config: fix JSON unmarshaling for HostPort (#2134)

Signed-off-by: Simon Pasquier <spasquie@redhat.com>

client/client_test.go

@@ -90,9 +90,18 @@ func TestAPI(t *testing.T) {
 	client := &fakeAPIClient{T: t, ch: make(chan fakeAPIResponse, 1)}
 	now := time.Now()
 
+	u, err := url.Parse("http://example.com")
+	if err != nil {
+		t.Errorf("unexpected error: %v", err)
+	}
 	statusData := &ServerStatus{
 		ConfigYAML: "{}",
-		ConfigJSON:    &config.Config{},
+		ConfigJSON: &config.Config{
+			Global: &config.GlobalConfig{
+				PagerdutyURL:  &config.URL{URL: u},
+				SMTPSmarthost: config.HostPort{Host: "localhost", Port: "25"},
+			},
+		},
 		VersionInfo:   map[string]string{"version": "v1"},
 		Uptime:        now,
 		ClusterStatus: &ClusterStatus{Peers: []PeerStatus{}},

config/config.go

@@ -516,6 +516,28 @@ func (hp *HostPort) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	return nil
 }
 
+// UnmarshalJSON implements the json.Unmarshaler interface for HostPort.
+func (hp *HostPort) UnmarshalJSON(data []byte) error {
+	var (
+		s   string
+		err error
+	)
+	if err = json.Unmarshal(data, &s); err != nil {
+		return err
+	}
+	if s == "" {
+		return nil
+	}
+	hp.Host, hp.Port, err = net.SplitHostPort(s)
+	if err != nil {
+		return err
+	}
+	if hp.Port == "" {
+		return errors.Errorf("address %q: port cannot be empty", s)
+	}
+	return nil
+}
+
 // MarshalYAML implements the yaml.Marshaler interface for HostPort.
 func (hp HostPort) MarshalYAML() (interface{}, error) {
 	return hp.String(), nil