generalize the way screens are skipped when installing desktop

Also skip identity screen when installing neither server nor desktop
(i.e. core).

subiquity/server/controller.py

@@ -43,9 +43,21 @@ class SubiquityController(BaseController):
     # deprecated in favor of autoinstall_key.
     autoinstall_key_alias: Optional[str] = None
 
+    interactive_for_variants = None
+    _active = True
+
     def __init__(self, app):
         super().__init__(app)
         self.context.set('controller', self)
+        if self.interactive_for_variants is not None:
+            self.app.hub.subscribe(
+                InstallerChannels.INSTALL_CONFIRMED, self._confirmed)
+
+    async def _confirmed(self):
+        variant = self.app.base_model.source.current.variant
+        if variant not in self.interactive_for_variants:
+            await self.configured()
+            self._active = False
 
     def setup_autoinstall(self):
         if not self.app.autoinstall_config:
@@ -89,18 +101,19 @@ async def apply_autoinstall_config(self, context):
 
     def interactive(self):
         if not self.app.autoinstall_config:
-            return True
+            return self._active
         i_sections = self.app.autoinstall_config.get(
             'interactive-sections', [])
 
         if "*" in i_sections:
-            return True
+            return self._active
 
         if self.autoinstall_key in i_sections:
-            return True
+            return self._active
 
-        return (self.autoinstall_key_alias is not None
-                and self.autoinstall_key_alias in i_sections)
+        if self.autoinstall_key_alias is not None \
+           and self.autoinstall_key_alias in i_sections:
+            return self._active
 
     async def configured(self):
         """Let the world know that this controller's model is now configured.

subiquity/server/controllers/identity.py

@@ -62,6 +62,8 @@ class IdentityController(SubiquityController):
         'additionalProperties': False,
         }
 
+    interactive_for_variants = {'desktop', 'server'}
+
     def __init__(self, app):
         super().__init__(app)
         core_reserved_path = resource_path("reserved-usernames")

subiquity/server/controllers/snaplist.py

@@ -160,6 +160,8 @@ class SnapListController(SubiquityController):
         }
     model_name = "snaplist"
 
+    interactive_for_variants = {'server'}
+
     def _make_loader(self):
         return SnapdSnapInfoLoader(
             self.model, self.app.snapd, self.opts.snap_section,
@@ -170,20 +172,6 @@ def __init__(self, app):
         self.loader = self._make_loader()
         self.app.hub.subscribe(
             InstallerChannels.SNAPD_NETWORK_CHANGE, self.snapd_network_changed)
-        self.app.hub.subscribe(
-            InstallerChannels.INSTALL_CONFIRMED, self._confirmed)
-        self._active = True
-
-    async def _confirmed(self):
-        if self.app.base_model.source.current.variant == 'desktop':
-            await self.configured()
-            self._active = False
-            self.loader.stop()
-
-    def interactive(self):
-        if super().interactive():
-            return self._active
-        return False
 
     def load_autoinstall_data(self, ai_data):
         to_install = []

subiquity/server/controllers/ssh.py

@@ -51,26 +51,15 @@ class SSHController(SubiquityController):
         },
     }
 
+    interactive_for_variants = {'server'}
+
     def __init__(self, app):
         super().__init__(app)
-        self.app.hub.subscribe(
-            InstallerChannels.INSTALL_CONFIRMED, self._confirmed)
-        self._active = True
         if app.opts.dry_run:
             self.fetcher = DryRunSSHKeyFetcher(app)
         else:
             self.fetcher = SSHKeyFetcher(app)
 
-    async def _confirmed(self):
-        if self.app.base_model.source.current.variant == 'desktop':
-            await self.configured()
-            self._active = False
-
-    def interactive(self):
-        if super().interactive():
-            return self._active
-        return False
-
     def load_autoinstall_data(self, data):
         if data is None:
             return