Allow a non-default logger to be used in Task

By default a Task uses its full name to set its logger (self.log).
This commit allows a Log to be passed in the Task's ctor and used.

python/lsst/pipe/base/task.py

@@ -92,8 +92,8 @@ def __init__(self, config=None, name=None, parentTask=None, log=None):
         @param[in] parentTask   the parent task of this subtask, if any.
             - If None (a top-level task) then you must specify config and name is ignored.
             - If not None (a subtask) then you must specify name
-        @param[in] log          lsst.log Log; if None then the default is used;
-            in either case a copy is made using the full task name.
+        @param[in] log          a lsst.log Log to be used as the logger
+            - if None then a Log with the full task name is used
 
         @throw RuntimeError if parentTask is None and config is None.
         @throw RuntimeError if parentTask is not None and name is None.
@@ -121,7 +121,10 @@ def __init__(self, config=None, name=None, parentTask=None, log=None):
             if config is None:
                 config = self.ConfigClass()
             self._taskDict = dict()
-        self.log = Log.getLogger(self._fullName)
+        if log is not None and isinstance(log, Log):
+            self.log = log
+        else:
+            self.log = Log.getLogger(self._fullName)
 
         self.config = config
         self._display = lsstDebug.Info(self.__module__).display

tests/testTask.py

@@ -28,6 +28,7 @@
 
 import lsst.utils.tests
 import lsst.daf.base as dafBase
+from lsst.log import Log
 import lsst.pex.config as pexConfig
 import lsst.pipe.base as pipeBase
 
@@ -159,6 +160,15 @@ def testNames(self):
         self.assertEqual(addMultTask.add._fullName, "addMult.add")
         self.assertEqual(addMultTask.mult._fullName, "addMult.mult")
 
+    def testLog(self):
+        """Test the Task's logger
+        """
+        addMultTask = AddMultTask()
+        self.assertEqual(addMultTask.log.getName(), addMultTask.getFullName())
+        log = Log.getLogger("testLogger")
+        addMultTask = AddMultTask(log=log)
+        self.assertEqual(addMultTask.log.getName(), "testLogger")
+
     def testGetFullMetadata(self):
         """Test getFullMetadata()
         """