modules: main: Add CDDL CBOR encoding of device shadow

Add missing CDDL CBOR decoding of incoming data.
Used to decode update interval set in cloud.

Signed-off-by: Simen S. Røstad <simen.rostad@nordicsemi.no>

Author: simensrostad

app/src/cbor/CMakeLists.txt

@@ -6,3 +6,31 @@
 
 target_sources(app PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/cbor_helper.c)
 target_include_directories(app PRIVATE .)
+
+# generate encoder code using zcbor
+set(zcbor_command
+        zcbor code # Invoke code generation
+	--cddl ${CMAKE_CURRENT_SOURCE_DIR}/device_shadow.cddl
+	--decode # Generate decoding functions
+	--short-names # Attempt to make generated symbol names shorter (at the risk of collision)
+	-t config-object # Create a public API for decoding the "config-object" type from the cddl file
+	--output-cmake device_shadow.cmake # The generated cmake file will be placed here
+)
+execute_process(COMMAND ${zcbor_command}
+		WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+		COMMAND_ERROR_IS_FATAL ANY)
+
+# Include the cmake file generated by zcbor. It adds the
+# generated code and the necessary zcbor C code files.
+include(${CMAKE_CURRENT_BINARY_DIR}/device_shadow.cmake)
+
+# Ensure that the cmake reconfiguration is triggerred everytime the cddl file changes.
+# This ensures that the codec generation is triggered.
+set_property(
+	DIRECTORY
+	PROPERTY
+	CMAKE_CONFIGURE_DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/device_shadow.cddl
+)
+
+zephyr_link_libraries(device_shadow)
+target_link_libraries(device_shadow PRIVATE zephyr_interface)

app/src/cbor/cbor_helper.c

@@ -3,15 +3,23 @@
  *
  * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
  */
-
-#include <zephyr/logging/log.h>
-
-LOG_MODULE_DECLARE(main, CONFIG_APP_LOG_LEVEL);
+#include <errno.h>
+#include "device_shadow_decode.h"
 
 int get_update_interval_from_cbor_response(const uint8_t *cbor,
 					   size_t len,
 					   uint64_t *interval_sec)
 {
-	*interval_sec = 1800;
+	struct config_object object = { 0 };
+	size_t not_used;
+
+	int err = cbor_decode_config_object(cbor, len, &object, &not_used);
+
+	if (err) {
+		return -EFAULT;
+	}
+
+	*interval_sec = object.update_interval;
+
 	return 0;
 }

app/src/cbor/cbor_helper.h

@@ -6,6 +6,18 @@
 
 #include <zephyr/types.h>
 
+/**
+ * @brief Get the update interval from a CBOR buffer.
+ *
+ * @param[in]  cbor         The CBOR buffer.
+ * @param[in]  len          The length of the CBOR buffer.
+ * @param[out] interval_sec The update interval in seconds.
+ *
+ * @returns 0 If the operation was successful.
+ *	    Otherwise, a (negative) error code is returned.
+ * @retval -EFAULT if the CBOR buffer is invalid.
+ *
+ */
 int get_update_interval_from_cbor_response(const uint8_t *cbor,
 					   size_t len,
 					   uint64_t *interval_sec);

app/src/cbor/device_shadow.cddl

@@ -1,53 +1,5 @@
-; Define the basic structure of the JSON object
-
-; The 'any' type is used in this schema to allow forward compatibility.
-; They are inserted into maps that may contain additional fields in the future.
-; This prevents cbor decoding from failing in the field when the cloud side has new fields.
-app-object = {
-    ? "nrfcloud_mqtt_topic_prefix": tstr,
-    ? "pairing": pairing-type,
-    ? "lwm2m": lwm2m-map,
-    * tstr => any
-}
-
-; Define the pairing object with nested topics
-pairing-type = {
-    "state": tstr,
-    "topics": {
-        "d2c": tstr,
-        "c2d": tstr,
-        * tstr => any
-    },
-    * any => any
-}
-
-lwm2m-map = {
-  ? "14240:1.0": led,
-  ? "14301:1.0": config,
-  * tstr => any
-}
-
-led = {
-  "0": led_inner_object,
-  * tstr => any
-}
-
-led_inner_object = {
-  ? "0": int .size 4,
-  ? "1": int .size 4,
-  ? "2": int .size 4,
-  "99": int .size 8,
-  * tstr => any
-}
-
-config = {
-  "0": config_inner_object,
-  * tstr => any
-}
-
-config_inner_object = {
-  ? "0": int .size 8,
-  ? "1": bool,
-  "99": int .size 8,
-  * tstr => any
+config-object = {
+    "config": {
+        "update_interval": uint .size 8
+    }
 }

app/src/main.c

@@ -460,7 +460,7 @@ static void triggering_run(void *o)
 								     msg.response.buffer_data_len,
 								     &state_object->interval_sec);
 			if (err) {
-				LOG_ERR("json_parse, error: %d", err);
+				LOG_ERR("get_update_interval_from_cbor_response, error: %d", err);
 				SEND_FATAL_ERROR();
 				return;
 			}

tests/module/main/CMakeLists.txt

@@ -11,7 +11,7 @@ project(app_module_test)
 
 test_runner_generate(src/main.c)
 
