fix(skills): clean up bash process groups on timeout and cancellation

tests/tools/test_skills_bash_tool.py

@@ -0,0 +1,195 @@
+# Copyright (c) 2025 Beijing Volcano Engine Technology Co., Ltd. and/or its affiliates.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import asyncio
+import importlib
+import os
+import signal
+import subprocess
+from types import SimpleNamespace
+from unittest.mock import AsyncMock, Mock
+
+import pytest
+
+bash_module = importlib.import_module("veadk.tools.skills_tools.bash_tool")
+pytestmark = [
+    pytest.mark.asyncio,
+    pytest.mark.skipif(os.name != "posix", reason="POSIX process groups"),
+]
+
+
+@pytest.fixture
+def execution(tmp_path, monkeypatch):
+    monkeypatch.setattr(bash_module, "get_session_path", lambda **kwargs: tmp_path)
+    context = SimpleNamespace(session=SimpleNamespace(id="timeout-test"))
+    processes = []
+    original = asyncio.create_subprocess_shell
+
+    async def spawn(*args, **kwargs):
+        process = await original(*args, **kwargs)
+        processes.append(process)
+        return process
+
+    monkeypatch.setattr(asyncio, "create_subprocess_shell", spawn)
+
+    async def run(command, timeout=5):
+        return await bash_module.bash_tool(
+            command, "timeout regression", context, timeout
+        )
+
+    yield run, processes
+    # Independent cleanup also makes a regression failure safe to run locally.
+    for process in processes:
+        try:
+            os.killpg(process.pid, signal.SIGKILL)
+        except ProcessLookupError:
+            pass
+
+
+def live_group(pgid):
+    rows = subprocess.check_output(
+        ["ps", "-eo", "pgid=,stat=,comm="], text=True
+    ).splitlines()
+    return [
+        row
+        for row in rows
+        if row.split()[0] == str(pgid) and not row.split()[1].startswith("Z")
+    ]
+
+
+async def test_pipeline_timeout_cleans_children_and_allows_next_call(execution):
+    run, processes = execution
+    result = await asyncio.wait_for(run("sleep 900 | cat", timeout=5), 12)
+    assert result == "Error: Command timed out after 5s"
+    assert not live_group(processes[0].pid)
+    assert (
+        await asyncio.wait_for(run("echo TOOL_TIMEOUT_RECOVERED"), 7)
+        == "TOOL_TIMEOUT_RECOVERED"
+    )
+
+
+async def test_timeout_cleans_group_after_shell_has_already_exited(execution):
+    run, processes = execution
+    assert (
+        await asyncio.wait_for(run("sleep 900 & exit 0", timeout=0.2), 7)
+        == "Error: Command timed out after 0.2s"
+    )
+    assert processes[0].returncode == 0
+    assert not live_group(processes[0].pid)
+
+
+async def test_cancellation_cleans_pipeline_and_propagates(execution):
+    run, processes = execution
+    task = asyncio.create_task(run("sleep 900 | cat", timeout=600))
+    for _ in range(100):
+        if processes:
+            break
+        await asyncio.sleep(0.01)
+    assert processes
+    await asyncio.sleep(0.05)
+    task.cancel()
+    with pytest.raises(asyncio.CancelledError):
+        await asyncio.wait_for(task, 7)
+    assert not live_group(processes[0].pid)
+    assert await run("echo recovered") == "recovered"
+
+
+async def test_cancellation_during_spawn_still_cleans_children(execution, monkeypatch):
+    run, processes = execution
+    spawn = asyncio.create_subprocess_shell
+    started = asyncio.Event()
+    release = asyncio.Event()
+
+    async def delayed_spawn(*args, **kwargs):
+        process = await spawn(*args, **kwargs)
+        started.set()
+        await release.wait()
+        return process
+
+    monkeypatch.setattr(asyncio, "create_subprocess_shell", delayed_spawn)
+    task = asyncio.create_task(run("sleep 900 | cat", timeout=600))
+    await asyncio.wait_for(started.wait(), 3)
+    task.cancel()
+    await asyncio.sleep(0)
+    release.set()
+    with pytest.raises(asyncio.CancelledError):
+        await asyncio.wait_for(task, 7)
+    assert not live_group(processes[0].pid)
+
+
+async def test_cleanup_wait_is_bounded(execution, monkeypatch):
+    run, _ = execution
+
+    async def stuck():
+        await asyncio.Event().wait()
+
+    process = SimpleNamespace(
+        pid=12345,
+        communicate=AsyncMock(side_effect=stuck),
+        wait=AsyncMock(side_effect=stuck),
+        _transport=Mock(),
+    )
+    monkeypatch.setattr(
+        asyncio, "create_subprocess_shell", AsyncMock(return_value=process)
+    )
+    kill = Mock()
+    monkeypatch.setattr(os, "killpg", kill)
+    monkeypatch.setattr(bash_module, "_PROCESS_CLEANUP_TIMEOUT", 0.05)
+    assert (
+        await asyncio.wait_for(run("test", timeout=0.05), 1)
+        == "Error: Command timed out after 0.05s"
+    )
+    kill.assert_called_once_with(process.pid, signal.SIGKILL)
+    process._transport.close.assert_called_once()
+
+
+async def test_process_lookup_race_preserves_timeout(execution, monkeypatch):
+    run, _ = execution
+    process = SimpleNamespace(
+        pid=12345,
+        communicate=AsyncMock(side_effect=asyncio.TimeoutError),
+        wait=AsyncMock(return_value=0),
+    )
+    monkeypatch.setattr(
+        asyncio, "create_subprocess_shell", AsyncMock(return_value=process)
+    )
+    monkeypatch.setattr(os, "killpg", Mock(side_effect=ProcessLookupError))
+    assert await run("test") == "Error: Command timed out after 5s"
+    process.wait.assert_awaited_once()
+
+
+@pytest.mark.parametrize(
+    "command,expected",
+    [
+        ("", "Error: No command provided"),
+        ("printf ok", "ok"),
+        ("true", "Command completed successfully."),
+        ("printf error >&2; exit 7", "Command failed with exit code 7:\nerror"),
+        ("printf output; exit 2", "Command failed with exit code 2:\noutput"),
+        ("printf ok; printf WARNING >&2", "ok"),
+    ],
+)
+async def test_output_compatibility(execution, command, expected):
+    run, _ = execution
+    assert await run(command) == expected
+
+
+async def test_spawn_failure_is_returned_as_tool_error(execution, monkeypatch):
+    run, _ = execution
+    monkeypatch.setattr(
+        asyncio,
+        "create_subprocess_shell",
+        AsyncMock(side_effect=OSError("spawn failed")),
+    )
+    assert await run("test") == "Error executing command 'test': spawn failed"

