126 lines
3.3 KiB
Go
126 lines
3.3 KiB
Go
package grpchealth
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import (
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"context"
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"time"
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"google.golang.org/grpc/codes"
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healthgrpc "google.golang.org/grpc/health/grpc_health_v1"
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healthpb "google.golang.org/grpc/health/grpc_health_v1"
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"google.golang.org/grpc/status"
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)
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const (
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// StatusOK 表示单个健康检查项通过。
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StatusOK = "ok"
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// StatusFail 表示单个健康检查项失败。
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StatusFail = "fail"
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)
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// Check 描述一项 readiness 子检查；gRPC health 只返回总状态，子项用于服务内聚合。
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type Check struct {
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Name string
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Status string
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Message string
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}
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// Checker 把服务自己的 ready 语义适配到标准 gRPC health protocol。
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type Checker interface {
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ServiceName() string
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Ready(ctx context.Context) []Check
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}
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// Server 实现 grpc.health.v1.Health，并把 SERVING 严格映射到 Checker.Ready。
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type Server struct {
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healthgrpc.UnimplementedHealthServer
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checker Checker
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}
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// NewServer 创建标准 gRPC health server。
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func NewServer(checker Checker) *Server {
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return &Server{checker: checker}
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}
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// Check 返回当前服务是否 ready；未知服务名按标准返回 NotFound。
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func (s *Server) Check(ctx context.Context, req *healthpb.HealthCheckRequest) (*healthpb.HealthCheckResponse, error) {
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if !s.supports(req.GetService()) {
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return nil, status.Error(codes.NotFound, "unknown service")
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}
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return &healthpb.HealthCheckResponse{Status: s.status(ctx)}, nil
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}
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// Watch 定时推送 ready 状态变化，供支持 gRPC health watch 的服务发现系统消费。
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func (s *Server) Watch(req *healthpb.HealthCheckRequest, stream healthgrpc.Health_WatchServer) error {
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if !s.supports(req.GetService()) {
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if err := stream.Send(&healthpb.HealthCheckResponse{Status: healthpb.HealthCheckResponse_SERVICE_UNKNOWN}); err != nil {
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return status.Error(codes.Canceled, "health watch stream ended")
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}
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<-stream.Context().Done()
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return status.Error(codes.Canceled, "health watch stream ended")
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}
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ticker := time.NewTicker(2 * time.Second)
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defer ticker.Stop()
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var last healthpb.HealthCheckResponse_ServingStatus = -1
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for {
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current := s.status(stream.Context())
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if current != last {
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if err := stream.Send(&healthpb.HealthCheckResponse{Status: current}); err != nil {
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return status.Error(codes.Canceled, "health watch stream ended")
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}
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last = current
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}
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select {
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case <-ticker.C:
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case <-stream.Context().Done():
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return status.Error(codes.Canceled, "health watch stream ended")
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}
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}
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}
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// Healthy 聚合子检查，任何失败项都会让服务从 ready 池摘除。
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func Healthy(checks []Check) bool {
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for _, check := range checks {
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if check.Status != StatusOK {
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return false
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}
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}
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return true
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}
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// OK 创建通过项。
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func OK(name string) Check {
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return Check{Name: name, Status: StatusOK}
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}
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// Fail 创建失败项。
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func Fail(name string, message string) Check {
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return Check{Name: name, Status: StatusFail, Message: message}
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}
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// Bool 根据布尔条件创建检查项。
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func Bool(name string, ok bool, message string) Check {
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if ok {
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return OK(name)
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}
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return Fail(name, message)
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}
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func (s *Server) supports(service string) bool {
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return service == "" || service == s.checker.ServiceName()
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}
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func (s *Server) status(ctx context.Context) healthpb.HealthCheckResponse_ServingStatus {
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if Healthy(s.checker.Ready(ctx)) {
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return healthpb.HealthCheckResponse_SERVING
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}
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return healthpb.HealthCheckResponse_NOT_SERVING
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}
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