No-SilverBullet commented on issue #2039: URL: https://github.com/apache/dubbo-go/issues/2039#issuecomment-3350426453
> 目标：为 dubbo-go 添加 HTTP 健康检查 API，支持 K8S 的 readiness 和 liveness probe。 > > 前置了解： > > K8S通过两种探针与健康检查API交互： > > 1. Liveness Probe（存活探针） > > * 目的：检查容器是否还活着 > * 失败后果：K8S会重启容器 > * 调用端点：GET http://pod-ip:8080/health/live > > 2. Readiness Probe（就绪探针） > > * 目的：检查容器是否准备好接收流量 > * 失败后果：K8S会从Service的endpoint中移除该Pod，停止转发流量 > * 调用端点：GET http://pod-ip:8080/health/ready > > 1. 配置扩展 > > config/metric_config.go： > > // MetricsConfig This is the config struct for all metrics implementation > type MetricsConfig struct { > Enable *bool `default:"false" yaml:"enable" json:"enable,omitempty" property:"enable"` > Port string `default:"9090" yaml:"port" json:"port,omitempty" property:"port"` > Path string `default:"/metrics" yaml:"path" json:"path,omitempty" property:"path"` > Protocol string `default:"prometheus" yaml:"protocol" json:"protocol,omitempty" property:"protocol"` > EnableMetadata *bool `default:"false" yaml:"enable-metadata" json:"enable-metadata,omitempty" property:"enable-metadata"` > EnableRegistry *bool `default:"false" yaml:"enable-registry" json:"enable-registry,omitempty" property:"enable-registry"` > EnableConfigCenter *bool `default:"false" yaml:"enable-config-center" json:"enable-config-center,omitempty" property:"enable-config-center"` > Prometheus *PrometheusConfig `yaml:"prometheus" json:"prometheus" property:"prometheus"` > Aggregation *AggregateConfig `yaml:"aggregation" json:"aggregation" property:"aggregation"` > // added health check configuration > HealthCheck *HealthCheckConfig `yaml:"health-check" json:"health-check" property:"health-check"` > rootConfig *RootConfig > } > > type HealthCheckConfig struct { > Enabled *bool `default:"false" yaml:"enabled" json:"enabled,omitempty" property:"enabled"` > Port string `default:"8080" yaml:"port" json:"port,omitempty" property:"port"` > LivePath string `default:"/health/live" yaml:"live-path" json:"live-path,omitempty" property:"live-path"` > ReadyPath string `default:"/health/ready" yaml:"ready-path" json:"ready-path,omitempty" property:"ready-path"` > Timeout string `default:"10s" yaml:"timeout" json:"timeout,omitempty" property:"timeout"` > } > 2. 添加常量定义 > > common/constant/key.go： > > const ( > HealthCheckHttpEnabledKey = "health-check.enabled" > HealthCheckHttpPortKey = "health-check.port" > HealthCheckLivePathKey = "health-check.live-path" > HealthCheckReadyPathKey = "health-check.ready-path" > HealthCheckTimeoutKey = "health-check.timeout" > ) > common/constant/default.go： > > const ( > HealthCheckDefaultPort = "8080" > HealthCheckDefaultLivePath = "/health/live" > HealthCheckDefaultReadyPath = "/health/ready" > HealthCheckDefaultTimeout = "10s" > ) > 3. 创建 HTTP 健康检查服务 > > server/health.go： > > /* > * 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 server > > import ( > "context" > "encoding/json" > "net/http" > "time" > ) > > import ( > "github.com/dubbogo/gost/log/logger" > ) > > import ( > "dubbo.apache.org/dubbo-go/v3/common" > "dubbo.apache.org/dubbo-go/v3/common/constant" > "dubbo.apache.org/dubbo-go/v3/common/extension" > "dubbo.apache.org/dubbo-go/v3/protocol/triple/health/triple_health" > ) > > // HealthCheckServer HTTP health check server > type HealthCheckServer struct { > url *common.URL > server *http.Server > } > > // HealthResponse health check response > type HealthResponse struct { > Status string `json:"status"` > Timestamp int64 `json:"timestamp"` > Details map[string]string `json:"details,omitempty"` > } > > // NewHealthCheckServer creates a new health check server > func NewHealthCheckServer(url *common.URL) *HealthCheckServer { > return &HealthCheckServer{url: url} > } > > // Start starts the health check server > func (h *HealthCheckServer) Start() { > if !h.url.GetParamBool(constant.HealthCheckEnabledKey, false) { > return > } > > mux := http.NewServeMux() > port := h.url.GetParam(constant.HealthCheckPortKey, constant.HealthCheckDefaultPort) > livePath := h.url.GetParam(constant.HealthCheckLivePathKey, constant.HealthCheckDefaultLivePath) > readyPath := h.url.GetParam(constant.HealthCheckReadyPathKey, constant.HealthCheckDefaultReadyPath) > > mux.HandleFunc(livePath, h.livenessHandler) > mux.HandleFunc(readyPath, h.readinessHandler) > > h.server = &http.Server{Addr: ":" + port, Handler: mux} > > // Register graceful shutdown callback > extension.AddCustomShutdownCallback(func() { > timeoutStr := h.url.GetParam(constant.HealthCheckTimeoutKey, constant.HealthCheckDefaultTimeout) > timeout, err := time.ParseDuration(timeoutStr) > if err != nil { > timeout = 10 * time.Second > } > ctx, cancel := context.WithTimeout(context.Background(), timeout) > defer cancel() > if err := h.server.Shutdown(ctx); err != nil { > logger.Errorf("health check server shutdown failed, err: %v", err) > } else { > logger.Info("health check server gracefully shutdown success") > } > }) > > logger.Infof("health check endpoints: %s%s, %s%s", port, livePath, port, readyPath) > go func() { > if err := h.server.ListenAndServe(); err != nil && err != http.ErrServerClosed { > logger.Errorf("health check server error: %v", err) > } > }() > } > > // livenessHandler liveness probe handler > func (h *HealthCheckServer) livenessHandler(w http.ResponseWriter, r *http.Request) { > if r.Method != http.MethodGet { > http.Error(w, "Method not allowed", http.StatusMethodNotAllowed) > return > } > > // liveness check - whether the process is alive > h.writeResponse(w, "UP", http.StatusOK, map[string]string{ > "check": "liveness", > }) > } > > // readinessHandler readiness probe handler > func (h *HealthCheckServer) readinessHandler(w http.ResponseWriter, r *http.Request) { > if r.Method != http.MethodGet { > http.Error(w, "Method not allowed", http.StatusMethodNotAllowed) > return > } > > // readiness check - whether the service is ready > if h.isServiceReady() { > h.writeResponse(w, "UP", http.StatusOK, map[string]string{ > "check": "readiness", > }) > } else { > h.writeResponse(w, "DOWN", http.StatusServiceUnavailable, map[string]string{ > "check": "readiness", > "reason": "service not ready", > }) > } > } > > // isServiceReady checks if the service is ready > func (h *HealthCheckServer) isServiceReady() bool { > // todo > return true > } > > // writeResponse writes the response > func (h *HealthCheckServer) writeResponse(w http.ResponseWriter, status string, httpStatus int, details map[string]string) { > response := HealthResponse{ > Status: status, > Timestamp: time.Now().UnixMilli(), > Details: details, > } > > w.Header().Set("Content-Type", "application/json") > w.WriteHeader(httpStatus) > > if err := json.NewEncoder(w).Encode(response); err != nil { > logger.Errorf("failed to encode health response: %v", err) > } > } > 检查逻辑（讨论） > > 4. 集成到现有系统 > > metrics/health/health_registry.go： > > /* > * 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 health > > import ( > "dubbo.apache.org/dubbo-go/v3/common" > "dubbo.apache.org/dubbo-go/v3/metrics" > "dubbo.apache.org/dubbo-go/v3/server" > ) > > func init() { > metrics.AddCollector(func(registry metrics.MetricRegistry, url *common.URL) { > healthServer := server.NewHealthCheckServer(url) > healthServer.Start() > }) > } > 然后在 imports/imports.go 中导入： > > _ "dubbo.apache.org/dubbo-go/v3/metrics/health" > 用户使用案例... // isServiceReady checks if the service is ready func (h *HealthCheckServer) isServiceReady() bool { // todo return true } 这里最好设计成interface或者回调，支持用户自定义健康检查逻辑。主要原因是liveness探针是有风险的，直接影响pod重启，因此最好开放给用户。而且本来就绪与否和用户依赖的中间件甚至业务逻辑都是有关系的。 -- This is an automated message from the Apache Git Service. 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