importer: give a title to the 'import' and 'writeback' subprocesses

'title' means both process name and command line.

This is cosmetics so it won't fail if the 'setproctitle' module
is not available.

neo/lib/util.py

@@ -15,7 +15,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 
-import socket
+import os, socket
 from binascii import a2b_hex, b2a_hex
 from datetime import timedelta, datetime
 from hashlib import sha1
@@ -226,3 +226,25 @@ class cached_property(object):
         if obj is None: return self
         value = obj.__dict__[self.func.__name__] = self.func(obj)
         return value
+
+# This module is always imported before multiprocessing is used, and the
+# main process does not want to change name when task are run in threads.
+spt_pid = os.getpid()
+
+def setproctitle(title):
+    global spt_pid
+    pid = os.getpid()
+    if spt_pid == pid:
+        return
+    spt_pid = pid
+    # Try using https://pypi.org/project/setproctitle/
+    try:
+        # On Linux, this is done by clobbering argv, and the main process
+        # usually has a longer command line than the title of subprocesses.
+        os.environ['SPT_NOENV'] = '1'
+        from setproctitle import setproctitle
+    except ImportError:
+        return
+    finally:
+        del os.environ['SPT_NOENV']
+    setproctitle(title)

neo/storage/database/importer.py

@@ -463,6 +463,7 @@ class ImporterDatabaseManager(DatabaseManager):
             setattr(self, x, getattr(self.db, x))
 
     def _iter_zodb(self):
+        util.setproctitle('neostorage: import')
         p64 = util.p64
         u64 = util.u64
         tid = p64(self.zodb_tid + 1) if self.zodb_tid else None
@@ -683,6 +684,7 @@ class WriteBack(object):
         return self._idle.wait
 
     def _run(self):
+        util.setproctitle('neostorage: write back')
         self._db = cPickle.loads(self._db)
         try:
             @self._db.autoReconnect

setup.py

@@ -38,7 +38,7 @@ extras_require = {
     'master': [],
     'storage-sqlite': [],
     'storage-mysqldb': ['mysqlclient'],
-    'storage-importer': zodb_require + ['msgpack>=0.5.6'],
+    'storage-importer': zodb_require + ['msgpack>=0.5.6', 'setproctitle'],
 }
 extras_require['tests'] = ['coverage', 'zope.testing', 'psutil>=2',
     'neoppod[%s]' % ', '.join(extras_require)]