identity: look-ahead on source variant

The current check for Desktop doesn't work in load_autoinstall_data
because the variant isn't set until the controllers have started
(and load_autoinstall_data happens before this). The simple way
to get around this is to re-implement this logic in the identity
controller so it can tell ahead of time what the result will be in
the source controller/model. We should remove this logic once we can move
this check to a time after all the controllers have started.

subiquity/server/controllers/identity.py

@@ -14,14 +14,18 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import logging
+import os
 import re
-from typing import Set
+from typing import List, Set
 
 import attr
+import yaml
 
 from subiquity.common.apidef import API
 from subiquity.common.resources import resource_path
+from subiquity.common.serialize import Serializer
 from subiquity.common.types import IdentityData, UsernameValidation
+from subiquity.models.source import CatalogEntry
 from subiquity.server.autoinstall import AutoinstallError
 from subiquity.server.controller import SubiquityController
 from subiquitycore.context import with_context
@@ -89,6 +93,9 @@ def load_autoinstall_data(self, data):
         # 2. we are installing not-Server (Desktop)
         if self.app.base_model.source.current.variant != "server":
             return
+        # 2.1 (see definition of _install_source_is_desktop)
+        if self._install_source_is_desktop():
+            return
         # 3. we are only refreshing the reset partition
         # (The identity controller doesn't figure this out until the apply
         # step, so we are going to cheat and inspect the situation here)
@@ -151,3 +158,49 @@ async def validate_username_GET(self, username: str) -> UsernameValidation:
             return UsernameValidation.TOO_LONG
 
         return UsernameValidation.OK
+
+    # The identity section (and user-data) section are entirely optional
+    # on Desktop, but setting the variant doesn't happen until controllers
+    # are started. For the identity controller to properly validate
+    # this behavior, we need to do look-ahead on the source controller
+    # logic for loading the available sources.
+    # See: https://github.com/canonical/subiquity/pull/1965
+    def _install_source_is_desktop(self) -> bool:
+        # Check the autoinstall config first
+        source_config = self.app.autoinstall_config.get("source")
+        if (
+            source_config is not None
+            and (id := source_config.get("id")) is not None
+            and "server" not in id
+        ):
+            return True
+
+        # In dryrun we are on server, unless you spoof with:
+        #   source:
+        #    id: desktop
+        if self.app.opts.dry_run:
+            return False
+
+        # Check the sources available the same way the source controller does
+        # but return a bool for if the variant is desktop
+        path = "/cdrom/casper/install-sources.yaml"
+        if self.app.opts.source_catalog is not None:
+            path = self.app.opts.source_catalog
+        if not os.path.exists(path):
+            # Be restrictive here, default variant is Server
+            return False
+        current = None
+        with open(path) as fp:
+            sources = Serializer(ignore_unknown_fields=True).deserialize(
+                List[CatalogEntry], yaml.safe_load(fp)
+            )
+        for entry in sources:
+            if entry.default:
+                current = entry
+        if current is None:
+            current = sources[0]
+
+        if "server" in current.variant:
+            return False
+
+        return True

subiquity/server/controllers/tests/test_identity.py

@@ -13,6 +13,8 @@
 # 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/>.
 
+from unittest.mock import mock_open, patch
+
 import jsonschema
 from jsonschema.validators import validator_for
 
@@ -83,3 +85,40 @@ async def test_desktop_does_not_require_identity_case_4a2(self, config, valid):
         self.app.autoinstall_config = config
         # should never raise
         self.ic.load_autoinstall_data(None)
+
+    def test_install_source_is_desktop__autoinstall(self):
+        """Test _install_source_is_desktop autoinstall."""
+
+        self.app.autoinstall_config = {"source": {"id": "desktop"}}
+        self.assertTrue(self.ic._install_source_is_desktop())
+
+        self.app.autoinstall_config = {"source": {"id": "server"}}
+        self.assertFalse(self.ic._install_source_is_desktop())
+
+    def test_install_source_is_desktop__no_sources(self):
+        """Test _install_source_is_desktop no sources."""
+
+        # Default server if /cdrom/casper/install-sources.yaml DNE
+        with patch("os.path.exists", return_value=False):
+            self.assertFalse(self.ic._install_source_is_desktop())
+
+    @parameterized.expand(
+        #   (Sources list, is_desktop)
+        (
+            ("examples/sources/desktop.yaml", True),
+            ("examples/sources/install.yaml", False),
+        )
+    )
+    def test_install_source_is_desktop__sources(self, sources, is_desktop):
+        """Test _install_source_is_desktop sources."""
+
+        self.app.opts.dry_run = False  # Fun!
+
+        with open(sources) as f:
+            source_data = f.read()
+
+        with (
+            patch("os.path.exists", return_value=True),
+            patch("builtins.open", mock_open(read_data=source_data)),
+        ):
+            self.assertEqual(self.ic._install_source_is_desktop(), is_desktop)