Merge lp:~salgado/launchpad/meliae-librarian into lp:launchpad

[Guilherme Salgado]

Make the librarian dump its memory (using meliae) upon a 'kill -44'

This is to help debug bug 556245.

= Launchpad lint =

Checking for conflicts. and issues in doctests and templates.
Running jslint, xmllint, pyflakes, and pylint.
Using normal rules.

Linting changed files:
  lib/canonical/librarian/interfaces.py
  lib/canonical/librarian/tests/test_sigdumpmem.py
  daemons/librarian.tac

== Pylint notices ==

lib/canonical/librarian/tests/test_sigdumpmem.py
    11: [F0401] Unable to import 'canonical.librarian.interfaces'
    12: [F0401] Unable to import 'canonical.librarian.ftests.harness'
    13: [F0401] Unable to import 'canonical.testing.layers'
    14: [F0401] Unable to import 'lp.testing'

[Gary Poster (gary)]

Thank you

Gary

review: Approve

=== modified file 'daemons/librarian.tac'
--- daemons/librarian.tac	2009-06-24 20:55:31 +0000
+++ daemons/librarian.tac	2010-04-20 14:37:25 +0000
@@ -4,6 +4,10 @@
 # Twisted Application Configuration file.
 # Use with "twistd2.4 -y <file.tac>", e.g. "twistd -noy server.tac"
 
+import signal
+
+from meliae import scanner
+
 from twisted.application import service, strports
 from twisted.web import server
 
@@ -11,6 +15,7 @@
 from canonical.launchpad.daemons import tachandler
 from canonical.launchpad.scripts import execute_zcml_for_scripts
 
+from canonical.librarian.interfaces import DUMP_FILE, SIGDUMPMEM
 from canonical.librarian.libraryprotocol import FileUploadFactory
 from canonical.librarian import storage, db
 from canonical.librarian import web as fatweb
@@ -64,3 +69,9 @@
 webPort = config.librarian.restricted_download_port
 uploadPort = config.librarian.restricted_upload_port
 setUpListener(uploadPort, webPort, restricted=True)
+
+# Setup a signal handler to dump the process' memory upon 'kill -44'.
+def sigdumpmem_handler(signum, frame):
+    scanner.dump_all_objects(DUMP_FILE)
+
+signal.signal(SIGDUMPMEM, sigdumpmem_handler)
 
=== modified file 'lib/canonical/librarian/interfaces.py'
--- lib/canonical/librarian/interfaces.py	2009-06-25 05:30:52 +0000
+++ lib/canonical/librarian/interfaces.py	2010-04-20 14:37:25 +0000
@@ -5,9 +5,15 @@
 # pylint: disable-msg=E0213
 __metaclass__ = type
 
+import signal
+
 from zope.interface import Interface
 
 
+SIGDUMPMEM = signal.SIGRTMIN + 10
+DUMP_FILE = '/tmp/librarian-memory.dump'
+
+
 class LibrarianFailure(Exception):
     """Base class for failures trying to use the libararian."""
 
 
=== added file 'lib/canonical/librarian/tests/test_sigdumpmem.py'
--- lib/canonical/librarian/tests/test_sigdumpmem.py	1970-01-01 00:00:00 +0000
+++ lib/canonical/librarian/tests/test_sigdumpmem.py	2010-04-20 14:37:25 +0000
@@ -0,0 +1,37 @@
+# Copyright 2010 Canonical Ltd.  This software is licensed under the
+# GNU Affero General Public License version 3 (see the file LICENSE).
+
+"""Test the SIGDUMPMEM signal handler."""
+
+__metaclass__ = type
+
+import os
+import time
+
+from canonical.librarian.interfaces import DUMP_FILE, SIGDUMPMEM
+from canonical.librarian.ftests.harness import TacLibrarianTestSetup
+from canonical.testing.layers import LibrarianLayer
+from lp.testing import TestCase
+
+
+class SIGDUMPMEMTestCase(TestCase):
+    layer = LibrarianLayer
+
+    def test_sigdumpmem(self):
+        # Remove the dump file, if one exists.
+        if os.path.exists(DUMP_FILE):
+            os.unlink(DUMP_FILE)
+        self.assertFalse(os.path.exists(DUMP_FILE))
+
+        # We rely on the fact that the librarian was started by the test
+        # runner here as we use the LibrarianLayer.
+        pid = int(open(TacLibrarianTestSetup().pidfile).read())
+
+        # Send the signal and ensure the dump file is created.
+        os.kill(pid, SIGDUMPMEM)
+        timeout = 5
+        start_time = time.time()
+        while time.time() < start_time + timeout:
+            if os.path.exists(DUMP_FILE):
+                break
+        self.assertTrue(os.path.exists(DUMP_FILE))