Remove runtime pkg_resources dependency in default and server_ingester (#7057)

## Motivation for features / changes

Fixes #7003.

`pkg_resources` is removed in newer setuptools, which can break
TensorBoard at import/runtime. This change removes runtime reliance on
`pkg_resources` in the two affected code paths.

## Technical description of changes

- Replaced dynamic plugin discovery in `tensorboard/default.py`:
  - from `pkg_resources.iter_entry_points(...)`
- to `importlib.metadata.entry_points(...)` with compatibility handling
for different Python return shapes.
- Replaced version parsing in `tensorboard/data/server_ingester.py`:
  - from `pkg_resources.parse_version(...)`
  - to `packaging.version.parse(...)`.
- Updated related tests:
- `tensorboard/default_test.py` now patches `_iter_entry_points` and
uses `load()`-style fake entry points.
- `tensorboard/version_test.py` now validates PEP 440 behavior using
`packaging.version`.
- Updated Bazel deps to use `expect_packaging_installed` where
`packaging` is now required.

## Detailed steps to verify changes work correctly (as executed by you)

Executed locally in an isolated venv:

- `python -m py_compile tensorboard/default.py
tensorboard/default_test.py tensorboard/data/server_ingester.py
tensorboard/version_test.py`
- `PYTHONPATH=. python tensorboard/version_test.py` (passes)

Attempted but environment-limited locally:

- `bazel test //tensorboard:version_test //tensorboard:default_test
//tensorboard/data:server_ingester_test` (bazel not available in local
shell)
- Direct execution of `default_test.py` and `server_ingester_test.py`
without Bazel-generated artifacts hit local environment/import
constraints.

## Alternate designs / implementations considered (or N/A)

- N/A

Author: 0xmagnus91

tensorboard/BUILD

@@ -309,7 +309,6 @@ py_library(
     srcs = ["default.py"],
     srcs_version = "PY3",
     deps = [
-        "//tensorboard:expect_pkg_resources_installed",
         "//tensorboard/backend:experimental_plugin",
         "//tensorboard/plugins/audio:audio_plugin",
         "//tensorboard/plugins/core:core_plugin",
@@ -347,7 +346,6 @@ py_test(
     deps = [
         ":default",
         ":test",
-        "//tensorboard:expect_pkg_resources_installed",
         "//tensorboard/plugins:base_plugin",
     ],
 )
@@ -367,7 +365,7 @@ py_test(
     deps = [
         ":test",
         ":version",
-        "//tensorboard:expect_pkg_resources_installed",
+        "//tensorboard:expect_packaging_installed",
     ],
 )
 
@@ -461,10 +459,10 @@ py_library(name = "expect_absl_logging_installed")
 # `pip install absl-py`
 py_library(name = "expect_absl_testing_absltest_installed")
 
-# This is a dummy rule used as a pkg-resources dependency in open-source.
-# We expect pkg-resources to already be installed on the system, e.g., via
-# `pip install setuptools`.
-py_library(name = "expect_pkg_resources_installed")
+# This is a dummy rule used as a packaging dependency in open-source.
+# We expect packaging to already be installed on the system, e.g. via
+# `pip install packaging`.
+py_library(name = "expect_packaging_installed")
 
 # This is a dummy rule used as a pandas dependency in open-source.
 # We expect pandas to already be installed on the system, e.g. via

tensorboard/data/BUILD

@@ -62,7 +62,7 @@ py_library(
         ":grpc_provider",
         ":ingester",
         "//tensorboard:expect_grpc_installed",
-        "//tensorboard:expect_pkg_resources_installed",
+        "//tensorboard:expect_packaging_installed",
         "//tensorboard/data/proto:protos_all_py_pb2",
         "//tensorboard/util:tb_logging",
     ],

tensorboard/data/server_ingester.py

@@ -22,14 +22,13 @@
 import time
 
 import grpc
-import pkg_resources
+from packaging import version as packaging_version
 
 from tensorboard.data import grpc_provider
 from tensorboard.data import ingester
 from tensorboard.data.proto import data_provider_pb2
 from tensorboard.util import tb_logging
 
-
 logger = tb_logging.get_logger()
 
 # If this environment variable is non-empty, it will be used as the path to the
@@ -202,7 +201,7 @@ def _maybe_read_file(path):
 
 
 def _make_stub(addr, channel_creds_type):
-    (creds, options) = channel_creds_type.channel_config()
+    creds, options = channel_creds_type.channel_config()
     options.append(("grpc.max_receive_message_length", 1024 * 1024 * 256))
     channel = grpc.secure_channel(addr, creds, options=options)
     return grpc_provider.make_stub(channel)
@@ -231,9 +230,7 @@ def __init__(self, path, version):
         """
         self._path = path
         self._version = (
-            pkg_resources.parse_version(version)
-            if version is not None
-            else version
+            packaging_version.parse(version) if version is not None else version
         )
 
