Minor improvements:

EngineConfig:
o Let mutators return this to make it possible to chain calls.
mqtt_support:
o Store client_id so it can be logged when connecting.
createEngine:
o Comment out debug logging of URL parsing.
o Better error message when the URL is not set at all.

Author: trygvis

include/msgflo.h

@@ -121,16 +121,18 @@ class EngineConfig {
         _debugOutput = std::getenv("MSGFLO_CPP_DEBUG") ? true : false;
     }
 
-    void debugOutput(bool on) {
+    EngineConfig& debugOutput(bool on) {
         _debugOutput = on;
+        return *this;
     };
 
     bool debugOutput() const {
         return _debugOutput;
     }
 
-    void url(const std::string &url) {
+    EngineConfig& url(const std::string &url) {
         _url = url;
+        return *this;
     };
 
     std::string url() const {

src/mqtt_support.h

@@ -207,6 +207,7 @@ class mqtt_client : public waitable, private mqtt_lib {
     const string host;
     const int port;
     bool connecting_, connected_;
+    const string client_id;
     const int keep_alive;
     int unacked_messages_;
 
@@ -224,7 +225,7 @@ class mqtt_client : public waitable, private mqtt_lib {
     mqtt_client(mqtt_event_listener *event_listener, const string &host, const int port, const int keep_alive,
                 const string &client_id, const bool clean_session) :
         event_listener(event_listener), host(host), port(port), connecting_(false), connected_(false),
-        keep_alive(keep_alive), unacked_messages_(0) {
+        client_id(client_id), keep_alive(keep_alive), unacked_messages_(0) {
         const char *id = nullptr;
 
         if (!client_id.empty()) {
@@ -302,7 +303,7 @@ class mqtt_client : public waitable, private mqtt_lib {
     void connect() {
         guard lock(this_mutex);
 
-        auto msg = "Connecting to " + host + ":" + to_string(port) + ", keep_alive=" + to_string(keep_alive);
+        auto msg = "Connecting to " + host + ":" + to_string(port) + ", client_id=" + client_id + ", keep_alive=" + to_string(keep_alive);
         event_listener->on_msg(msg);
 
         if (connecting_ || connected_) {

src/msgflo.cpp

@@ -382,6 +382,10 @@ shared_ptr<Engine> createEngine(const EngineConfig config) {
         }
     }
 
+    if (url.empty()) {
+        throw invalid_argument("Missing msgflo url and MSGFLO_BROKER is not set.");
+    }
+
     if (string_starts_with(url, "mqtt://")) {
         string host, username, password;
         int port = 1883;
@@ -394,7 +398,7 @@ shared_ptr<Engine> createEngine(const EngineConfig config) {
 
         if (i_up != string::npos) {
             string up = s.substr(0, i_up);
-            cout << "up: " << up << endl;
+            // cout << "up: " << up << endl;
 
             auto i_u = up.find(':');
 
@@ -404,19 +408,19 @@ shared_ptr<Engine> createEngine(const EngineConfig config) {
             } else {
                 username = up;
             }
-            cout << "username: " << username << endl;
-            cout << "password: " << password << endl;
+            // cout << "username: " << username << endl;
+            // cout << "password: " << password << endl;
 
             s = s.substr(i_up + 1);
-            cout << "s: " << s << endl;
+            // cout << "s: " << s << endl;
         }
 
         auto i_q = s.find('?');
 
         if (i_q != string::npos) {
             host = s.substr(0, i_q);
             s = s.substr(i_q + 1);
-            cout << "s: " << s << endl;
+            // cout << "s: " << s << endl;
 
             while (!s.empty()) {
                 auto i_amp = s.find('&');
@@ -428,7 +432,7 @@ shared_ptr<Engine> createEngine(const EngineConfig config) {
                 } else {
                     kv = s.substr(0, i_amp);
                 }
-                cout << "kv: " << kv << endl;
+                // cout << "kv: " << kv << endl;
 
                 auto i_eq = kv.find('=');
 
@@ -439,6 +443,7 @@ shared_ptr<Engine> createEngine(const EngineConfig config) {
                 } else {
                     key = kv;
                 }
+                // cout << "key: " << key << endl;
 
                 if (key == "keepAlive") {
                     try {
@@ -464,7 +469,7 @@ shared_ptr<Engine> createEngine(const EngineConfig config) {
                     break;
                 }
                 s = s.substr(i_amp + 1);
-                cout << "s: " << s << endl;
+                // cout << "s: " << s << endl;
             }
         } else {
             host = s;