AlexStocks commented on code in PR #1017: URL: https://github.com/apache/dubbo-go-pixiu/pull/1017#discussion_r3802797670
########## pkg/filter/http/grpcproxy/connection_manager.go: ########## @@ -0,0 +1,423 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You 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 grpcproxy + +import ( + "container/list" + "context" + "fmt" + "sync" + "time" +) + +import ( + "golang.org/x/sync/singleflight" + + "google.golang.org/grpc" + "google.golang.org/grpc/connectivity" + "google.golang.org/grpc/credentials/insecure" +) + +const ( + defaultGRPCDialTimeout = 5 * time.Second + // Endpoint tombstones only need to cover recently delivered lifecycle + // events. Active connections and in-flight dials are pinned separately and + // are never evicted by this bound. + maxEndpointTombstones = 1024 +) + +type grpcConnectionDialer func(context.Context, string) (*grpc.ClientConn, error) + +// grpcConnectionManager owns long-lived backend connections for the HTTP gRPC +// proxy. A grpc.ClientConn is safe for concurrent use and multiplexes calls +// over HTTP/2, so a sync.Pool is both unnecessary and incorrect here. +type grpcConnectionManager struct { + connections sync.Map + creates singleflight.Group + dial grpcConnectionDialer + dialTimeout time.Duration + onRemove func(*grpc.ClientConn) + + mu sync.Mutex + closed bool + endpointGenerations map[string]uint64 + endpointEventVers map[string]uint64 + endpointRefs map[string]int + endpointRemoved map[string]bool + endpointTombstones map[string]*list.Element + tombstoneOrder *list.List +} + +func newGRPCConnectionManager() *grpcConnectionManager { + return &grpcConnectionManager{ + dial: dialGRPCConnection, + dialTimeout: defaultGRPCDialTimeout, + endpointGenerations: make(map[string]uint64), + endpointEventVers: make(map[string]uint64), + endpointRefs: make(map[string]int), + endpointRemoved: make(map[string]bool), + endpointTombstones: make(map[string]*list.Element), + tombstoneOrder: list.New(), + } +} + +func (m *grpcConnectionManager) initEndpointStateLocked() { + if m.endpointGenerations == nil { + m.endpointGenerations = make(map[string]uint64) + } + if m.endpointEventVers == nil { + m.endpointEventVers = make(map[string]uint64) + } + if m.endpointRefs == nil { + m.endpointRefs = make(map[string]int) + } + if m.endpointRemoved == nil { + m.endpointRemoved = make(map[string]bool) + } + if m.endpointTombstones == nil { + m.endpointTombstones = make(map[string]*list.Element) + } + if m.tombstoneOrder == nil { + m.tombstoneOrder = list.New() + } +} + +func (m *grpcConnectionManager) discardEndpointTombstoneLocked(key string) { + if element, ok := m.endpointTombstones[key]; ok { + m.tombstoneOrder.Remove(element) + delete(m.endpointTombstones, key) + } +} + +func (m *grpcConnectionManager) discardEndpointStateLocked(key string) { + m.discardEndpointTombstoneLocked(key) + delete(m.endpointGenerations, key) + delete(m.endpointEventVers, key) + delete(m.endpointRemoved, key) +} + +func (m *grpcConnectionManager) rememberEndpointTombstoneLocked(key string) { + m.initEndpointStateLocked() + if element, ok := m.endpointTombstones[key]; ok { + m.tombstoneOrder.MoveToFront(element) + return + } + element := m.tombstoneOrder.PushFront(key) + m.endpointTombstones[key] = element + + for len(m.endpointTombstones) > maxEndpointTombstones { + var evict *list.Element + for element := m.tombstoneOrder.Back(); element != nil; element = element.Prev() { + candidate := element.Value.(string) + if m.endpointRefs[candidate] == 0 && !m.hasConnection(candidate) { + evict = element + break + } + } + if evict == nil { + return + } + candidate := evict.Value.