Billy D.
39673d31b8
- Add error checks for unchecked return values (errcheck) - Remove unused struct fields (unused) - Fix gofmt formatting issues
85 lines
2.2 KiB
Go
85 lines
2.2 KiB
Go
// Package health provides an HTTP server for Kubernetes liveness and readiness probes.
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package health
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import (
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"context"
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"encoding/json"
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"fmt"
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"log/slog"
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"net"
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"net/http"
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"time"
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)
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// ReadyFunc is called to determine if the service is ready. Return true if ready.
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type ReadyFunc func() bool
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// Server serves /health and /ready endpoints.
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type Server struct {
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port int
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healthPath string
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readyPath string
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readyCheck ReadyFunc
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srv *http.Server
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}
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// New creates a health server on the given port.
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func New(port int, healthPath, readyPath string, readyCheck ReadyFunc) *Server {
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s := &Server{
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port: port,
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healthPath: healthPath,
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readyPath: readyPath,
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readyCheck: readyCheck,
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}
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mux := http.NewServeMux()
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mux.HandleFunc(healthPath, s.handleHealth)
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mux.HandleFunc(readyPath, s.handleReady)
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s.srv = &http.Server{
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Addr: fmt.Sprintf(":%d", port),
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Handler: mux,
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ReadHeaderTimeout: 5 * time.Second,
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}
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return s
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}
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// Start begins serving in the background. Call Stop to shut down.
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func (s *Server) Start() {
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ln, err := net.Listen("tcp", s.srv.Addr)
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if err != nil {
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slog.Error("health server listen failed", "error", err)
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return
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}
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slog.Info("health server started", "port", s.port, "health", s.healthPath, "ready", s.readyPath)
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go func() {
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if err := s.srv.Serve(ln); err != nil && err != http.ErrServerClosed {
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slog.Error("health server error", "error", err)
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}
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}()
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}
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// Stop gracefully shuts down the server.
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func (s *Server) Stop(ctx context.Context) {
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if s.srv != nil {
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_ = s.srv.Shutdown(ctx)
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slog.Info("health server stopped")
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}
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}
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func (s *Server) handleHealth(w http.ResponseWriter, _ *http.Request) {
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writeJSON(w, http.StatusOK, map[string]string{"status": "healthy"})
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}
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func (s *Server) handleReady(w http.ResponseWriter, _ *http.Request) {
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if s.readyCheck != nil && !s.readyCheck() {
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writeJSON(w, http.StatusServiceUnavailable, map[string]string{"status": "not ready"})
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return
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}
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writeJSON(w, http.StatusOK, map[string]string{"status": "ready"})
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}
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func writeJSON(w http.ResponseWriter, status int, data any) {
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w.Header().Set("Content-Type", "application/json")
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w.WriteHeader(status)
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_ = json.NewEncoder(w).Encode(data)
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}
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