1 files changed, 197 insertions, 0 deletions
diff --git a/vendor/google.golang.org/grpc/resolver_wrapper.go b/vendor/google.golang.org/grpc/resolver_wrapper.go
new file mode 100644
index 000000000..c79bab121
--- /dev/null
+++ b/vendor/google.golang.org/grpc/resolver_wrapper.go
@@ -0,0 +1,197 @@
+/*
+ *
+ * Copyright 2017 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 grpc
+
+import (
+	"context"
+	"strings"
+	"sync"
+
+	"google.golang.org/grpc/internal/channelz"
+	"google.golang.org/grpc/internal/grpcsync"
+	"google.golang.org/grpc/internal/pretty"
+	"google.golang.org/grpc/resolver"
+	"google.golang.org/grpc/serviceconfig"
+)
+
+// ccResolverWrapper is a wrapper on top of cc for resolvers.
+// It implements resolver.ClientConn interface.
+type ccResolverWrapper struct {
+	// The following fields are initialized when the wrapper is created and are
+	// read-only afterwards, and therefore can be accessed without a mutex.
+	cc                  *ClientConn
+	ignoreServiceConfig bool
+	serializer          *grpcsync.CallbackSerializer
+	serializerCancel    context.CancelFunc
+
+	resolver resolver.Resolver // only accessed within the serializer
+
+	// The following fields are protected by mu.  Caller must take cc.mu before
+	// taking mu.
+	mu       sync.Mutex
+	curState resolver.State
+	closed   bool
+}
+
+// newCCResolverWrapper initializes the ccResolverWrapper.  It can only be used
+// after calling start, which builds the resolver.
+func newCCResolverWrapper(cc *ClientConn) *ccResolverWrapper {
+	ctx, cancel := context.WithCancel(cc.ctx)
+	return &ccResolverWrapper{
+		cc:                  cc,
+		ignoreServiceConfig: cc.dopts.disableServiceConfig,
+		serializer:          grpcsync.NewCallbackSerializer(ctx),
+		serializerCancel:    cancel,
+	}
+}
+
+// start builds the name resolver using the resolver.Builder in cc and returns
+// any error encountered.  It must always be the first operation performed on
+// any newly created ccResolverWrapper, except that close may be called instead.
+func (ccr *ccResolverWrapper) start() error {
+	errCh := make(chan error)
+	ccr.serializer.Schedule(func(ctx context.Context) {
+		if ctx.Err() != nil {
+			return
+		}
+		opts := resolver.BuildOptions{
+			DisableServiceConfig: ccr.cc.dopts.disableServiceConfig,
+			DialCreds:            ccr.cc.dopts.copts.TransportCredentials,
+			CredsBundle:          ccr.cc.dopts.copts.CredsBundle,
+			Dialer:               ccr.cc.dopts.copts.Dialer,
+		}
+		var err error
+		ccr.resolver, err = ccr.cc.resolverBuilder.Build(ccr.cc.parsedTarget, ccr, opts)
+		errCh <- err
+	})
+	return <-errCh
+}
+
+func (ccr *ccResolverWrapper) resolveNow(o resolver.ResolveNowOptions) {
+	ccr.serializer.Schedule(func(ctx context.Context) {
+		if ctx.Err() != nil || ccr.resolver == nil {
+			return
+		}
+		ccr.resolver.ResolveNow(o)
+	})
+}
+
+// close initiates async shutdown of the wrapper.  To determine the wrapper has
+// finished shutting down, the channel should block on ccr.serializer.Done()
+// without cc.mu held.
+func (ccr *ccResolverWrapper) close() {
+	channelz.Info(logger, ccr.cc.channelzID, "Closing the name resolver")
+	ccr.mu.Lock()
+	ccr.closed = true
+	ccr.mu.Unlock()
+
+	ccr.serializer.Schedule(func(context.Context) {
+		if ccr.resolver == nil {
+			return
+		}
+		ccr.resolver.Close()
+		ccr.resolver = nil
+	})
+	ccr.serializerCancel()
+}
+
+// UpdateState is called by resolver implementations to report new state to gRPC
+// which includes addresses and service config.
