AzureIoTLiteClient

Azure IoT Hub / Central lite client library for ESP32, using MQTT. It's written in C++, and meant to be as lighter library if compared to esp-azure library. It currently needs Arduino framework.

You can still use ESP-IDF framework, as long as you include arduino-esp32 as ESP-IDF component.

I'm trying to make the library works for another platform, like K210 with Maixduino framework. Code optimization and seperation are already prepared. Need more testing.

Sample code

Azure IoT Central

This is simple sample code to connect to Azure IoT Central and publish some telemetry and property.

#include <Arduino.h>
#include "AzureIoTLiteClient.h"
#include <WiFiClientSecure.h>

const char* ssidName = "<CHANGE_THIS>";      // your network SSID (name of wifi network)
const char* ssidPass = "<CHANGE_THIS>";      // your network password

AzureIoTConfig_t iotconfig {
        "<CHANGE_THIS>",                    // Azure IoT Central - scopeId
        "<CHANGE_THIS>",                    // deviceId
        "<CHANGE_THIS>",                    // deviceKey
        AZURE_IOTC_CONNECT_SYMM_KEY         // Connection method
};

WiFiClientSecure wifiClient;
AzureIoTLiteClient iotclient(wifiClient);
bool isConnected = false;

static bool connectWiFi() {
    Serial.printf("Connecting WIFI to SSID: %s\r\n", ssidName);

    WiFi.begin(ssidName, ssidPass);

    // Attempt to connect to Wifi network:
    while (WiFi.status() != WL_CONNECTED) {
        Serial.print(".");
        // wait 1 second for re-trying
        delay(1000);
    }

    Serial.printf("Connected to %s\r\n", ssidName);
    Serial.print("IP: "); Serial.println(WiFi.localIP());

    return true;
}

void onAzureIoTEvent(const AzureIoTCallbacks_e cbType, const AzureIoTCallbackInfo_t *callbackInfo) {
    // ConnectionStatus
    if (strcmp(callbackInfo->eventName, "ConnectionStatus") == 0) {
        LOG_VERBOSE("Is connected ? %s (%d)", callbackInfo->statusCode == AzureIoTConnectionOK ? "YES" : "NO",  callbackInfo->statusCode);
        isConnected = callbackInfo->statusCode == AzureIoTConnectionOK;
        return;
    }

    // payload buffer doesn't have a null ending.
    // add null ending in another buffer before print
    AzureIOT::StringBuffer buffer;
    if (callbackInfo->payloadLength > 0) {
        buffer.initialize(callbackInfo->payload, callbackInfo->payloadLength);
    }

    LOG_VERBOSE("[%s] event was received. Payload => %s\n", callbackInfo->eventName, buffer.getLength() ? *buffer : "EMPTY");

    if (strcmp(callbackInfo->eventName, "Command") == 0) {
        LOG_VERBOSE("Command name was => %s\r\n", callbackInfo->tag);
    }
}

void setup() {
    Serial.begin(115200);
    
    if (!connectWiFi()) {
        while(1)
            ;
        // No point to continue
    }

    // Add callbacks
    iotclient.setCallback(AzureIoTCallbackMessageSent, onAzureIoTEvent);
    iotclient.setCallback(AzureIoTCallbackCommand, onAzureIoTEvent);
    iotclient.setCallback(AzureIoTCallbackSettingsUpdated, onAzureIoTEvent);
    
    // Must call this
    iotclient.begin(&iotconfig);
    
    // Do connect
    iotclient.connect();
}

unsigned long lastTick = 0;

void loop() {

    if (!iotclient.run()) {
        return; //No point to continue
    }

    unsigned long now = millis();

    // Send telemetry every 10 seconds
    if (ms - lastTick > 10000) { 
 
        char msg[64] = {0};
        int pos = 0;
        bool errorCode = 0;

        lastTick = now;

        // Send telemetry, randomized for now
        long tempVal = random(35, 40);
        pos = snprintf(msg, sizeof(msg) - 1, "{\"temperature\": %.2f}", tempVal*1.0f);
        msg[pos] = 0;
        errorCode = iotclient.sendTelemetry(msg, pos);

        // Send property
        pos = snprintf(msg, sizeof(msg) - 1, "{\"temperatureAlert\": %d}", (tempVal >= 38));
        msg[pos] = 0;
        errorCode = iotclient.sendProperty(msg, pos);

        if (!errorCode) {
            LOG_ERROR("Sending message has failed with error code %d", errorCode);
        }
    }
}

Azure IoT Hub

This sample is to connect with Azure IoT Hub. Notice that I use connection string, instead of SYM KEY. This example is targetted for ESP-WROVER-KIT board.

