New option to cap the max wait between reconnection attempts. Still default to 10s. (setMaxWaitBetweenReconnectionRetries) (#108)

ixwebsocket/IXExponentialBackoff.cpp

@@ -0,0 +1,26 @@
+/*
+ *  IXExponentialBackoff.h
+ *  Author: Benjamin Sergeant
+ *  Copyright (c) 2017-2019 Machine Zone, Inc. All rights reserved.
+ */
+
+#include "IXExponentialBackoff.h"
+
+#include <cmath>
+
+namespace ix
+{
+    uint32_t calculateRetryWaitMilliseconds(
+        uint32_t retry_count,
+        uint32_t maxWaitBetweenReconnectionRetries)
+    {
+        uint32_t wait_time = std::pow(2, retry_count) * 100;
+
+        if (wait_time > maxWaitBetweenReconnectionRetries || wait_time == 0)
+        {
+            wait_time = maxWaitBetweenReconnectionRetries;
+        }
+
+        return wait_time;
+    }
+}

ixwebsocket/IXExponentialBackoff.h

@@ -0,0 +1,16 @@
+/*
+ *  IXExponentialBackoff.h
+ *  Author: Benjamin Sergeant
+ *  Copyright (c) 2017-2019 Machine Zone, Inc. All rights reserved.
+ */
+
+#pragma once
+
+#include <cstdint>
+
+namespace ix
+{
+    uint32_t calculateRetryWaitMilliseconds(
+        uint32_t retry_count,
+        uint32_t maxWaitBetweenReconnectionRetries);
+} // namespace ix

ixwebsocket/IXWebSocket.cpp

@@ -7,30 +7,11 @@
 #include "IXWebSocket.h"
 #include "IXSetThreadName.h"
 #include "IXWebSocketHandshake.h"
+#include "IXExponentialBackoff.h"
 
 #include <cmath>
 #include <cassert>
 
-namespace
-{
-    uint64_t calculateRetryWaitMilliseconds(uint32_t retry_count)
-    {
-        uint64_t wait_time;
-
-        if (retry_count <= 6)
-        {
-            // max wait_time is 6400 ms (2 ^ 6 = 64)
-            wait_time = ((uint64_t)std::pow(2, retry_count) * 100L);
-        }
-        else
-        {
-            wait_time = 10 * 1000; // 10 sec
-        }
-
-        return wait_time;
-    }
-}
-
 namespace ix
 {
     OnTrafficTrackerCallback WebSocket::_onTrafficTrackerCallback = nullptr;
@@ -38,11 +19,13 @@ namespace ix
     const int WebSocket::kDefaultPingIntervalSecs(-1);
     const int WebSocket::kDefaultPingTimeoutSecs(-1);
     const bool WebSocket::kDefaultEnablePong(true);
+    const uint32_t WebSocket::kDefaultMaxWaitBetweenReconnectionRetries(10 * 1000); // 10s
 
     WebSocket::WebSocket() :
         _onMessageCallback(OnMessageCallback()),
         _stop(false),
         _automaticReconnection(true),
+        _maxWaitBetweenReconnectionRetries(kDefaultMaxWaitBetweenReconnectionRetries),
         _handshakeTimeoutSecs(kDefaultHandShakeTimeoutSecs),
         _enablePong(kDefaultEnablePong),
         _pingIntervalSecs(kDefaultPingIntervalSecs),
@@ -149,6 +132,18 @@ namespace ix
         _perMessageDeflateOptions = perMessageDeflateOptions;
     }
 
+    void WebSocket::setMaxWaitBetweenReconnectionRetries(uint32_t maxWaitBetweenReconnectionRetries)
+    {
+        std::lock_guard<std::mutex> lock(_configMutex);
+        _maxWaitBetweenReconnectionRetries = maxWaitBetweenReconnectionRetries;
+    }
+
+    uint32_t WebSocket::getMaxWaitBetweenReconnectionRetries() const
+    {
+        std::lock_guard<std::mutex> lock(_configMutex);
+        return _maxWaitBetweenReconnectionRetries;
+    }
+
     void WebSocket::start()
     {
         if (_thread.joinable()) return; // we've already been started
@@ -276,7 +271,7 @@ namespace ix
 
                 if (_automaticReconnection)
                 {
-                    duration = millis(calculateRetryWaitMilliseconds(retries++));
+                    duration = millis(calculateRetryWaitMilliseconds(retries++, _maxWaitBetweenReconnectionRetries));
 
                     connectErr.wait_time = duration.count();
                     connectErr.retries = retries;

ixwebsocket/IXWebSocket.h

@@ -97,6 +97,8 @@ namespace ix
         void enableAutomaticReconnection();
         void disableAutomaticReconnection();
         bool isAutomaticReconnectionEnabled() const;
+        void setMaxWaitBetweenReconnectionRetries(uint32_t maxWaitBetweenReconnectionRetries);
+        uint32_t getMaxWaitBetweenReconnectionRetries() const;
 
     private:
         WebSocketSendInfo sendMessage(const std::string& text,
@@ -123,10 +125,14 @@ namespace ix
         static OnTrafficTrackerCallback _onTrafficTrackerCallback;
 
         std::atomic<bool> _stop;
-        std::atomic<bool> _automaticReconnection;
         std::thread _thread;
         std::mutex _writeMutex;
 
+        // Automatic reconnection
+        std::atomic<bool> _automaticReconnection;
+        static const uint32_t kDefaultMaxWaitBetweenReconnectionRetries;
+        uint32_t _maxWaitBetweenReconnectionRetries;
+
         std::atomic<int> _handshakeTimeoutSecs;
         static const int kDefaultHandShakeTimeoutSecs;