Add a framework for working with services

- Basic information about each service is available for consumers
- Information about whether service is enabled or disabled is available
- Interested parties may listen to enabling/disabling of a service
- Information about some core services are made available

Makefile

@@ -17,7 +17,7 @@ default: config dirs template css docs
 all: default
 
 predepend:
-	sudo sh -c "apt-get install augeas-tools libpython2.7 pandoc psmisc python2.7 python-augeas python-passlib python-bcrypt python-bjsonrpc python-cheetah python-cherrypy3 python-simplejson python-contract sudo"
+	sudo sh -c "apt-get install augeas-tools libpython2.7 pandoc psmisc python2.7 python-augeas python-passlib python-bcrypt python-bjsonrpc python-cheetah python-cherrypy3 python-simplejson python-contract python-django sudo"
 	git submodule init
 	git submodule update
 	touch predepend

plinth.py

@@ -12,6 +12,7 @@ from cherrypy.process.plugins import Daemonizer
 Daemonizer(cherrypy.engine).subscribe()
 
 import plugin_mount
+import service
 import util as u
 
 from logger import Logger
@@ -177,6 +178,9 @@ def setup():
    cherrypy.engine.signal_handler.subscribe()
 
 def main():
+   # Initialize basic services
+   service.init()
+
    setup()
 
    cherrypy.engine.start()

service.py

@@ -0,0 +1,73 @@
+#
+# This file is part of Plinth.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program 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 Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+Framework for working with servers and theirs services
+"""
+
+from gettext import gettext as _
+
+import django.dispatch
+
+ENABLED = django.dispatch.Signal(providing_args=['service_id', 'enabled'])
+
+SERVICES = {}
+
+
+class Service(object):
+    """
+    Representation of an application service provided by the machine
+    containing information such as current status and ports required
+    for operation.
+    """
+
+    def __init__(self, service_id, name, ports=None, enabled=True):
+        if not ports:
+            ports = [service_id]
+
+        self.service_id = service_id
+        self.name = name
+        self.ports = ports
+        self._enabled = enabled
+
+        # Maintain a complete list of services
+        SERVICES[service_id] = self
+
+    def is_enabled(self):
+        """Return whether the service is enabled"""
+        if callable(self._enabled):
+            return self._enabled()
+
+        return self._enabled
+
+    def notify_enabled(self, sender, enabled):
+        """Notify observers about change in state of service"""
+        if not callable(self._enabled):
+            self._enabled = enabled
+
+        ENABLED.send_robust(sender=sender, service_id=self.service_id,
+                            enabled=enabled)
+
+
+def init():
+    """Register some misc. services that don't fit elsewhere"""
+    Service('http', _('Web Server'), ['http'], True)
+    Service('https', _('Web Server over Secure Socket Layer'),
+            ['https'], True)
+    Service('ssh', _('Secure Shell (SSH) Server'), ['ssh'], True)
+    Service('plinth', _('FreedomBox Web Interface (Plinth)'),
+            ['https'], True)