Go's Context Package Not Propagating Cancellation Signals to HTTP Handlers
I've been researching this but I've searched everywhere and can't find a clear answer... I just started working with I'm experimenting with I'm having trouble with Go's context cancellation not being properly propagated to my HTTP handlers..... I'm using Go version 1.19 and I have a typical web server setup with gorilla/mux for routing. I expected that if the parent context is cancelled, all handlers using that context would also recognize the cancellation, but that doesn't seem to be happening. Here's a simplified version of my code: ```go package main import ( "context" "fmt" "net/http" "time" "github.com/gorilla/mux" ) func handler(w http.ResponseWriter, r *http.Request) { ctx := r.Context() select { case <-time.After(5 * time.Second): fmt.Fprintln(w, "Request processed") case <-ctx.Done(): http.Error(w, ctx.Err().Error(), http.StatusRequestTimeout) } } func main() { r := mux.NewRouter() r.HandleFunc("/long-task", handler).Methods("GET") srv := &http.Server{ Addr: ":8080", Handler: r, } go func() { time.Sleep(2 * time.Second) cancelCtx, cancel := context.WithTimeout(context.Background(), 3*time.Second) defer cancel() <-cancelCtx.Done() // Simulating cancellation }() if err := srv.ListenAndServe(); err != nil { fmt.Println(err) } } ``` In this setup, I start the HTTP server and then simulate a cancellation after 2 seconds. The expectation is that once the cancellation occurs, the handler should respond with a timeout error. However, when I hit the `/long-task` endpoint, I see that the handler continues to run until it completes the 5-second delay, rather than responding immediately. I've verified that the context is indeed cancelled by checking `ctx.Err()` but it seems like the select statement is never receiving the signal in the case of cancellation. I've also tried using `http.TimeoutHandler`, but that didn't yield the desired results either. Is there a proper way to ensure that cancellation signals are respected in my handler? Any insights would be greatly appreciated! For context: I'm using Go on macOS. Any help would be greatly appreciated! Has anyone dealt with something similar? I'm on Windows 10 using the latest version of Go. Has anyone dealt with something similar?