feat(gapic): support mTLS certificates when available (#1467)

feat: update image to
us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator@sha256:b8058df4c45e9a6e07f6b4d65b458d0d059241dd34c814f151c8bf6b89211209

Author: daniel-sanche

.librarian/generator-input/noxfile.py

@@ -35,14 +35,15 @@
 DEFAULT_PYTHON_VERSION = "3.14"
 
 DEFAULT_MOCK_SERVER_TESTS_PYTHON_VERSION = "3.12"
-SYSTEM_TEST_PYTHON_VERSIONS: List[str] = ["3.12"]
+SYSTEM_TEST_PYTHON_VERSIONS: List[str] = ["3.14"]
 
 UNIT_TEST_PYTHON_VERSIONS: List[str] = [
     "3.9",
     "3.10",
     "3.11",
     "3.12",
     "3.13",
+    "3.14",
 ]
 UNIT_TEST_STANDARD_DEPENDENCIES = [
     "mock",
@@ -81,6 +82,7 @@
     "unit-3.11",
     "unit-3.12",
     "unit-3.13",
+    "unit-3.14",
     "system",
     "cover",
     "lint",
@@ -195,7 +197,12 @@ def install_unittest_dependencies(session, *constraints):
 def unit(session, protobuf_implementation):
     # Install all test dependencies, then install this package in-place.
 
-    if protobuf_implementation == "cpp" and session.python in ("3.11", "3.12", "3.13"):
+    if protobuf_implementation == "cpp" and session.python in (
+        "3.11",
+        "3.12",
+        "3.13",
+        "3.14",
+    ):
         session.skip("cpp implementation is not supported in python 3.11+")
 
     constraints_path = str(
@@ -213,6 +220,7 @@ def unit(session, protobuf_implementation):
     session.run(
         "py.test",
         "--quiet",
+        "-s",
         f"--junitxml=unit_{session.python}_sponge_log.xml",
         "--cov=google",
         "--cov=tests/unit",
@@ -326,7 +334,12 @@ def system(session, protobuf_implementation, database_dialect):
             "Only run system tests on real Spanner with one protobuf implementation to speed up the build"
         )
 
-    if protobuf_implementation == "cpp" and session.python in ("3.11", "3.12", "3.13"):
+    if protobuf_implementation == "cpp" and session.python in (
+        "3.11",
+        "3.12",
+        "3.13",
+        "3.14",
+    ):
         session.skip("cpp implementation is not supported in python 3.11+")
 
     # Install pyopenssl for mTLS testing.
@@ -470,7 +483,7 @@ def docfx(session):
     )
 
 
-@nox.session(python="3.13")
+@nox.session(python="3.14")
 @nox.parametrize(
     "protobuf_implementation,database_dialect",
     [
@@ -485,7 +498,12 @@ def docfx(session):
 def prerelease_deps(session, protobuf_implementation, database_dialect):
     """Run all tests with prerelease versions of dependencies installed."""
 
-    if protobuf_implementation == "cpp" and session.python in ("3.11", "3.12", "3.13"):
+    if protobuf_implementation == "cpp" and session.python in (
+        "3.11",
+        "3.12",
+        "3.13",
+        "3.14",
+    ):
         session.skip("cpp implementation is not supported in python 3.11+")
 
     # Install all dependencies

.librarian/generator-input/setup.py

@@ -44,18 +44,15 @@
     "proto-plus >= 1.22.2, <2.0.0; python_version>='3.11'",
     "protobuf>=3.20.2,<7.0.0,!=4.21.0,!=4.21.1,!=4.21.2,!=4.21.3,!=4.21.4,!=4.21.5",
     "grpc-interceptor >= 0.15.4",
+    # Make OpenTelemetry a core dependency
+    "opentelemetry-api >= 1.22.0",
+    "opentelemetry-sdk >= 1.22.0",
+    "opentelemetry-semantic-conventions >= 0.43b0",
+    "opentelemetry-resourcedetector-gcp >= 1.8.0a0",
+    "google-cloud-monitoring >= 2.16.0",
+    "mmh3 >= 4.1.0 ",
 ]
-extras = {
-    "tracing": [
-        "opentelemetry-api >= 1.22.0",
-        "opentelemetry-sdk >= 1.22.0",
-        "opentelemetry-semantic-conventions >= 0.43b0",
-        "opentelemetry-resourcedetector-gcp >= 1.8.0a0",
-        "google-cloud-monitoring >= 2.16.0",
-        "mmh3 >= 4.1.0 ",
-    ],
-    "libcst": "libcst >= 0.2.5",
-}
+extras = {"libcst": "libcst >= 0.2.5"}
 
 url = "https://github.com/googleapis/python-spanner"
 
@@ -90,6 +87,7 @@
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
         "Programming Language :: Python :: 3.12",
+        "Programming Language :: Python :: 3.14",
         "Operating System :: OS Independent",
         "Topic :: Internet",
     ],

