[enhancement] Added "device_registered" signal

"device_registered" signal is emitted when a new device is registered
automatically through the controller.

Author: pandafy

README.rst

@@ -865,6 +865,17 @@ This signal is emitted every time ``DeviceConnection.is_working`` changes.
 
 It is not triggered when the device is created for the first time.
 
+``device_registered``
+~~~~~~~~~~~~~~~~~~~~~
+
+**Path**: ``openwisp_controller.config.signals.device_registered``
+
+**Arguments**:
+
+- ``instance``: instance of ``Device`` which got registered.
+
+This signal is emitted once the device gets registered automatically through the controller.
+
 Setup (Integrate into other Apps)
 ---------------------------------
 

openwisp_controller/config/controller/views.py

@@ -11,7 +11,7 @@
 from swapper import load_model
 
 from .. import settings as app_settings
-from ..signals import checksum_requested, config_download_requested
+from ..signals import checksum_requested, config_download_requested, device_registered
 from ..utils import (
     ControllerResponse,
     forbid_unallowed,
@@ -342,6 +342,8 @@ def post(self, request, *args, **kwargs):
             )
         # add templates specified in tags
         self.add_tagged_templates(config, request)
+        # emit device registered signal
+        device_registered.send(sender=config.__class__, instance=device)
         # prepare response
         s = (
             'registration-result: success\n'

openwisp_controller/config/signals.py

@@ -5,3 +5,4 @@
 config_status_changed = Signal(providing_args=['instance'])
 # device and config args are maintained for backward compatibility
 config_modified = Signal(providing_args=['instance', 'device', 'config'])
+device_registered = Signal(providing_args=['instance'])

openwisp_controller/config/tests/test_controller.py

@@ -14,6 +14,7 @@
     config_download_requested,
     config_modified,
     config_status_changed,
+    device_registered,
 )
 from .utils import CreateConfigTemplateMixin, TestVpnX509Mixin
 
@@ -998,3 +999,10 @@ def test_config_modified_not_sent_in_registration(self):
             self.client.post(self.register_url, options)
             handler.assert_not_called()
         self.assertEqual(qs.count(), 1)
+
+    def test_device_registered_signal(self):
+        with catch_signal(device_registered) as handler:
+            device = self.test_register()
+            handler.assert_called_once_with(
+                sender=Config, signal=device_registered, instance=device,
+            )