Simple demo project running sntp with static IP on IDF v4.3

sntp_static_ip_example.c

/* SNTP example with static IP

   This example code is in the Public Domain (or CC0 licensed, at your option.)

   Unless required by applicable law or agreed to in writing, this
   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
   CONDITIONS OF ANY KIND, either express or implied.
*/
#include <string.h>
#include <time.h>
#include "freertos/FreeRTOS.h"
#include "freertos/event_groups.h"
#include "esp_system.h"
#include "esp_event.h"
#include "esp_log.h"
#include "esp_attr.h"
#include "nvs_flash.h"
#include "esp_sntp.h"
#include "esp_wifi.h"


#define WIFI_CONNECTED_BIT BIT0
#define WIFI_FAIL_BIT      BIT1
#define EXAMPLE_STATIC_IP_ADDR        "192.168.10.222"
#define EXAMPLE_STATIC_NETMASK_ADDR   "255.255.255.0"
#define EXAMPLE_STATIC_GW_ADDR        "192.168.10.1"
#define EXAMPLE_MAIN_DNS_SERVER       "8.8.8.8"
#define EXAMPLE_MAXIMUM_RETRY         10

static int s_retry_num = 0;
static const char *TAG = "sntp_static_ip";
static EventGroupHandle_t s_wifi_event_group;

static void obtain_time(void);
static void initialize_sntp(void);


void time_sync_notification_cb(struct timeval *tv)
{
    ESP_LOGI(TAG, "Notification of a time synchronization event");
}

static void example_set_static_ip(esp_netif_t *netif)
{
    if (esp_netif_dhcpc_stop(netif) != ESP_OK) {
        ESP_LOGE(TAG, "Failed to stop dhcp client");
        return;
    }
    esp_netif_ip_info_t ip;
    memset(&ip, 0 , sizeof(esp_netif_ip_info_t));
    ip.ip.addr = ipaddr_addr(EXAMPLE_STATIC_IP_ADDR);
    ip.netmask.addr = ipaddr_addr(EXAMPLE_STATIC_NETMASK_ADDR);
    ip.gw.addr = ipaddr_addr(EXAMPLE_STATIC_GW_ADDR);
    if (esp_netif_set_ip_info(netif, &ip) != ESP_OK) {
        ESP_LOGE(TAG, "Failed to set ip info");
        return;
    }
    ESP_LOGD(TAG, "Success to set static ip: %s, netmask: %s, gw: %s", EXAMPLE_STATIC_IP_ADDR, EXAMPLE_STATIC_NETMASK_ADDR, EXAMPLE_STATIC_GW_ADDR);
    esp_netif_dns_info_t dns;
    dns.ip.u_addr.ip4.addr = ipaddr_addr(EXAMPLE_MAIN_DNS_SERVER);
    dns.ip.type = IPADDR_TYPE_V4;
    ESP_ERROR_CHECK(esp_netif_set_dns_info(netif, ESP_NETIF_DNS_MAIN, &dns));
}

static void event_handler(void* arg, esp_event_base_t event_base,
                          int32_t event_id, void* event_data)
{
    if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_START) {
        esp_wifi_connect();
    } else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_CONNECTED) {
        example_set_static_ip(arg);
    } else if (event_base == WIFI_EVENT && event_id == WIFI_EVENT_STA_DISCONNECTED) {
        if (s_retry_num < EXAMPLE_MAXIMUM_RETRY) {
            esp_wifi_connect();
            s_retry_num++;
            ESP_LOGI(TAG, "retry to connect to the AP");
        } else {
            xEventGroupSetBits(s_wifi_event_group, WIFI_FAIL_BIT);
        }
        ESP_LOGI(TAG,"connect to the AP fail");
    } else if (event_base == IP_EVENT && event_id == IP_EVENT_STA_GOT_IP) {
        ip_event_got_ip_t* event = (ip_event_got_ip_t*) event_data;
        ESP_LOGI(TAG, "static ip:" IPSTR, IP2STR(&event->ip_info.ip));
        s_retry_num = 0;
        xEventGroupSetBits(s_wifi_event_group, WIFI_CONNECTED_BIT);
    }
}

void wifi_init_sta(void)
{
    s_wifi_event_group = xEventGroupCreate();

    ESP_ERROR_CHECK(esp_netif_init());

    ESP_ERROR_CHECK(esp_event_loop_create_default());

    esp_netif_t *sta_netif = esp_netif_create_default_wifi_sta();
    assert(sta_netif);

