fix(esp-modem): Example to use variable mqtt topic/data

This example is used in the CI with public broker and
users playing with the example can influence stability
of tests if we share the same topic id

components/esp_modem/examples/pppos_client/main/Kconfig.projbuild

@@ -184,4 +184,22 @@ menu "Example Configuration"
 
     endmenu
 
+    config EXAMPLE_MQTT_BROKER_URI
+        string "MQTT Broker URL"
+        default "mqtt://mqtt.eclipseprojects.io"
+        help
+            URL of the mqtt broker which this example connects to.
+
+    config EXAMPLE_MQTT_TEST_TOPIC
+        string "MQTT topic to publish/subscribe"
+        default "/topic/esp-pppos"
+        help
+            MQTT topic, which we subscribe on and publish to.
+
+    config EXAMPLE_MQTT_TEST_DATA
+        string "MQTT data to publish/receive"
+        default "esp32-pppos"
+        help
+            MQTT data message, which we publish and expect to receive.
+
 endmenu

components/esp_modem/examples/pppos_client/main/pppos_client_main.c

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2022-2023 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Unlicense OR CC0-1.0
  */
@@ -30,7 +30,6 @@
 #define EXAMPLE_FLOW_CONTROL ESP_MODEM_FLOW_CONTROL_HW
 #endif
 
-#define BROKER_URL "mqtt://mqtt.eclipseprojects.io"
 
 static const char *TAG = "pppos_example";
 static EventGroupHandle_t event_group = NULL;
@@ -68,15 +67,15 @@ static void mqtt_event_handler(void *handler_args, esp_event_base_t base, int32_
     switch ((esp_mqtt_event_id_t)event_id) {
     case MQTT_EVENT_CONNECTED:
         ESP_LOGI(TAG, "MQTT_EVENT_CONNECTED");
-        msg_id = esp_mqtt_client_subscribe(client, "/topic/esp-pppos", 0);
+        msg_id = esp_mqtt_client_subscribe(client, CONFIG_EXAMPLE_MQTT_TEST_TOPIC, 0);
         ESP_LOGI(TAG, "sent subscribe successful, msg_id=%d", msg_id);
         break;
     case MQTT_EVENT_DISCONNECTED:
         ESP_LOGI(TAG, "MQTT_EVENT_DISCONNECTED");
         break;
     case MQTT_EVENT_SUBSCRIBED:
         ESP_LOGI(TAG, "MQTT_EVENT_SUBSCRIBED, msg_id=%d", event->msg_id);
-        msg_id = esp_mqtt_client_publish(client, "/topic/esp-pppos", "esp32-pppos", 0, 0, 0);
+        msg_id = esp_mqtt_client_publish(client, CONFIG_EXAMPLE_MQTT_TEST_TOPIC, CONFIG_EXAMPLE_MQTT_TEST_DATA, 0, 0, 0);
         ESP_LOGI(TAG, "sent publish successful, msg_id=%d", msg_id);
         break;
     case MQTT_EVENT_UNSUBSCRIBED:
@@ -271,11 +270,11 @@ void app_main(void)
     /* Config MQTT */
 #if ESP_IDF_VERSION >= ESP_IDF_VERSION_VAL(5, 0, 0)
     esp_mqtt_client_config_t mqtt_config = {
-        .broker.address.uri = BROKER_URL,
+        .broker.address.uri = CONFIG_EXAMPLE_MQTT_BROKER_URI,
     };
 #else
     esp_mqtt_client_config_t mqtt_config = {
-        .uri = BROKER_URL,
+        .uri = CONFIG_EXAMPLE_MQTT_BROKER_URI,
     };
 #endif
     esp_mqtt_client_handle_t mqtt_client = esp_mqtt_client_init(&mqtt_config);

components/esp_modem/examples/pppos_client/pytest_pppos_client.py

@@ -1,4 +1,4 @@
-# SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
+# SPDX-FileCopyrightText: 2022-2023 Espressif Systems (Shanghai) CO LTD
 # SPDX-License-Identifier: Unlicense OR CC0-1.0
 from __future__ import print_function, unicode_literals
 
@@ -16,7 +16,7 @@ def test_pppos_connect(dut):
     # Check for MQTT connection and the data event
     dut.expect('MQTT_EVENT_CONNECTED')
     dut.expect('MQTT_EVENT_DATA')
-    dut.expect('TOPIC=/topic/esp-pppos')
+    dut.expect('TOPIC=/ci/esp-modem/pppos-client')
     dut.expect('DATA=esp32-pppos')
     # Check that we have disconnected
     dut.expect('User interrupted event')

components/esp_modem/examples/pppos_client/sdkconfig.ci.sim800

@@ -9,5 +9,6 @@ CONFIG_EXAMPLE_MODEM_UART_RX_PIN=5
 CONFIG_EXAMPLE_MODEM_DEVICE_SIM800=y
 CONFIG_EXAMPLE_MODEM_DEVICE_BG96=n
 CONFIG_EXAMPLE_MODEM_PPP_APN="lpwa.vodafone.com"
+CONFIG_EXAMPLE_MQTT_TEST_TOPIC="/ci/esp-modem/pppos-client"
 CONFIG_ESP_SYSTEM_PANIC_PRINT_HALT=y
 CONFIG_ESP32_PANIC_PRINT_HALT=y