(string) + m.tombstoneOrder.Remove(evict) + delete(m.endpointTombstones, candidate) + delete(m.endpointGenerations, candidate) + delete(m.endpointEventVers, candidate) + delete(m.endpointRemoved, candidate) + } +} + +func (m *grpcConnectionManager) hasConnection(key string) bool { + _, ok := m.connections.Load(key) + return ok +} + +func (m *grpcConnectionManager) pinEndpoint(key string) (uint64, error) { + m.mu.Lock() + defer m.mu.Unlock() + m.initEndpointStateLocked() + if m.closed { + return 0, fmt.Errorf("grpc connection manager is closed") + } + if m.endpointRemoved[key] { + return 0, fmt.Errorf("grpc endpoint was removed") + } + m.endpointRefs[key]++ + return m.endpointGenerations[key], nil +} + +func (m *grpcConnectionManager) unpinEndpoint(key string) { + m.mu.Lock() + defer m.mu.Unlock() + if m.endpointRefs[key] > 1 { + m.endpointRefs[key]-- + return + } + delete(m.endpointRefs, key) + if m.endpointRemoved[key] && !m.hasConnection(key) { + m.rememberEndpointTombstoneLocked(key) + } else if !m.endpointRemoved[key] && m.endpointEventVers[key] == 0 && !m.hasConnection(key) { + // Get may create a temporary generation entry for a direct endpoint + // before the cluster manager has delivered a lifecycle event. Do not + // retain that request-only state after a failed or canceled dial. + m.discardEndpointStateLocked(key) + } +} + +func (m *grpcConnectionManager) finalizeRemovedEndpoint(key string) { + m.mu.Lock() + defer m.mu.Unlock() + if m.endpointRemoved[key] && m.endpointRefs[key] == 0 && !m.hasConnection(key) { + m.rememberEndpointTombstoneLocked(key) + } +} + +func dialGRPCConnection(ctx context.Context, endpoint string) (*grpc.ClientConn, error) { + return grpc.DialContext( //nolint:staticcheck // SA1019: the context is required to enforce the dial timeout. + ctx, + endpoint, + grpc.WithTransportCredentials(insecure.NewCredentials()), + ) +} + +func (m *grpcConnectionManager) Get(ctx context.Context, key, endpoint string) (*grpc.ClientConn, error) { + if key == "" || endpoint == "" { + return nil, fmt.Errorf("grpc connection key and endpoint must not be empty") + } + if ctx == nil { + ctx = context.Background() + } + + if conn, ok := m.loadHealthy(key); ok { + return conn, nil + } + + endpointGeneration, err := m.pinEndpoint(key) + if err != nil { + return nil, err + } + createKey := fmt.Sprintf("%s\x00%d", key, endpointGeneration) + result := m.creates.DoChan(createKey, func() (any, error) { + m.mu.Lock() + currentGeneration := m.endpointGenerations[key] + removed := m.endpointRemoved[key] + m.mu.Unlock() + if removed || currentGeneration != endpointGeneration { + return nil, fmt.Errorf("grpc endpoint was removed while connecting") + } + if conn, ok := m.loadHealthy(key); ok { + return conn, nil + } + + m.mu.Lock() + if m.closed { + m.mu.Unlock() + return nil, fmt.Errorf("grpc connection manager is closed") + } + dial := m.dial + dialTimeout := m.dialTimeout + m.mu.Unlock() + + dialCtx, cancel := context.WithTimeout(context.Background(), dialTimeout) + defer cancel() + conn, err := dial(dialCtx, endpoint) + if err != nil { + return nil, err + } + + m.mu.Lock() + closed := m.closed + removed = m.endpointRemoved[key] || m.endpointGenerations[key] != endpointGeneration + if !closed && !removed { + m.connections.Store(key, conn) + } + m.mu.Unlock() + if closed || removed { + _ = conn.Close() + if closed { + return nil, fmt.Errorf("grpc connection manager closed while dialing") + } + return nil, fmt.Errorf("grpc endpoint was removed while connecting") + } + + return conn, nil + }) + + select { + case <-ctx.Done(): + go func() { + <-result + m.unpinEndpoint(key) + }() + return nil, ctx.Err() + case result := <-result: + m.unpinEndpoint(key) + if result.Err != nil { + return nil, result.Err + } + return result.Val.(*grpc.ClientConn), nil + } +} + +func (m *grpcConnectionManager) loadHealthy(key string) (*grpc.ClientConn, bool) { + m.mu.Lock() + removed := m.endpointRemoved[key] + m.mu.Unlock() + if removed { + return nil, false + } + value, ok := m.connections.Load(key) + if !ok { + return nil, false + } + + conn, ok := value.(*grpc.ClientConn) + if ok && m.isHealthy(conn) { + return conn, true + } + if ok { + m.remove(key, conn) + } + return nil, false +} + +func (m *grpcConnectionManager) isHealthy(conn *grpc.ClientConn) bool { + if conn == nil { + return false + } + state := conn.GetState() + return state != connectivity.Shutdown && state != connectivity.TransientFailure Review Comment: [P1] TransientFailure 是 gRPC ClientConn 状态机中的可恢复状态，连接会按自身 backoff 继续重连；这里却把它和永久的 Shutdown 一起判为失效并立即 Close/Delete。判别探针让真实 ClientConn 进入 TransientFailure 后放入 manager，下一次 loadHealthy 会立刻将其关闭。后端短暂不可用时，每个请求因此都可能销毁可自恢复连接、重新拨号并重置 backoff，连接复用会退化成握手和 goroutine 抖动。请只把 Shutdown（或明确不可恢复的状态）作为淘汰条件，并补充后端恢复后复用同一 ClientConn、dial 次数不增长的测试。 -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