veadk/tools/skills_tools/bash_tool.py

@@ -16,12 +16,57 @@
 
 import asyncio
 import os
+import signal
 
 from google.adk.tools import ToolContext
 from veadk.tools.skills_tools.session_path import get_session_path
 from veadk.utils.logger import get_logger
 
 logger = get_logger(__name__)
+_PROCESS_CLEANUP_TIMEOUT = 5.0
+
+
+async def _run_command(command, working_dir, env, timeout):
+    process = None
+    completed = False
+    spawning = asyncio.create_task(
+        asyncio.create_subprocess_shell(
+            command,
+            stdout=asyncio.subprocess.PIPE,
+            stderr=asyncio.subprocess.PIPE,
+            cwd=working_dir,
+            env=env,
+            start_new_session=os.name == "posix",
+        )
+    )
+    try:
+        try:
+            process = await asyncio.shield(spawning)
+        except asyncio.CancelledError:
+            # Cancellation can arrive after fork but before the Process is
+            # returned. Retain ownership so that its children are cleaned up.
+            process = await spawning
+            raise
+        stdout, stderr = await asyncio.wait_for(process.communicate(), timeout)
+        completed = True
+        return process.returncode, stdout, stderr
+    finally:
+        if process is not None and not completed:
+            try:
+                if os.name == "posix":
+                    # Do this even if the shell has exited: its descendants
+                    # can still hold stdout/stderr open and block communicate.
+                    os.killpg(process.pid, signal.SIGKILL)
+                else:
+                    process.kill()
+            except ProcessLookupError:
+                pass
+            try:
+                await asyncio.wait_for(process.wait(), _PROCESS_CLEANUP_TIMEOUT)
+            except asyncio.TimeoutError:
+                # A detached descendant may keep a pipe open. Process has no
+                # public close API; release the local transports on this path.
+                process._transport.close()
 
 
 async def bash_tool(
@@ -61,6 +106,7 @@ async def bash_tool(
     Timeouts:
     - Default timeout is 600 seconds (10 minutes).
     - Adjust the 'timeout' parameter as needed for longer-running commands.
+    - Interrupted commands have up to 5 additional seconds for process cleanup.
 
     Args:
         command: Bash command to execute. Use && to chain commands.
@@ -102,29 +148,19 @@ async def bash_tool(
         # Execute with local bash shell
         local_bash_command = f"{command}"
 
-        process = await asyncio.create_subprocess_shell(
-            local_bash_command,
-            stdout=asyncio.subprocess.PIPE,
-            stderr=asyncio.subprocess.PIPE,
-            cwd=working_dir,
-            env=env,  # Pass the modified environment
-        )
-
         try:
-            stdout, stderr = await asyncio.wait_for(
-                process.communicate(), timeout=timeout
+            returncode, stdout, stderr = await _run_command(
+                local_bash_command, working_dir, env, timeout
             )
         except asyncio.TimeoutError:
-            process.kill()
-            await process.wait()
             return f"Error: Command timed out after {timeout}s"
 
         stdout_str = stdout.decode("utf-8", errors="replace") if stdout else ""
         stderr_str = stderr.decode("utf-8", errors="replace") if stderr else ""
 
         # Handle command failure
-        if process.returncode != 0:
-            error_msg = f"Command failed with exit code {process.returncode}"
+        if returncode != 0:
+            error_msg = f"Command failed with exit code {returncode}"
             if stderr_str:
                 error_msg += f":\n{stderr_str}"
             elif stdout_str: