[iot] Fixes to Azure IoT Hub ESP8266 sample (Azure#899)

* [iot] Fixes to Azure IoT Hub ESP8266 sample

- Renamed the directory so it can be opened directly on Arduino IDE
- Added call to .loop() on pubsubclient
- Added call to .setBufferSize() on pubsubclient, removed step to manually fix MQTT_MAX_PACKET_SIZE

sdk/docs/iot/README.md

@@ -35,7 +35,7 @@ The library targets made available via CMake are the following:
 
   - Windows: [How to Setup and Run Azure SDK for Embedded C IoT Hub Samples on Microsoft Windows](../../../sdk/samples/iot/hub/windows/how_to_iot_hub_samples_windows.md).
 
-  - ESP8266: [How to Setup and Run Azure SDK for Embedded C IoT Hub Client on Esp8266 NodeMCU](../../../sdk/samples/iot/hub/esp8266nodemcu/how_to_esp8266_nodemcu.md)
+  - ESP8266: [How to Setup and Run Azure SDK for Embedded C IoT Hub Client on Esp8266 NodeMCU](../../../sdk/samples/iot/hub/aziot_esp8266/how_to_esp8266_nodemcu.md)
 
   **Note**: While Windows and Linux devices are not likely to be considered as constrained ones, these samples were created to make it simpler to test the Azure SDK for Embedded C libraries, even without a real device. 
 

sdk/samples/iot/hub/README.md

@@ -16,7 +16,7 @@ This document explains samples for the Azure SDK for Embedded C IoT Hub Client a
 For step-by-step guides starting from scratch, you may refer to these documents:
   - Linux: [How to setup and run Azure SDK for Embedded C IoT Hub Samples on Linux](./linux/how_to_iot_hub_samples_linux.md)
   - Windows: [How to setup and run Azure SDK for Embedded C IoT Hub Samples on Microsoft Windows](./windows/how_to_iot_hub_samples_windows.md).
-  - ESP8266: [How to Setup and Run Azure SDK for Embedded C IoT Hub Client on Esp8266 NodeMCU](./esp8266nodemcu/how_to_esp8266_nodemcu.md)
+  - ESP8266: [How to Setup and Run Azure SDK for Embedded C IoT Hub Client on Esp8266 NodeMCU](./aziot_esp8266/how_to_esp8266_nodemcu.md)
 
   **Note**: While Windows and Linux devices are not likely to be considered as constrained ones, these samples were created to make it simpler to test the Azure SDK for Embedded C libraries, even without a real device. 
 

sdk/samples/iot/hub/esp8266nodemcu/azure_iot_hub_telemetry.ino → sdk/samples/iot/hub/aziot_esp8266/aziot_esp8266.ino

@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// SPDX-License-Identifier: MIT
+
 #include <string.h>
 #include <stdbool.h>
 #include <time.h>
@@ -21,6 +24,7 @@
 #define sizeofarray(a) (sizeof(a) / sizeof(a[0]))
 #define ONE_HOUR_IN_SECS 3600
 #define NTP_SERVERS "pool.ntp.org", "time.nist.gov"
+#define MQTT_PACKET_SIZE 1024
 
 static const char* ssid = IOT_CONFIG_WIFI_SSID;
 static const char* password = IOT_CONFIG_WIFI_PASSWORD;
@@ -213,6 +217,8 @@ static int connectToAzureIoTHub()
   Serial.print("Username: ");
   Serial.println(mqtt_username);
 
+  mqtt_client.setBufferSize(MQTT_PACKET_SIZE);
+
   while (!mqtt_client.connected())
   {
     time_t now = time(NULL);
@@ -279,6 +285,8 @@ void loop()
       sendTelemetry();
     }
 
+    mqtt_client.loop();
+
     next_telemetry_send_time_ms = millis() + TELEMETRY_FREQUENCY_MILLISECS;
   }
 }

sdk/samples/iot/hub/esp8266nodemcu/how_to_esp8266_nodemcu.md → sdk/samples/iot/hub/aziot_esp8266/how_to_esp8266_nodemcu.md

@@ -25,7 +25,7 @@ _The following was run on an Ubuntu Desktop 18.04 environment, with Arduino IDE
 01. Create an Arduino library for Azure Embedded SDK for C 
 
     ```
-    $ wget https://raw.githubusercontent.com/Azure/azure-sdk-for-c/master/sdk/samples/iot/hub/esp8266nodemcu/generate_arduino_zip_library.sh
+    $ wget https://raw.githubusercontent.com/Azure/azure-sdk-for-c/master/sdk/samples/iot/hub/aziot_esp8266/generate_arduino_zip_library.sh
     $ chmod 777 generate_arduino_zip_library.sh
     $ ./generate_arduino_zip_library.sh
     ```
@@ -53,41 +53,9 @@ _The following was run on an Ubuntu Desktop 18.04 environment, with Arduino IDE
     - Search for `PubSubClient` (by Nick O'Leary)
     - Hover over the library item on the result list, then click on Install.
 
