feat(msteams): split ref storage into main+meta sidecar files

- Separate updated_at into a meta sidecar file (msteams_conversations_meta.json)
    to keep backward compatibility with legacy data that never had updated_at.
    On first upgrade, legacy refs are kept alive by initializing updated_at to now
    instead of purging them immediately.
  - Add cross-process locking via fcntl (with Windows fallback) to prevent
    concurrent writes from different gateway processes overwriting each other.
  - Add ref_touch_interval_s config (default 300s) to throttle how often
    successful sends refresh updated_at, preventing unnecessary I/O.
  - Touch active refs on send success to prevent them from expiring while in use.
  - Add _safe_float and _normalize_ref_record for robust schema migration.
  - All refs operations now use threading.RLock within a process.

docs/chat-apps.md

@@ -645,7 +645,8 @@ Create or reuse a Microsoft Teams / Azure bot app registration. Set the bot mess
       "validateInboundAuth": true,
       "refTtlDays": 30,
       "pruneWebChatRefs": true,
-      "pruneNonPersonalRefs": true
+      "pruneNonPersonalRefs": true,
+      "refTouchIntervalS": 300
     }
   }
 }
@@ -657,6 +658,7 @@ Create or reuse a Microsoft Teams / Azure bot app registration. Set the bot mess
 > - `refTtlDays` (default `30`) controls how old stored conversation refs can be before they are pruned.
 > - `pruneWebChatRefs` (default `true`) drops refs with `webchat.botframework.com` service URLs.
 > - `pruneNonPersonalRefs` (default `true`) drops refs whose `conversation_type` is not `personal`.
+> - `refTouchIntervalS` (default `300`) throttles how often successful sends refresh `updated_at` for active refs.
 
 **4. Run**
 

nanobot/channels/msteams.py

@@ -20,11 +20,17 @@ import re
 import tempfile
 import threading
 import time
+from contextlib import contextmanager
 from dataclasses import dataclass
 from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer
 from typing import TYPE_CHECKING, Any
 from urllib.parse import urlparse
 
+try:  # pragma: no cover - Windows fallback path
+    import fcntl
+except ImportError:  # pragma: no cover
+    fcntl = None
+
 import httpx
 from loguru import logger
 from pydantic import Field
@@ -49,6 +55,9 @@ if MSTEAMS_AVAILABLE:
 MSTEAMS_REF_TTL_DAYS = 30
 MSTEAMS_REF_TTL_S = MSTEAMS_REF_TTL_DAYS * 24 * 60 * 60
 MSTEAMS_WEBCHAT_HOST = "webchat.botframework.com"
+MSTEAMS_REF_META_FILENAME = "msteams_conversations_meta.json"
+MSTEAMS_REF_LOCK_FILENAME = "msteams_conversations.lock"
+MSTEAMS_REF_TOUCH_INTERVAL_S = 300
 
 
 class MSTeamsConfig(Base):
@@ -68,6 +77,7 @@ class MSTeamsConfig(Base):
     ref_ttl_days: int = Field(default=MSTEAMS_REF_TTL_DAYS, ge=1)
     prune_web_chat_refs: bool = True
     prune_non_personal_refs: bool = True
+    ref_touch_interval_s: int = Field(default=MSTEAMS_REF_TOUCH_INTERVAL_S, ge=0)
 
 
 @dataclass
@@ -113,9 +123,13 @@ class MSTeamsChannel(BaseChannel):
         self._botframework_jwks_expires_at: float = 0.0
         self._refs_path = get_workspace_path() / "state" / "msteams_conversations.json"
         self._refs_path.parent.mkdir(parents=True, exist_ok=True)
+        self._refs_meta_path = self._refs_path.parent / MSTEAMS_REF_META_FILENAME
+        self._refs_lock_path = self._refs_path.parent / MSTEAMS_REF_LOCK_FILENAME
+        self._refs_guard = threading.RLock()
         self._conversation_refs: dict[str, ConversationRef] = self._load_refs()
+        with self._refs_guard:
             if self._prune_conversation_refs():
-            self._save_refs(prune=False)
+                self._save_refs_locked(prune=True)
 
