Transport module: Update state machine

app/src/common/message_channel.c

@@ -75,7 +75,7 @@ ZBUS_CHAN_DEFINE(CONFIG_CHAN,
 );
 
 ZBUS_CHAN_DEFINE(CLOUD_CHAN,
-		 enum cloud_status,
+		 enum cloud_msg_type,
 		 NULL,
 		 NULL,
 		 ZBUS_OBSERVERS_EMPTY,

app/src/common/message_channel.h

@@ -207,13 +207,20 @@ struct battery_msg {
 
 #define MSG_TO_BATTERY_MSG(_msg)	(*(const struct battery_msg *)_msg)
 
-enum cloud_status {
+enum cloud_msg_type {
 	CLOUD_DISCONNECTED = 0x1,
 	CLOUD_CONNECTED_READY_TO_SEND,
 	CLOUD_CONNECTED_PAUSED,
+	CLOUD_CONNECTION_ATTEMPT_COUNT_REACHED,
+	CLOUD_PAYLOAD_JSON,
 };
 
-#define MSG_TO_CLOUD_STATUS(_msg)	(*(const enum cloud_status *)_msg)
+struct cloud_msg {
+	enum cloud_msg_type type;
+	struct payload payload;
+};
+
+#define MSG_TO_CLOUD_MSG(_msg)	(*(const struct cloud_msg *)_msg)
 
 enum trigger_type {
 	TRIGGER_POLL = 0x1,

app/src/modules/app/app.c

@@ -28,7 +28,7 @@ ZBUS_MSG_SUBSCRIBER_DEFINE(app);
 ZBUS_CHAN_ADD_OBS(TRIGGER_CHAN, app, 0);
 ZBUS_CHAN_ADD_OBS(CLOUD_CHAN, app, 0);
 
-#define MAX_MSG_SIZE (MAX(sizeof(enum trigger_type), sizeof(enum cloud_status)))
+#define MAX_MSG_SIZE (MAX(sizeof(enum trigger_type), sizeof(enum cloud_msg_type)))
 
 BUILD_ASSERT(CONFIG_APP_MODULE_WATCHDOG_TIMEOUT_SECONDS > CONFIG_APP_MODULE_EXEC_TIME_SECONDS_MAX,
 	     "Watchdog timeout must be greater than maximum execution time");
@@ -122,7 +122,7 @@ static void app_task(void)
 		if (&CLOUD_CHAN == chan) {
 			LOG_DBG("Cloud connection status received");
 
-			const enum cloud_status *status = (const enum cloud_status *)msg_buf;
+			const enum cloud_msg_type *status = (const enum cloud_msg_type *)msg_buf;
 
 			if (*status == CLOUD_CONNECTED_READY_TO_SEND) {
 				LOG_DBG("Cloud ready to send");

app/src/modules/fota/fota.c

@@ -34,7 +34,7 @@ ZBUS_MSG_SUBSCRIBER_DEFINE(fota);
 ZBUS_CHAN_ADD_OBS(TRIGGER_CHAN, fota, 0);
 ZBUS_CHAN_ADD_OBS(CLOUD_CHAN, fota, 0);
 
-#define MAX_MSG_SIZE MAX(sizeof(enum trigger_type), sizeof(enum cloud_status))
+#define MAX_MSG_SIZE MAX(sizeof(enum trigger_type), sizeof(enum cloud_msg_type))
 
 /* FOTA support context */
 static void fota_reboot(enum nrf_cloud_fota_reboot_status status);
@@ -157,7 +157,7 @@ static void state_wait_for_cloud_run(void *o)
 	struct state_object *state_object = o;
 
 	if (&CLOUD_CHAN == state_object->chan) {
-		const enum cloud_status status = MSG_TO_CLOUD_STATUS(state_object->msg_buf);
+		const enum cloud_msg_type status = MSG_TO_CLOUD_MSG(state_object->msg_buf).type;
 
