[DPE-3647] Pin snap to rev37 (2.10.0-ubuntu1) (#197)

Add snap pinning and make sure we are installing the correct version in integration tests.

Closes #123

src/opensearch.py

@@ -34,6 +34,9 @@
 logger = logging.getLogger(__name__)
 
 
+OPENSEARCH_SNAP_REVISION = 37
+
+
 class OpenSearchSnap(OpenSearchDistribution):
     """Snap distribution of opensearch, only overrides properties and logic proper to the snap."""
 
@@ -58,11 +61,13 @@ def __init__(self, charm, peer_relation: str):
     @override
     def install(self):
         """Install opensearch from the snapcraft store."""
-        if self._opensearch.present:
-            return
         try:
-            self._opensearch.ensure(snap.SnapState.Latest, channel="edge")
+            self._opensearch.ensure(snap.SnapState.Latest, revision=OPENSEARCH_SNAP_REVISION)
             self._opensearch.connect("process-control")
+            if not self._opensearch.held:
+                # hold the snap in charm determined revision
+                self._opensearch.hold()
+
         except SnapError as e:
             logger.error(f"Failed to install opensearch. \n{e}")
             raise OpenSearchInstallError()

tests/integration/helpers.py

@@ -29,6 +29,7 @@
 METADATA = yaml.safe_load(Path("./metadata.yaml").read_text())
 APP_NAME = METADATA["name"]
 
+EXPECTED_SNAP_REVISION = 37
 SERIES = "jammy"
 UNIT_IDS = [0, 1, 2]
 IDLE_PERIOD = 75

tests/integration/test_charm.py

@@ -3,12 +3,15 @@
 # See LICENSE file for licensing details.
 
 import logging
+import subprocess
 
 import pytest
+import yaml
 from pytest_operator.plugin import OpsTest
 
 from .helpers import (
     APP_NAME,
+    EXPECTED_SNAP_REVISION,
     MODEL_CONFIG,
     SERIES,
     get_admin_secrets,
@@ -141,3 +144,31 @@ async def test_actions_rotate_admin_password(ops_test: OpsTest) -> None:
         ops_test, "GET", test_url, resp_status_code=True, user_password=password1
     )
     assert http_resp_code == 401
+
+
+@pytest.mark.group(1)
+@pytest.mark.abort_on_fail
+async def test_check_pinned_revision(ops_test: OpsTest) -> None:
+    """Test check the pinned revision."""
+    leader_id = await get_leader_unit_id(ops_test)
+
+    installed_info = yaml.safe_load(
+        subprocess.check_output(
+            [
+                "juju",
+                "ssh",
+                f"opensearch/{leader_id}",
+                "--",
+                "sudo",
+                "snap",
+                "info",
+                "opensearch",
+                "--color=never",
+                "--unicode=always",
+            ],
+            text=True,
+        ).replace("\r\n", "\n")
+    )["installed"].split()
+    logger.info(f"Installed snap: {installed_info}")
+    assert installed_info[1] == f"({EXPECTED_SNAP_REVISION})"
+    assert installed_info[3] == "held"