Rename trace action module to 'action'

tracetools_launch/tracetools_launch/action.py

@@ -0,0 +1,82 @@
+# Copyright 2019 Robert Bosch GmbH
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Module for the Trace action."""
+
+import os
+from typing import List
+from typing import Optional
+
+from launch.action import Action
+from launch.event import Event
+from launch.event_handlers import OnShutdown
+from launch.launch_context import LaunchContext
+from tracetools_trace.tools import lttng
+from tracetools_trace.tools import names
+
+
+class Trace(Action):
+    """
+    Tracing action for launch.
+
+    Sets up and enables tracing through a launch file description.
+    """
+
+    def __init__(
+        self,
+        *,
+        session_name: str,
+        base_path: str = '/tmp',
+        events_ust: List[str] = names.DEFAULT_EVENTS_ROS,
+        events_kernel: List[str] = names.DEFAULT_EVENTS_KERNEL,
+        **kwargs,
+    ) -> None:
+        """
+        Constructor.
+
+        :param session_name: the name of the tracing session
+        :param base_path: the base directory in which to create the trace directory
+        :param events_ust: the list of ROS UST events to enable
+        :param events_kernel: the list of kernel events to enable
+        """
+        super().__init__(**kwargs)
+        self.__session_name = session_name
+        self.__path = os.path.join(base_path, session_name)
+        self.__events_ust = events_ust
+        self.__events_kernel = events_kernel
+
+    def execute(self, context: LaunchContext) -> Optional[List[Action]]:
+        # TODO make sure this is done as late as possible
+        context.register_event_handler(OnShutdown(on_shutdown=self._destroy))
+        # TODO make sure this is done as early as possible
+        self._setup()
+
+    def _setup(self) -> None:
+        lttng.lttng_init(
+            self.__session_name,
+            self.__path,
+            ros_events=self.__events_ust,
+            kernel_events=self.__events_kernel)
+
+    def _destroy(self, event: Event, context: LaunchContext) -> None:
+        lttng.lttng_fini(self.__session_name)
+
+    def __repr__(self):
+        return (
+            "Trace("
+            f"session_name='{self.__session_name}', "
+            f"path='{self.__path}', "
+            f"num_events_ust={len(self.__events_ust)}, "
+            f"num_events_kernel={len(self.__events_kernel)})"
+        )