forked from lix-project/lix
![Eelco Dolstra](/assets/img/avatar_default.png)
* Add `--help' flag; fixes NIX-5. * Add `--remove' flag; fixes NIX-6. * Add `--list' flag.
175 lines
4 KiB
Plaintext
175 lines
4 KiB
Plaintext
#! @perl@ -w
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use strict;
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my $rootsDir = "@localstatedir@/nix/gcroots/channels";
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# Figure out the name of the `.nix-channels' file to use.
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my $home = $ENV{"HOME"};
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die '$HOME not set' unless defined $home;
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my $channelsList = "$home/.nix-channels";
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my @channels;
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# Reads the list of channels from the file $channelsList;
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sub readChannels {
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return if (!-f $channelsList);
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open CHANNELS, "<$channelsList" or die "cannot open `$channelsList': $!";
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while (<CHANNELS>) {
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chomp;
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push @channels, $_;
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}
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close CHANNELS;
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}
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# Writes the list of channels to the file $channelsList;
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sub writeChannels {
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open CHANNELS, ">$channelsList" or die "cannot open `$channelsList': $!";
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foreach my $url (@channels) {
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print CHANNELS "$url\n";
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}
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close CHANNELS;
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}
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# Adds a channel to the file $channelsList;
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sub addChannel {
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my $url = shift;
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readChannels;
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foreach my $url2 (@channels) {
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return if $url eq $url2;
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}
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push @channels, $url;
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writeChannels;
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}
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# Remove a channel from the file $channelsList;
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sub removeChannel {
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my $url = shift;
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my @left = ();
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readChannels;
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foreach my $url2 (@channels) {
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push @left, $url2 if $url ne $url2;
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}
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@channels = @left;
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writeChannels;
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}
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# Fetch Nix expressions and pull cache manifests from the subscribed
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# channels.
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sub update {
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readChannels;
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# Get rid of all the old substitutes.
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system "@bindir@/nix-store --clear-substitutes";
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die "cannot clear substitutes" if ($? != 0);
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# Pull cache manifests.
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foreach my $url (@channels) {
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print "pulling cache manifest from `$url'\n";
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system "@bindir@/nix-pull '$url'/MANIFEST";
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die "cannot pull cache manifest from `$url'" if ($? != 0);
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}
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# Create a Nix expression that fetches and unpacks the channel Nix
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# expressions.
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my $nixExpr = "[";
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foreach my $url (@channels) {
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my $fullURL = "$url/nixexprs.tar.bz2";
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my $hash = `@bindir@/nix-prefetch-url '$fullURL' 2> /dev/null`
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or die "cannot fetch `$fullURL'";
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chomp $hash;
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# !!! escaping
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$nixExpr .= "((import @datadir@/nix/corepkgs/fetchurl) " .
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"{url = $fullURL; sha1 = \"$hash\"; system = \"@system@\";}) "
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}
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$nixExpr .= "]";
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$nixExpr =
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"(import @datadir@/nix/corepkgs/channels/unpack.nix) " .
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"{inputs = $nixExpr; system = \"@system@\";}";
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# Figure out a name for the GC root.
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my $userName = getpwuid($<);
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die "who ARE you? go away" unless defined $userName;
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my $rootFile = "$rootsDir/$userName";
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# Instantiate the Nix expression.
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my $storeExpr = `echo '$nixExpr' | @bindir@/nix-instantiate --add-root '$rootFile'.tmp -`
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or die "cannot instantiate Nix expression";
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chomp $storeExpr;
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# Build the resulting derivation.
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my $outPath = `nix-store --add-root '$rootFile' -r '$storeExpr'`
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or die "cannot realise store expression";
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chomp $outPath;
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unlink "$rootFile.tmp";
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# Make it the default Nix expression for `nix-env'.
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system "@bindir@/nix-env --import '$outPath'";
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die "cannot pull set default Nix expression to `$outPath'" if ($? != 0);
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}
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sub usageError {
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print STDERR <<EOF;
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Usage:
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nix-channel --add URL
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nix-channel --remove URL
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nix-channel --list
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nix-channel --update
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EOF
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exit 1;
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}
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while (scalar @ARGV) {
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my $arg = shift @ARGV;
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if ($arg eq "--add") {
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usageError if scalar @ARGV != 1;
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addChannel (shift @ARGV);
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last;
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}
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if ($arg eq "--remove") {
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usageError if scalar @ARGV != 1;
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removeChannel (shift @ARGV);
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last;
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}
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if ($arg eq "--list") {
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usageError if scalar @ARGV != 0;
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readChannels;
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foreach my $url (@channels) {
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print "$url\n";
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}
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last;
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}
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elsif ($arg eq "--update") {
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usageError if scalar @ARGV != 0;
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update;
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last;
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}
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elsif ($arg eq "--help") {
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usageError;
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}
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else {
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die "unknown argument `$arg'; try `--help'";
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}
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}
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