eval_started event: change interface to traceID\tjobsetID

I was not going to break the interface until I noticed
the current implementation uses the string literal \t.

src/lib/Hydra/Event.pm

@@ -7,6 +7,7 @@ use Hydra::Event::BuildQueued;
 use Hydra::Event::BuildStarted;
 use Hydra::Event::CachedBuildFinished;
 use Hydra::Event::CachedBuildQueued;
+use Hydra::Event::EvalStarted;
 use Hydra::Event::StepFinished;
 
 my %channels_to_events = (
@@ -15,6 +16,7 @@ my %channels_to_events = (
   build_started => \&Hydra::Event::BuildStarted::parse,
   cached_build_finished => \&Hydra::Event::CachedBuildFinished::parse,
   cached_build_queued => \&Hydra::Event::CachedBuildQueued::parse,
+  eval_started => \&Hydra::Event::EvalStarted::parse,
   step_finished => \&Hydra::Event::StepFinished::parse,
 );
 

src/lib/Hydra/Event/EvalStarted.pm

@@ -0,0 +1,53 @@
+package Hydra::Event::EvalStarted;
+
+use strict;
+use warnings;
+
+sub parse :prototype(@) {
+    unless (@_ == 2) {
+        die "eval_started: payload takes two arguments, but ", scalar(@_), " were given";
+    }
+
+    my ($trace_id, $jobset_id) = @_;
+
+    unless ($jobset_id =~ /^\d+$/) {
+        die "eval_started: payload argument should be an integer, but '", $jobset_id, "' was given"
+    }
+
+    return Hydra::Event::EvalStarted->new($trace_id, int($jobset_id));
+}
+
+sub new {
+    my ($self, $trace_id, $jobset_id) = @_;
+    return bless {
+        "trace_id" => $trace_id,
+        "jobset_id" => $jobset_id,
+        "jobset" => undef
+    }, $self;
+}
+
+sub interestedIn {
+    my ($self, $plugin) = @_;
+    return int(defined($plugin->can('evalStarted')));
+}
+
+sub load {
+    my ($self, $db) = @_;
+
+    if (!defined($self->{"jobset"})) {
+        $self->{"jobset"} = $db->resultset('Jobsets')->find({ id => $self->{"jobset_id"}})
+            or die "Jobset $self->{'jobset_id'} does not exist\n";
+    }
+}
+
+sub execute {
+    my ($self, $db, $plugin) = @_;
+
+    $self->load($db);
+
+    $plugin->evalStarted($self->{"trace_id"}, $self->{"jobset"});
+
+    return 1;
+}
+
+1;

src/lib/Hydra/Plugin.pm

@@ -31,6 +31,12 @@ sub instantiate {
 # See the tests in t/Event/*.t for arguments, and the documentation for
 # notify events for semantics.
 #
+
+# # Called when an evaluation of $jobset has begun.
+# sub evalStarted {
+#     my ($self, $traceID, $jobset) = @_;
+# }
+
 # # Called when build $build has been queued.
 # sub buildQueued {
 #     my ($self, $build) = @_;

src/script/hydra-eval-jobset

@@ -861,7 +861,7 @@ sub checkJobset {
     my $tmpId = "${startTime}.$$";
 
     $db->storage->dbh->do("notify eval_started, ?", undef,
-                          join('\t', $tmpId, $jobset->get_column('project'), $jobset->name));
+                          join("\t", $tmpId, $jobset->get_column('id')));
 
     eval {
         checkJobsetWrapped($jobset, $tmpId);

src/script/hydra-notify

@@ -98,6 +98,7 @@ $listener->subscribe("build_queued");
 $listener->subscribe("build_started");
 $listener->subscribe("cached_build_finished");
 $listener->subscribe("cached_build_queued");
+$listener->subscribe("eval_started");
 $listener->subscribe("hydra_notify_dump_metrics");
 $listener->subscribe("step_finished");