     async def start(self) -> None:
         """Start the Teams webhook listener."""
@@ -249,6 +263,7 @@ class MSTeamsChannel(BaseChannel):
             resp = await self._http.post(url, headers=headers, json=payload)
             resp.raise_for_status()
             logger.info("MSTeams message sent to {}", ref.conversation_id)
+            self._touch_conversation_ref(str(msg.chat_id), persist=True)
         except Exception as e:
             logger.error("MSTeams send failed: {}", e)
             raise
@@ -295,6 +310,7 @@ class MSTeamsChannel(BaseChannel):
             )
             return
 
+        with self._refs_guard:
             self._conversation_refs[conversation_id] = ConversationRef(
                 service_url=service_url,
                 conversation_id=conversation_id,
@@ -304,7 +320,7 @@ class MSTeamsChannel(BaseChannel):
                 tenant_id=str((channel_data.get("tenant") or {}).get("id") or "") or None,
                 updated_at=time.time(),
             )
-        self._save_refs()
+            self._save_refs_locked()
 
         await self._handle_message(
             sender_id=sender_id,
@@ -491,20 +507,110 @@ class MSTeamsChannel(BaseChannel):
         self._botframework_jwks_expires_at = now + 3600
         return self._botframework_jwks
 
-    def _load_refs(self) -> dict[str, ConversationRef]:
+    @staticmethod
-        """Load stored conversation references."""
+    def _safe_float(value: Any) -> float | None:
-        if not self._refs_path.exists():
-            return {}
         try:
-            data = json.loads(self._refs_path.read_text(encoding="utf-8"))
+            out = float(value)
-            out: dict[str, ConversationRef] = {}
+            if out > 0:
-            for key, value in data.items():
-                out[key] = ConversationRef(**value)
                 return out
+        except (TypeError, ValueError):
+            return None
+        return None
+
+    def _normalize_ref_record(self, value: Any) -> ConversationRef | None:
+        """Normalize a stored ref record from legacy/current schema."""
+        if not isinstance(value, dict):
+            return None
+        service_url = str(value.get("service_url") or "").strip()
+        conversation_id = str(value.get("conversation_id") or "").strip()
+        if not service_url or not conversation_id:
+            return None
+        return ConversationRef(
+            service_url=service_url,
+            conversation_id=conversation_id,
+            bot_id=str(value.get("bot_id") or "") or None,
+            activity_id=str(value.get("activity_id") or "") or None,
+            conversation_type=str(value.get("conversation_type") or "") or None,
+            tenant_id=str(value.get("tenant_id") or "") or None,
+            updated_at=self._safe_float(value.get("updated_at")),
+        )
+
+    def _load_refs_raw(self) -> tuple[dict[str, Any], dict[str, Any], bool]:
+        """Load raw refs/main+meta JSON payloads."""
+        main_data: dict[str, Any] = {}
+        meta_data: dict[str, Any] = {}
+        meta_exists = self._refs_meta_path.exists()
+
+        if self._refs_path.exists():
+            try:
+                loaded = json.loads(self._refs_path.read_text(encoding="utf-8"))
+                if isinstance(loaded, dict):
+                    main_data = loaded
             except Exception as e:
                 logger.warning("Failed to load MSTeams conversation refs: {}", e)
+
+        if meta_exists:
+            try:
+                loaded_meta = json.loads(self._refs_meta_path.read_text(encoding="utf-8"))
+                if isinstance(loaded_meta, dict):
+                    meta_data = loaded_meta
+            except Exception as e:
+                logger.warning("Failed to load MSTeams conversation refs metadata: {}", e)
+
+        return main_data, meta_data, meta_exists
+
+    def _load_refs_from_disk(self) -> dict[str, ConversationRef]:
+        """Load refs from disk with compatibility fallback for legacy layouts."""
+        main_data, meta_data, meta_exists = self._load_refs_raw()
+        if not main_data:
             return {}
 
