[NB] Add new core plugin: command_plugin

Add new core plugin, `command_plugin`, with the following 0MQ API:

 - `register_command(command_name, plugin_name=None, namespace='')`
     * Register command.
     * If `plugin_name` is not specified, use name of request source
       plugin.
 - `unregister_command(command_name, plugin_name=None, namespace='')`
     * Unregister command.
     * If `plugin_name` is not specified, use name of request source
       plugin.
 - `get_commands()`
     * Return `pandas.DataFrame` containing command list.

microdrop/core_plugins/command_plugin/__init__.py

@@ -0,0 +1,6 @@
+try:
+    import microdrop_plugin
+except ImportError:
+    import sys
+
+    print >> sys.stderr, 'Error importing command_plugin'

microdrop/core_plugins/command_plugin/microdrop_plugin.py

@@ -0,0 +1,96 @@
+"""
+Copyright 2016 Christian Fobel
+
+This file is part of command_plugin.
+
+command_plugin 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.
+
+command_plugin 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 command_plugin.  If not, see <http://www.gnu.org/licenses/>.
+"""
+import logging
+
+import gobject
+import zmq
+
+from .plugin import CommandZmqPlugin
+from ...app_context import get_hub_uri
+from ...plugin_manager import (PluginGlobals, SingletonPlugin, IPlugin,
+                               implements)
+
+logger = logging.getLogger(__name__)
+
+
+PluginGlobals.push_env('microdrop')
+
+
+class CommandPlugin(SingletonPlugin):
+    """
+    This class is automatically registered with the PluginManager.
+    """
+    implements(IPlugin)
+    plugin_name = 'wheelerlab.command_plugin'
+
+    def __init__(self):
+        self.name = self.plugin_name
+        self.plugin = None
+        self.command_timeout_id = None
+
+    def on_plugin_enable(self):
+        """
+        Handler called once the plugin instance is enabled.
+
+        Note: if you inherit your plugin from AppDataController and don't
+        implement this handler, by default, it will automatically load all
+        app options from the config file. If you decide to overide the
+        default handler, you should call:
+
+            AppDataController.on_plugin_enable(self)
+
+        to retain this functionality.
+        """
+        self.cleanup()
+        self.plugin = CommandZmqPlugin(self, self.name, get_hub_uri())
+        # Initialize sockets.
+        self.plugin.reset()
+
+        def check_command_socket():
+            try:
+                msg_frames = (self.plugin.command_socket
+                              .recv_multipart(zmq.NOBLOCK))
+            except zmq.Again:
+                pass
+            else:
+                self.plugin.on_command_recv(msg_frames)
+            return True
+
+        self.command_timeout_id = gobject.timeout_add(10, check_command_socket)
+
+    def cleanup(self):
+        if self.command_timeout_id is not None:
+            gobject.source_remove(self.command_timeout_id)
+        if self.plugin is not None:
+            self.plugin = None
+
+    def on_plugin_disable(self):
+        """
+        Handler called once the plugin instance is disabled.
+        """
+        self.cleanup()
+
+    def on_app_exit(self):
+        """
+        Handler called just before the Microdrop application exits.
+        """
+        self.cleanup()
+
+
+PluginGlobals.pop_env()

microdrop/core_plugins/command_plugin/plugin.py

@@ -0,0 +1,126 @@
+"""
+Copyright 2016 Christian Fobel
+
+This file is part of command_plugin.
+
+command_plugin 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.
+
+command_plugin 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 command_plugin.  If not, see <http://www.gnu.org/licenses/>.
+"""
+from multiprocessing import Process
+import logging
+import sys
+
+from zmq_plugin.plugin import Plugin as ZmqPlugin
+from zmq_plugin.schema import decode_content_data
+import pandas as pd
+
+
+logger = logging.getLogger(__name__)
+
+
+class CommandZmqPlugin(ZmqPlugin):
+    '''
+    API for registering commands.
+    '''
+    def __init__(self, parent, *args, **kwargs):
+        self.parent = parent
+        self.control_board = None
+        self._commands = pd.DataFrame(None, columns=['namespace',
+                                                     'plugin_name',
+                                                     'command_name', 'title'])
+        super(CommandZmqPlugin, self).__init__(*args, **kwargs)
+
+    def on_execute__unregister_command(self, request):
+        data = decode_content_data(request)
+        commands = self._commands
+        ix = commands.loc[(commands.namespace == data['namespace']) &
+                          (commands.plugin_name == data['plugin_name']) &
+                          (commands.command_name == data['command_name']) &
+                          (commands.title == data['title'])].index
+        self._commands.drop(ix, inplace=True)
+        self._commands.reset_index(drop=True, inplace=True)
+        return self.commands
+
+    def on_execute__register_command(self, request):
+        data = decode_content_data(request)
+        plugin_name = data.get('plugin_name', request['header']['source'])
+        return self.register_command(plugin_name, data['command_name'],
+                                     namespace=data.get('namespace', ''),
+                                     title=data.get('title'))
+
+    def on_execute__get_commands(self, request):
+        return self.commands
+
+    def register_command(self, plugin_name, command_name, namespace='',
+                         title=None):
+        '''
+        Register command.
+
+        Each command is unique by:
+
+            (namespace, plugin_name, command_name)
+        '''
+        if title is None:
+            title = (command_name[:1].upper() +
+                     command_name[1:]).replace('_', ' ')
+        row_i = dict(zip(self._commands, [namespace, plugin_name, command_name,
+                                          title]))
+        self._commands = self._commands.append(row_i, ignore_index=True)
+        return self.commands
+
+    @property
+    def commands(self):
+        '''
+        Returns
+        -------
+        pd.Series
+            Series of command groups, where each group name maps to a series of
+            commands.
+        '''
+        return self._commands.copy()
+
+
+
+def parse_args(args=None):
+    """Parses arguments, returns (options, args)."""
+    from argparse import ArgumentParser
+
+    if args is None:
+        args = sys.argv
+
+    parser = ArgumentParser(description='ZeroMQ Plugin process.')
+    log_levels = ('critical', 'error', 'warning', 'info', 'debug', 'notset')
+    parser.add_argument('-l', '--log-level', type=str, choices=log_levels,
+                        default='info')
+    parser.add_argument('hub_uri')
+    parser.add_argument('name', type=str)
+
+    args = parser.parse_args()
+    args.log_level = getattr(logging, args.log_level.upper())
+    return args
+
+
+if __name__ == '__main__':
+    from zmq_plugin.bin.plugin import run_plugin
+
+    def run_plugin_process(uri, name, subscribe_options, log_level):
+        plugin_process = Process(target=run_plugin,
+                                 args=())
+        plugin_process.daemon = False
+        plugin_process.start()
+
+    args = parse_args()
+
+    logging.basicConfig(level=args.log_level)
+    task = CommandZmqPlugin(None, args.name, args.hub_uri, {})
+    run_plugin(task, args.log_level)

microdrop/microdrop.py

@@ -44,6 +44,7 @@ def initialize_core_plugins():
     # These imports automatically load (and initialize) core singleton plugins.
     from .core_plugins import zmq_hub_plugin
     from .core_plugins import device_info_plugin
+    from .core_plugins import command_plugin
     from .core_plugins import electrode_controller_plugin
     from .gui import experiment_log_controller
     from .gui import config_controller