 		if (status == CLOUD_CONNECTED_READY_TO_SEND) {
 			STATE_SET(fota_state, STATE_WAIT_FOR_TRIGGER);
@@ -178,7 +178,7 @@ static void state_wait_for_trigger_run(void *o)
 	}
 
 	if (&CLOUD_CHAN == state_object->chan) {
-		const enum cloud_status status = MSG_TO_CLOUD_STATUS(state_object->msg_buf);
+		const enum cloud_msg_type status = MSG_TO_CLOUD_MSG(state_object->msg_buf).type;
 
 		if (status == CLOUD_CONNECTED_PAUSED) {
 			STATE_SET(fota_state, STATE_WAIT_FOR_CLOUD);

app/src/modules/location/location.c

@@ -36,7 +36,7 @@ ZBUS_CHAN_ADD_OBS(NETWORK_CHAN, location, 0);
 
 #define MAX_MSG_SIZE \
 	(MAX(sizeof(enum trigger_type), \
-		 (MAX(sizeof(enum cloud_status), \
+		 (MAX(sizeof(enum cloud_msg_type), \
 		     (MAX(sizeof(struct configuration), \
 		         sizeof(struct network_msg)))))))
 

app/src/modules/memfault/memfault.c

@@ -27,7 +27,7 @@ ZBUS_MSG_SUBSCRIBER_DEFINE(memfault);
 /* Observe channels */
 ZBUS_CHAN_ADD_OBS(CLOUD_CHAN, memfault, 0);
 
-#define MAX_MSG_SIZE sizeof(enum cloud_status)
+#define MAX_MSG_SIZE sizeof(enum cloud_msg_type)
 
 static void task_wdt_callback(int channel_id, void *user_data)
 {
@@ -196,7 +196,8 @@ static void on_connected(void)
 #endif /* CONFIG_NRF_MODEM_LIB_TRACE && CONFIG_NRF_MODEM_LIB_TRACE_BACKEND_FLASH */
 }
 
-void handle_cloud_chan(enum cloud_status status) {
+void handle_cloud_chan(enum cloud_msg_type status)
+{
 	if (status == CLOUD_CONNECTED_READY_TO_SEND) {
 		on_connected();
 	}
@@ -239,7 +240,7 @@ void memfault_task(void)
 
 		if (&CLOUD_CHAN == chan) {
 			LOG_DBG("Cloud status received");
-			handle_cloud_chan(MSG_TO_CLOUD_STATUS(&msg_buf));
+			handle_cloud_chan(MSG_TO_CLOUD_MSG(&msg_buf).type);
 		}
 	}
 }

app/src/modules/shell/shell.c

@@ -18,11 +18,18 @@
 #include <date_time.h>
 #include <zephyr/task_wdt/task_wdt.h>
 #include <modem/nrf_modem_lib_trace.h>
+#include <net/nrf_cloud_defs.h>
 
 #include "message_channel.h"
 
 LOG_MODULE_REGISTER(shell, CONFIG_APP_SHELL_LOG_LEVEL);
 
+#define PAYLOAD_MSG_TEMPLATE	\
+	"{\""NRF_CLOUD_JSON_MSG_TYPE_KEY"\":\""NRF_CLOUD_JSON_MSG_TYPE_VAL_DATA"\","	\
+	"\""NRF_CLOUD_JSON_APPID_KEY"\":\"%s\","					\
+	"\""NRF_CLOUD_JSON_DATA_KEY"\":\"%s\","						\
+	"\""NRF_CLOUD_MSG_TIMESTAMP_KEY"\":%lld}"
+
 static const struct device *const shell_uart_dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_shell_uart));
 static const struct device *const uart1_dev = DEVICE_DT_GET(DT_NODELABEL(uart1));
 
@@ -191,13 +198,44 @@ static int cmd_button_press(const struct shell *sh, size_t argc,
 	return 0;
 }
 
-static int cmd_publish_on_payload_chan(const struct shell *sh, size_t argc,
-                           char **argv)
+static int cmd_publish_on_payload_chan(const struct shell *sh, size_t argc, char **argv)
 {
+	int err, ret;
+	struct payload payload = {
+		.buffer_len = strlen(argv[1]),
+	};
+	int64_t current_time;
+
 	ARG_UNUSED(argc);
-	ARG_UNUSED(argv);
 
