fix: multiple platform adaptors concurrency

gateway/pairing.py

@@ -21,6 +21,8 @@ Storage: ~/.hermes/pairing/
 import json
 import os
 import secrets
+import tempfile
+import threading
 import time
 from pathlib import Path
 from typing import Optional
@@ -45,13 +47,29 @@ PAIRING_DIR = get_hermes_dir("platforms/pairing", "pairing")
 
 
 def _secure_write(path: Path, data: str) -> None:
-    """Write data to file with restrictive permissions (owner read/write only)."""
+    """Write data to file with restrictive permissions (owner read/write only).
+
+    Uses a temp-file + atomic rename so readers always see either the old
+    complete file or the new one — never a partial write.
+    """
     path.parent.mkdir(parents=True, exist_ok=True)
-    path.write_text(data, encoding="utf-8")
+    fd, tmp_path = tempfile.mkstemp(dir=str(path.parent), suffix=".tmp")
     try:
-        os.chmod(path, 0o600)
-    except OSError:
-        pass  # Windows doesn't support chmod the same way
+        with os.fdopen(fd, "w", encoding="utf-8") as f:
+            f.write(data)
+            f.flush()
+            os.fsync(f.fileno())
+        os.replace(tmp_path, str(path))
+        try:
+            os.chmod(path, 0o600)
+        except OSError:
+            pass  # Windows doesn't support chmod the same way
+    except BaseException:
+        try:
+            os.unlink(tmp_path)
+        except OSError:
+            pass
+        raise
 
 
 class PairingStore:
@@ -66,6 +84,9 @@ class PairingStore:
 
     def __init__(self):
         PAIRING_DIR.mkdir(parents=True, exist_ok=True)
+        # Protects all read-modify-write cycles. The gateway runs multiple
+        # platform adapters concurrently in threads sharing one PairingStore.
+        self._lock = threading.RLock()
 
     def _pending_path(self, platform: str) -> Path:
         return PAIRING_DIR / f"{platform}-pending.json"
@@ -105,7 +126,7 @@ class PairingStore:
         return results
 
     def _approve_user(self, platform: str, user_id: str, user_name: str = "") -> None:
-        """Add a user to the approved list."""
+        """Add a user to the approved list. Must be called under self._lock."""
         approved = self._load_json(self._approved_path(platform))
         approved[user_id] = {
             "user_name": user_name,
@@ -116,11 +137,12 @@ class PairingStore:
     def revoke(self, platform: str, user_id: str) -> bool:
         """Remove a user from the approved list. Returns True if found."""
         path = self._approved_path(platform)
-        approved = self._load_json(path)
-        if user_id in approved:
-            del approved[user_id]
-            self._save_json(path, approved)
-            return True
+        with self._lock:
+            approved = self._load_json(path)
+            if user_id in approved:
+                del approved[user_id]
+                self._save_json(path, approved)
+                return True
         return False
 
     # ----- Pending codes -----
@@ -136,36 +158,37 @@ class PairingStore:
           - Max pending codes reached for this platform
           - User/platform is in lockout due to failed attempts
         """
-        self._cleanup_expired(platform)
+        with self._lock:
+            self._cleanup_expired(platform)
 
-        # Check lockout
-        if self._is_locked_out(platform):
-            return None
+            # Check lockout
+            if self._is_locked_out(platform):
+                return None
 
-        # Check rate limit for this specific user
-        if self._is_rate_limited(platform, user_id):
-            return None
+            # Check rate limit for this specific user
+            if self._is_rate_limited(platform, user_id):
+                return None
 
-        # Check max pending
-        pending = self._load_json(self._pending_path(platform))
-        if len(pending) >= MAX_PENDING_PER_PLATFORM:
-            return None
+            # Check max pending
+            pending = self._load_json(self._pending_path(platform))
+            if len(pending) >= MAX_PENDING_PER_PLATFORM:
+                return None
 
-        # Generate cryptographically random code
-        code = "".join(secrets.choice(ALPHABET) for _ in range(CODE_LENGTH))
+            # Generate cryptographically random code
+            code = "".join(secrets.choice(ALPHABET) for _ in range(CODE_LENGTH))
 
-        # Store pending request
-        pending[code] = {
-            "user_id": user_id,
-            "user_name": user_name,
-            "created_at": time.time(),
-        }
-        self._save_json(self._pending_path(platform), pending)
+            # Store pending request
+            pending[code] = {
+                "user_id": user_id,
+                "user_name": user_name,
+                "created_at": time.time(),
+            }
+            self._save_json(self._pending_path(platform), pending)
 
-        # Record rate limit
-        self._record_rate_limit(platform, user_id)
+            # Record rate limit
+            self._record_rate_limit(platform, user_id)
 
-        return code
+            return code
 
     def approve_code(self, platform: str, code: str) -> Optional[dict]:
         """
@@ -173,24 +196,25 @@ class PairingStore:
 
         Returns {user_id, user_name} on success, None if code is invalid/expired.
         """
-        self._cleanup_expired(platform)
-        code = code.upper().strip()
+        with self._lock:
+            self._cleanup_expired(platform)
+            code = code.upper().strip()
 
-        pending = self._load_json(self._pending_path(platform))
-        if code not in pending:
-            self._record_failed_attempt(platform)
-            return None
+            pending = self._load_json(self._pending_path(platform))
+            if code not in pending:
+                self._record_failed_attempt(platform)
+                return None
 
-        entry = pending.pop(code)
-        self._save_json(self._pending_path(platform), pending)
+            entry = pending.pop(code)
+            self._save_json(self._pending_path(platform), pending)
 
-        # Add to approved list
-        self._approve_user(platform, entry["user_id"], entry.get("user_name", ""))
+            # Add to approved list
+            self._approve_user(platform, entry["user_id"], entry.get("user_name", ""))
 
-        return {
-            "user_id": entry["user_id"],
-            "user_name": entry.get("user_name", ""),
-        }
+            return {
+                "user_id": entry["user_id"],
+                "user_name": entry.get("user_name", ""),
+            }
 
     def list_pending(self, platform: str = None) -> list:
         """List pending pairing requests, optionally filtered by platform."""
@@ -212,12 +236,13 @@ class PairingStore:
 
     def clear_pending(self, platform: str = None) -> int:
         """Clear all pending requests. Returns count removed."""
-        count = 0
-        platforms = [platform] if platform else self._all_platforms("pending")
-        for p in platforms:
-            pending = self._load_json(self._pending_path(p))
-            count += len(pending)
-            self._save_json(self._pending_path(p), {})
+        with self._lock:
+            count = 0
+            platforms = [platform] if platform else self._all_platforms("pending")
+            for p in platforms:
+                pending = self._load_json(self._pending_path(p))
+                count += len(pending)
+                self._save_json(self._pending_path(p), {})
         return count
 
     # ----- Rate limiting and lockout -----