-set(ASSET_TRACKER_TEMPLATE_DIR ../../..)
+set(ASSET_TRACKER_TEMPLATE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/../../..)
 
 target_sources(app
 	PRIVATE
@@ -67,3 +67,33 @@ target_compile_definitions(app PRIVATE
 	-DZEPHYR_INCLUDE_SYS_REBOOT_H_
 	-DCONFIG_APP_REQUEST_NETWORK_QUALITY=1
 )
+
+# CONSIDER: REUSING THE CODEC GENERATION LOGIC FROM THE MAIN APP
+
+# generate encoder code using zcbor
+set(zcbor_command
+        zcbor code # Invoke code generation
+	--cddl ${ASSET_TRACKER_TEMPLATE_DIR}/app/src/cbor/device_shadow.cddl
+	--decode # Generate decoding functions
+	--short-names # Attempt to make generated symbol names shorter (at the risk of collision)
+	-t config-object # Create a public API for decoding the "config-object" type from the cddl file
+	--output-cmake device_shadow.cmake # The generated cmake file will be placed here
+)
+execute_process(COMMAND ${zcbor_command}
+		WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}
+		COMMAND_ERROR_IS_FATAL ANY)
+
+# Include the cmake file generated by zcbor. It adds the
+# generated code and the necessary zcbor C code files.
+include(${CMAKE_CURRENT_BINARY_DIR}/device_shadow.cmake)
+
+# Ensure that the cmake reconfiguration is triggerred everytime the cddl file changes.
+# This ensures that the codec generation is triggered.
+set_property(
+	DIRECTORY
+	PROPERTY
+	CMAKE_CONFIGURE_DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/device_shadow.cddl
+)
+
+zephyr_link_libraries(device_shadow)
+target_link_libraries(device_shadow PRIVATE zephyr_interface)

tests/module/main/src/main.c

@@ -141,20 +141,25 @@ static void send_location_search_done(void)
 	TEST_ASSERT_EQUAL(0, err);
 }
 
-/*
-static void send_config(uint64_t interval)
+static void twelve_hour_interval_set(void)
 {
+	// MISSING: set interval for 12 hours, or even different intervals.
+
 	const struct cloud_msg msg = {
 		.type = CLOUD_SHADOW_RESPONSE,
-		.response.buffer = "{\"update_interval\": 60}",
-		.response.buffer_data_len = strlen("{\"update_interval\": 60}"),
+		/* JSON equivalent string: "{"config":{"update_interval": 60 }}" */
+		.response.buffer = {
+			0xA1, 0x66, 0x63, 0x6F, 0x6E, 0x66, 0x69, 0x67, 0xA1,
+			0x6F, 0x75, 0x70, 0x64, 0x61, 0x74, 0x65, 0x5F, 0x69,
+			0x6E, 0x74, 0x65, 0x72, 0x76, 0x61, 0x6C, 0x18, 0x3C
+		},
+		.response.buffer_data_len = 27,
 	};
 
-	int err = zbus_chan_pub(&CLOUD_CHAN, &shadow_response, K_SECONDS(1));
+	int err = zbus_chan_pub(&CLOUD_CHAN, &msg, K_SECONDS(1));
 
 	TEST_ASSERT_EQUAL(0, err);
 }
-*/
 
 static void send_cloud_disconnected(void)
 {
@@ -215,11 +220,10 @@ void test_button_press_on_disconnected(void)
 	check_no_events(7200);
 }
 
-/*
 void test_trigger_interval_change_in_connected(void)
 {
 	send_cloud_connected_ready_to_send();
-	send_config(HOUR_IN_SECONDS * 12);
+	twelve_hour_interval_set();
 
 	for (int i = 0; i < 10; i++) {
 		send_location_search_done();
@@ -231,13 +235,11 @@ void test_trigger_interval_change_in_connected(void)
 	send_cloud_disconnected();
 	check_no_events(WEEK_IN_SECONDS);
 }
-*/
 
-/*
 void test_trigger_disconnect_and_connect_when_triggering(void)
 {
 	send_cloud_connected_ready_to_send();
-	send_config(HOUR_IN_SECONDS * 12);
+	twelve_hour_interval_set();
 
 	for (int i = 0; i < 10; i++) {
 
@@ -256,7 +258,6 @@ void test_trigger_disconnect_and_connect_when_triggering(void)
 	send_cloud_disconnected();
 	check_no_events(WEEK_IN_SECONDS);
 }
-*/
 
 /* This is required to be added to each test. That is because unity's
  * main may return nonzero, while zephyr's main currently must