package recovery import ( "context" "net/http" "runtime" "github.com/traefik/traefik/v2/pkg/middlewares" ) const ( typeName = "Recovery" middlewareName = "traefik-internal-recovery" ) type recovery struct { next http.Handler } // New creates recovery middleware. func New(ctx context.Context, next http.Handler) (http.Handler, error) { middlewares.GetLogger(ctx, middlewareName, typeName).Debug().Msg("Creating middleware") return &recovery{ next: next, }, nil } func (re *recovery) ServeHTTP(rw http.ResponseWriter, req *http.Request) { defer recoverFunc(rw, req) re.next.ServeHTTP(rw, req) } func recoverFunc(rw http.ResponseWriter, req *http.Request) { if err := recover(); err != nil { logger := middlewares.GetLogger(req.Context(), middlewareName, typeName) if !shouldLogPanic(err) { logger.Debug().Msgf("Request has been aborted [%s - %s]: %v", req.RemoteAddr, req.URL, err) return } logger.Error().Msgf("Recovered from panic in HTTP handler [%s - %s]: %+v", req.RemoteAddr, req.URL, err) const size = 64 << 10 buf := make([]byte, size) buf = buf[:runtime.Stack(buf, false)] logger.Error().Msgf("Stack: %s", buf) http.Error(rw, 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 { //nolint:errorlint // false-positive because panicValue is an interface. return panicValue != nil && panicValue != http.ErrAbortHandler }