Hook in commit flag to /readyz

http/service.go

@@ -76,6 +76,10 @@ type Store interface {
 	// Ready returns whether the Store is ready to service requests.
 	Ready() bool
 
+	// Committed blocks until the local commit index is greater than or
+	// equal to the Leader index, as checked when the function is called.
+	Committed(timeout time.Duration) (uint64, error)
+
 	// Stats returns stats on the Store.
 	Stats() (map[string]interface{}, error)
 
@@ -1003,8 +1007,17 @@ func (s *Service) handleReadyz(w http.ResponseWriter, r *http.Request, qp QueryP
 		return
 	}
 
+	okMsg := "[+]node ok\n[+]leader ok\n[+]store ok"
+	if qp.Commit() {
+		if _, err := s.store.Committed(qp.Timeout(defaultTimeout)); err != nil {
+			w.WriteHeader(http.StatusServiceUnavailable)
+			w.Write([]byte(fmt.Sprintf("[+]node ok\n[+]leader ok\n[+]store ok\n[+]commit %s", err.Error())))
+			return
+		}
+		okMsg += "\n[+]commit ok"
+	}
 	w.WriteHeader(http.StatusOK)
-	w.Write([]byte("[+]node ok\n[+]leader ok\n[+]store ok"))
+	w.Write([]byte(okMsg))
 }
 
 func (s *Service) handleExecute(w http.ResponseWriter, r *http.Request, qp QueryParams) {

http/service_test.go

@@ -1419,6 +1419,10 @@ func (m *MockStore) Ready() bool {
 	return !m.notReady
 }
 
+func (m *MockStore) Committed(timeout time.Duration) (uint64, error) {
+	return 0, nil
+}
+
 func (m *MockStore) Stats() (map[string]interface{}, error) {
 	return nil, nil
 }

store/store.go

@@ -633,6 +633,17 @@ func (s *Store) Ready() bool {
 	}()
 }
 
+// Committed blocks until the local commit index is greater than or
+// equal to the Leader index, as checked when the function is called.
+// It returns the committed index.
+func (s *Store) Committed(timeout time.Duration) (uint64, error) {
+	lci, err := s.LeaderCommitIndex()
+	if err != nil {
+		return lci, err
+	}
+	return lci, s.WaitForCommitIndex(lci, timeout)
+}
+
 // Close closes the store. If wait is true, waits for a graceful shutdown.
 func (s *Store) Close(wait bool) (retErr error) {
 	defer func() {