Allow Hydra's binary cache to be signed

Dependencies

• [2] IDT3SO3P Generate *.narinfo files on the fly to support the binary cache substituter

Change contents

• edit in src/lib/Hydra/View/NARInfo.pm at line 7
  [2.778]

  [2.778]
  + use Nix::Crypto;
• edit in src/lib/Hydra/View/NARInfo.pm at line 31
  [2.1654]

  [2.1654]
  + }

  +

  + # Optionally, sign the NAR info file we just created.

  + my $privateKeyFile = $c->config->{binary_cache_private_key_file};

  + my $keyName = $c->config->{binary_cache_key_name};

  +

  + if (defined $privateKeyFile && defined $keyName) {

  + my $sig = signString($privateKeyFile, $info);

  + $info .= "Signature: 1;$keyName;$sig\n";