     @property
@@ -260,7 +257,7 @@ def at_least_version(self, required_version):
         """
         if self._version is None:
             return True
-        return self._version >= pkg_resources.parse_version(required_version)
+        return self._version >= packaging_version.parse(required_version)
 
 
 def get_server_binary():

tensorboard/default.py

@@ -24,10 +24,8 @@
 for less repetition.
 """
 
-
 import logging
-
-import pkg_resources
+from importlib import metadata
 
 from tensorboard.plugins.audio import audio_plugin
 from tensorboard.plugins.core import core_plugin
@@ -46,7 +44,6 @@
 from tensorboard.plugins.mesh import mesh_plugin
 from tensorboard.plugins.wit_redirect import wit_redirect_plugin
 
-
 logger = logging.getLogger(__name__)
 
 
@@ -119,8 +116,17 @@ def get_dynamic_plugins():
     [1]: https://packaging.python.org/specifications/entry-points/
     """
     return [
-        entry_point.resolve()
-        for entry_point in pkg_resources.iter_entry_points(
-            "tensorboard_plugins"
-        )
+        entry_point.load()
+        for entry_point in _iter_entry_points("tensorboard_plugins")
     ]
+
+
+def _iter_entry_points(group):
+    """Returns entry points for a given group across Python versions."""
+    entry_points = metadata.entry_points()
+    # In newer Python versions, `metadata.entry_points()` returns an
+    # `EntryPoints` object with a `select()` method.
+    # Before "selectable" entry points existed, it would return a dictionary.
+    if hasattr(entry_points, "select"):
+        return entry_points.select(group=group)
+    return entry_points.get(group, ())

tensorboard/default_test.py

@@ -14,52 +14,30 @@
 # ==============================================================================
 """Unit tests for `tensorboard.default`."""
 
-
 from unittest import mock
 
-import pkg_resources
-
 from tensorboard import default
-from tensorboard.plugins import base_plugin
 from tensorboard import test
 
 
-class FakePlugin(base_plugin.TBPlugin):
-    """FakePlugin for testing."""
-
-    plugin_name = "fake"
-
-
-class FakeEntryPoint(pkg_resources.EntryPoint):
-    """EntryPoint class that fake loads FakePlugin."""
-
-    @classmethod
-    def create(cls):
-        """Creates an instance of FakeEntryPoint.
-
-        Returns:
-          instance of FakeEntryPoint
-        """
-        return cls("foo", "bar")
-
-    def resolve(self):
-        """Returns FakePlugin instead of resolving module.
+class FakeEntryPoint:
+    def __init__(self, value):
+        self._value = value
 
-        Returns:
-          FakePlugin
-        """
-        return FakePlugin
+    def load(self):
+        return self._value
 
 
 class DefaultTest(test.TestCase):
-    @mock.patch.object(pkg_resources, "iter_entry_points")
+    @mock.patch.object(default, "_iter_entry_points")
     def test_get_dynamic_plugin(self, mock_iter_entry_points):
-        mock_iter_entry_points.return_value = [FakeEntryPoint.create()]
+        fake_plugin = object()
+        mock_iter_entry_points.return_value = [FakeEntryPoint(fake_plugin)]
 
         actual_plugins = default.get_dynamic_plugins()
 
         mock_iter_entry_points.assert_called_with("tensorboard_plugins")
-        self.assertEqual(actual_plugins, [FakePlugin])
+        self.assertEqual(actual_plugins, [fake_plugin])
 
 
 if __name__ == "__main__":

tensorboard/version_test.py

@@ -13,7 +13,7 @@
 # limitations under the License.
 
 
-import pkg_resources
+from packaging import version as packaging_version
 
 from tensorboard import test as tb_test
 from tensorboard import version
@@ -22,22 +22,11 @@
 class VersionTest(tb_test.TestCase):
     def test_valid_pep440_version(self):
         """Ensure that our version is PEP 440-compliant."""
-        # pkg_resources.parse_version() doesn't have a public return type,
-        # so we get a handle to it by parsing known good and bad versions.
-        #
-        # Note: depending on the version of the module (which is bundled
-        # with setuptools), when called with a non-compliant version, it
-        # either returns a `LegacyVersion` (setuptools < 66) or raises an
-        # `InvalidVersion` exception (setuptools >= 66). Handle both cases.
-        compliant_version = pkg_resources.parse_version("1.0.0")
-        try:
-            legacy_version = pkg_resources.parse_version("arbitrary string")
-        except Exception:
-            legacy_version = None
-        self.assertNotEqual(type(compliant_version), type(legacy_version))
-
-        tensorboard_version = pkg_resources.parse_version(version.VERSION)
-        self.assertIsInstance(tensorboard_version, type(compliant_version))
+        with self.assertRaises(packaging_version.InvalidVersion):
+            packaging_version.parse("arbitrary string")
+
+        tensorboard_version = packaging_version.parse(version.VERSION)
+        self.assertIsInstance(tensorboard_version, packaging_version.Version)
 
 
 if __name__ == "__main__":