[DPE-3202] Architecture specific snap revision (#345)

* Arm tweaks

* Bump snap revision

* Snap version bump

* Tweak plugins test

* Architecture based snap revision

* Try to set channel

* Revert conftest

* Remove string revision check

Author: dragomirp

src/charm.py

@@ -6,6 +6,7 @@
 import json
 import logging
 import os
+import platform
 import subprocess
 import time
 from typing import Dict, List, Literal, Optional, Set, get_args
@@ -965,12 +966,9 @@ def _setup_exporter(self) -> None:
         cache = snap.SnapCache()
         postgres_snap = cache[POSTGRESQL_SNAP_NAME]
 
-        if (
-            postgres_snap.revision
-            != list(
-                filter(lambda snap_package: snap_package[0] == POSTGRESQL_SNAP_NAME, SNAP_PACKAGES)
-            )[0][1]["revision"]
-        ):
+        if postgres_snap.revision != list(
+            filter(lambda snap_package: snap_package[0] == POSTGRESQL_SNAP_NAME, SNAP_PACKAGES)
+        )[0][1]["revision"].get(platform.machine()):
             logger.debug(
                 "Early exit _setup_exporter: snap was not refreshed to the right version yet"
             )
@@ -1274,9 +1272,15 @@ def _install_snap_packages(self, packages: List[str], refresh: bool = False) ->
                 snap_package = snap_cache[snap_name]
 
                 if not snap_package.present or refresh:
-                    if snap_version.get("revision"):
+                    if revision := snap_version.get("revision"):
+                        try:
+                            revision = revision[platform.machine()]
+                        except Exception:
+                            logger.error("Unavailable snap architecture %s", platform.machine())
+                            raise
+                        channel = snap_version.get("channel", "")
                         snap_package.ensure(
-                            snap.SnapState.Latest, revision=snap_version["revision"]
+                            snap.SnapState.Latest, revision=revision, channel=channel
                         )
                         snap_package.hold()
                     else:

src/constants.py

@@ -32,7 +32,9 @@
 # Snap constants.
 PGBACKREST_EXECUTABLE = "charmed-postgresql.pgbackrest"
 POSTGRESQL_SNAP_NAME = "charmed-postgresql"
-SNAP_PACKAGES = [(POSTGRESQL_SNAP_NAME, {"revision": "96"})]
+SNAP_PACKAGES = [
+    (POSTGRESQL_SNAP_NAME, {"revision": {"aarch64": "97", "x86_64": "98"}, "channel": "14/stable"})
+]
 
 SNAP_COMMON_PATH = "/var/snap/charmed-postgresql/common"
 SNAP_CURRENT_PATH = "/var/snap/charmed-postgresql/current"

tests/unit/test_charm.py

@@ -1,6 +1,7 @@
 # Copyright 2021 Canonical Ltd.
 # See LICENSE file for licensing details.
 import logging
+import platform
 import subprocess
 import unittest
 from unittest.mock import MagicMock, Mock, PropertyMock, mock_open, patch
@@ -1025,31 +1026,56 @@ def test_install_snap_packages(self, _snap_cache):
         _snap_cache.reset_mock()
         _snap_package.reset_mock()
         _snap_package.ensure.side_effect = None
-        self.charm._install_snap_packages([("postgresql", {"revision": 42})])
+        self.charm._install_snap_packages(
+            [("postgresql", {"revision": {platform.machine(): "42"}})]
+        )
         _snap_cache.assert_called_once_with()
         _snap_cache.return_value.__getitem__.assert_called_once_with("postgresql")
-        _snap_package.ensure.assert_called_once_with(snap.SnapState.Latest, revision=42)
+        _snap_package.ensure.assert_called_once_with(
+            snap.SnapState.Latest, revision="42", channel=""
+        )
         _snap_package.hold.assert_called_once_with()
 
         # Test with refresh
         _snap_cache.reset_mock()
         _snap_package.reset_mock()
         _snap_package.present = True
-        self.charm._install_snap_packages([("postgresql", {"revision": 42})], refresh=True)
+        self.charm._install_snap_packages(
+            [("postgresql", {"revision": {platform.machine(): "42"}, "channel": "latest/test"})],
+            refresh=True,
+        )
         _snap_cache.assert_called_once_with()
         _snap_cache.return_value.__getitem__.assert_called_once_with("postgresql")
-        _snap_package.ensure.assert_called_once_with(snap.SnapState.Latest, revision=42)
+        _snap_package.ensure.assert_called_once_with(
+            snap.SnapState.Latest, revision="42", channel="latest/test"
+        )
         _snap_package.hold.assert_called_once_with()
 
         # Test without refresh
         _snap_cache.reset_mock()
         _snap_package.reset_mock()
-        self.charm._install_snap_packages([("postgresql", {"revision": 42})])
+        self.charm._install_snap_packages(
+            [("postgresql", {"revision": {platform.machine(): "42"}})]
+        )
         _snap_cache.assert_called_once_with()
         _snap_cache.return_value.__getitem__.assert_called_once_with("postgresql")
         _snap_package.ensure.assert_not_called()
         _snap_package.hold.assert_not_called()
 
+        # test missing architecture
+        _snap_cache.reset_mock()
+        _snap_package.reset_mock()
+        _snap_package.present = True
+        with self.assertRaises(KeyError):
+            self.charm._install_snap_packages(
+                [("postgresql", {"revision": {"missingarch": "42"}})],
+                refresh=True,
+            )
+        _snap_cache.assert_called_once_with()
+        _snap_cache.return_value.__getitem__.assert_called_once_with("postgresql")
+        assert not _snap_package.ensure.called
+        assert not _snap_package.hold.called
+
     @patch(
         "subprocess.check_call",
         side_effect=[None, subprocess.CalledProcessError(1, "fake command")],