Update ProcessResourceDetector to not set full CLI attrs by default

.changelog/5364.fixed

@@ -0,0 +1,3 @@
+`opentelemetry-sdk`: `ProcessResourceDetector` no longer collects or emits
+`process.command_args` and `process.command_line` by default. Users who depend
+on these resource attributes must pass `include_command_args=True`.

opentelemetry-sdk/src/opentelemetry/sdk/resources/__init__.py

@@ -321,7 +321,24 @@ def detect(self) -> "Resource":
 
 
 class ProcessResourceDetector(ResourceDetector):
-    # pylint: disable=no-self-use
+    """Detect process resource attributes.
+
+    Args:
+        raise_on_error: Raise errors from detection instead of logging them.
+        include_command_args: Include ``process.command_args`` and
+            ``process.command_line``. These attributes can contain sensitive
+            command-line values, so they are excluded by default.
+    """
+
+    def __init__(
+        self,
+        raise_on_error: bool = False,
+        *,
+        include_command_args: bool = False,
+    ) -> None:
+        super().__init__(raise_on_error=raise_on_error)
+        self._include_command_args = include_command_args
+
     def detect(self) -> "Resource":
         _runtime_version = ".".join(
             map(
@@ -340,24 +357,23 @@ def detect(self) -> "Resource":
         # Use sys.orig_argv, which preserves the original arguments received
         # by the interpreter. This correctly captures ``python -m <module>``
         # invocations where sys.argv is rewritten to the resolved module path
-        # and the ``-m <module>`` information is lost. sys.orig_argv also
-        # aligns with /proc/<pid>/cmdline, which the OTel semantic
-        # conventions reference for these attributes.
-        _process_argv = list(sys.orig_argv)
-        _process_command = _process_argv[0] if _process_argv else ""
-        _process_command_line = " ".join(_process_argv)
-        _process_command_args = _process_argv
-        resource_info = {
+        # and the ``-m <module>`` information is lost. Only read argv[0] by
+        # default because full command arguments are opt-in.
+        _process_command = sys.orig_argv[0] if sys.orig_argv else ""
+        resource_info: dict[str, AttributeValue] = {
             PROCESS_RUNTIME_DESCRIPTION: sys.version,
             PROCESS_RUNTIME_NAME: sys.implementation.name,
             PROCESS_RUNTIME_VERSION: _runtime_version,
             PROCESS_PID: _process_pid,
             PROCESS_EXECUTABLE_NAME: _process_executable_name,
             PROCESS_EXECUTABLE_PATH: _process_executable_path,
             PROCESS_COMMAND: _process_command,
-            PROCESS_COMMAND_LINE: _process_command_line,
-            PROCESS_COMMAND_ARGS: _process_command_args,
         }
+        if self._include_command_args:
+            _process_argv = list(sys.orig_argv)
+            resource_info[PROCESS_COMMAND_LINE] = " ".join(_process_argv)
+            resource_info[PROCESS_COMMAND_ARGS] = _process_argv
+
         if hasattr(os, "getppid"):
             # pypy3 does not have getppid()
             resource_info[PROCESS_PARENT_PID] = os.getppid()

opentelemetry-sdk/tests/resources/test_resources.py

@@ -657,6 +657,26 @@ def test_process_detector(self):
         self.assertEqual(
             aggregated_resource.attributes[PROCESS_COMMAND], sys.orig_argv[0]
         )
+        self.assertNotIn(
+            PROCESS_COMMAND_LINE,
+            aggregated_resource.attributes,
+        )
+        self.assertNotIn(
+            PROCESS_COMMAND_ARGS,
+            aggregated_resource.attributes,
+        )
+
+    @patch(
+        "sys.orig_argv",
+        ["uvicorn", "main:app", "--host", "0.0.0.0", "--port", "8000"],
+    )
+    def test_process_detector_includes_command_args_on_opt_in(self):
+        initial_resource = Resource({"foo": "bar"})
+        aggregated_resource = get_aggregated_resources(
+            [ProcessResourceDetector(include_command_args=True)],
+            initial_resource,
+        )
+
         self.assertEqual(
             aggregated_resource.attributes[PROCESS_COMMAND_LINE],
             " ".join(sys.orig_argv),
@@ -666,6 +686,35 @@ def test_process_detector(self):
             tuple(sys.orig_argv),
         )
 
+    def test_process_detector_does_not_iterate_orig_argv_by_default(self):
+        class SensitiveOrigArgv:
+            def __getitem__(self, index):
+                if index == 0:
+                    return "uvicorn"
+                raise AssertionError("unexpected argv access")
+
+            def __iter__(self):
+                raise AssertionError("unexpected argv iteration")
+
+        with patch("sys.orig_argv", SensitiveOrigArgv()):
+            aggregated_resource = get_aggregated_resources(
+                [ProcessResourceDetector()],
+                Resource({"foo": "bar"}),
+            )
+
+        self.assertEqual(
+            aggregated_resource.attributes[PROCESS_COMMAND],
+            "uvicorn",
+        )
+        self.assertNotIn(
+            PROCESS_COMMAND_LINE,
+            aggregated_resource.attributes,
+        )
+        self.assertNotIn(
+            PROCESS_COMMAND_ARGS,
+            aggregated_resource.attributes,
+        )
+
     @patch("sys.orig_argv", ["/usr/bin/python", "-m", "myapp"])
     def test_process_detector_uses_orig_argv_for_python_m(self):
         """For ``python -m <module>`` invocations sys.argv[0] is rewritten to
@@ -677,6 +726,26 @@ def test_process_detector_uses_orig_argv_for_python_m(self):
             [ProcessResourceDetector()], Resource({"foo": "bar"})
         )
 
+        self.assertEqual(
+            aggregated_resource.attributes[PROCESS_COMMAND],
+            "/usr/bin/python",
+        )
+        self.assertNotIn(
+            PROCESS_COMMAND_LINE,
+            aggregated_resource.attributes,
+        )
+        self.assertNotIn(
+            PROCESS_COMMAND_ARGS,
+            aggregated_resource.attributes,
+        )
+
+    @patch("sys.orig_argv", ["/usr/bin/python", "-m", "myapp"])
+    def test_process_detector_uses_orig_argv_for_python_m_on_opt_in(self):
+        aggregated_resource = get_aggregated_resources(
+            [ProcessResourceDetector(include_command_args=True)],
+            Resource({"foo": "bar"}),
+        )
+
         self.assertEqual(
             aggregated_resource.attributes[PROCESS_COMMAND],
             "/usr/bin/python",