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* Channels. These allow you to stay current with an evolving set of

Browse source 
Nix expressions.

  To subscribe to a channel (needs to be done only once):

    nix-channel --add \
      http://catamaran.labs.cs.uu.nl/dist/nix/channels/nixpkgs-unstable

  This just adds the given URL to ~/.nix-channels (which can also be
  edited manually).

  To update from all channels:

    nix-channel --update

  This fetches the latest expressions and pulls cache manifests.  The
  default Nix expression (~/.nix-defexpr) is made to point to the
  conjunction of the expressions downloaded from all channels.

  So to update all installed derivations in the current user
  environment:

    nix-channel --update
    nix-env --upgrade '*'

  If you are really courageous, you can put this in a cronjob or
  something.

  You can subscribe to multiple channels.  It is not entirely clear
  what happens when there are name clashes between derivations from
  different channels.  From nix-env/main.cc it appears that the one
  with the lowest (highest?) hash will be used, which is pretty
  meaningless.
This commit is contained in:
Eelco Dolstra 2004-04-21 14:54:05 +00:00
parent f79e9c2d22
commit 21655a70f5
10 changed files with 194 additions and 52 deletions
Download patch file Download diff file Expand all files Collapse all files

115
scripts/nix-channel.in Executable file
View file

@ -0,0 +1,115 @@
#! @perl@ -w
use strict;
# Figure out the name of the `.nix-channels' file to use.
my $home = $ENV{"HOME"};
die '$HOME not set' unless defined $home;
my $channelsList = "$home/.nix-channels";
my @channels;
# Reads the list of channels from the file $channelsList;
sub readChannels {
return if (!-f $channelsList);
open CHANNELS, "<$channelsList" or die "cannot open `$channelsList'";
while (<CHANNELS>) {
chomp;
push @channels, $_;
}
close CHANNELS;
}
# Writes the list of channels to the file $channelsList;
sub writeChannels {
open CHANNELS, ">$channelsList" or die "cannot open `$channelsList'";
foreach my $url (@channels) {
print CHANNELS "$url\n";
}
close CHANNELS;
}
# Adds a channel to the file $channelsList;
sub addChannel {
my $url = shift;
readChannels;
foreach my $url2 (@channels) {
return if $url eq $url2;
}
push @channels, $url;
writeChannels;
}
# Fetch Nix expressions and pull cache manifests from the subscribed
# channels.
sub update {
readChannels;
# Pull cache manifests.
foreach my $url (@channels) {
print "pulling cache manifest from `$url'\n";
system "@bindir@/nix-pull '$url'/MANIFEST";
die "cannot pull cache manifest from `$url'" if ($? != 0);
}
# Create a Nix expression that fetches and unpacks the channel Nix
# expressions.
my $nixExpr = "[";
foreach my $url (@channels) {
my $fullURL = "$url/nixexprs.tar.bz2";
my $hash = `@bindir@/nix-prefetch-url '$fullURL' 2> /dev/null`
or die "cannot fetch `$fullURL'";
chomp $hash;
# !!! escaping
$nixExpr .= "((import @datadir@/nix/corepkgs/fetchurl) " .
"{url = $fullURL; md5 = \"$hash\"; system = \"@system@\";}) "
}
$nixExpr .= "]";
$nixExpr =
"(import @datadir@/nix/corepkgs/channels/unpack.nix) " .
"{inputs = $nixExpr; system = \"@system@\";}";
# Instantiate and realise it.
my $storeExpr = `echo '$nixExpr' | @bindir@/nix-instantiate -`
or die "cannot instantiate Nix expression";
chomp $storeExpr;
my $outPath = `nix-store -qnfB '$storeExpr'`
or die "cannot realise store expression";
chomp $outPath;
# Make it the default Nix expression for `nix-env'.
system "@bindir@/nix-env --import '$outPath'";
die "cannot pull set default Nix expression to `$outPath'" if ($? != 0);
}
while (scalar @ARGV) {
my $arg = shift @ARGV;
if ($arg eq "--add") {
die "syntax: nix-channel --add URL" if (scalar @ARGV != 1);
addChannel (shift @ARGV);
last;
}
elsif ($arg eq "--update") {
die "syntax: nix-channel --update" if (scalar @ARGV != 0);
update;
last;
}
else {
die "unknown argument `$arg'";
}
}