kacerrandClaude Fable 5
7219eb5a23
Includes solved 02-worker-pool and 09-safe-counter (mutex, atomic, sharded). Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01GbnJj9ZqEx9nUvzkjdwfMq
70 lines
2.3 KiB
Go
70 lines
2.3 KiB
Go
// Exercise 08 — Graceful HTTP Server Shutdown
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//
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// ASSIGNMENT
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// ----------
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// Implement NewServer and Run:
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//
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// 1. NewServer(addr, handler) returns an *http.Server with EXPLICIT
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// ReadTimeout, WriteTimeout and IdleTimeout (pick sane values; the
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// zero-value server has none, which is the bug).
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// 2. Run(ctx, srv, drainTimeout):
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// a. Starts the server (ListenAndServe) in a goroutine.
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// b. Blocks until ctx is cancelled (that's your SIGTERM signal).
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// c. Then calls srv.Shutdown with a FRESH context carrying
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// drainTimeout — NOT the already-cancelled ctx (why? see README).
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// d. In-flight requests must be allowed to complete (up to drainTimeout);
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// new connections are refused during drain.
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// e. Returns nil on clean drain; returns an error if the drain deadline
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// was exceeded or ListenAndServe failed for a real reason.
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// (http.ErrServerClosed is NOT a real reason.)
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//
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// Run the tests: go test -race ./08-graceful-shutdown/
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// Run the demo: go run ./08-graceful-shutdown/ (then Ctrl+C)
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package main
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import (
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"context"
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"fmt"
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"net/http"
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"os/signal"
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"syscall"
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"time"
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)
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// NewServer builds an http.Server with production timeouts.
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// TODO: implement me.
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func NewServer(addr string, h http.Handler) *http.Server {
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return &http.Server{}
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}
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// Run serves until ctx is cancelled, then drains gracefully.
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// TODO: implement me.
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func Run(ctx context.Context, srv *http.Server, drainTimeout time.Duration) error {
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// TODO:
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// - errCh := make(chan error, 1); go srv.ListenAndServe() into it
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// (why buffered? so the goroutine never leaks if we exit via ctx)
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// - select on ctx.Done() vs errCh
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// - on ctx.Done(): context.WithTimeout(context.Background(), drainTimeout)
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// and srv.Shutdown(shutCtx)
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// - filter http.ErrServerClosed with errors.Is
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return nil
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}
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func main() {
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ctx, stop := signal.NotifyContext(context.Background(), syscall.SIGTERM, syscall.SIGINT)
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defer stop()
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mux := http.NewServeMux()
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mux.HandleFunc("/slow", func(w http.ResponseWriter, r *http.Request) {
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time.Sleep(3 * time.Second)
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fmt.Fprintln(w, "done")
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})
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srv := NewServer(":8080", mux)
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fmt.Println("serving on :8080 — curl localhost:8080/slow, then Ctrl+C mid-request")
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if err := Run(ctx, srv, 10*time.Second); err != nil {
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fmt.Println("shutdown error:", err)
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}
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fmt.Println("bye")
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}
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