+func (ccr *ccResolverWrapper) UpdateState(s resolver.State) error {
+	ccr.cc.mu.Lock()
+	ccr.mu.Lock()
+	if ccr.closed {
+		ccr.mu.Unlock()
+		ccr.cc.mu.Unlock()
+		return nil
+	}
+	if s.Endpoints == nil {
+		s.Endpoints = make([]resolver.Endpoint, 0, len(s.Addresses))
+		for _, a := range s.Addresses {
+			ep := resolver.Endpoint{Addresses: []resolver.Address{a}, Attributes: a.BalancerAttributes}
+			ep.Addresses[0].BalancerAttributes = nil
+			s.Endpoints = append(s.Endpoints, ep)
+		}
+	}
+	ccr.addChannelzTraceEvent(s)
+	ccr.curState = s
+	ccr.mu.Unlock()
+	return ccr.cc.updateResolverStateAndUnlock(s, nil)
+}
+
+// ReportError is called by resolver implementations to report errors
+// encountered during name resolution to gRPC.
+func (ccr *ccResolverWrapper) ReportError(err error) {
+	ccr.cc.mu.Lock()
+	ccr.mu.Lock()
+	if ccr.closed {
+		ccr.mu.Unlock()
+		ccr.cc.mu.Unlock()
+		return
+	}
+	ccr.mu.Unlock()
+	channelz.Warningf(logger, ccr.cc.channelzID, "ccResolverWrapper: reporting error to cc: %v", err)
+	ccr.cc.updateResolverStateAndUnlock(resolver.State{}, err)
+}
+
+// NewAddress is called by the resolver implementation to send addresses to
+// gRPC.
+func (ccr *ccResolverWrapper) NewAddress(addrs []resolver.Address) {
+	ccr.cc.mu.Lock()
+	ccr.mu.Lock()
+	if ccr.closed {
+		ccr.mu.Unlock()
+		ccr.cc.mu.Unlock()
+		return
+	}
+	s := resolver.State{Addresses: addrs, ServiceConfig: ccr.curState.ServiceConfig}
+	ccr.addChannelzTraceEvent(s)
+	ccr.curState = s
+	ccr.mu.Unlock()
+	ccr.cc.updateResolverStateAndUnlock(s, nil)
+}
+
+// ParseServiceConfig is called by resolver implementations to parse a JSON
+// representation of the service config.
+func (ccr *ccResolverWrapper) ParseServiceConfig(scJSON string) *serviceconfig.ParseResult {
+	return parseServiceConfig(scJSON)
+}
+
+// addChannelzTraceEvent adds a channelz trace event containing the new
+// state received from resolver implementations.
+func (ccr *ccResolverWrapper) addChannelzTraceEvent(s resolver.State) {
+	var updates []string
+	var oldSC, newSC *ServiceConfig
+	var oldOK, newOK bool
+	if ccr.curState.ServiceConfig != nil {
+		oldSC, oldOK = ccr.curState.ServiceConfig.Config.(*ServiceConfig)
+	}
+	if s.ServiceConfig != nil {
+		newSC, newOK = s.ServiceConfig.Config.(*ServiceConfig)
+	}
+	if oldOK != newOK || (oldOK && newOK && oldSC.rawJSONString != newSC.rawJSONString) {
+		updates = append(updates, "service config updated")
+	}
+	if len(ccr.curState.Addresses) > 0 && len(s.Addresses) == 0 {
+		updates = append(updates, "resolver returned an empty address list")
+	} else if len(ccr.curState.Addresses) == 0 && len(s.Addresses) > 0 {
+		updates = append(updates, "resolver returned new addresses")
+	}
+	channelz.Infof(logger, ccr.cc.channelzID, "Resolver state updated: %s (%v)", pretty.ToJSON(s), strings.Join(updates, "; "))
+}