-	shell_print(sh, "Not implemented yet!");
+	if (argc != 3) {
+		shell_print(sh, "Invalid number of arguments (%d)", argc);
+		shell_print(sh, "Usage: zbus publish payload_chan <appid> <data>");
+		return 1;
+	}
+
+	err = date_time_now(&current_time);
+	if (err) {
+		shell_print(sh, "Failed to get current time, error: %d", err);
+		return 1;
+	}
+
+	ret = snprintk(payload.buffer, sizeof(payload.buffer),
+		PAYLOAD_MSG_TEMPLATE,
+		argv[1], argv[2], current_time);
+	if (ret < 0 || ret >= sizeof(payload.buffer)) {
+		shell_print(sh, "Failed to format payload, error: %d", ret);
+		return 1;
+	}
+
+	shell_print(sh, "Sending on payload channel: %s (%d bytes)",
+		    payload.buffer, payload.buffer_len);
+
+	err = zbus_chan_pub(&PAYLOAD_CHAN, &payload, K_SECONDS(1));
+	if (err) {
+		shell_print(sh, "zbus_chan_pub, error: %d", err);
+		return 1;
+	}
 
 	return 0;
 }

app/src/modules/transport/Kconfig.transport

@@ -7,11 +7,50 @@
 menu "Transport"
 	depends on NRF_CLOUD_COAP
 
-config APP_TRANSPORT_RECONNECTION_TIMEOUT_SECONDS
-	int "Reconnection timeout in seconds"
+config APP_TRANSPORT_BACKOFF_INITIAL_SECONDS
+	int "Reconnection backoff time in seconds"
 	default 60
 	help
-	  Time in between reconnection attempts to the MQTT broker.
+	  Time in between reconnection attempts to the CoAP server.
+	  The timer starts after the last failed attempt.
+
+choice APP_TRANSPORT_BACKOFF_BACKOFF_TYPE
+	prompt "Reconnection backoff type"
+	default APP_TRANSPORT_BACKOFF_BACKOFF_TYPE_LINEAR
+
+config APP_TRANSPORT_BACKOFF_BACKOFF_TYPE_EXPONENTIAL
+	bool "Exponential backoff"
+	help
+	  Exponential backoff doubles the reconnection timeout after each failed attempt.
+	  The maximum reconnection timeout is defined by APP_TRANSPORT_BACKOFF_MAX_SECONDS.
+
+config APP_TRANSPORT_BACKOFF_BACKOFF_TYPE_LINEAR
+	bool "Linear backoff"
+	help
+	  Linear backoff adds a fixed amount of time to the reconnection timeout after each failed attempt,
+	  as defined by APP_TRANSPORT_BACKOFF_LINEAR_INCREMENT_SECONDS.
+
+config APP_TRANSPORT_BACKOFF_BACKOFF_TYPE_NONE
+	bool "No backoff"
+	help
+	  No backoff means that the reconnection timeout is constant at the value defined by
+	  APP_TRANSPORT_BACKOFF_INITIAL_SECONDS.
+
+endchoice
+
+config APP_TRANSPORT_BACKOFF_LINEAR_INCREMENT_SECONDS
+	int "Reconnection backoff time increment"
+	default 60
+	depends on APP_TRANSPORT_BACKOFF_BACKOFF_TYPE_LINEAR
+	help
+	  Time added to the reconnection timeout after each failed attempt in seconds.
+	  The maximum reconnection timeout is defined by APP_TRANSPORT_BACKOFF_MAX_SECONDS.
+
+config APP_TRANSPORT_BACKOFF_MAX_SECONDS
+	int "Maximum reconnection timeout"
+	default 3600
+	help
+	  Maximum reconnection backoff value in seconds.
 
 config APP_TRANSPORT_THREAD_STACK_SIZE
 	int "Thread stack size"