nix-fallback-paths.pl

#! /usr/bin/env nix-shell
#! nix-shell -i perl -p perl perlPackages.LWPUserAgent perlPackages.LWPProtocolHttps

use strict;
use JSON::PP;
use LWP::UserAgent;

my $evalId = $ARGV[0] or die "Usage: $0 EVAL-ID\n";

sub fetch {
    my ($url, $type) = @_;

    my $ua = LWP::UserAgent->new;
    $ua->default_header('Accept', $type) if defined $type;

    my $response = $ua->get($url);
    die "could not download $url: ", $response->status_line, "\n" unless $response->is_success;

    return $response->decoded_content;
}

my $evalUrl = "https://hydra.nixos.org/eval/$evalId";

sub getStorePath {
    my ($jobName) = @_;
    my $buildInfo = decode_json(fetch("$evalUrl/job/$jobName", 'application/json'));
    return $buildInfo->{buildoutputs}->{out}->{path} or die "cannot get store path for '$jobName'";
}

print("{\n" .
      "  x86_64-linux = \"" . getStorePath("build.x86_64-linux") . "\";\n" .
      "  i686-linux = \"" . getStorePath("build.i686-linux") . "\";\n" .
      "  aarch64-linux = \"" . getStorePath("build.aarch64-linux") . "\";\n" .
      "  x86_64-darwin = \"" . getStorePath("build.x86_64-darwin") . "\";\n" .
      "  aarch64-darwin = \"" . getStorePath("build.aarch64-darwin") . "\";\n" .
      "}\n");