ESP32 OTA with espmqtt

esp_mqtt_ota.c

static void handle_ota(esp_mqtt_event_handle_t event, char *path[], int numComponents)
{
    esp_err_t err;
    static esp_ota_handle_t update_handle = 0;

    if (numComponents < 3)
    {
        ESP_LOGW(TAG, "too few components");
        return;
    }
    if (strcmp("version", path[2]) == 0)
    {
        ESP_LOGI(TAG, "ota: version=%.*s", event->data_len, event->data);
        if (strncmp(BUILD_TAG, event->data, strlen(BUILD_TAG)) < 0)
        {
            ESP_LOGI(TAG, "ota: firmware outdated, requesting update");
            mqtt_subscribe("ota/firmware");
        }
    }
    else if (strcmp("firmware", path[2]) == 0)
    {
        ESP_LOGI(TAG, "ota: receiving firmware image");
        if (event->current_data_offset == 0)
        {
            update_partition = esp_ota_get_next_update_partition(NULL);
            ESP_LOGI(TAG, "Writing to partition subtype %d at offset 0x%x",
                     update_partition->subtype, update_partition->address);
            assert(update_partition != NULL);
            
            err = esp_ota_begin(update_partition, OTA_SIZE_UNKNOWN, &update_handle);
            if (err != ESP_OK)
            {
                ESP_LOGE(TAG, "esp_ota_begin failed (%s)", esp_err_to_name(err));
                return;
            }
            ESP_LOGI(TAG, "esp_ota_begin succeeded");
        }
        if (update_handle)
        {
            // ESP_LOGI(TAG, "ota: writing %d bytes at offset %d", event->data_len, event->current_data_offset);
            err = esp_ota_write(update_handle, event->data, event->data_len);
            if (err != ESP_OK)
            {
                ESP_LOGE(TAG, "Error: esp_ota_write failed (%s)!", esp_err_to_name(err));
                return;
            }
        }
        if (event->data_len + event->current_data_offset >= event->total_data_len)
        {
            if (esp_ota_end(update_handle) != ESP_OK)
            {
                ESP_LOGE(TAG, "esp_ota_end failed!");
                return;
            }
            err = esp_ota_set_boot_partition(update_partition);
            if (err != ESP_OK)
            {
                ESP_LOGE(TAG, "esp_ota_set_boot_partition failed (%s)!", esp_err_to_name(err));
                return;
            }
            ESP_LOGI(TAG, "Prepare to restart system!");
            esp_restart();
            return;
        }
    }
}