oem: allow to disable install on desktop and force install on server

By default, OEM meta-packages get installed on ubuntu-desktop and don't
get installed on ubuntu-server. Using autoinstall, we can now give more
control. The autoinstall section supports the following:

Install on server and desktop:

  oem:
    install: true

Do not install even on desktop:

  oem:
    install: false

Install only on desktop (the default):

  oem:
    install: auto

Signed-off-by: Olivier Gayot <olivier.gayot@canonical.com>

autoinstall-schema.json

@@ -489,6 +489,25 @@
                 }
             }
         },
+        "oem": {
+            "type": "object",
+            "properties": {
+                "install": {
+                    "oneOf": [
+                        {
+                            "type": "boolean"
+                        },
+                        {
+                            "type": "string",
+                            "const": "auto"
+                        }
+                    ]
+                }
+            },
+            "required": [
+                "install"
+            ]
+        },
         "timezone": {
             "type": "string"
         },

documentation/autoinstall-reference.md

@@ -575,6 +575,21 @@ Whether to install the ubuntu-restricted-addons package.
 
 Whether to install the available third-party drivers.
 
+<a name="oem"></a>
+
+### oem
+
+**type:** mapping, see below
+**default:** see below
+**can be interactive:** no
+
+#### install
+
+**type:** boolean or string (special value `auto`)
+**default:**: `auto`
+
+Whether to install the available OEM meta-packages. The special value `auto` - which is the default - enables the installation on ubuntu-desktop but not on ubuntu-server.
+
 <a name="snaps"></a>
 
 ### snaps

documentation/autoinstall-schema.md

@@ -509,6 +509,25 @@ The [JSON schema](https://json-schema.org/) for autoinstall data is as follows:
                 }
             }
         },
+        "oem": {
+            "type": "object",
+            "properties": {
+                "install": {
+                    "oneOf": [
+                        {
+                            "type": "boolean"
+                        },
+                        {
+                            "type": "string",
+                            "const": "auto"
+                        }
+                    ]
+                }
+            },
+            "required": [
+                "install"
+            ]
+        },
         "timezone": {
             "type": "string"
         },

subiquity/models/oem.py

@@ -14,7 +14,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import logging
-from typing import List, Optional
+from typing import Any, Dict, List, Optional, Union
 
 import attr
 
@@ -32,3 +32,34 @@ class OEMModel:
         # List of OEM metapackages relevant to the current hardware.
         # When the list is None, it has not yet been retrieved.
         self.metapkgs: Optional[List[OEMMetaPkg]] = None
+
+        # By default, skip looking for OEM meta-packages if we are running
+        # ubuntu-server. OEM meta-packages expect the default kernel flavor to
+        # be HWE (which is only true for ubuntu-desktop).
+        self.install_on = {
+            "server": False,
+            "desktop": True,
+        }
+
+    def make_autoinstall(self) -> Dict[str, Union[str, bool]]:
+        server = self.install_on["server"]
+        desktop = self.install_on["desktop"]
+
+        if server and desktop:
+            return {"install": True}
+        if not server and not desktop:
+            return {"install": False}
+
+        # Having server = True and desktop = False is not supported.
+        assert desktop and not server
+
+        return {"install": "auto"}
+
+    def load_autoinstall_data(self, data: Dict[str, Any]) -> None:
+        if data["install"] == "auto":
+            self.install_on["server"] = False
+            self.install_on["desktop"] = True
+            return
+
+        self.install_on["server"] = data["install"]
+        self.install_on["desktop"] = data["install"]

subiquity/server/controllers/oem.py

@@ -39,7 +39,25 @@ class OEMController(SubiquityController):
 
     endpoint = API.oem
 
-    model_name = "oem"
+    autoinstall_key = model_name = "oem"
+    autoinstall_schema = {
+        "type": "object",
+        "properties": {
+            "install": {
+                "oneOf": [
+                    {
+                        "type": "boolean",
+                    },
+                    {
+                        "type": "string",
+                        "const": "auto",
+                    },
+                ],
+            },
+        },
+        "required": ["install"],
+    }
+    autoinstall_default = {"install": "auto"}
 
     def __init__(self, app) -> None:
         super().__init__(app)
@@ -67,6 +85,12 @@ class OEMController(SubiquityController):
         self.load_metapkgs_task = asyncio.create_task(
                 list_and_mark_configured())
 
+    def make_autoinstall(self):
+        return self.model.make_autoinstall()
+
+    def load_autoinstall_data(self, *args, **kwargs) -> None:
+        self.model.load_autoinstall_data(*args, **kwargs)
+
     async def wants_oem_kernel(self, pkgname: str,
                                *, context, overlay) -> bool:
         """ For a given package, tell whether it wants the OEM or the default
@@ -103,9 +127,9 @@ class OEMController(SubiquityController):
         # Skip looking for OEM meta-packages if we are running ubuntu-server.
         # OEM meta-packages expect the default kernel flavor to be HWE (which
         # is only true for ubuntu-desktop).
-        if self.app.base_model.source.current.variant == "server":
-            log.debug("not listing OEM meta-packages since we are installing"
-                      " ubuntu-server")
+        variant: str = self.app.base_model.source.current.variant
+        if not self.model.install_on[variant]:
+            log.debug("listing of OEM meta-packages disabled on %s", variant)
             self.model.metapkgs = []
             return