etcd: add support for user specified ports for testing

channeldb/kvdb/backend.go

@@ -253,7 +253,7 @@ func GetTestBackend(path, name string) (Backend, func(), error) {
 		}
 		return db, empty, nil
 	} else if TestBackend == EtcdBackendName {
-		return GetEtcdTestBackend(path, name)
+		return GetEtcdTestBackend(path, 0, 0)
 	}
 
 	return nil, nil, fmt.Errorf("unknown backend")

channeldb/kvdb/config.go

@@ -36,7 +36,11 @@ type BoltConfig struct {
 
 // EtcdConfig holds etcd configuration.
 type EtcdConfig struct {
-	Embedded bool `long:"embedded" description:"Use embedded etcd instance instead of the external one."`
+	Embedded bool `long:"embedded" description:"Use embedded etcd instance instead of the external one. Note: use for testing only."`
+
+	EmbeddedClientPort uint16 `long:"embedded_client_port" description:"Client port to use for the embedded instance. Note: use for testing only."`
+
+	EmbeddedPeerPort uint16 `long:"embedded_peer_port" description:"Peer port to use for the embedded instance. Note: use for testing only."`
 
 	Host string `long:"host" description:"Etcd database host."`
 

channeldb/kvdb/etcd/embed.go

@@ -61,7 +61,9 @@ func getFreePort() int {
 // NewEmbeddedEtcdInstance creates an embedded etcd instance for testing,
 // listening on random open ports. Returns the backend config and a cleanup
 // func that will stop the etcd instance.
-func NewEmbeddedEtcdInstance(path string) (*BackendConfig, func(), error) {
+func NewEmbeddedEtcdInstance(path string, clientPort, peerPort uint16) (
+	*BackendConfig, func(), error) {
+
 	cfg := embed.NewConfig()
 	cfg.Dir = path
 
@@ -69,9 +71,17 @@ func NewEmbeddedEtcdInstance(path string) (*BackendConfig, func(), error) {
 	cfg.MaxTxnOps = 8192
 	cfg.MaxRequestBytes = 16384 * 1024
 
-	// Listen on random free ports.
-	clientURL := fmt.Sprintf("127.0.0.1:%d", getFreePort())
-	peerURL := fmt.Sprintf("127.0.0.1:%d", getFreePort())
+	// Listen on random free ports if no ports were specified.
+	if clientPort == 0 {
+		clientPort = uint16(getFreePort())
+	}
+
+	if peerPort == 0 {
+		peerPort = uint16(getFreePort())
+	}
+
+	clientURL := fmt.Sprintf("127.0.0.1:%d", clientPort)
+	peerURL := fmt.Sprintf("127.0.0.1:%d", peerPort)
 	cfg.LCUrls = []url.URL{{Host: clientURL}}
 	cfg.LPUrls = []url.URL{{Host: peerURL}}
 

channeldb/kvdb/etcd/fixture_test.go

@@ -32,7 +32,7 @@ type EtcdTestFixture struct {
 func NewTestEtcdInstance(t *testing.T, path string) (*BackendConfig, func()) {
 	t.Helper()
 
-	config, cleanup, err := NewEmbeddedEtcdInstance(path)
+	config, cleanup, err := NewEmbeddedEtcdInstance(path, 0, 0)
 	if err != nil {
 		t.Fatalf("error while staring embedded etcd instance: %v", err)
 	}

channeldb/kvdb/kvdb_etcd.go

@@ -37,10 +37,14 @@ func GetEtcdBackend(ctx context.Context, prefix string,
 
 // GetEtcdTestBackend creates an embedded etcd backend for testing
 // storig the database at the passed path.
-func GetEtcdTestBackend(path, name string) (Backend, func(), error) {
+func GetEtcdTestBackend(path string, clientPort, peerPort uint16) (
+	Backend, func(), error) {
+
 	empty := func() {}
 
-	config, cleanup, err := etcd.NewEmbeddedEtcdInstance(path)
+	config, cleanup, err := etcd.NewEmbeddedEtcdInstance(
+		path, clientPort, peerPort,
+	)
 	if err != nil {
 		return nil, empty, err
 	}

channeldb/kvdb/kvdb_no_etcd.go

@@ -22,6 +22,8 @@ func GetEtcdBackend(ctx context.Context, prefix string,
 
 // GetTestEtcdBackend  is a stub returning nil, an empty closure and an
 // errEtcdNotAvailable error.
-func GetEtcdTestBackend(path, name string) (Backend, func(), error) {
+func GetEtcdTestBackend(path string, clientPort, peerPort uint16) (
+	Backend, func(), error) {
+
 	return nil, func() {}, errEtcdNotAvailable
 }

lncfg/db.go

@@ -83,10 +83,15 @@ func (db *DB) GetBackends(ctx context.Context, dbPath string,
 
 	if db.Backend == EtcdBackend {
 		if db.Etcd.Embedded {
-			remoteDB, _, err = kvdb.GetEtcdTestBackend(dbPath, dbName)
+			remoteDB, _, err = kvdb.GetEtcdTestBackend(
+				dbPath, db.Etcd.EmbeddedClientPort,
+				db.Etcd.EmbeddedPeerPort,
+			)
 		} else {
 			// Prefix will separate key/values in the db.
-			remoteDB, err = kvdb.GetEtcdBackend(ctx, networkName, db.Etcd)
+			remoteDB, err = kvdb.GetEtcdBackend(
+				ctx, networkName, db.Etcd,
+			)
 		}
 		if err != nil {
 			return nil, err

sample-lnd.conf

@@ -984,6 +984,12 @@ litecoin.node=ltcd
 ; Useful for testing.
 ; db.etcd.embedded=false
 
+; If non zero, LND will use this as client port for the embedded etcd instance.
+; db.etcd.embedded_client_port=1234
+
+; If non zero, LND will use this as peer port for the embedded etcd instance.
+; db.etcd.embedded_peer_port=1235
+
 [bolt]
 ; If true, prevents the database from syncing its freelist to disk. 
 ; db.bolt.nofreelistsync=1