Perform manual failover during the scale down

pkg/util/patroni/patroni.go

@@ -41,7 +41,7 @@ func New(logger *logrus.Entry) *Patroni {
 	}
 }
 
-func (p *Patroni) apiURL(masterPod *v1.Pod) string {
+func apiURL(masterPod *v1.Pod) string {
 	return fmt.Sprintf("http://%s:%d", masterPod.Status.PodIP, apiPort)
 }
 
@@ -54,7 +54,7 @@ func (p *Patroni) Failover(master *v1.Pod, candidate string) error {
 		return fmt.Errorf("could not encode json: %v", err)
 	}
 
-	request, err := http.NewRequest(http.MethodPost, p.apiURL(master)+failoverPath, buf)
+	request, err := http.NewRequest(http.MethodPost, apiURL(master)+failoverPath, buf)
 	if err != nil {
 		return fmt.Errorf("could not create request: %v", err)
 	}
@@ -77,4 +77,4 @@ func (p *Patroni) Failover(master *v1.Pod, candidate string) error {
 	}
 
 	return nil
-}
+}

pkg/util/util.go

@@ -103,3 +103,19 @@ func FindNamedStringSubmatch(r *regexp.Regexp, s string) map[string]string {
 
 	return res
 }
+
+// MapContains returns true if and only if haystack contains all the keys from the needle with matching corresponding values
+func MapContains(haystack, needle map[string]string) bool {
+	if len(haystack) < len(needle) {
+		return false
+	}
+
+	for k, v := range needle {
+		v2, ok := haystack[k]
+		if !ok || v2 != v {
+			return false
+		}
+	}
+
+	return true
+}

pkg/util/util_test.go

@@ -46,6 +46,18 @@ var substractTest = []struct {
 	{[]string{"a", "b", "c", "d"}, []string{"a", "bb", "c", "d"}, []string{"b"}, false},
 }
 
+var mapContaintsTest = []struct {
+	inA map[string]string
+	inB map[string]string
+	out bool
+}{
+	{map[string]string{"1": "a", "2": "b", "3": "c", "4": "c"}, map[string]string{"1": "a", "2": "b", "3": "c"}, true},
+	{map[string]string{"1": "a", "2": "b", "3": "c", "4": "c"}, map[string]string{"1": "a", "2": "b", "3": "d"}, false},
+	{map[string]string{}, map[string]string{}, true},
+	{map[string]string{"3": "c", "4": "c"}, map[string]string{"1": "a", "2": "b", "3": "c"}, false},
+	{map[string]string{"3": "c", "4": "c"}, map[string]string{}, true},
+}
+
 var substringMatch = []struct {
 	inRegex *regexp.Regexp
 	inStr   string
@@ -122,3 +134,12 @@ func TestFindNamedStringSubmatch(t *testing.T) {
 		}
 	}
 }
+
+func TestMapContains(t *testing.T) {
+	for _, tt := range mapContaintsTest {
+		res := MapContains(tt.inA, tt.inB)
+		if res != tt.out {
+			t.Errorf("MapContains expected: %#v, got: %#v", tt.out, res)
+		}
+	}
+}