Centralize default trace location

tracetools_trace/tracetools_trace/tools/args.py

@@ -18,6 +18,7 @@ import argparse
 import time
 
 from . import names
+from . import path
 
 
 class DefaultArgValueCompleter:
@@ -45,7 +46,7 @@ def add_arguments(parser):
         help='the name of the tracing session (default: session-YYYYMMDDHHMMSS)')
     parser.add_argument(
         '--path', '-p', dest='path',
-        default='/tmp',
+        default=path.DEFAULT_BASE_PATH,
         help='path of the base directory for trace data (default: %(default)s)')
     arg = parser.add_argument(
         '--ust', '-u', nargs='*', dest='events_ust', default=names.DEFAULT_EVENTS_ROS,

tracetools_trace/tracetools_trace/tools/lttng.py

@@ -21,11 +21,13 @@ import lttng
 from .names import DEFAULT_CONTEXT
 from .names import DEFAULT_EVENTS_KERNEL
 from .names import DEFAULT_EVENTS_ROS
+from .path import DEFAULT_BASE_PATH
+from .path import get_full_session_path
 
 
 def lttng_init(
     session_name: str,
-    full_path: str,
+    base_path: str = DEFAULT_BASE_PATH,
     ros_events: List[str] = DEFAULT_EVENTS_ROS,
     kernel_events: List[str] = DEFAULT_EVENTS_KERNEL,
     context_names: List[str] = DEFAULT_CONTEXT
@@ -34,12 +36,12 @@ def lttng_init(
     Set up and start LTTng session.
 
     :param session_name: the name of the session
-    :param full_path: the full path to the main directory to write trace data to
+    :param base_path: the path to the directory in which to create the tracing session directory
     :param ros_events: list of ROS events to enable
     :param kernel_events: list of kernel events to enable
     :param context_names: list of context elements to enable
     """
-    _lttng_setup(session_name, full_path, ros_events, kernel_events, context_names)
+    _lttng_setup(session_name, base_path, ros_events, kernel_events, context_names)
     _lttng_start(session_name)
 
 
@@ -55,7 +57,7 @@ def lttng_fini(session_name: str) -> None:
 
 def _lttng_setup(
     session_name: str,
-    full_path: str,
+    base_path: str = DEFAULT_BASE_PATH,
     ros_events: List[str] = DEFAULT_EVENTS_ROS,
     kernel_events: List[str] = DEFAULT_EVENTS_KERNEL,
     context_names: List[str] = DEFAULT_CONTEXT,
@@ -68,13 +70,16 @@ def _lttng_setup(
     See: https://lttng.org/docs/#doc-core-concepts
 
     :param session_name: the name of the session
-    :param full_path: the full path to the main directory to write trace data to
+    :param base_path: the path to the directory in which to create the tracing session directory
     :param ros_events: list of ROS events to enable
     :param kernel_events: list of kernel events to enable
     :param context_names: list of context elements to enable
     :param channel_name_ust: the UST channel name
     :param channel_name_kernel: the kernel channel name
     """
+    # Resolve full tracing directory path
+    full_path = get_full_session_path(session_name, base_path=base_path)
+
     ust_enabled = ros_events is not None and len(ros_events) > 0
     kernel_enabled = kernel_events is not None and len(kernel_events) > 0
 

tracetools_trace/tracetools_trace/tools/path.py

@@ -0,0 +1,34 @@
+# 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.
+
+import os
+
+
+DEFAULT_BASE_PATH = '~/.ros/tracing/'
+
+
+def get_full_session_path(
+    session_name: str,
+    base_path: str = DEFAULT_BASE_PATH
+) -> str:
+    """
+    Get the full path to the trace directory of a given session.
+
+    :param session_name: the name of the tracing session
+    :param base_path: the path to the directory containing the trace directory
+    :return: the full path to the tracing session directory
+    """
+    if base_path is None:
+        base_path = DEFAULT_BASE_PATH
+    return os.path.expanduser(os.path.join(base_path, session_name))

tracetools_trace/tracetools_trace/trace.py

@@ -15,10 +15,9 @@
 
 """Entrypoint/script to setup and start an LTTng tracing session."""
 
-import os
-
 from tracetools_trace.tools import args
 from tracetools_trace.tools import lttng
+from tracetools_trace.tools import path
 
 
 def main():
@@ -26,7 +25,6 @@ def main():
 
     session_name = params.session_name
     base_path = params.path
-    full_path = os.path.join(base_path, session_name)
     ros_events = params.events_ust
     kernel_events = params.events_kernel
 
@@ -45,9 +43,14 @@ def main():
     else:
         print('kernel tracing disabled')
 
-    print(f'writting tracing session to: {full_path}')
+    full_session_path = path.get_full_session_path(session_name, base_path)
+    print(f'writting tracing session to: {full_session_path}')
     input('press enter to start...')
-    lttng.lttng_init(session_name, full_path, ros_events=ros_events, kernel_events=kernel_events)
+    lttng.lttng_init(
+        session_name,
+        base_path=base_path,
+        ros_events=ros_events,
+        kernel_events=kernel_events)
     input('press enter to stop...')
 
     print('stopping & destroying tracing session')