From a23464dfa1e707eddb997071e24c8e2979d95b02 Mon Sep 17 00:00:00 2001
From: Klaus Post <klauspost@gmail.com>
Date: Sun, 13 Sep 2015 16:22:41 +0200
Subject: [PATCH] Retry if a timeout occurs.

This happens more rarely than 500, but can still be encountered.
---
 amazonclouddrive/amazonclouddrive.go | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/amazonclouddrive/amazonclouddrive.go b/amazonclouddrive/amazonclouddrive.go
index 82adbd9fe..f85e77b93 100644
--- a/amazonclouddrive/amazonclouddrive.go
+++ b/amazonclouddrive/amazonclouddrive.go
@@ -15,7 +15,9 @@ import (
 	"fmt"
 	"io"
 	"log"
+	"net"
 	"net/http"
+	"net/url"
 	"regexp"
 	"strings"
 	"time"
@@ -126,8 +128,7 @@ func parsePath(path string) (root string) {
 // shouldRetry returns a boolean as to whether this resp and err
 // deserve to be retried.  It returns the err as a convenience
 func shouldRetry(resp *http.Response, err error) (bool, error) {
-	// FIXME retry other http codes?
-	// 409 conflict ?
+	// Retry on 429 Rate exceeded.
 	if err != nil && resp != nil && resp.StatusCode == 429 {
 		return true, err
 	}
@@ -135,6 +136,18 @@ func shouldRetry(resp *http.Response, err error) (bool, error) {
 	if err != nil && resp != nil && resp.StatusCode == 500 {
 		return true, err
 	}
+	// Allow retry if request times out. Adapted from
+	// http://stackoverflow.com/questions/23494950/specifically-check-for-timeout-error
+	switch err := err.(type) {
+	case *url.Error:
+		if err, ok := err.Err.(net.Error); ok && err.Timeout() {
+			return true, err
+		}
+	case net.Error:
+		if err.Timeout() {
+			return true, err
+		}
+	}
 	return false, err
 }