filesystem: permit match spec to be a list

(cherry picked from commit 70970b3)

doc/reference/autoinstall-reference.rst

@@ -576,6 +576,18 @@ To match a Seagate drive:
      match:
        model: Seagate
 
+As of Subiquity 24.08.1, match specs may optionally be specified in an ordered
+list, and will use the first match spec that matches one or more unused disks:
+
+.. code-block:: yaml
+
+   # attempt first to match by serial, then by path
+   - type: disk
+     id: data-disk
+     match:
+       - serial: Foodisk_1TB_ABC123_1
+       - path: /dev/nvme0n1
+
 Partition/logical volume extensions
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

subiquity/models/filesystem.py

@@ -1660,14 +1660,22 @@ def _filtered_matches(self, disks: Sequence[_Device], match: dict):
         matchers = self._make_matchers(match)
         return [disk for disk in disks if all(match_fn(disk) for match_fn in matchers)]
 
-    def disk_for_match(self, disks, match):
+    def disk_for_match(
+        self, disks: Sequence[_Device], match: dict | Sequence[dict]
+    ) -> _Device:
+        # a match directive is a dict, or a list of dicts, that specify
+        # * zero or more keys to filter on
+        # * an optional sort on size
         log.info(f"considering {disks} for {match}")
-        candidates = self._filtered_matches(disks, match)
-        candidates = self._sorted_matches(candidates, match)
-        if candidates:
-            log.info(f"For match {match}, using the first candidate from {candidates}")
-            return candidates[0]
-        log.info(f"For match {match}, no devices match")
+        if isinstance(match, dict):
+            match = [match]
+        for m in match:
+            candidates = self._filtered_matches(disks, m)
+            candidates = self._sorted_matches(candidates, m)
+            if candidates:
+                log.info(f"For match {m}, using the first candidate from {candidates}")
+                return candidates[0]
+        log.info(f"No devices satisfy criteria {match}")
         return None
 
     def assign_omitted_offsets(self):

subiquity/models/tests/test_filesystem.py

@@ -1834,3 +1834,25 @@ def test_matcher_install_media(self):
         fake_up_blockdata(m)
         actual = m.disk_for_match([iso, disk], {"install-media": True})
         self.assertEqual(iso, actual)
+
+    def test_match_from_list_first(self):
+        m = make_model()
+        vda = make_disk(m, path="/dev/vda", serial="s1")
+        vdb = make_disk(m, path="/dev/vdb", serial="s2")
+        fake_up_blockdata(m)
+        match = [
+            {"serial": "s1"},
+            {"path": "/dev/vdb"},
+        ]
+        self.assertEqual(vda, m.disk_for_match([vda, vdb], match))
+
+    def test_match_from_list_second(self):
+        m = make_model()
+        vda = make_disk(m, path="/dev/vda", serial="s1")
+        vdb = make_disk(m, path="/dev/vdb", serial="s2")
+        fake_up_blockdata(m)
+        match = [
+            {"serial": "not-found"},
+            {"path": "/dev/vdb"},
+        ]
+        self.assertEqual(vdb, m.disk_for_match([vda, vdb], match))

subiquity/server/controllers/filesystem.py

@@ -22,7 +22,7 @@
 import pathlib
 import subprocess
 import time
-from typing import Any, Callable, Dict, List, Optional, Union
+from typing import Any, Callable, Dict, List, Optional, Sequence, Union
 
 import attr
 import pyudev
@@ -1341,7 +1341,9 @@ async def _probe(self, *, context=None):
                 self.start_monitor()
             break
 
-    def get_bootable_matching_disk(self, match: dict[str, str]):
+    def get_bootable_matching_disk(
+        self, match: dict[str, str] | Sequence[dict[str, str]]
+    ):
         """given a match directive, find disks or disk-like devices for which
         we have a plan to boot, and return the best matching one of those.
         As match directives are autoinstall-supplied, raise AutoinstallError if