Dependencies for the affinity router and the
affinity routing daemon.
Change-Id: Icda72c3594ef7f8f0bc0c33dc03087a4c25529ca
diff --git a/vendor/google.golang.org/grpc/health/client.go b/vendor/google.golang.org/grpc/health/client.go
new file mode 100644
index 0000000..e15f04c
--- /dev/null
+++ b/vendor/google.golang.org/grpc/health/client.go
@@ -0,0 +1,107 @@
+/*
+ *
+ * Copyright 2018 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 health
+
+import (
+ "context"
+ "fmt"
+ "io"
+ "time"
+
+ "google.golang.org/grpc"
+ "google.golang.org/grpc/codes"
+ healthpb "google.golang.org/grpc/health/grpc_health_v1"
+ "google.golang.org/grpc/internal"
+ "google.golang.org/grpc/internal/backoff"
+ "google.golang.org/grpc/status"
+)
+
+const maxDelay = 120 * time.Second
+
+var backoffStrategy = backoff.Exponential{MaxDelay: maxDelay}
+var backoffFunc = func(ctx context.Context, retries int) bool {
+ d := backoffStrategy.Backoff(retries)
+ timer := time.NewTimer(d)
+ select {
+ case <-timer.C:
+ return true
+ case <-ctx.Done():
+ timer.Stop()
+ return false
+ }
+}
+
+func init() {
+ internal.HealthCheckFunc = clientHealthCheck
+}
+
+func clientHealthCheck(ctx context.Context, newStream func() (interface{}, error), reportHealth func(bool), service string) error {
+ tryCnt := 0
+
+retryConnection:
+ for {
+ // Backs off if the connection has failed in some way without receiving a message in the previous retry.
+ if tryCnt > 0 && !backoffFunc(ctx, tryCnt-1) {
+ return nil
+ }
+ tryCnt++
+
+ if ctx.Err() != nil {
+ return nil
+ }
+ rawS, err := newStream()
+ if err != nil {
+ continue retryConnection
+ }
+
+ s, ok := rawS.(grpc.ClientStream)
+ // Ideally, this should never happen. But if it happens, the server is marked as healthy for LBing purposes.
+ if !ok {
+ reportHealth(true)
+ return fmt.Errorf("newStream returned %v (type %T); want grpc.ClientStream", rawS, rawS)
+ }
+
+ if err = s.SendMsg(&healthpb.HealthCheckRequest{Service: service}); err != nil && err != io.EOF {
+ // Stream should have been closed, so we can safely continue to create a new stream.
+ continue retryConnection
+ }
+ s.CloseSend()
+
+ resp := new(healthpb.HealthCheckResponse)
+ for {
+ err = s.RecvMsg(resp)
+
+ // Reports healthy for the LBing purposes if health check is not implemented in the server.
+ if status.Code(err) == codes.Unimplemented {
+ reportHealth(true)
+ return err
+ }
+
+ // Reports unhealthy if server's Watch method gives an error other than UNIMPLEMENTED.
+ if err != nil {
+ reportHealth(false)
+ continue retryConnection
+ }
+
+ // As a message has been received, removes the need for backoff for the next retry by reseting the try count.
+ tryCnt = 0
+ reportHealth(resp.Status == healthpb.HealthCheckResponse_SERVING)
+ }
+ }
+}