fix: preserve ReleaseSet rollback and readiness budget

cmd/supervisor/main.go

@@ -45,7 +45,7 @@ func main() {
 		fatal(err)
 	}
 
-	s := &server{lifeboat: lifeboat, stableUpstream: stable, candidate: candidate, client: &http.Client{Timeout: 5 * time.Second}}
+	s := &server{lifeboat: lifeboat, stableUpstream: stable, candidate: candidate, client: &http.Client{Timeout: 30 * time.Second}}
 	public := http.NewServeMux()
 	public.HandleFunc("GET /healthz", s.health)
 	public.HandleFunc("GET /readyz", s.ready)

runtime/supervisor/supervisor.go

@@ -193,6 +193,11 @@ func (l *Lifeboat) PromoteSet() bool {
 	if l.CandidateReleaseSet == nil || l.Current.State != ReleaseHealthy {
 		return false
 	}
+	if l.StableReleaseSet != nil {
+		previous := *l.StableReleaseSet
+		l.RollbackTargetReleaseSet = &previous
+		l.RollbackTarget = l.LastKnownGood
+	}
 	set := *l.CandidateReleaseSet
 	l.StableReleaseSet = &set
 	l.LastKnownGoodReleaseSet = &set
@@ -202,7 +207,6 @@ func (l *Lifeboat) PromoteSet() bool {
 	l.Current.Set = &set
 	l.Current.LastKnownGood = true
 	l.CandidateReleaseSet = nil
-	l.RollbackTargetReleaseSet = nil
 	return l.setSetUpstreams(&set, nil)
 }
 

runtime/supervisor/supervisor_test.go

@@ -139,3 +139,22 @@ func TestPersistentReleaseSetRollbackPreservesWholeLastKnownGood(t *testing.T) {
 		t.Fatalf("state=%+v", state)
 	}
 }
+
+func TestReleaseSetPromotionRetainsPreviousStableForRollback(t *testing.T) {
+	good := testReleaseSet("stable-r1", "r1", "http://web", "http://core", "http://cognitive", "http://research")
+	candidate := testReleaseSet("candidate-r2", "r2", "http://web-c", "http://core-c", "http://cognitive-c", "http://research-c")
+	l := supervisor.Lifeboat{}
+	if !l.EstablishBaselineSet(good) || !l.StartSet(candidate) {
+		t.Fatal("release set setup failed")
+	}
+	observation := supervisor.ReleaseSetObservation{ReleaseID: candidate.ID, Ready: true, Components: map[string]supervisor.ComponentObservation{}}
+	for name := range candidate.Components {
+		observation.Components[name] = supervisor.ComponentObservation{Revision: candidate.Revision, Health: true, Ready: true}
+	}
+	if !l.RecordSet(observation) || !l.PromoteSet() {
+		t.Fatal("promotion failed")
+	}
+	if l.RollbackTargetReleaseSet == nil || l.RollbackTargetReleaseSet.Revision != "r1" {
+		t.Fatalf("rollback target=%+v", l.RollbackTargetReleaseSet)
+	}
+}