Revert "update OpenTelemetry dependencies"

This reverts commit 82e9ce79c7.

vendor/google.golang.org/grpc/resolver_conn_wrapper.go

@@ -0,0 +1,247 @@
+/*
+ *
+ * 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/balancer"
+	"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"
+)
+
+// resolverStateUpdater wraps the single method used by ccResolverWrapper to
+// report a state update from the actual resolver implementation.
+type resolverStateUpdater interface {
+	updateResolverState(s resolver.State, err error) error
+}
+
+// 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                  resolverStateUpdater
+	channelzID          *channelz.Identifier
+	ignoreServiceConfig bool
+	opts                ccResolverWrapperOpts
+	serializer          *grpcsync.CallbackSerializer // To serialize all incoming calls.
+	serializerCancel    context.CancelFunc           // To close the serializer, accessed only from close().
+
+	// All incoming (resolver --> gRPC) calls are guaranteed to execute in a
+	// mutually exclusive manner as they are scheduled on the serializer.
+	// Fields accessed *only* in these serializer callbacks, can therefore be
+	// accessed without a mutex.
+	curState resolver.State
+
+	// mu guards access to the below fields.
+	mu       sync.Mutex
+	closed   bool
+	resolver resolver.Resolver // Accessed only from outgoing calls.
+}
+
+// ccResolverWrapperOpts wraps the arguments to be passed when creating a new
+// ccResolverWrapper.
+type ccResolverWrapperOpts struct {
+	target     resolver.Target       // User specified dial target to resolve.
+	builder    resolver.Builder      // Resolver builder to use.
+	bOpts      resolver.BuildOptions // Resolver build options to use.
+	channelzID *channelz.Identifier  // Channelz identifier for the channel.
+}
+
+// newCCResolverWrapper uses the resolver.Builder to build a Resolver and
+// returns a ccResolverWrapper object which wraps the newly built resolver.
+func newCCResolverWrapper(cc resolverStateUpdater, opts ccResolverWrapperOpts) (*ccResolverWrapper, error) {
+	ctx, cancel := context.WithCancel(context.Background())
+	ccr := &ccResolverWrapper{
+		cc:                  cc,
+		channelzID:          opts.channelzID,
+		ignoreServiceConfig: opts.bOpts.DisableServiceConfig,
+		opts:                opts,
+		serializer:          grpcsync.NewCallbackSerializer(ctx),
+		serializerCancel:    cancel,
+	}
+
+	// Cannot hold the lock at build time because the resolver can send an
+	// update or error inline and these incoming calls grab the lock to schedule
+	// a callback in the serializer.
+	r, err := opts.builder.Build(opts.target, ccr, opts.bOpts)
+	if err != nil {
+		cancel()
+		return nil, err
+	}
+
+	// Any error reported by the resolver at build time that leads to a
+	// re-resolution request from the balancer is dropped by grpc until we
+	// return from this function. So, we don't have to handle pending resolveNow
+	// requests here.
+	ccr.mu.Lock()
+	ccr.resolver = r
+	ccr.mu.Unlock()
+
+	return ccr, nil
+}
+
+func (ccr *ccResolverWrapper) resolveNow(o resolver.ResolveNowOptions) {
+	ccr.mu.Lock()
+	defer ccr.mu.Unlock()
+
+	// ccr.resolver field is set only after the call to Build() returns. But in
+	// the process of building, the resolver may send an error update which when
+	// propagated to the balancer may result in a re-resolution request.
+	if ccr.closed || ccr.resolver == nil {
+		return
+	}
+	ccr.resolver.ResolveNow(o)
+}
+
+func (ccr *ccResolverWrapper) close() {
+	ccr.mu.Lock()
+	if ccr.closed {
+		ccr.mu.Unlock()
+		return
+	}
+
+	channelz.Info(logger, ccr.channelzID, "Closing the name resolver")
+
+	// Close the serializer to ensure that no more calls from the resolver are
+	// handled, before actually closing the resolver.
+	ccr.serializerCancel()
+	ccr.closed = true
+	r := ccr.resolver
+	ccr.mu.Unlock()
+
+	// Give enqueued callbacks a chance to finish.
+	<-ccr.serializer.Done()
+
+	// Spawn a goroutine to close the resolver (since it may block trying to
+	// cleanup all allocated resources) and return early.
+	go r.Close()
+}
+
+// serializerScheduleLocked is a convenience method to schedule a function to be
+// run on the serializer while holding ccr.mu.
+func (ccr *ccResolverWrapper) serializerScheduleLocked(f func(context.Context)) {
+	ccr.mu.Lock()
+	ccr.serializer.Schedule(f)
+	ccr.mu.Unlock()
+}
+
+// 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 {
+	errCh := make(chan error, 1)
+	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)
+		}
+	}
+	ok := ccr.serializer.Schedule(func(context.Context) {
+		ccr.addChannelzTraceEvent(s)
+		ccr.curState = s
+		if err := ccr.cc.updateResolverState(ccr.curState, nil); err == balancer.ErrBadResolverState {
+			errCh <- balancer.ErrBadResolverState
+			return
+		}
+		errCh <- nil
+	})
+	if !ok {
+		// The only time when Schedule() fail to add the callback to the
+		// serializer is when the serializer is closed, and this happens only
+		// when the resolver wrapper is closed.
+		return nil
+	}
+	return <-errCh
+}
+
+// ReportError is called by resolver implementations to report errors
+// encountered during name resolution to gRPC.
+func (ccr *ccResolverWrapper) ReportError(err error) {
+	ccr.serializerScheduleLocked(func(_ context.Context) {
+		channelz.Warningf(logger, ccr.channelzID, "ccResolverWrapper: reporting error to cc: %v", err)
+		ccr.cc.updateResolverState(resolver.State{}, err)
+	})
+}
+
+// NewAddress is called by the resolver implementation to send addresses to
+// gRPC.
+func (ccr *ccResolverWrapper) NewAddress(addrs []resolver.Address) {
+	ccr.serializerScheduleLocked(func(_ context.Context) {
+		ccr.addChannelzTraceEvent(resolver.State{Addresses: addrs, ServiceConfig: ccr.curState.ServiceConfig})
+		ccr.curState.Addresses = addrs
+		ccr.cc.updateResolverState(ccr.curState, nil)
+	})
+}
+
+// NewServiceConfig is called by the resolver implementation to send service
+// configs to gRPC.
+func (ccr *ccResolverWrapper) NewServiceConfig(sc string) {
+	ccr.serializerScheduleLocked(func(_ context.Context) {
+		channelz.Infof(logger, ccr.channelzID, "ccResolverWrapper: got new service config: %s", sc)
+		if ccr.ignoreServiceConfig {
+			channelz.Info(logger, ccr.channelzID, "Service config lookups disabled; ignoring config")
+			return
+		}
+		scpr := parseServiceConfig(sc)
+		if scpr.Err != nil {
+			channelz.Warningf(logger, ccr.channelzID, "ccResolverWrapper: error parsing service config: %v", scpr.Err)
+			return
+		}
+		ccr.addChannelzTraceEvent(resolver.State{Addresses: ccr.curState.Addresses, ServiceConfig: scpr})
+		ccr.curState.ServiceConfig = scpr
+		ccr.cc.updateResolverState(ccr.curState, 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.channelzID, "Resolver state updated: %s (%v)", pretty.ToJSON(s), strings.Join(updates, "; "))
+}