Improve documentation and log output

This patchset improves the description of how client/server mode is
used. It also updates some log prints to make things clearer.

Change-Id: I11583812546138c4015dd3842277f797b4c7d160
Signed-off-by: Joakim Roubert <joakimr@axis.com>

README.md

@@ -120,23 +120,35 @@ curl -k --anyauth -u root:<password> \
 
 ## Usage
 
-The application can be run in either client mode or server mode (default),
+> [!IMPORTANT]
+> The default Modbus/TCP port 502 requires running as a privileged user.
+> In order to run as a non-privileged user, this ACAP application only allows
+> ports in the non-privileged range 1024–65535.
+
+The application can be run in either *client* mode (default) or *server* mode,
 configured with the application parameter `Mode`:
 
-In client mode, it will subscribe to
+### Client mode (default)
+
+![Camera to modbus device](images/cam_to_modbus.svg)
+
+The application subscribes to
 [AXIS Object Analytics](https://www.axis.com/products/axis-object-analytics)
-(AOA) events for the AOA scenario specified in the application parameter
-`Scenario` (default: Scenario 1) and send the trigger status (active/inactive)
-over Modbus (TCP) to the Modbus server running on the host set in the ACAP's
-parameter `Server`.
+(AOA) events for the specified scenario *(default: Scenario 1)* and sends
+trigger status *(active/inactive)* over Modbus (TCP) to the server specified
+in the application configuration. **This the typical use case** where the Axis
+device pushes AOA events to a receiving Modbus device.
 
-In server mode, it will listen for incoming TCP requests and print incoming
-AOA status updates to the application log.
+### Server mode
 
-> [!IMPORTANT]
-> The default Modbus/TCP port 502 requires running as a privileged user.
-> In order to run as a non-privileged user, this ACAP application only allows
-> ports in the non-privileged range 1024–65535.
+![Camera to other camera](images/cam_to_cam.svg)
+
+In server mode, the application listens for incoming TCP requests and logs AOA
+status updates from a connected device running in client mode. **This mode is
+useful for testing and debugging without a separate Modbus device.**
+*In server mode, the application also subscribes to AOA events from its host
+device, but does not send them anywhere. That is solely for easy debugging and
+testing the application's subscription mechanism.*
 
 ## License
 

manifest.json

@@ -7,12 +7,12 @@
             "vendor": "Axis Communications AB",
             "embeddedSdkVersion": "3.0",
             "runMode": "respawn",
-            "version": "1.2.1"
+            "version": "1.2.2"
         },
         "configuration": {
             "settingPage": "config.html",
             "paramConfig": [
-                {"name": "Mode", "type": "enum:0|Server, 1|Client", "default": "0"},
+                {"name": "Mode", "type": "enum:0|Server, 1|Client", "default": "1"},
                 {"name": "Port", "type": "int:min=1024,max=65535", "default": "5020"},
                 {"name": "Scenario", "type": "int:min=1,max=99", "default": "1"},
                 {"name": "Server", "type": "string", "default": "172.25.75.172"}

modbusacap.c

@@ -64,7 +64,11 @@ static void event_callback(guint subscription, AXEvent *event, void *data)
 
     if (ax_event_key_value_set_get_boolean(key_value_set, "active", NULL, &active, NULL))
     {
-        LOG_I("aoa-event %s active", active ? "is" : "NOT");
+        LOG_I(
+            "aoa-event %s active (%s)",
+            active ? "is" : "NOT",
+            CLIENT == mode ? "running in client mode, passing on via Modbus"
+                           : "running in server mode, not forwarded anywhere");
         // Send event over Modbus
         if (CLIENT == mode)
         {
@@ -76,7 +80,10 @@ static void event_callback(guint subscription, AXEvent *event, void *data)
     }
     else
     {
-        LOG_I("%s/%s: Failed to get boolean value active from event", __FILE__, __FUNCTION__);
+        LOG_I(
+            "%s/%s: Received event without boolean value 'active' (probably not a stateful event)",
+            __FILE__,
+            __FUNCTION__);
     }
 
     // Free the received event, n.b. AXEventKeyValueSet should not be freed