zbchi commented on code in PR #3281: URL: https://github.com/apache/dubbo-go/pull/3281#discussion_r3007506967
########## protocol/triple/dual_transport.go: ########## @@ -0,0 +1,353 @@ +/* + * 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 triple + +import ( + "context" + "crypto/tls" + "errors" + "io" + "net/http" + "net/url" + "sync" + "time" +) + +import ( + "github.com/dubbogo/gost/log/logger" + + "github.com/quic-go/quic-go" + "github.com/quic-go/quic-go/http3" + + "golang.org/x/net/http2" +) + +import ( + "dubbo.apache.org/dubbo-go/v3/common/constant" + tri "dubbo.apache.org/dubbo-go/v3/protocol/triple/triple_protocol" +) + +type originMode int + +const ( + // originUnknown means the origin has not advertised HTTP/3 yet. + originUnknown originMode = iota + // originCandidate means the origin advertised HTTP/3 and is waiting for validation. + originCandidate + // originProbing means an out-of-band HTTP/3 probe is in flight. + originProbing + // originH3Healthy means later requests may be sent over HTTP/3. + originH3Healthy + // originCooldown means HTTP/3 recently failed and should be avoided for a while. + originCooldown +) + +const ( + defaultH3ProbeTimeout = 3 * time.Second + defaultH3BaseCooldown = 4 * time.Second + defaultH3MaxCooldown = 1 * time.Minute +) + +// originState tracks whether the current upstream origin is ready for HTTP/3. +type originState struct { + mode originMode + failures int + cooldownUntil time.Time +} + +// dualTransport keeps HTTP/2 as the stable path and only uses HTTP/3 after discovery and probe. +type dualTransport struct { + http2Transport http.RoundTripper + http3Transport http.RoundTripper + // Cache for alternative services to avoid repeated lookups + altSvcCache *tri.AltSvcCache + + // state tracks HTTP/3 readiness for the bound upstream origin. + state originState + + // mu protects state and serializes transitions between unknown/probing/healthy/cooldown. + mu sync.Mutex + + probeTimeout time.Duration + baseCooldown time.Duration + maxCooldown time.Duration +} + +// newDualTransport creates a new dual transport that supports both HTTP/2 and HTTP/3 +func newDualTransport(tlsConfig *tls.Config, keepAliveInterval, keepAliveTimeout time.Duration) http.RoundTripper { + http2Transport := &http2.Transport{ + TLSClientConfig: tlsConfig, + ReadIdleTimeout: keepAliveInterval, + PingTimeout: keepAliveTimeout, + } + + http3Transport := &http3.Transport{ + TLSClientConfig: tlsConfig, + QUICConfig: &quic.Config{ + KeepAlivePeriod: keepAliveInterval, + MaxIdleTimeout: keepAliveTimeout, + }, + } + + return &dualTransport{ + http2Transport: http2Transport, + http3Transport: http3Transport, + altSvcCache: tri.NewAltSvcCache(), + probeTimeout: defaultH3ProbeTimeout, + baseCooldown: defaultH3BaseCooldown, + maxCooldown: defaultH3MaxCooldown, + } +} + +// RoundTrip implements http.RoundTripper interface with HTTP Alternative Services support +func (dt *dualTransport) RoundTrip(req *http.Request) (*http.Response, error) { + host := req.URL.Host + + if dt.shouldUseH3(host) { + // Only use HTTP/3 after a separate probe marks the origin healthy. + // If the HTTP/3 request fails, return the error directly instead of + // replaying the same request over HTTP/2 with a partially consumed body. + resp, err := dt.http3Transport.RoundTrip(req) + if err == nil { + dt.markH3Success(host) + return resp, nil + } + if dt.shouldMarkH3Failure(req, err) { + logger.Warnf("HTTP/3 request failed for %s: %v", req.URL.String(), err) + dt.markH3Failure(host) + } + return nil, err + } + + resp, err := dt.http2Transport.RoundTrip(req) + if err != nil { + return nil, err + } + + // Learn HTTP/3 availability from HTTP/2 responses and validate it with + // an independent probe before routing later requests over HTTP/3. + dt.observeH2Response(req.URL, resp.Header) + return resp, nil +} + +// shouldUseH3 only decides whether the current request may use HTTP/3. +func (dt *dualTransport) shouldUseH3(host string) bool { + if host == "" { + return false + } + + altSvc := dt.altSvcCache.Get(host) + if altSvc == nil || altSvc.Protocol != constant.AltSvcProtocolH3 { + return false + } + + now := time.Now() + + dt.mu.Lock() + defer dt.mu.Unlock() + + switch dt.state.mode { + case originH3Healthy: + return true + + case originCooldown: + // Wait for the cooldown window to expire before probing HTTP/3 again. + if now.Before(dt.state.cooldownUntil) { + return false + } + + logger.Debugf("HTTP/3 cooldown expired for %s", host) + dt.state.mode = originCandidate + dt.state.cooldownUntil = time.Time{} + return false Review Comment: 每一个clientManager /tri 客户端实例都会创建一个独立的dualTransport，且该通道会固定绑定唯一的host -- This is an automated message from the Apache Git Service. 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