fix: set PSC ip type based on pscEnabled (#1158)

With CAS-based instances being supported soon and also using dnsName,
we can no longer rely on the presence of dnsName in the connectSettings
API as identifying that PSC is enabled on an instance.

Instead we should check pscEnabled from the response as source of truth.

Check if pscEnabled is True before setting PSC ip type.

google/cloud/sql/connector/client.py

@@ -141,10 +141,13 @@ async def _get_metadata(
             if "ipAddresses" in ret_dict
             else {}
         )
-        # Remove trailing period from PSC DNS name.
-        psc_dns = ret_dict.get("dnsName")
-        if psc_dns:
-            ip_addresses["PSC"] = psc_dns.rstrip(".")
+        # resolve dnsName into IP address for PSC
+        # Note that we have to check for PSC enablement also because CAS
+        # instances also set the dnsName field.
+        # Remove trailing period from DNS name. Required for SSL in Python
+        dns_name = ret_dict.get("dnsName", "").rstrip(".")
+        if dns_name and ret_dict.get("pscEnabled"):
+            ip_addresses["PSC"] = dns_name
 
         return {
             "ip_addresses": ip_addresses,

tests/unit/mocks.py

@@ -234,6 +234,7 @@ def __init__(
         self.name = name
         self.db_version = db_version
         self.ip_addrs = ip_addrs
+        self.psc_enabled = False
         self.cert_before = cert_before
         self.cert_expiration = cert_expiration
         # create self signed CA cert
@@ -255,6 +256,7 @@ async def connect_settings(self, request: Any) -> web.Response:
                 "expirationTime": str(self.cert_expiration),
             },
             "dnsName": "abcde.12345.us-central1.sql.goog",
+            "pscEnabled": self.psc_enabled,
             "ipAddresses": ip_addrs,
             "region": self.region,
             "databaseVersion": self.db_version,

tests/unit/test_client.py

@@ -24,16 +24,36 @@
 
 
 @pytest.mark.asyncio
-async def test_get_metadata(fake_client: CloudSQLClient) -> None:
+async def test_get_metadata_no_psc(fake_client: CloudSQLClient) -> None:
     """
-    Test _get_metadata returns successfully.
+    Test _get_metadata returns successfully and does not include PSC IP type.
     """
     resp = await fake_client._get_metadata(
         "test-project",
         "test-region",
         "test-instance",
     )
     assert resp["database_version"] == "POSTGRES_15"
+    assert resp["ip_addresses"] == {
+        "PRIMARY": "127.0.0.1",
+        "PRIVATE": "10.0.0.1",
+    }
+    assert isinstance(resp["server_ca_cert"], str)
+
+
+@pytest.mark.asyncio
+async def test_get_metadata_with_psc(fake_client: CloudSQLClient) -> None:
+    """
+    Test _get_metadata returns successfully with PSC IP type.
+    """
+    # set PSC to enabled on test instance
+    fake_client.instance.psc_enabled = True
+    resp = await fake_client._get_metadata(
+        "test-project",
+        "test-region",
+        "test-instance",
+    )
+    assert resp["database_version"] == "POSTGRES_15"
     assert resp["ip_addresses"] == {
         "PRIMARY": "127.0.0.1",
         "PRIVATE": "10.0.0.1",