Add 'routing_group_id' as bridge option

By specifying that manually, loop detection works accross multiple
FlashMQ servers bridged together.

Author: halfgaar

bridgeconfig.cpp

@@ -334,6 +334,11 @@ const std::optional<std::string> &BridgeConfig::getFmqClientGroupId() const
     return this->fmq_client_group_id;
 }
 
+void BridgeConfig::setFmqClientGroupId(const std::string &group_id)
+{
+    this->fmq_client_group_id = group_id;
+}
+
 void BridgeConfig::isValid()
 {
     if (sslPrivkey.empty() != sslFullchain.empty())
@@ -432,7 +437,8 @@ std::vector<BridgeConfig> BridgeConfig::multiply() const
              */
             result.back().appendConnectionNumber(i);
 
-            result.back().fmq_client_group_id = group_id;
+            if (!result.back().fmq_client_group_id)
+                result.back().fmq_client_group_id = group_id;
         }
 
         result.back().setClientId();

bridgeconfig.h

@@ -123,6 +123,7 @@ class BridgeConfig
     void setClientId(const std::string &prefix, const std::string &id);
     const std::string &getClientid() const;
     const std::optional<std::string> &getFmqClientGroupId() const;
+    void setFmqClientGroupId(const std::string &group_id);
     void isValid();
     std::vector<BridgeConfig> multiply() const;
     void setSharedSubscriptionName(const std::string &share_name);

configfileparser.cpp

@@ -302,6 +302,7 @@ ConfigFileParser::ConfigFileParser(const std::string &path) :
     validBridgeKeys.insert("minimum_tls_version");
     validBridgeKeys.insert("connection_count");
     validBridgeKeys.insert("max_buffer_size");
+    validBridgeKeys.insert("routing_group_id");
 
     validBridgeLazySubscriptionKeys.insert("subscribe");
     validBridgeLazySubscriptionKeys.insert("qos");
@@ -948,6 +949,13 @@ void ConfigFileParser::loadFile(bool test)
 
                     curBridge->maxBufferSize = val;
                 }
+                if (testKeyValidity(key, "routing_group_id", validBridgeKeys))
+                {
+                    if (valueTrimmed.length() != 12)
+                        throw ConfigFileException("Length of " + key + " must be 12 chars (and fully random)");
+
+                    curBridge->setFmqClientGroupId(valueTrimmed);
+                }
 
                 testCorrectNumberOfValues(key, number_of_expected_values, values);
                 continue;