Update reconnection example (#913) (#916)

* Update reconnection example

Signed-off-by: Pablo Garrido <[email protected]>

* FIx indentation

Signed-off-by: Pablo Garrido <[email protected]>

* Typo

Signed-off-by: Pablo Garrido <[email protected]>

* Typo

Signed-off-by: Pablo Garrido <[email protected]>

* Typo

Signed-off-by: Pablo Garrido <[email protected]>
(cherry picked from commit 561c615)

Co-authored-by: Pablo Garrido <[email protected]>

Author: mergify[bot]

examples/micro-ros_reconnection_example/micro-ros_reconnection_example.ino

@@ -11,6 +11,11 @@
 
 #define LED_PIN 13
 #define RCCHECK(fn) { rcl_ret_t temp_rc = fn; if((temp_rc != RCL_RET_OK)){return false;}}
+#define EXECUTE_EVERY_N_MS(MS, X)  do { \
+  static volatile int64_t init = -1; \
+  if (init == -1) { init = uxr_millis();} \
+  if (uxr_millis() - init > MS) { X; init = uxr_millis();} \
+} while (0)\
 
 rclc_support_t support;
 rcl_node_t node;
@@ -21,89 +26,109 @@ rcl_publisher_t publisher;
 std_msgs__msg__Int32 msg;
 bool micro_ros_init_successful;
 
+enum states {
+  WAITING_AGENT,
+  AGENT_AVAILABLE,
+  AGENT_CONNECTED,
+  AGENT_DISCONNECTED
+} state;
+
 void timer_callback(rcl_timer_t * timer, int64_t last_call_time)
 {
-	(void) last_call_time;
-	if (timer != NULL) {
-		rcl_publish(&publisher, &msg, NULL);
-		msg.data++;
-	}
+  (void) last_call_time;
+  if (timer != NULL) {
+    rcl_publish(&publisher, &msg, NULL);
+    msg.data++;
+  }
 }
 
 // Functions create_entities and destroy_entities can take several seconds.
-// In order to reduce this rebuild the library with 
+// In order to reduce this rebuild the library with
 // - RMW_UXRCE_ENTITY_CREATION_DESTROY_TIMEOUT=0
 // - UCLIENT_MAX_SESSION_CONNECTION_ATTEMPTS=3
 
 bool create_entities()
-{	
-	allocator = rcl_get_default_allocator();
-
-	// create init_options
-	RCCHECK(rclc_support_init(&support, 0, NULL, &allocator));
-
-	// create node
-	RCCHECK(rclc_node_init_default(&node, "int32_publisher_rclc", "", &support));
-
-	// create publisher
-	RCCHECK(rclc_publisher_init_best_effort(
-		&publisher,
-		&node,
-		ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, Int32),
-		"std_msgs_msg_Int32"));
-
-	// create timer,
-	const unsigned int timer_timeout = 1000;
-	RCCHECK(rclc_timer_init_default(
-		&timer,
-		&support,
-		RCL_MS_TO_NS(timer_timeout),
-		timer_callback));
-
-	// create executor
-	executor = rclc_executor_get_zero_initialized_executor();
-	RCCHECK(rclc_executor_init(&executor, &support.context, 1, &allocator));
-	RCCHECK(rclc_executor_add_timer(&executor, &timer));
-
-	micro_ros_init_successful = true;
+{
+  allocator = rcl_get_default_allocator();
+
+  // create init_options
+  RCCHECK(rclc_support_init(&support, 0, NULL, &allocator));
+
+  // create node
+  RCCHECK(rclc_node_init_default(&node, "int32_publisher_rclc", "", &support));
+
+  // create publisher
+  RCCHECK(rclc_publisher_init_best_effort(
+    &publisher,
+    &node,
+    ROSIDL_GET_MSG_TYPE_SUPPORT(std_msgs, msg, Int32),
+    "std_msgs_msg_Int32"));
+
+  // create timer,
+  const unsigned int timer_timeout = 1000;
+  RCCHECK(rclc_timer_init_default(
+    &timer,
+    &support,
+    RCL_MS_TO_NS(timer_timeout),
+    timer_callback));
+
+  // create executor
+  executor = rclc_executor_get_zero_initialized_executor();
+  RCCHECK(rclc_executor_init(&executor, &support.context, 1, &allocator));
+  RCCHECK(rclc_executor_add_timer(&executor, &timer));
+
+  return true;
 }
 
 void destroy_entities()
 {
-	rcl_publisher_fini(&publisher, &node);
-	rcl_node_fini(&node);
-	rcl_timer_fini(&timer);
-	rclc_executor_fini(&executor);
-	rclc_support_fini(&support);
-
-	micro_ros_init_successful = false;
+  rmw_context_t * rmw_context = rcl_context_get_rmw_context(&support.context);
+  (void) rmw_uros_set_context_entity_destroy_session_timeout(rmw_context, 0);
+
+  rcl_publisher_fini(&publisher, &node);
+  rcl_timer_fini(&timer);
+  rclc_executor_fini(&executor);
+  rcl_node_fini(&node);
+  rclc_support_fini(&support);
 }
 
 void setup() {
-  set_microros_transports(); 
+  set_microros_transports();
   pinMode(LED_PIN, OUTPUT);
-  digitalWrite(LED_PIN, HIGH);  
 
-  micro_ros_init_successful = false;
+  state = WAITING_AGENT;
+
   msg.data = 0;
 }
 
 void loop() {
-  uint32_t delay = 100000;
-  if (RMW_RET_OK == rmw_uros_ping_agent(50, 2))
-  {
-    delay = 500000;
-    if (!micro_ros_init_successful) {
-      create_entities();
-    } else {
-      rclc_executor_spin_some(&executor, RCL_MS_TO_NS(10));
-    }
-  } 
-  else if (micro_ros_init_successful)
-  {
-    destroy_entities();
+  switch (state) {
+    case WAITING_AGENT:
+      EXECUTE_EVERY_N_MS(500, state = (RMW_RET_OK == rmw_uros_ping_agent(100, 1)) ? AGENT_AVAILABLE : WAITING_AGENT;);
+      break;
+    case AGENT_AVAILABLE:
+      state = (true == create_entities()) ? AGENT_CONNECTED : WAITING_AGENT;
+      if (state == WAITING_AGENT) {
+        destroy_entities();
+      };
+      break;
+    case AGENT_CONNECTED:
+      EXECUTE_EVERY_N_MS(200, state = (RMW_RET_OK == rmw_uros_ping_agent(100, 1)) ? AGENT_CONNECTED : AGENT_DISCONNECTED;);
+      if (state == AGENT_CONNECTED) {
+        rclc_executor_spin_some(&executor, RCL_MS_TO_NS(100));
+      }
+      break;
+    case AGENT_DISCONNECTED:
+      destroy_entities();
+      state = WAITING_AGENT;
+      break;
+    default:
+      break;
   }
 
-  digitalWrite(LED_PIN, !digitalRead(LED_PIN));
-  delayMicroseconds(delay); 
+  if (state == AGENT_CONNECTED) {
+    digitalWrite(LED_PIN, 1);
+  } else {
+    digitalWrite(LED_PIN, 0);
+  }
 }