fix(runtime): contain and supervise detached Bash jobs (ODY-145)

core/atomic_io.py

@@ -16,9 +16,48 @@ from __future__ import annotations
 import json
 import os
 import uuid
+import functools
+import threading
 from typing import Any, Optional
 
 
+_STORE_LOCKS: dict[str, threading.RLock] = {}
+_STORE_LOCKS_GUARD = threading.Lock()
+
+
+def store_transaction(path_factory):
+    """Serialize a JSON read/modify/write across runtime threads and processes."""
+    def decorate(function):
+        @functools.wraps(function)
+        def locked(*args, **kwargs):
+            path = os.path.abspath(str(path_factory())) + ".lock"
+            with _STORE_LOCKS_GUARD:
+                lock = _STORE_LOCKS.setdefault(path, threading.RLock())
+            with lock:
+                os.makedirs(os.path.dirname(path), exist_ok=True)
+                with open(path, "a+b") as handle:
+                    if os.name == "nt":
+                        import msvcrt
+                        if os.fstat(handle.fileno()).st_size == 0:
+                            handle.write(b"0")
+                            handle.flush()
+                        handle.seek(0)
+                        msvcrt.locking(handle.fileno(), msvcrt.LK_LOCK, 1)
+                    else:
+                        import fcntl
+                        fcntl.flock(handle, fcntl.LOCK_EX)
+                    try:
+                        return function(*args, **kwargs)
+                    finally:
+                        if os.name == "nt":
+                            handle.seek(0)
+                            msvcrt.locking(handle.fileno(), msvcrt.LK_UNLCK, 1)
+                        else:
+                            fcntl.flock(handle, fcntl.LOCK_UN)
+        return locked
+    return decorate
+
+
 def atomic_write_json(path: str, data: Any, *, indent: Optional[int] = None) -> None:
     """Atomically persist `data` as JSON at `path`.
 
@@ -64,4 +103,4 @@ def atomic_write_text(path: str, text: str) -> None:
         try:
             os.unlink(tmp)
         except OSError:
-            pass
+            pass