ringhash: the balancer (#4741)

xds/internal/balancer/ringhash/logging.go

@@ -0,0 +1,34 @@
+/*
+ *
+ * Copyright 2021 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package ringhash
+
+import (
+	"fmt"
+
+	"google.golang.org/grpc/grpclog"
+	internalgrpclog "google.golang.org/grpc/internal/grpclog"
+)
+
+const prefix = "[ring-hash-lb %p] "
+
+var logger = grpclog.Component("xds")
+
+func prefixLogger(p *ringhashBalancer) *internalgrpclog.PrefixLogger {
+	return internalgrpclog.NewPrefixLogger(logger, fmt.Sprintf(prefix, p))
+}

xds/internal/balancer/ringhash/picker.go

@@ -24,11 +24,17 @@ import (
 	"google.golang.org/grpc/balancer"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/connectivity"
+	"google.golang.org/grpc/internal/grpclog"
 	"google.golang.org/grpc/status"
 )
 
 type picker struct {
-	ring *ring
+	ring   *ring
+	logger *grpclog.PrefixLogger
+}
+
+func newPicker(ring *ring, logger *grpclog.PrefixLogger) *picker {
+	return &picker{ring: ring, logger: logger}
 }
 
 // handleRICSResult is the return type of handleRICS. It's needed to wrap the
@@ -47,7 +53,7 @@ type handleRICSResult struct {
 // The first return value indicates if the state is in Ready, Idle, Connecting
 // or Shutdown. If it's true, the PickResult and error should be returned from
 // Pick() as is.
-func handleRICS(e *ringEntry) (handleRICSResult, bool) {
+func (p *picker) handleRICS(e *ringEntry) (handleRICSResult, bool) {
 	switch state := e.sc.effectiveState(); state {
 	case connectivity.Ready:
 		return handleRICSResult{pr: balancer.PickResult{SubConn: e.sc.sc}}, true
@@ -67,15 +73,14 @@ func handleRICS(e *ringEntry) (handleRICSResult, bool) {
 	default:
 		// Should never reach this. All the connectivity states are already
 		// handled in the cases.
-		//
-		// FIXME: add an error log.
+		p.logger.Errorf("SubConn has undefined connectivity state: %v", state)
 		return handleRICSResult{err: status.Errorf(codes.Unavailable, "SubConn has undefined connectivity state: %v", state)}, true
 	}
 }
 
 func (p *picker) Pick(info balancer.PickInfo) (balancer.PickResult, error) {
 	e := p.ring.pick(getRequestHash(info.Ctx))
-	if hr, ok := handleRICS(e); ok {
+	if hr, ok := p.handleRICS(e); ok {
 		return hr.pr, hr.err
 	}
 	// ok was false, the entry is in transient failure.
@@ -95,7 +100,7 @@ func (p *picker) handleTransientFailure(e *ringEntry) (balancer.PickResult, erro
 
 	// For the second SubConn, also check Ready/Idle/Connecting as if it's the
 	// first entry.
-	if hr, ok := handleRICS(e2); ok {
+	if hr, ok := p.handleRICS(e2); ok {
 		return hr.pr, hr.err
 	}