document InstallerChannels and add INSTALL_CONFIRMED event

subiquity/models/subiquity.py

@@ -287,6 +287,7 @@ class SubiquityModel:
 
     def confirm(self):
         self._confirmation.set()
+        self.hub.broadcast(InstallerChannels.INSTALL_CONFIRMED)
 
     def validate_cloudconfig_schema(self, data: dict, data_source: str):
         """Validate data config adheres to strict cloud-config schema

subiquity/server/controllers/snaplist.py

@@ -169,11 +169,10 @@ class SnapListController(SubiquityController):
     def __init__(self, app):
         super().__init__(app)
         self.loader = self._make_loader()
-        self.app.hub.subscribe(InstallerChannels.SNAPD_NETWORK_CHANGE,
-                               self.snapd_network_changed)
         self.app.hub.subscribe(
-            (InstallerChannels.CONFIGURED, 'filesystem'),
-            self._confirmed)
+            InstallerChannels.SNAPD_NETWORK_CHANGE, self.snapd_network_changed)
+        self.app.hub.subscribe(
+            InstallerChannels.INSTALL_CONFIRMED, self._confirmed)
         self._active = True
 
     async def _confirmed(self):

subiquity/server/controllers/ssh.py

@@ -59,8 +59,7 @@ class SSHController(SubiquityController):
     def __init__(self, app):
         super().__init__(app)
         self.app.hub.subscribe(
-            (InstallerChannels.CONFIGURED, 'filesystem'),
-            self._confirmed)
+            InstallerChannels.INSTALL_CONFIRMED, self._confirmed)
         self._active = True
 
     async def _confirmed(self):

subiquity/server/types.py

@@ -15,10 +15,31 @@
 
 from subiquitycore.pubsub import CoreChannels
 
+# This module defines constants to be used with "hub.{a,}broadcast" to
+# allow controllers to find out when various things have happened.
+
 
 class InstallerChannels(CoreChannels):
+    # This message is sent when a value is provided for the http proxy
+    # setting.
     NETWORK_PROXY_SET = 'network-proxy-set'
+    # This message is sent there has been a network change that might affect
+    # snapd's ability to talk to the network.
     SNAPD_NETWORK_CHANGE = 'snapd-network-change'
+    # This message is send when results from the geoip service are received.
     GEOIP = 'geoip'
+    # (CONFIGURED, $model_name) is sent when a model is marked
+    # configured. Note that this can happen several times for each controller
+    # (at least in theory) if the users goes back to a screen and makes a
+    # different choice.
     CONFIGURED = 'configured'
+    # This message is sent when apt has been configured in the overlay that
+    # will be used as the source for the install step of the
+    # installation. Currently this is only done once, but this might change in
+    # the future.
     APT_CONFIGURED = 'apt-configured'
+    # This message is sent when the user has confirmed that the install has
+    # been confirmed. Once this has happened one can be sure that all the
+    # models in the "install" side of the install/postinstall divide will not
+    # be reconfigured.
+    INSTALL_CONFIRMED = 'install-confirmed'