fix(watcher): sanitize tenant_id in asyncio task and thread names (#106)

Strip non-printable characters from tenant_id before embedding it in the
asyncio task name (async_watcher) and threading.Thread name (watcher).
A module-level compiled regex removes everything outside the printable
ASCII range (0x20–0x7E), so user-controlled tenant IDs containing
control characters no longer propagate into task/thread names.

Closes #70

Co-authored-by: Claude <noreply@anthropic.com>

Author: zeevdr

sdk/src/opendecree/async_watcher.py

@@ -21,6 +21,7 @@
 import asyncio
 import logging
 import random
+import re
 from collections.abc import AsyncIterator, Callable
 from typing import Any, TypeVar
 
@@ -38,6 +39,8 @@
 
 logger = logging.getLogger("opendecree.async_watcher")
 
+_CONTROL_CHARS_RE = re.compile(r"[^\x20-\x7E]")
+
 T = TypeVar("T")
 
 
@@ -152,9 +155,8 @@ async def start(self) -> None:
 
         await self._load_snapshot()
         self._stopped = False
-        self._task = asyncio.create_task(
-            self._subscribe_loop(), name=f"decree-watcher-{self._tenant_id}"
-        )
+        safe_id = _CONTROL_CHARS_RE.sub("", self._tenant_id)
+        self._task = asyncio.create_task(self._subscribe_loop(), name=f"decree-watcher-{safe_id}")
 
     async def stop(self) -> None:
         """Stop watching and cancel the background task."""

sdk/src/opendecree/watcher.py

@@ -18,6 +18,7 @@
 import logging
 import queue
 import random
+import re
 import threading
 import time
 from collections.abc import Callable, Iterator
@@ -37,6 +38,8 @@
 
 logger = logging.getLogger("opendecree.watcher")
 
+_CONTROL_CHARS_RE = re.compile(r"[^\x20-\x7E]")
+
 T = TypeVar("T")
 
 
@@ -156,8 +159,9 @@ def start(self) -> None:
 
         self._load_snapshot()
         self._stop_event.clear()
+        safe_id = _CONTROL_CHARS_RE.sub("", self._tenant_id)
         self._thread = threading.Thread(
-            target=self._subscribe_loop, daemon=True, name=f"decree-watcher-{self._tenant_id}"
+            target=self._subscribe_loop, daemon=True, name=f"decree-watcher-{safe_id}"
         )
         self._thread.start()
 

sdk/tests/test_async_watcher.py

@@ -341,3 +341,25 @@ async def empty_stream():
         stub.Subscribe.assert_called_once()
         _, sub_kwargs = stub.Subscribe.call_args
         assert sub_kwargs.get("metadata") == auth_meta
+
+    @pytest.mark.asyncio
+    async def test_task_name_sanitizes_control_chars(self):
+        stub = MagicMock()
+        pb2 = MagicMock()
+        mock_resp = MagicMock()
+        mock_resp.config.values = []
+        stub.GetConfig = AsyncMock(return_value=mock_resp)
+
+        async def empty_stream():
+            return
+            yield
+
+        stub.Subscribe.return_value = empty_stream()
+
+        w = AsyncConfigWatcher(stub, pb2, "tenant\x00evil\x1f", timeout=5.0)
+        await w.start()
+        assert w._task is not None
+        assert "\x00" not in w._task.get_name()
+        assert "\x1f" not in w._task.get_name()
+        assert "tenantevil" in w._task.get_name()
+        await w.stop()

sdk/tests/test_watcher.py

@@ -403,3 +403,19 @@ def cancel(self):
         # Thread must have joined within the timeout.
         assert not thread_ref.is_alive()
         assert w._thread is None
+
+    def test_thread_name_sanitizes_control_chars(self):
+        stub = MagicMock()
+        pb2 = MagicMock()
+        mock_resp = MagicMock()
+        mock_resp.config.values = []
+        stub.GetConfig.return_value = mock_resp
+        stub.Subscribe.return_value = iter([])
+
+        w = ConfigWatcher(stub, pb2, "tenant\x00evil\x1f", timeout=5.0)
+        w.start()
+        assert w._thread is not None
+        assert "\x00" not in w._thread.name
+        assert "\x1f" not in w._thread.name
+        assert "tenantevil" in w._thread.name
+        w.stop()