.librarian/state.yaml

@@ -1,4 +1,4 @@
-image: us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator@sha256:8e2c32496077054105bd06c54a59d6a6694287bc053588e24debe6da6920ad91
+image: us-central1-docker.pkg.dev/cloud-sdk-librarian-prod/images-prod/python-librarian-generator@sha256:b8058df4c45e9a6e07f6b4d65b458d0d059241dd34c814f151c8bf6b89211209
 libraries:
   - id: google-cloud-spanner
     version: 3.60.0

google/cloud/spanner_admin_database_v1/__init__.py

@@ -15,8 +15,18 @@
 #
 from google.cloud.spanner_admin_database_v1 import gapic_version as package_version
 
+import google.api_core as api_core
+import sys
+
 __version__ = package_version.__version__
 
+if sys.version_info >= (3, 8):  # pragma: NO COVER
+    from importlib import metadata
+else:  # pragma: NO COVER
+    # TODO(https://github.com/googleapis/python-api-core/issues/835): Remove
+    # this code path once we drop support for Python 3.7
+    import importlib_metadata as metadata
+
 
 from .services.database_admin import DatabaseAdminClient
 from .services.database_admin import DatabaseAdminAsyncClient
@@ -83,6 +93,100 @@
 from .types.spanner_database_admin import UpdateDatabaseRequest
 from .types.spanner_database_admin import RestoreSourceType
 
+if hasattr(api_core, "check_python_version") and hasattr(
+    api_core, "check_dependency_versions"
+):  # pragma: NO COVER
+    api_core.check_python_version("google.cloud.spanner_admin_database_v1")  # type: ignore
+    api_core.check_dependency_versions("google.cloud.spanner_admin_database_v1")  # type: ignore
+else:  # pragma: NO COVER
+    # An older version of api_core is installed which does not define the
+    # functions above. We do equivalent checks manually.
+    try:
+        import warnings
+        import sys
+
+        _py_version_str = sys.version.split()[0]
+        _package_label = "google.cloud.spanner_admin_database_v1"
+        if sys.version_info < (3, 9):
+            warnings.warn(
+                "You are using a non-supported Python version "
+                + f"({_py_version_str}).  Google will not post any further "
+                + f"updates to {_package_label} supporting this Python version. "
+                + "Please upgrade to the latest Python version, or at "
+                + f"least to Python 3.9, and then update {_package_label}.",
+                FutureWarning,
+            )
+        if sys.version_info[:2] == (3, 9):
+            warnings.warn(
+                f"You are using a Python version ({_py_version_str}) "
+                + f"which Google will stop supporting in {_package_label} in "
+                + "January 2026. Please "
+                + "upgrade to the latest Python version, or at "
+                + "least to Python 3.10, before then, and "
+                + f"then update {_package_label}.",
+                FutureWarning,
+            )
+
+        def parse_version_to_tuple(version_string: str):
+            """Safely converts a semantic version string to a comparable tuple of integers.
+            Example: "4.25.8" -> (4, 25, 8)
+            Ignores non-numeric parts and handles common version formats.
+            Args:
+                version_string: Version string in the format "x.y.z" or "x.y.z<suffix>"
+            Returns:
+                Tuple of integers for the parsed version string.
+            """
+            parts = []
+            for part in version_string.split("."):
+                try:
+                    parts.append(int(part))
+                except ValueError:
+                    # If it's a non-numeric part (e.g., '1.0.0b1' -> 'b1'), stop here.
+                    # This is a simplification compared to 'packaging.parse_version', but sufficient
+                    # for comparing strictly numeric semantic versions.
+                    break
+            return tuple(parts)
+
+        def _get_version(dependency_name):
+            try:
+                version_string: str = metadata.version(dependency_name)
+                parsed_version = parse_version_to_tuple(version_string)
+                return (parsed_version, version_string)
+            except Exception:
+                # Catch exceptions from metadata.version() (e.g., PackageNotFoundError)
+                # or errors during parse_version_to_tuple
+                return (None, "--")
+
+        _dependency_package = "google.protobuf"
+        _next_supported_version = "4.25.8"
+        _next_supported_version_tuple = (4, 25, 8)
+        _recommendation = " (we recommend 6.x)"
+        (_version_used, _version_used_string) = _get_version(_dependency_package)
+        if _version_used and _version_used < _next_supported_version_tuple:
+            warnings.warn(
+                f"Package {_package_label} depends on "
+                + f"{_dependency_package}, currently installed at version "
+                + f"{_version_used_string}. Future updates to "
+                + f"{_package_label} will require {_dependency_package} at "
+                + f"version {_next_supported_version} or higher{_recommendation}."
+                + " Please ensure "
+                + "that either (a) your Python environment doesn't pin the "
+                + f"version of {_dependency_package}, so that updates to "
+                + f"{_package_label} can require the higher version, or "
+                + "(b) you manually update your Python environment to use at "
+                + f"least version {_next_supported_version} of "
+                + f"{_dependency_package}.",
+                FutureWarning,
+            )
+    except Exception:
+        warnings.warn(
+            "Could not determine the version of Python "
+            + "currently being used. To continue receiving "
+            + "updates for {_package_label}, ensure you are "
+            + "using a supported version of Python; see "
+            + "https://devguide.python.org/versions/"
+        )
+
 __all__ = (
     "DatabaseAdminAsyncClient",
     "AddSplitPointsRequest",

