eval_cached event: change interface to traceID\tjobsetID\tevaluationID

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

doc/manual/src/notifications.md

@@ -69,7 +69,7 @@ It is possible for subsequent deliveries of the same `build_finished` data to im
 
 ### `eval_cached`
 
-* **Payload:** Exactly one value: an opaque trace ID representing this evaluation.
+* **Payload:** Exactly three values: an opaque trace ID representing this evaluation, the ID of the jobset, and the ID of the previous identical evaluation.
 * **When:** After the evaluator fetches inputs, if none of the inputs changed.
 * **Delivery Semantics:** Ephemeral. `hydra-notify` must be running to react to this event. No record of this event is stored.
 

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::EvalCached;
 use Hydra::Event::EvalStarted;
 use Hydra::Event::StepFinished;
 
@@ -16,6 +17,7 @@ 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_cached => \&Hydra::Event::EvalCached::parse,
   eval_started => \&Hydra::Event::EvalStarted::parse,
   step_finished => \&Hydra::Event::StepFinished::parse,
 );

src/lib/Hydra/Event/EvalCached.pm

@@ -0,0 +1,63 @@
+package Hydra::Event::EvalCached;
+
+use strict;
+use warnings;
+
+sub parse :prototype(@) {
+    unless (@_ == 3) {
+        die "eval_cached: payload takes exactly three arguments, but ", scalar(@_), " were given";
+    }
+
+    my ($trace_id, $jobset_id, $evaluation_id) = @_;
+
+    unless ($jobset_id =~ /^\d+$/) {
+        die "eval_cached: payload argument jobset_id should be an integer, but '", $jobset_id, "' was given"
+    }
+    unless ($evaluation_id =~ /^\d+$/) {
+        die "eval_cached: payload argument evaluation_id should be an integer, but '", $evaluation_id, "' was given"
+    }
+
+    return Hydra::Event::EvalCached->new($trace_id, int($jobset_id), int($evaluation_id));
+}
+
+sub new {
+    my ($self, $trace_id, $jobset_id, $evaluation_id) = @_;
+    return bless {
+        "trace_id" => $trace_id,
+        "jobset_id" => $jobset_id,
+        "evaluation_id" => $evaluation_id,
+        "jobset" => undef,
+        "evaluation" => undef
+    }, $self;
+}
+
+sub interestedIn {
+    my ($self, $plugin) = @_;
+    return int(defined($plugin->can('evalCached')));
+}
+
+sub load {
+    my ($self, $db) = @_;
+
+    if (!defined($self->{"jobset"})) {
+        $self->{"jobset"} = $db->resultset('Jobsets')->find({ id => $self->{"jobset_id"}})
+            or die "Jobset $self->{'jobset_id'} does not exist\n";
+    }
+
+    if (!defined($self->{"evaluation"})) {
+        $self->{"evaluation"} = $db->resultset('JobsetEvals')->find({ id => $self->{"evaluation_id"}})
+            or die "Jobset $self->{'jobset_id'} does not exist\n";
+    }
+}
+
+sub execute {
+    my ($self, $db, $plugin) = @_;
+
+    $self->load($db);
+
+    $plugin->evalCached($self->{"trace_id"}, $self->{"jobset"}, $self->{"evaluation"});
+
+    return 1;
+}
+
+1;

src/lib/Hydra/Plugin.pm

@@ -37,6 +37,11 @@ sub instantiate {
 #     my ($self, $traceID, $jobset) = @_;
 # }
 
+# # Called when an evaluation of $jobset determined the inputs had not changed.
+# sub evalCached {
+#     my ($self, $traceID, $jobset, $evaluation) = @_;
+# }
+
 # # Called when build $build has been queued.
 # sub buildQueued {
 #     my ($self, $build) = @_;

src/script/hydra-eval-jobset

@@ -670,7 +670,11 @@ sub checkJobsetWrapped {
         Net::Statsd::increment("hydra.evaluator.unchanged_checkouts");
         $db->txn_do(sub {
             $jobset->update({ lastcheckedtime => time, fetcherrormsg => undef });
-            $db->storage->dbh->do("notify eval_cached, ?", undef, join('\t', $tmpId));
+            $db->storage->dbh->do("notify eval_cached, ?", undef, join("\t",
+                $tmpId,
+                $jobset->get_column('id'),
+                $prevEval->get_column('id'))
+            );
         });
         return;
     }

src/script/hydra-notify

@@ -98,10 +98,12 @@ $listener->subscribe("build_queued");
 $listener->subscribe("build_started");
 $listener->subscribe("cached_build_finished");
 $listener->subscribe("cached_build_queued");
+$listener->subscribe("eval_cached");
 $listener->subscribe("eval_started");
 $listener->subscribe("hydra_notify_dump_metrics");
 $listener->subscribe("step_finished");
 
