WIP: backport message flow tracing to foxy

rcl_lifecycle/CMakeLists.txt

@@ -4,6 +4,7 @@ project(rcl_lifecycle)
 
 find_package(ament_cmake_ros REQUIRED)
 
+find_package(tracetools REQUIRED)
 find_package(lifecycle_msgs REQUIRED)
 find_package(rcl REQUIRED)
 find_package(rcutils REQUIRED)
@@ -45,6 +46,7 @@ target_include_directories(${PROJECT_NAME} PUBLIC
 
 # specific order: dependents before dependencies
 ament_target_dependencies(rcl_lifecycle
+  "tracetools"
   "lifecycle_msgs"
   "rcl"
   "rcutils"

rcl_lifecycle/package.xml

@@ -9,6 +9,7 @@
 
   <buildtool_depend>ament_cmake_ros</buildtool_depend>
 
+  <build_depend>tracetools</build_depend>
   <build_depend>lifecycle_msgs</build_depend>
   <build_depend>rcl</build_depend>
   <build_depend>rcutils</build_depend>

rcl_lifecycle/src/rcl_lifecycle.c

@@ -33,6 +33,8 @@ extern "C"
 #include "rcl_lifecycle/default_state_machine.h"
 #include "rcl_lifecycle/transition_map.h"
 
+#include "tracetools/tracetools.h"
+
 #include "./com_interface.h"
 
 rcl_lifecycle_state_t
@@ -242,6 +244,10 @@ rcl_lifecycle_state_machine_init(
     }
   }
 
+  TRACEPOINT(
+    rcl_lifecycle_state_machine_init,
+    (const void *)node_handle,
+    (const void *)state_machine);
   return RCL_RET_OK;
 }
 
@@ -369,6 +375,11 @@ _trigger_transition(
     }
   }
 
+  TRACEPOINT(
+    rcl_lifecycle_transition,
+    (const void *)state_machine,
+    transition->start->label,
+    state_machine->current_state->label);
   return RCL_RET_OK;
 }