package middlewares import ( "net/http" "runtime" "github.com/containous/traefik/old/log" "github.com/urfave/negroni" ) // RecoverHandler recovers from a panic in http handlers func RecoverHandler(next http.Handler) http.Handler { fn := func(w http.ResponseWriter, r *http.Request) { defer recoverFunc(w, r) next.ServeHTTP(w, r) } return http.HandlerFunc(fn) } // NegroniRecoverHandler recovers from a panic in negroni handlers func NegroniRecoverHandler() negroni.Handler { fn := func(w http.ResponseWriter, r *http.Request, next http.HandlerFunc) { defer recoverFunc(w, r) next.ServeHTTP(w, r) } return negroni.HandlerFunc(fn) } func recoverFunc(w http.ResponseWriter, r *http.Request) { if err := recover(); err != nil { if !shouldLogPanic(err) { log.Debugf("Request has been aborted [%s - %s]: %v", r.RemoteAddr, r.URL, err) return } log.Errorf("Recovered from panic in HTTP handler [%s - %s]: %+v", r.RemoteAddr, r.URL, err) const size = 64 << 10 buf := make([]byte, size) buf = buf[:runtime.Stack(buf, false)] log.Errorf("Stack: %s", buf) http.Error(w, http.StatusText(http.StatusInternalServerError), http.StatusInternalServerError) } } // https://github.com/golang/go/blob/a0d6420d8be2ae7164797051ec74fa2a2df466a1/src/net/http/server.go#L1761-L1775 // https://github.com/golang/go/blob/c33153f7b416c03983324b3e8f869ce1116d84bc/src/net/http/httputil/reverseproxy.go#L284 func shouldLogPanic(panicValue interface{}) bool { return panicValue != nil && panicValue != http.ErrAbortHandler }