) } catch (Error & e) { croak(e.what()); } + + +SV * derivationFromPath(char * drvPath) + PREINIT: + HV *hash; + CODE: + try { + doInit(); + Derivation drv = derivationFromPath(*store, drvPath); + hash = newHV(); + + /* TODO: handle drv.outputs */ + + AV * inputDrvs = newAV(); + for (DerivationInputs::iterator i = drv.inputDrvs.begin(); i != drv.inputDrvs.end(); ++i) + av_push(inputDrvs, newSVpv(i->first.c_str(), 0)); // !!! ignores i->second + hv_stores(hash, "inputDrvs", newRV((SV *) inputDrvs)); + + AV * inputSrcs = newAV(); + for (PathSet::iterator i = drv.inputSrcs.begin(); i != drv.inputSrcs.end(); ++i) + av_push(inputSrcs, newSVpv(i->c_str(), 0)); + hv_stores(hash, "inputSrcs", newRV((SV *) inputSrcs)); + + hv_stores(hash, "platform", newSVpv(drv.platform.c_str(), 0)); + hv_stores(hash, "builder", newSVpv(drv.builder.c_str(), 0)); + + AV * args = newAV(); + for (Strings::iterator i = drv.args.begin(); i != drv.args.end(); ++i) + av_push(args, newSVpv(i->c_str(), 0)); + hv_stores(hash, "args", newRV((SV *) args)); + + HV * env = newHV(); + for (StringPairs::iterator i = drv.env.begin(); i != drv.env.end(); ++i) + hv_store(env, i->first.c_str(), i->first.size(), newSVpv(i->second.c_str(), 0), 0); + hv_stores(hash, "env", newRV((SV *) env)); + + RETVAL = newRV_noinc((SV *)hash); + } catch (Error & e) { + croak(e.what()); + } + OUTPUT: + RETVAL diff --git a/scripts/nix-build.in b/scripts/nix-build.in index 5cbcd1139..b36ec0208 100755 --- a/scripts/nix-build.in +++ b/scripts/nix-build.in @@ -2,11 +2,13 @@ use strict; use Nix::Config; +use Nix::Store; use File::Temp qw(tempdir); my $dryRun = 0; my $verbose = 0; +my $runEnv = 0; my @instArgs = (); my @buildArgs = (); @@ -119,6 +121,10 @@ EOF push @instArgs, $arg; } + elsif ($arg eq "--run-env") { + $runEnv = 1; + } + elsif (substr($arg, 0, 1) eq "-") { push @buildArgs, $arg; } @@ -143,6 +149,29 @@ foreach my $expr (@exprs) { exit 1; } + if ($runEnv) { + die "$0: ‘--run-env’ requires a single derivation\n" if scalar @drvPaths != 1; + my $drvPath = readlink $drvPaths[0] or die "cannot read symlink `$drvPaths[0]'"; + my $drv = derivationFromPath($drvPath); + + # Build or fetch all dependencies of the derivation. + system("$Nix::Config::binDir/nix-store -r @buildArgs @{$drv->{inputDrvs}} @{$drv->{inputSrcs}} > /dev/null") == 0 + or die "$0: failed to build all dependencies\n"; + + # Set the environment. + $ENV{'NIX_BUILD_TOP'} = $ENV{'TMPDIR'} || "/tmp"; + foreach (keys %{$drv->{env}}) { + $ENV{$_} = $drv->{env}->{$_}; + } + + # Run a shell using the derivation's environment. For + # convenience, source $stdenv/setup to setup additional + # environment variables. Also don't lose the current $PATH + # directories. + exec($ENV{SHELL}, "-c", "p=\$PATH; source \$stdenv/setup; PATH=\$PATH:\$p; exec $ENV{SHELL}"); + die; + } + foreach my $drvPath (@drvPaths) { my $target = readlink $drvPath or die "cannot read symlink `$drvPath'"; print STDERR "derivation is $target\n" if $verbose;