* Start to get rid of pylint; it's more trouble than it's worth and pyflakes

  does a pretty good job anyway.
* Remove master.get_lock_data() now that flufl.lock 2.1 provides the same
  detailed information.
* Add WatcherState.none to indicate that the master is not running.
* Instrument master_state() and acquire_lock_1() for testing, and add
  unittests.
* LBYL for 'bin/mailman start' so that the error message when the master is
  already running happens in the foreground process and is more user friendly.
* Add 'bin/mailman status' to provide master queue runner status on the
  command line.

3 files changed, 117 insertions, 1 deletions

diff --git a/src/mailman/commands/cli_control.py b/src/mailman/commands/cli_control.py
index 83432a6e8..2c693621d 100644
--- a/src/mailman/commands/cli_control.py
+++ b/src/mailman/commands/cli_control.py
@@ -36,6 +36,7 @@ import logging
 
 from zope.interface import implements
 
+from mailman.bin.master import WatcherState, master_state
 from mailman.config import config
 from mailman.core.i18n import _
 from mailman.interfaces.command import ICLISubCommand
@@ -54,6 +55,7 @@ class Start:
 
     def add(self, parser, command_parser):
         """See `ICLISubCommand`."""
+        self.parser = parser
         command_parser.add_argument(
             '-f', '--force',
             default=False, action='store_true',
@@ -92,6 +94,15 @@ class Start:
 
     def process(self, args):
         """See `ICLISubCommand`."""
+        # Although there's a potential race condition here, it's a better user
+        # experience for the parent process to refuse to start twice, rather
+        # than having it try to start the master, which will error exit.
+        status, lock = master_state()
+        if status is WatcherState.conflict:
+            self.parser.error(_('GNU Mailman is already running'))
+        elif status in (WatcherState.stale_lock, WatcherState.host_mismatch):
+            self.parser.error(_('A previous run of GNU Mailman did not exit '
+                                'cleanly.  Try using --force.'))
         def log(message):
             if not args.quiet:
                 print message
@@ -152,7 +163,7 @@ def kill_watcher(sig):
 
 class SignalCommand:
     """Common base class for simple, signal sending commands."""
-    
+
     implements(ICLISubCommand)
 
     name = None
diff --git a/src/mailman/commands/cli_status.py b/src/mailman/commands/cli_status.py
new file mode 100644
index 000000000..abe8cfe3e
--- /dev/null
+++ b/src/mailman/commands/cli_status.py
@@ -0,0 +1,68 @@
+# Copyright (C) 2010 by the Free Software Foundation, Inc.
+#
+# This file is part of GNU Mailman.
+#
+# GNU Mailman is free software: you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your option)
+# any later version.
+#
+# GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+# more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# GNU Mailman.  If not, see <http://www.gnu.org/licenses/>.
+
+"""Module stuff."""
+
+from __future__ import absolute_import, unicode_literals
+
+__metaclass__ = type
+__all__ = [
+    'Status',
+    ]
+
+
+import socket
+
+from zope.interface import implements
+
+from mailman.bin.master import WatcherState, master_state
+from mailman.core.i18n import _
+from mailman.interfaces.command import ICLISubCommand
+
+
+
+class Status:
+    """Status of the Mailman system."""
+
+    implements(ICLISubCommand)
+
+    name = 'status'
+
+    def add(self, parser, command_parser):
+        """See `ICLISubCommand`."""
+        pass
+
+    def process(self, args):
+        """See `ICLISubCommand`."""
+        status, lock = master_state()
+        if status is WatcherState.none:
+            message = _('GNU Mailman is not running')
+        elif status is WatcherState.conflict:
+            hostname, pid, tempfile = lock.details
+            message = _('GNU Mailman is running (master pid: $pid)')
+        elif status is WatcherState.stale_lock:
+            hostname, pid, tempfile = lock.details
+            message =_('GNU Mailman is stopped (stale pid: $pid)')
+        else:
+            hostname, pid, tempfile = lock.details
+            fqdn_name = socket.getfqdn()
+            assert status is WatcherState.host_mismatch, (
+                'Invalid enum value: %s' % status)
+            message = _('GNU Mailman is in an unexpected state '
+                        '($hostname != $fqdn_name)')
+        print message
+        return int(status)
diff --git a/src/mailman/commands/docs/status.txt b/src/mailman/commands/docs/status.txt
new file mode 100644
index 000000000..6deb7fdc0
--- /dev/null
+++ b/src/mailman/commands/docs/status.txt
@@ -0,0 +1,37 @@
+==============
+Getting status
+==============
+
+The status of the Mailman master process can be queried from the command line.
+It's clear at this point that nothing is running.
+::
+
+    >>> from mailman.commands.cli_status import Status
+    >>> status = Status()
+
+    >>> class FakeArgs:
+    ...     pass
+
+The status is printed to stdout and a status code is returned.
+
+    >>> status.process(FakeArgs)
+    GNU Mailman is not running
+    0
+
+We can simulate the master queue runner starting up by acquiring its lock.
+
+    >>> from flufl.lock import Lock
+    >>> lock = Lock(config.LOCK_FILE)
+    >>> lock.lock()
+
+Getting the status confirms that the master queue runner is running.
+
+    >>> status.process(FakeArgs)
+    GNU Mailman is running (master pid: ...
+
+We shutdown the master queue runner, and confirm the status.
+
+    >>> lock.unlock()
+    >>> status.process(FakeArgs)
+    GNU Mailman is not running
+    0