-05. Fix PubSubClient library locally
+05. Create a sketch on Arduino IDE for the IoT Hub client telemetry sample
 
-    PubSubClient defines the default MQTT maximum packet size to be 128 bytes.
-
-    That is not enough to send and receive packets to/from the Azure IoT Hub.
-
-    Currently the library also does not provide a dynamic way to change the maximum MQTT packet size ([see known issue](https://github.com/knolleary/pubsubclient/issues/110)).
-
-    Also, the Arduino IDE does not propage #defines into the library dependencies (they get compiled before the sketch).
-
-    Finally, the Arduino IDE does not take compiler flags.
-
-    So the PubSubClient library code must be changed to make `MQTT_MAX_PACKET_SIZE` larger (e.g, 1024).
-
-    To make the change, search for the file in your system
-
-    ```
-    find / -iname PubSubClient.h
-    ```
-
-    Open the PubSubClient.h file in your favorite text editor.
-
-    Search for the line that defines the macro `MQTT_MAX_PACKET_SIZE`.
-
-    Change the value of the macro to a higher number, like 1024.
-
-    ```c
-    #define MQTT_MAX_PACKET_SIZE 1024
-    ```
-
-    Save and close the `PubSubClient.h` file.
-
-06. Create a sketch on Arduino IDE for the IoT Hub client telemetry sample
-
-    Copy the code from the [ESP8266 Node MCU sample](https://github.com/Azure/azure-sdk-for-c/blob/master/sdk/samples/iot/hub/esp8266nodemcu) into your sketch.
+    Clone the [azure-sdk-for-c](https://github.com/Azure/azure-sdk-for-c) repo locally then open the [ESP8266 sample](https://github.com/Azure/azure-sdk-for-c/blob/master/sdk/samples/iot/hub/aziot_esp8266) (from local clone) on Arduino IDE. 
     
     Edit the following parameters in `iot_configs.h`, filling in your own information:
 
@@ -104,14 +72,14 @@ _The following was run on an Ubuntu Desktop 18.04 environment, with Arduino IDE
 
     Save the file.
 
-07. Connect the Esp8266 NodeMCU microcontroller to your USB port
+06. Connect the Esp8266 NodeMCU microcontroller to your USB port
 
-08. On the Arduino IDE, select the board and port
+07. On the Arduino IDE, select the board and port
 
     - Go to menu `Tools`, `Board` and select `NodeMCU 1.0 (ESP-12E Module)`
     - Go to menu `Tools`, `Port` and select the port where the microcontroller is connected to.
 
-09. Upload the sketch
+08. Upload the sketch
 
     - Go to menu `Sketch` and click on `Upload`.
 
@@ -167,7 +135,7 @@ _The following was run on an Ubuntu Desktop 18.04 environment, with Arduino IDE
     Hard resetting via RTS pin...
     </details>
 
-10. Monitor the micro-controller
+09. Monitor the micro-controller
 
     Go to menu `Tools`, `Serial Monitor`.
 
@@ -186,7 +154,7 @@ _The following was run on an Ubuntu Desktop 18.04 environment, with Arduino IDE
 
     ```
 
-11. Monitor the telemetry messages sent to the Azure IoT Hub 
+10. Monitor the telemetry messages sent to the Azure IoT Hub 
 
     ```
     $ az iot hub monitor-events --login <your Azure IoT Hub connection string in quotes> --device-id <your device id>

sdk/samples/iot/hub/esp8266nodemcu/iot_configs.h → sdk/samples/iot/hub/aziot_esp8266/iot_configs.h

@@ -1,3 +1,6 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// SPDX-License-Identifier: MIT
+
 // Wifi
 #define IOT_CONFIG_WIFI_SSID            "SSID"
 #define IOT_CONFIG_WIFI_PASSWORD        "PWD"