google/cloud/spanner_admin_database_v1/services/database_admin/client.py

@@ -172,6 +172,34 @@ def _get_default_mtls_endpoint(api_endpoint):
     _DEFAULT_ENDPOINT_TEMPLATE = "spanner.{UNIVERSE_DOMAIN}"
     _DEFAULT_UNIVERSE = "googleapis.com"
 
+    @staticmethod
+    def _use_client_cert_effective():
+        """Returns whether client certificate should be used for mTLS if the
+        google-auth version supports should_use_client_cert automatic mTLS enablement.
+
+        Alternatively, read from the GOOGLE_API_USE_CLIENT_CERTIFICATE env var.
+
+        Returns:
+            bool: whether client certificate should be used for mTLS
+        Raises:
+            ValueError: (If using a version of google-auth without should_use_client_cert and
+            GOOGLE_API_USE_CLIENT_CERTIFICATE is set to an unexpected value.)
+        """
+        # check if google-auth version supports should_use_client_cert for automatic mTLS enablement
+        if hasattr(mtls, "should_use_client_cert"):  # pragma: NO COVER
+            return mtls.should_use_client_cert()
+        else:  # pragma: NO COVER
+            # if unsupported, fallback to reading from env var
+            use_client_cert_str = os.getenv(
+                "GOOGLE_API_USE_CLIENT_CERTIFICATE", "false"
+            ).lower()
+            if use_client_cert_str not in ("true", "false"):
+                raise ValueError(
+                    "Environment variable `GOOGLE_API_USE_CLIENT_CERTIFICATE` must be"
+                    " either `true` or `false`"
+                )
+            return use_client_cert_str == "true"
+
     @classmethod
     def from_service_account_info(cls, info: dict, *args, **kwargs):
         """Creates an instance of this client using the provided credentials
@@ -518,20 +546,16 @@ def get_mtls_endpoint_and_cert_source(
         )
         if client_options is None:
             client_options = client_options_lib.ClientOptions()
-        use_client_cert = os.getenv("GOOGLE_API_USE_CLIENT_CERTIFICATE", "false")
+        use_client_cert = DatabaseAdminClient._use_client_cert_effective()
         use_mtls_endpoint = os.getenv("GOOGLE_API_USE_MTLS_ENDPOINT", "auto")
-        if use_client_cert not in ("true", "false"):
-            raise ValueError(
-                "Environment variable `GOOGLE_API_USE_CLIENT_CERTIFICATE` must be either `true` or `false`"
-            )
         if use_mtls_endpoint not in ("auto", "never", "always"):
             raise MutualTLSChannelError(
                 "Environment variable `GOOGLE_API_USE_MTLS_ENDPOINT` must be `never`, `auto` or `always`"
             )
 
         # Figure out the client cert source to use.
         client_cert_source = None
-        if use_client_cert == "true":
+        if use_client_cert:
             if client_options.client_cert_source:
                 client_cert_source = client_options.client_cert_source
             elif mtls.has_default_client_cert_source():
@@ -563,20 +587,14 @@ def _read_environment_variables():
             google.auth.exceptions.MutualTLSChannelError: If GOOGLE_API_USE_MTLS_ENDPOINT
                 is not any of ["auto", "never", "always"].
         """
-        use_client_cert = os.getenv(
-            "GOOGLE_API_USE_CLIENT_CERTIFICATE", "false"
-        ).lower()
+        use_client_cert = DatabaseAdminClient._use_client_cert_effective()
         use_mtls_endpoint = os.getenv("GOOGLE_API_USE_MTLS_ENDPOINT", "auto").lower()
         universe_domain_env = os.getenv("GOOGLE_CLOUD_UNIVERSE_DOMAIN")
-        if use_client_cert not in ("true", "false"):
-            raise ValueError(
-                "Environment variable `GOOGLE_API_USE_CLIENT_CERTIFICATE` must be either `true` or `false`"
-            )
         if use_mtls_endpoint not in ("auto", "never", "always"):
             raise MutualTLSChannelError(
                 "Environment variable `GOOGLE_API_USE_MTLS_ENDPOINT` must be `never`, `auto` or `always`"
             )
-        return use_client_cert == "true", use_mtls_endpoint, universe_domain_env
+        return use_client_cert, use_mtls_endpoint, universe_domain_env
 
     @staticmethod
     def _get_client_cert_source(provided_cert_source, use_cert_flag):