[FIX] MultiProc starting workers at dubious wd

CHANGES

@@ -1,6 +1,7 @@
 Upcoming release (0.14.1)
 =========================
 
+* FIX: MultiProc starting workers at dubious wd (https://github.com/nipy/nipype/pull/2368)
 * REF+FIX: Move BIDSDataGrabber to `interfaces.io` + fix correct default behavior (https://github.com/nipy/nipype/pull/2336)
 * ENH: Add AFNI interface for 3dConvertDset (https://github.com/nipy/nipype/pull/2337)
 * MAINT: Cleanup EngineBase (https://github.com/nipy/nipype/pull/2376)

nipype/pipeline/engine/nodes.py

@@ -172,7 +172,7 @@ def __init__(self,
         self.synchronize = synchronize
         self.itersource = itersource
         self.overwrite = overwrite
-        self.parameterization = None
+        self.parameterization = []
         self.input_source = {}
         self.plugin_args = {}
 
@@ -242,9 +242,10 @@ def n_procs(self, value):
 
     @property
     def itername(self):
+        """Name for expanded iterable"""
         itername = self._id
         if self._hierarchy:
-            itername = self._hierarchy + '.' + self._id
+            itername = '%s.%s' % (self._hierarchy, self._id)
         return itername
 
     def output_dir(self):

nipype/pipeline/engine/utils.py

@@ -188,6 +188,7 @@ def write_report(node, report_type=None, is_mapnode=False):
     rst_dict = {
         'hostname': result.runtime.hostname,
         'duration': result.runtime.duration,
+        'working_dir': result.runtime.cwd,
     }
 
     if hasattr(result.runtime, 'cmdline'):

nipype/pipeline/plugins/multiproc.py

@@ -10,6 +10,7 @@
                         absolute_import)
 
 # Import packages
+import os
 from multiprocessing import Process, Pool, cpu_count, pool
 from traceback import format_exception
 import sys
@@ -50,6 +51,8 @@ def run_node(node, updatehash, taskid):
         the node to run
     updatehash : boolean
         flag for updating hash
+    taskid : int
+        an identifier for this task
 
     Returns
     -------
@@ -63,7 +66,7 @@ def run_node(node, updatehash, taskid):
     # Try and execute the node via node.run()
     try:
         result['result'] = node.run(updatehash=updatehash)
-    except:
+    except:  # noqa: E722, intendedly catch all here
         result['traceback'] = format_exception(*sys.exc_info())
         result['result'] = node.result
 
@@ -131,6 +134,10 @@ def __init__(self, plugin_args=None):
         self._task_obj = {}
         self._taskid = 0
 
+        # Cache current working directory and make sure we
+        # change to it when workers are set up
+        self._cwd = os.getcwd()
+
         # Read in options or set defaults.
         non_daemon = self.plugin_args.get('non_daemon', True)
         maxtasks = self.plugin_args.get('maxtasksperchild', 10)
@@ -143,19 +150,28 @@ def __init__(self, plugin_args=None):
 
         # Instantiate different thread pools for non-daemon processes
         logger.debug('[MultiProc] Starting in "%sdaemon" mode (n_procs=%d, '
-                     'mem_gb=%0.2f)', 'non' * int(non_daemon), self.processors,
-                     self.memory_gb)
+                     'mem_gb=%0.2f, cwd=%s)', 'non' * int(non_daemon),
+                     self.processors, self.memory_gb, self._cwd)
 
         NipypePool = NonDaemonPool if non_daemon else Pool
         try:
             self.pool = NipypePool(
-                processes=self.processors, maxtasksperchild=maxtasks)
+                processes=self.processors,
+                maxtasksperchild=maxtasks,
+                initializer=os.chdir,
+                initargs=(self._cwd,)
+            )
         except TypeError:
+            # Python < 3.2 does not have maxtasksperchild
+            # When maxtasksperchild is not set, initializer is not to be
+            # called
             self.pool = NipypePool(processes=self.processors)
 
         self._stats = None
 
     def _async_callback(self, args):
+        # Make sure runtime is not left at a dubious working directory
+        os.chdir(self._cwd)
         self._taskresult[args['taskid']] = args
 
     def _get_result(self, taskid):
@@ -360,7 +376,6 @@ def _sort_jobs(self, jobids, scheduler='tsort'):
         if scheduler == 'mem_thread':
             return sorted(
                 jobids,
-                key=
-                lambda item: (self.procs[item].mem_gb, self.procs[item].n_procs)
+                key=lambda item: (self.procs[item].mem_gb, self.procs[item].n_procs)
             )
         return jobids