Fix config being overwritten by olric init when manually embedding an…

…d defining Config

lib/nats.go

@@ -154,9 +154,24 @@ func (n *NatsDiscovery) Initialize() error {
 	opts.ReconnectWait = 2 * time.Second
 	opts.MaxReconnect = -1 // Keep trying forever
 
-	conn, err := opts.Connect()
-	if err != nil {
-		return fmt.Errorf("nats server connection failure: %w", err)
+	var (
+		conn *nats.Conn
+		err error
+	)
+	const N = 3
+	for i := 1;;i++ {
+		conn, err = opts.Connect()
+		if err != nil {
+			if i <= N {
+				n.log.Printf("[WARN] nats server connection failure %d/%d; " +
+					"retrying in %s", i, N, opts.ReconnectWait)
+				time.Sleep(opts.ReconnectWait)
+				continue
+			}
+			return fmt.Errorf("nats server connection failure: %w", err)
+		}
+		break
+
 	}
 
 	enc, err := nats.NewEncodedConn(conn, nats.JSON_ENCODER)
@@ -170,7 +185,13 @@ func (n *NatsDiscovery) Initialize() error {
 
 // SetConfig registers plugin configuration
 func (n *NatsDiscovery) SetConfig(c MapConfig) error {
-	var cfg Config
+	if n.Config == nil {
+		n.Config = &Config{}
+	}
+
+	if len(c) == 0 {
+		return nil
+	}
 
 	dec, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{
 		DecodeHook: func(src, tgt reflect.Type, val interface{}) (interface{}, error) {
@@ -182,17 +203,12 @@ func (n *NatsDiscovery) SetConfig(c MapConfig) error {
 			}
 			return time.ParseDuration(val.(string))
 		},
-		Result: &cfg,
+		Result: n.Config,
 	})
 	if err != nil {
 		return err
 	}
-
-	if err = dec.Decode(c); err != nil {
-		return err
-	}
-	n.Config = &cfg
-	return nil
+	return dec.Decode(c)
 }
 
 // SetLogger sets a custom logger instance

lib/nats_test.go

@@ -177,6 +177,28 @@ func TestInitialize(t *testing.T) {
 				expectTimeout, sd.Config.DiscoveryTimeout)
 		}
 	})
+
+	t.Run("config reset", func(t *testing.T) {
+		expect := "addr:1234"
+		sd := NatsDiscovery{Config: &Config{Url: expect}}
+		if err := sd.SetConfig(MapConfig{}); err != nil {
+			t.Fatal(err)
+		}
+		if sd.Config.Url != expect {
+			t.Fatalf("expected %q, got %q", expect, sd.Config.Url)
+		}
+
+		if err := sd.SetConfig(MapConfig{"subject": "foo"}); err != nil {
+			t.Fatal(err)
+		}
+		if sd.Config.Url != expect {
+			t.Fatalf("expected %q, got %q", expect, sd.Config.Url)
+		}
+		expect = "foo"
+		if sd.Config.Subject != expect {
+			t.Fatalf("expectec %q, got %q", expect, sd.Config.Subject)
+		}
+	})
 }
 
 func TestDiscover(t *testing.T) {