Add jobs API option "follow" to return latest clone of queried job

Ticket: https://progress.opensuse.org/issues/175305

lib/OpenQA/WebAPI/Controller/API/V1/Job.pm

@@ -453,9 +453,25 @@ sub show ($self) {
     my $job_id = int($self->stash('jobid'));
     my $details = $self->stash('details') || 0;
     my $check_assets = !!$self->param('check_assets');
-    my $job = $self->schema->resultset('Jobs')->find($job_id, {prefetch => 'settings'});
-    return $self->reply->not_found unless $job;
+    my $follow = $self->param('follow');    # follow job clones and report most recent result for given id
+
+    my @cloned_as;
+    my $job;
+    while (1) {
+        return unless $job = $self->find_job_or_render_not_found($job_id, {prefetch => 'settings'});
+        if ($follow && $job->clone_id) {
+            push(@cloned_as, $job->clone_id);
+            $job_id = $job->clone_id;
+            next;
+        }
+        last;
+    }
     $job = $job->to_hash(assets => 1, check_assets => $check_assets, deps => 1, details => $details, parent_group => 1);
+    if ($job_id != $self->stash('jobid')) {
+        # if follow=1 return cloned job with original id
+        # but indicate clone chain in cloned_as
+        $job->{cloned_as} = \@cloned_as;
+    }
     $self->render(json => {job => $job});
 }
 
@@ -597,9 +613,28 @@ interested in the status.
 =cut
 
 sub get_status ($self) {
+    my $follow = $self->param('follow');    # follow job clones and report most recent result for given id
     my @fields = qw(id state result blocked_by_id);
-    return unless my $job = $self->find_job_or_render_not_found($self->stash('jobid'));
-    $self->render(json => {map { $_ => $job->$_ } @fields});
+    my $query_jobid = $self->stash('jobid');
+    my @cloned_as;
+    my $job;
+    while (1) {
+        return unless $job = $self->find_job_or_render_not_found($query_jobid);
+        if ($follow && $job->clone_id) {
+            push(@cloned_as, $job->clone_id);
+            $query_jobid = $job->clone_id;
+            next;
+        }
+        last;
+    }
+    my $json = {map { $_ => $job->$_ } @fields};
+    if ($query_jobid != $self->stash('jobid')) {
+        # if follow=1 return cloned job with original id
+        # but indicate clone chain in cloned_as
+        $json->{id} = $self->stash('jobid');
+        $json->{cloned_as} = \@cloned_as;
+    }
+    $self->render(json => $json);
 }
 
 =over 4

lib/OpenQA/WebAPI/Plugin/Helpers.pm

@@ -522,10 +522,8 @@ sub _param_hash ($c, $name) {
     return @$values ? {map { $_ => 1 } @$values} : undef;
 }
 
-sub _find_job_or_render_not_found {
-    my ($c, $job_id) = @_;
-
-    my $job = $c->schema->resultset('Jobs')->find(int($job_id));
+sub _find_job_or_render_not_found ($c, $job_id, $query_settings = {}) {
+    my $job = $c->schema->resultset('Jobs')->find(int($job_id), $query_settings);
     return $job if $job;
     $c->render(json => {error => 'Job does not exist'}, status => 404);
     return undef;