add ReadFileStream deadline for disk call (#17745)

timeout the reader side if hung via disk max timeout

internal/ioutil/ioutil.go

@@ -73,7 +73,54 @@ type ioret struct {
 	err error
 }
 
-// DeadlineWriter deadline writer with context
+// DeadlineReader deadline reader with timeout
+type DeadlineReader struct {
+	io.ReadCloser
+	timeout time.Duration
+	err     error
+}
+
+// NewDeadlineReader wraps a writer to make it respect given deadline
+// value per Write(). If there is a blocking write, the returned Reader
+// will return whenever the timer hits (the return values are n=0
+// and err=context.DeadlineExceeded.)
+func NewDeadlineReader(r io.ReadCloser, timeout time.Duration) io.ReadCloser {
+	return &DeadlineReader{ReadCloser: r, timeout: timeout}
+}
+
+func (r *DeadlineReader) Read(buf []byte) (int, error) {
+	if r.err != nil {
+		return 0, r.err
+	}
+
+	c := make(chan ioret, 1)
+	t := time.NewTimer(r.timeout)
+	go func() {
+		n, err := r.ReadCloser.Read(buf)
+		c <- ioret{n, err}
+		close(c)
+	}()
+
+	select {
+	case res := <-c:
+		if !t.Stop() {
+			<-t.C
+		}
+		r.err = res.err
+		return res.n, res.err
+	case <-t.C:
+		r.ReadCloser.Close()
+		r.err = context.DeadlineExceeded
+		return 0, context.DeadlineExceeded
+	}
+}
+
+// Close closer interface to close the underlying closer
+func (r *DeadlineReader) Close() error {
+	return r.ReadCloser.Close()
+}
+
+// DeadlineWriter deadline writer with timeout
 type DeadlineWriter struct {
 	io.WriteCloser
 	timeout time.Duration
@@ -119,15 +166,15 @@ func (d *DeadlineWorker) Run(work func() error) error {
 		d.err = r.err
 		return r.err
 	case <-t.C:
-		d.err = context.Canceled
-		return context.Canceled
+		d.err = context.DeadlineExceeded
+		return context.DeadlineExceeded
 	}
 }
 
 // NewDeadlineWriter wraps a writer to make it respect given deadline
 // value per Write(). If there is a blocking write, the returned Writer
 // will return whenever the timer hits (the return values are n=0
-// and err=context.Canceled.)
+// and err=context.DeadlineExceeded.)
 func NewDeadlineWriter(w io.WriteCloser, timeout time.Duration) io.WriteCloser {
 	return &DeadlineWriter{WriteCloser: w, timeout: timeout}
 }
@@ -154,8 +201,8 @@ func (w *DeadlineWriter) Write(buf []byte) (int, error) {
 		return r.n, r.err
 	case <-t.C:
 		w.WriteCloser.Close()
-		w.err = context.Canceled
-		return 0, context.Canceled
+		w.err = context.DeadlineExceeded
+		return 0, context.DeadlineExceeded
 	}
 }