    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
    ESP_ERROR_CHECK(esp_wifi_init(&cfg));

    esp_event_handler_instance_t instance_any_id;
    esp_event_handler_instance_t instance_got_ip;
    ESP_ERROR_CHECK(esp_event_handler_instance_register(WIFI_EVENT,
                                                        ESP_EVENT_ANY_ID,
                                                        &event_handler,
                                                        sta_netif,
                                                        &instance_any_id));
    ESP_ERROR_CHECK(esp_event_handler_instance_register(IP_EVENT,
                                                        IP_EVENT_STA_GOT_IP,
                                                        &event_handler,
                                                        sta_netif,
                                                        &instance_got_ip));

    wifi_config_t wifi_config = {
            .sta = {
                    .ssid = CONFIG_EXAMPLE_WIFI_SSID,
                    .password = CONFIG_EXAMPLE_WIFI_PASSWORD,
                    .threshold.authmode = WIFI_AUTH_WPA2_PSK,
                    .pmf_cfg = {
                            .capable = true,
                            .required = false
                    },
            },
    };
    ESP_ERROR_CHECK(esp_wifi_set_mode(WIFI_MODE_STA) );
    ESP_ERROR_CHECK(esp_wifi_set_config(WIFI_IF_STA, &wifi_config) );
    ESP_ERROR_CHECK(esp_wifi_start() );

    ESP_LOGI(TAG, "wifi_init_sta finished.");

    /* Waiting until either the connection is established (WIFI_CONNECTED_BIT) or connection failed for the maximum
     * number of re-tries (WIFI_FAIL_BIT). The bits are set by event_handler() (see above) */
    EventBits_t bits = xEventGroupWaitBits(s_wifi_event_group,
                                           WIFI_CONNECTED_BIT | WIFI_FAIL_BIT,
                                           pdFALSE,
                                           pdFALSE,
                                           portMAX_DELAY);

    if (bits & WIFI_CONNECTED_BIT) {
        ESP_LOGI(TAG, "connected to ap SSID:%s password:%s",
                 CONFIG_EXAMPLE_WIFI_SSID, CONFIG_EXAMPLE_WIFI_PASSWORD);
    } else if (bits & WIFI_FAIL_BIT) {
        ESP_LOGI(TAG, "Failed to connect to SSID:%s, password:%s",
                 CONFIG_EXAMPLE_WIFI_SSID, CONFIG_EXAMPLE_WIFI_PASSWORD);
    } else {
        ESP_LOGE(TAG, "UNEXPECTED EVENT");
    }
    /* The event will not be processed after unregister */
    ESP_ERROR_CHECK(esp_event_handler_instance_unregister(IP_EVENT, IP_EVENT_STA_GOT_IP, instance_got_ip));
    ESP_ERROR_CHECK(esp_event_handler_instance_unregister(WIFI_EVENT, ESP_EVENT_ANY_ID, instance_any_id));
}

void app_main(void)
{
    time_t now;
    struct tm timeinfo;
    time(&now);
    localtime_r(&now, &timeinfo);
    obtain_time();
    time(&now);

    char strftime_buf[64];

    // Set timezone to China Standard Time
    setenv("TZ", "CST-8", 1);
    tzset();
    localtime_r(&now, &timeinfo);
    strftime(strftime_buf, sizeof(strftime_buf), "%c", &timeinfo);
    ESP_LOGI(TAG, "The current date/time in Shanghai is: %s", strftime_buf);
}

static void obtain_time(void)
{
    ESP_ERROR_CHECK( nvs_flash_init() );
    wifi_init_sta();

    initialize_sntp();

    // wait for time to be set
    time_t now = 0;
    struct tm timeinfo = { 0 };
    int retry = 0;
    const int retry_count = 10;
    while (sntp_get_sync_status() == SNTP_SYNC_STATUS_RESET && ++retry < retry_count) {
        ESP_LOGI(TAG, "Waiting for system time to be set... (%d/%d)", retry, retry_count);
        vTaskDelay(2000 / portTICK_PERIOD_MS);
    }
    time(&now);
    localtime_r(&now, &timeinfo);
}

static void initialize_sntp(void)
{
    ESP_LOGI(TAG, "Initializing SNTP");
    sntp_setoperatingmode(SNTP_OPMODE_POLL);
    sntp_setservername(0, "pool.ntp.org");
    sntp_set_time_sync_notification_cb(time_sync_notification_cb);
    sntp_init();
}