Merge pull request #227 from jonas747/retry

Retry on 502's

discord.go

@@ -42,6 +42,7 @@ func New(args ...interface{}) (s *Session, err error) {
 		ShouldReconnectOnError: true,
 		ShardID:                0,
 		ShardCount:             1,
+		MaxRestRetries:         3,
 	}
 
 	// If no arguments are passed return the empty Session interface.

restapi.go

@@ -45,11 +45,13 @@ func (s *Session) Request(method, urlStr string, data interface{}) (response []b
 		}
 	}
 
-	return s.request(method, urlStr, "application/json", body)
+	return s.request(method, urlStr, "application/json", body, 0)
 }
 
 // request makes a (GET/POST/...) Requests to Discord REST API.
-func (s *Session) request(method, urlStr, contentType string, b []byte) (response []byte, err error) {
+// Sequence is the sequence number, if it fails with a 502 it will
+// retry with sequence+1 until it either succeeds or sequence >= session.MaxRestRetries
+func (s *Session) request(method, urlStr, contentType string, b []byte, sequence int) (response []byte, err error) {
 
 	// rate limit mutex for this url
 	// TODO: review for performance improvements
@@ -135,6 +137,16 @@ func (s *Session) request(method, urlStr, contentType string, b []byte) (respons
 
 		// TODO check for 401 response, invalidate token if we get one.
 
+	case http.StatusBadGateway:
+		// Retry sending request if possible
+		if sequence < s.MaxRestRetries {
+
+			s.log(LogInformational, "%s Failed (%s), Retrying...", urlStr, resp.Status)
+			response, err = s.request(method, urlStr, contentType, b, sequence+1)
+		} else {
+			err = fmt.Errorf("Exceeded Max retries HTTP %s, %s", resp.Status, response)
+		}
+
 	case 429: // TOO MANY REQUESTS - Rate limiting
 
 		mu.Lock() // lock URL ratelimit mutex
@@ -151,10 +163,10 @@ func (s *Session) request(method, urlStr, contentType string, b []byte) (respons
 
 		time.Sleep(rl.RetryAfter * time.Millisecond)
 		// we can make the above smarter
-		// this method can cause longer delays then required
+		// this method can cause longer delays than required
 
 		mu.Unlock() // we have to unlock here
-		response, err = s.request(method, urlStr, contentType, b)
+		response, err = s.request(method, urlStr, contentType, b, sequence)
 
 	default: // Error condition
 		err = fmt.Errorf("HTTP %s, %s", resp.Status, response)
@@ -718,7 +730,7 @@ func (s *Session) GuildMemberNickname(guildID, userID, nickname string) (err err
 // guildID   : The ID of a Guild.
 func (s *Session) GuildChannels(guildID string) (st []*Channel, err error) {
 
-	body, err := s.request("GET", EndpointGuildChannels(guildID), "", nil)
+	body, err := s.request("GET", EndpointGuildChannels(guildID), "", nil, 0)
 	if err != nil {
 		return
 	}
@@ -1096,7 +1108,7 @@ func (s *Session) ChannelMessage(channelID, messageID string) (st *Message, err
 // messageID : the ID of a Message
 func (s *Session) ChannelMessageAck(channelID, messageID string) (err error) {
 
-	_, err = s.request("POST", EndpointChannelMessageAck(channelID, messageID), "", nil)
+	_, err = s.request("POST", EndpointChannelMessageAck(channelID, messageID), "", nil, 0)
 	return
 }
 
@@ -1264,7 +1276,7 @@ func (s *Session) ChannelFileSendWithMessage(channelID, content string, name str
 		return
 	}
 
-	response, err := s.request("POST", EndpointChannelMessages(channelID), bodywriter.FormDataContentType(), body.Bytes())
+	response, err := s.request("POST", EndpointChannelMessages(channelID), bodywriter.FormDataContentType(), body.Bytes(), 0)
 	if err != nil {
 		return
 	}

structs.go

@@ -53,6 +53,9 @@ type Session struct {
 	// Whether the Data Websocket is ready
 	DataReady bool // NOTE: Maye be deprecated soon
 
+	// Max number of REST API retries
+	MaxRestRetries int
+
 	// Status stores the currect status of the websocket connection
 	// this is being tested, may stay, may go away.
 	status int32