fix(logging): Support numbers when unmarshaling Severity (#4216)

* fix(logging): Support numbers when unmarshaling Severity

logging.Entry.Severity is written out as a JSON number during
Marshalling but has an UnmarshalJSON method that only supports Severity
as as string.

This commit adds support to unmarshal JSON numbers in addition to
strings so Marshalling then Unmarshalling the same object works without
error

* Run go fmt

logging/logging.go

@@ -464,10 +464,14 @@ func (v Severity) String() string {
 // Severity.
 func (v *Severity) UnmarshalJSON(data []byte) error {
 	var s string
-	if err := json.Unmarshal(data, &s); err != nil {
-		return err
+	var i int
+	if strErr := json.Unmarshal(data, &s); strErr == nil {
+		*v = ParseSeverity(s)
+	} else if intErr := json.Unmarshal(data, &i); intErr == nil {
+		*v = Severity(i)
+	} else {
+		return fmt.Errorf("%v; %v", strErr, intErr)
 	}
-	*v = ParseSeverity(s)
 	return nil
 }
 

logging/logging_test.go

@@ -806,3 +806,34 @@ func TestSeverityUnmarshal(t *testing.T) {
 		t.Fatalf("Severity: got %v, want %v", entry.Severity, logging.Error)
 	}
 }
+
+func TestSeverityAsNumberUnmarshal(t *testing.T) {
+	j := []byte(fmt.Sprintf(`{"logName": "test-log","severity": %d, "payload": "test"}`, logging.Info))
+	var entry logging.Entry
+	err := json.Unmarshal(j, &entry)
+	if err != nil {
+		t.Fatalf("en.Unmarshal: %v", err)
+	}
+	if entry.Severity != logging.Info {
+		t.Fatalf("Severity: got %v, want %v", entry.Severity, logging.Info)
+	}
+}
+
+func TestSeverityMarshalThenUnmarshal(t *testing.T) {
+	entry := logging.Entry{Severity: logging.Warning, Payload: "test"}
+	j, err := json.Marshal(entry)
+	if err != nil {
+		t.Fatalf("en.Marshal: %v", err)
+	}
+
+	var entryU logging.Entry
+
+	err = json.Unmarshal(j, &entryU)
+	if err != nil {
+		t.Fatalf("en.Unmarshal: %v", err)
+	}
+
+	if entryU.Severity != logging.Warning {
+		t.Fatalf("Severity: got %v, want %v", entryU.Severity, logging.Warning)
+	}
+}