#include <Arduino.h>
#include "AzureIoTLiteClient.h"
#include <WiFiClientSecure.h>

const char* ssidName = "<CHANGE_THIS>";      // your network SSID (name of wifi network)
const char* ssidPass = "<CHANGE_THIS>";      // your network password

//Conn String format example: HostName=[BLA_BLA];DeviceId=[BLA_BLA];SharedAccessKey=[BLA_BLA]
AzureIoTConfig_t iotconfig("<CHANGE_THIS>");

WiFiClientSecure wifiClient;
AzureIoTLiteClient iotclient(wifiClient);
bool isConnected = false;

static bool connectWiFi() {
    Serial.printf("Connecting WIFI to SSID: %s\r\n", ssidName);

    WiFi.begin(ssidName, ssidPass);

    // Attempt to connect to Wifi network:
    while (WiFi.status() != WL_CONNECTED) {
        Serial.print(".");
        // wait 1 second for re-trying
        delay(1000);
    }

    Serial.printf("Connected to %s\r\n", ssidName);
    Serial.print("IP: "); Serial.println(WiFi.localIP());

    return true;
}

void executeCommand(const char *cmdName, char *payload) {
    if (strcmp(cmdName, "setLED") == 0) {
        LOG_VERBOSE("Executing setLED -> value: %s", payload);
        int ledVal = atoi(payload);
        digitalWrite(2, ledVal);
    }
}

void onEvent(const AzureIoTCallbacks_e cbType, const AzureIoTCallbackInfo_t *callbackInfo) {
    // ConnectionStatus
    if (strcmp(callbackInfo->eventName, "ConnectionStatus") == 0) {
        LOG_VERBOSE("Is connected ? %s (%d)", callbackInfo->statusCode == AzureIoTConnectionOK ? "YES" : "NO",  callbackInfo->statusCode);
        isConnected = callbackInfo->statusCode == AzureIoTConnectionOK;
        return;
    }

    // payload buffer doesn't have a null ending.
    // add null ending in another buffer before print
    AzureIOT::StringBuffer buffer;
    if (callbackInfo->payloadLength > 0) {
        buffer.initialize(callbackInfo->payload, callbackInfo->payloadLength);
    }

    LOG_VERBOSE("[%s] event was received. Payload => %s\n", callbackInfo->eventName, buffer.getLength() ? *buffer : "EMPTY");

    if (strcmp(callbackInfo->eventName, "Command") == 0) {
        LOG_VERBOSE("Command name was => %s\r\n", callbackInfo->tag);
        executeCommand(callbackInfo->tag, *buffer);
    }
}

void setup() {
    delay(2000);
    Serial.begin(115200);
    Serial.println("It begins");

    if (!connectWiFi()) {
        while(1)
            ;
    }

    // Prepare LED on WROVER
    pinMode(0, OUTPUT);
    pinMode(2, OUTPUT);
    pinMode(4, OUTPUT);

    // Turn off all LEDs on WROVER
    digitalWrite(0, LOW);
    digitalWrite(2, LOW);
    digitalWrite(4, LOW);

    // Add callbacks
    iotclient.setCallback(AzureIoTCallbackConnectionStatus, onEvent);
    iotclient.setCallback(AzureIoTCallbackMessageSent, onEvent);
    iotclient.setCallback(AzureIoTCallbackCommand, onEvent);
    iotclient.setCallback(AzureIoTCallbackSettingsUpdated, onEvent);

    iotclient.begin(&iotconfig);
}

unsigned long lastTick = 0, loopId = 0;
void loop() {

    if (!iotclient.run()) {
        return; //No point to continue
    }

    unsigned long ms = millis();
    if (ms - lastTick > 15000) {  // send telemetry every 10 seconds
        char msg[64] = {0};
        int pos = 0;
        bool errorCode = false;

        lastTick = ms;

        // Randomize to simulate temperature
        long tempVal = random(35, 40);

        // Send telemetry
        if (tempVal >= 38) {
            pos = snprintf(msg, sizeof(msg) - 1, R"({"temperature": %.2f, "temperatureAlert": %d})", tempVal*1.0f, (tempVal >= 38));
            msg[pos] = 0;
            errorCode = iotclient.sendTelemetry(msg, pos);
        } else {
            pos = snprintf(msg, sizeof(msg) - 1, "{\"temperature\": %.2f}", tempVal*1.0f);
            msg[pos] = 0;
            errorCode = iotclient.sendTelemetry(msg, pos);
        }

        if (!errorCode) {
            LOG_ERROR("Sending message has failed");
        }

        if (!errorCode) {
            LOG_ERROR("Sending message has failed with error code %d", errorCode);
        }
    }
}

Invoke Direct Method

To invoke direct method of the device from the cloud, in this example, using VSCode, here's the flow:

Credits

Significant amount of code is adapted from here.
PubSubClient is changed and bundled in this repo.

andriyadi / azureiotliteclient Goto Github PK