+
 # Process builds that finished while hydra-notify wasn't running.
 for my $build ($db->resultset('Builds')->search(
                    { notificationpendingsince => { '!=', undef } }))

t/Hydra/Event/EvalCached.t

@@ -0,0 +1,112 @@
+use strict;
+use warnings;
+use Setup;
+use Hydra::Event;
+use Hydra::Event::EvalCached;
+use Test2::V0;
+use Test2::Tools::Exception;
+use Test2::Tools::Mock qw(mock_obj);
+
+
+my $ctx = test_context();
+my $builds = $ctx->makeAndEvaluateJobset(
+    expression => "basic.nix",
+    build => 1
+);
+
+
+subtest "Parsing eval_cached" => sub {
+    like(
+        dies { Hydra::Event::parse_payload("eval_cached", "") },
+        qr/three arguments/,
+        "empty payload"
+    );
+    like(
+        dies { Hydra::Event::parse_payload("eval_cached", "abc123") },
+        qr/three arguments/,
+        "one argument"
+    );
+    like(
+        dies { Hydra::Event::parse_payload("eval_cached", "abc123\tabc123") },
+        qr/three arguments/,
+        "two arguments"
+    );
+    like(
+        dies { Hydra::Event::parse_payload("eval_cached", "abc123\tabc123\tabc123\tabc123") },
+        qr/three arguments/,
+        "four arguments"
+    );
+    like(
+        dies { Hydra::Event::parse_payload("eval_cached", "abc123\tabc123\t123") },
+        qr/should be an integer/,
+        "not an integer: second position"
+    );
+    like(
+        dies { Hydra::Event::parse_payload("eval_cached", "abc123\t123\tabc123") },
+        qr/should be an integer/,
+        "not an integer: third position"
+    );
+    is(
+        Hydra::Event::parse_payload("eval_cached", "abc123\t123\t456"),
+        Hydra::Event::EvalCached->new("abc123", 123, 456)
+    );
+};
+
+subtest "interested" => sub {
+    my $event = Hydra::Event::EvalCached->new("abc123", 123, 456);
+
+    subtest "A plugin which does not implement the API" => sub {
+        my $plugin = {};
+        my $mock = mock_obj $plugin => ();
+
+        is($event->interestedIn($plugin), 0, "The plugin is not interesting.");
+    };
+
+    subtest "A plugin which does implement the API" => sub {
+        my $plugin = {};
+        my $mock = mock_obj $plugin => (
+            add => [
+                "evalCached" => sub {}
+            ]
+        );
+
+        is($event->interestedIn($plugin), 1, "The plugin is interesting.");
+    };
+};
+
+subtest "load" => sub {
+    my $jobset = $builds->{"empty_dir"}->jobset;
+    my $evaluation = $builds->{"empty_dir"}->jobsetevals->first();
+
+    my $event = Hydra::Event::EvalCached->new("traceID", $jobset->id, $evaluation->id);
+
+    $event->load($ctx->db());
+    is($event->{"trace_id"}, "traceID", "The Trace ID matches");
+    is($event->{"jobset_id"}, $jobset->id, "The Jobset ID matches");
+    is($event->{"evaluation_id"}, $evaluation->id, "The Evaluation ID matches");
+
+
+    # Create a fake "plugin" with a evalCached sub, the sub sets these
+    # "globals"
+    my $passedTraceID;
+    my $passedJobset;
+    my $passedEvaluation;
+    my $plugin = {};
+    my $mock = mock_obj $plugin => (
+        add => [
+            "evalCached" => sub {
+                my ($self, $traceID, $jobset, $evaluation) = @_;
+                $passedTraceID = $traceID;
+                $passedJobset = $jobset;
+                $passedEvaluation = $evaluation;
+            }
+        ]
+    );
+
+    $event->execute($ctx->db(), $plugin);
+    is($passedTraceID, "traceID", "We get the expected trace ID");
+    is($passedJobset->id, $jobset->id, "The correct jobset is passed");
+    is($passedEvaluation->id, $evaluation->id, "The correct evaluation is passed");
+};
+
+done_testing;

t/scripts/hydra-eval-jobset/notifications.t

@@ -55,6 +55,7 @@ my $builds = $ctx->makeAndEvaluateJobset(
     build => 0
 );
 my $jobset = $builds->{"stable-job-queued"}->jobset;
+my $evaluation = $builds->{"stable-job-queued"}->jobsetevals->first();
 
 subtest "on the initial evaluation" => sub {
     expectEvent($listener, "eval_started", sub {
@@ -72,9 +73,21 @@ subtest "on the initial evaluation" => sub {
 };
 
 subtest "on a subsequent, totally cached / unchanged evaluation" => sub {
-    ok(evalSucceeds($builds->{"variable-job"}->jobset), "evaluating for the second time");
-    is($listener->block_for_messages(0)->()->{"channel"}, "eval_started", "an evaluation has started");
-    is($listener->block_for_messages(0)->()->{"channel"}, "eval_cached", "the evaluation finished and nothing changed");
+    ok(evalSucceeds($jobset), "evaluating for the second time");
+
+    my $traceID;
+    expectEvent($listener, "eval_started", sub {
+        isnt($_->{"trace_id"}, "", "We got a trace ID");
+        $traceID = $_->{"trace_id"};
+        is($_->{"jobset_id"}, $jobset->get_column('id'), "the jobset ID matches");
+    });
+
+    expectEvent($listener, "eval_cached", sub {
+        is($_->{"trace_id"}, $traceID, "Trace ID matches");
+        is($_->{"jobset_id"}, $jobset->get_column('id'), "the jobset ID matches");
+        is($_->{"evaluation_id"}, $evaluation->get_column('id'), "the evaluation ID matches");
+    });
+
     is($listener->block_for_messages(0)->(), undef, "there are no more messages from the evaluator");
 };