Add slack plugin.

Respects <slack> blocks in the hydra config, with attributes:

* jobs: a regexp matching the job name (in the format project:jobset:job)
* url: The URL to a slack incoming webhook
* force: If true, always send messages. Otherwise, only when the build status changes

Multiple <slack> blocks are allowed

hydra-module.nix

@@ -20,6 +20,7 @@ let
     { NIX_REMOTE = "daemon";
       SSL_CERT_FILE = "/etc/ssl/certs/ca-certificates.crt";
       OPENSSL_X509_CERT_FILE = "/etc/ssl/certs/ca-certificates.crt"; # FIXME: remove on NixOS >= 15.07
+      PERL_LWP_SSL_CA_FILE = "/etc/ssl/certs/ca-certificates.crt";
       PGPASSFILE = "${baseDir}/pgpass";
     } // hydraEnv // cfg.extraEnv;
 

src/lib/Hydra/Plugin/SlackNotification.pm

@@ -0,0 +1,93 @@
+package Hydra::Plugin::SlackNotification;
+
+use strict;
+use parent 'Hydra::Plugin';
+use HTTP::Request;
+use LWP::UserAgent;
+use Hydra::Helper::CatalystUtils;
+use JSON;
+
+sub buildFinished {
+    my ($self, $build, $dependents) = @_;
+    my $cfg = $self->{config}->{slack};
+    my @config = defined $cfg ? ref $cfg eq "ARRAY" ? @$cfg : ($cfg) : ();
+
+    my $baseurl = $self->{config}->{'base_uri'} || "http://localhost:3000";
+
+    # Figure out to which channelss to send notification.  For each channel
+    # we send one aggregate message.
+    my %channels;
+    foreach my $b ($build, @{$dependents}) {
+        my $prevBuild = getPreviousBuild($b);
+        my $jobName = showJobName $b;
+
+        foreach my $channel (@config) {
+            my $force = $channel->{force};
+            next unless $jobName =~ /^$channel->{jobs}$/;
+
+            # If build is cancelled or aborted, do not send email.
+            next if ! $force && ($b->buildstatus == 4 || $b->buildstatus == 3);
+
+            # If there is a previous (that is not cancelled or aborted) build
+            # with same buildstatus, do not send email.
+            next if ! $force && defined $prevBuild && ($b->buildstatus == $prevBuild->buildstatus);
+
+            $channels{$channel->{url}} //= { channel => $channel, builds => [] };
+            push @{$channels{$channel->{url}}->{builds}}, $b;
+        }
+    }
+
+    return if scalar keys %channels == 0;
+
+    my ($authors, $nrCommits) = getResponsibleAuthors($build, $self->{plugins});
+
+    # Send a message to each room.
+    foreach my $url (keys %channels) {
+        my $channel = $channels{$url};
+        my @deps = grep { $_->id != $build->id } @{$channel->{builds}};
+
+        my $imgBase = "http://hydra.nixos.org";
+        my $img =
+            $build->buildstatus == 0 ? "$imgBase/static/images/checkmark_16.png" :
+            $build->buildstatus == 2 ? "$imgBase/static/images/dependency_16.png" :
+            $build->buildstatus == 4 ? "$imgBase/static/images/cancelled_16.png" :
+            "$imgBase/static/images/error_16.png";
+
+        my $color =
+            $build->buildstatus == 0 ? "good" :
+            $build->buildstatus == 4 ? "warning" :
+            "danger";
+
+        my $text = "";
+        $text .= "Job <$baseurl/job/${\$build->project->name}/${\$build->jobset->name}/${\$build->job->name}|${\showJobName($build)}>";
+        $text .= " (and ${\scalar @deps} others)" if scalar @deps > 0;
+        $text .= ": <$baseurl/build/${\$build->id}|" . showStatus($build) . ">";
+
+        if (scalar keys %{$authors} > 0) {
+            # FIXME: escaping
+            my @x = map { "<mailto:$authors->{$_}|$_>" } (sort keys %{$authors});
+            $text .= ", likely due to ";
+            $text .= "$nrCommits commits by " if $nrCommits > 1;
+            $text .= join(" or ", scalar @x > 1 ? join(", ", @x[0..scalar @x - 2]) : (), $x[-1]);
+        }
+
+        my $msg =
+        { attachments =>
+          [{ fallback => "Job " . showJobName($build) . " build number " . $build->id . ": " . showStatus($build),
+            text => $text,
+            thumb_url => $img,
+            color => $color,
+            title => "Job " . showJobName($build) . " build number " . $build->id,
+            title_link => "$baseurl/build/${\$build->id}"
+          }]
+        };
+
+        my $req = HTTP::Request->new('POST', $url);
+        $req->header('Content-Type' => 'application/json');
+        $req->content(encode_json($msg));
+        my $ua = LWP::UserAgent->new();
+        $ua->request($req);
+    }
+}
+
+1;