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1939d18ba8
Without IdleTimeout, clients holding keep-alive connections open indefinitely caused server-side goroutines (and their ~16KB of buffers) to accumulate linearly until OOM.
67 lines
2.1 KiB
Go
67 lines
2.1 KiB
Go
package server
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import (
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"context"
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"errors"
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"net/http"
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"os"
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"os/signal"
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"syscall"
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"time"
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"github.com/go-chi/chi/v5"
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log "github.com/sirupsen/logrus"
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"github.com/nais/wonderwall/pkg/config"
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)
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func Start(cfg *config.Config, r chi.Router) error {
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server := http.Server{
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Addr: cfg.BindAddress,
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Handler: r,
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ReadHeaderTimeout: 10 * time.Second, // Prevents slowloris attacks (connections held open without sending headers).
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IdleTimeout: 90 * time.Second, // Reclaims idle keep-alive connections; without this, goroutines and buffers leak indefinitely.
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MaxHeaderBytes: 1 << 16, // 64KB
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// ReadTimeout/WriteTimeout intentionally omitted - a reverse proxy must support slow transfers.
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}
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serverCtx, serverStopCtx := context.WithCancel(context.Background())
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sig := make(chan os.Signal, 1)
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signal.Notify(sig, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
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go func() {
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s := <-sig
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log.Infof("server: received %q; waiting for %s before starting graceful shutdown...", s, cfg.ShutdownWaitBeforePeriod)
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time.Sleep(cfg.ShutdownWaitBeforePeriod)
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// the total terminationGracePeriodSeconds in Kubernetes starts immediately when SIGTERM is sent, so we need to subtract the wait-before period to exit before SIGKILL
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shutdownTimeout := cfg.ShutdownGracefulPeriod - cfg.ShutdownWaitBeforePeriod
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shutdownCtx, shutdownStopCtx := context.WithTimeout(serverCtx, shutdownTimeout)
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go func() {
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<-shutdownCtx.Done()
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if errors.Is(shutdownCtx.Err(), context.DeadlineExceeded) {
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log.Fatalf("server: graceful shutdown timed out after %s; forcing exit.", shutdownTimeout)
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}
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}()
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log.Infof("server: starting graceful shutdown (will timeout after %s)...", shutdownTimeout)
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err := server.Shutdown(shutdownCtx)
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if err != nil {
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log.Fatal(err)
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}
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shutdownStopCtx()
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serverStopCtx()
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}()
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log.Infof("server: listening on %s", cfg.BindAddress)
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err := server.ListenAndServe()
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if err != nil && !errors.Is(err, http.ErrServerClosed) {
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return err
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}
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<-serverCtx.Done()
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log.Infof("server: shutdown completed")
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return nil
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}
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