+        out: dict[str, ConversationRef] = {}
+        now = time.time()
+        for key, value in main_data.items():
+            ref = self._normalize_ref_record(value)
+            if not ref:
+                continue
+
+            meta_entry = meta_data.get(key) if isinstance(meta_data, dict) else None
+            meta_ts = None
+            if isinstance(meta_entry, dict):
+                meta_ts = self._safe_float(meta_entry.get("updated_at"))
+            elif meta_entry is not None:
+                meta_ts = self._safe_float(meta_entry)
+
+            if meta_ts is not None:
+                ref.updated_at = meta_ts
+            elif not meta_exists:
+                # First run after introducing meta sidecar: keep legacy refs alive
+                # by initializing timestamps to "now" instead of purging immediately.
+                ref.updated_at = now
+            elif ref.updated_at is None:
+                ref.updated_at = now
+
+            out[key] = ref
+        return out
+
+    def _load_refs(self) -> dict[str, ConversationRef]:
+        """Load stored conversation references."""
+        return self._load_refs_from_disk()
+
+    @contextmanager
+    def _refs_file_lock(self):
+        """Cross-process lock while merging and writing refs state."""
+        self._refs_path.parent.mkdir(parents=True, exist_ok=True)
+        lock_fp = self._refs_lock_path.open("a+", encoding="utf-8")
+        try:
+            if fcntl is not None:
+                fcntl.flock(lock_fp.fileno(), fcntl.LOCK_EX)
+            yield
+        finally:
+            try:
+                if fcntl is not None:
+                    fcntl.flock(lock_fp.fileno(), fcntl.LOCK_UN)
+            finally:
+                lock_fp.close()
+
     def _is_webchat_service_url(self, service_url: str) -> bool:
         """Return True when service URL points to unsupported Bot Framework Web Chat."""
         normalized = service_url.strip()
@@ -554,21 +660,49 @@ class MSTeamsChannel(BaseChannel):
         )
         return True
 
-    def _write_refs_atomically(self, data: dict[str, Any]) -> None:
+    def _merge_refs_from_disk_locked(self) -> None:
+        """Merge disk refs into memory to reduce lost updates across processes."""
+        disk_refs = self._load_refs_from_disk()
+        for key, disk_ref in disk_refs.items():
+            mem_ref = self._conversation_refs.get(key)
+            if mem_ref is None:
+                self._conversation_refs[key] = disk_ref
+                continue
+            disk_ts = self._safe_float(disk_ref.updated_at) or 0.0
+            mem_ts = self._safe_float(mem_ref.updated_at) or 0.0
+            if disk_ts > mem_ts:
+                self._conversation_refs[key] = disk_ref
+
+    def _touch_conversation_ref(self, chat_id: str, *, persist: bool = False) -> None:
+        """Refresh updated_at for an active ref to keep it from expiring while used."""
+        with self._refs_guard:
+            ref = self._conversation_refs.get(str(chat_id))
+            if not ref:
+                return
+            now = time.time()
+            prev = self._safe_float(ref.updated_at) or 0.0
+            min_interval = max(0, int(self.config.ref_touch_interval_s))
+            if min_interval > 0 and prev > 0 and now - prev < min_interval:
+                return
+            ref.updated_at = now
+            if persist:
+                self._save_refs_locked()
+
+    def _write_json_atomically(self, path, data: dict[str, Any]) -> None:
         """Write refs JSON atomically to reduce corruption risk during crashes."""
         payload = json.dumps(data, indent=2)
         tmp_path: str | None = None
         try:
             fd, tmp_path = tempfile.mkstemp(
-                dir=str(self._refs_path.parent),
+                dir=str(path.parent),
-                prefix=f"{self._refs_path.name}.",
+                prefix=f"{path.name}.",
                 suffix=".tmp",
             )
             with os.fdopen(fd, "w", encoding="utf-8") as f:
                 f.write(payload)
                 f.flush()
                 os.fsync(f.fileno())
-            os.replace(tmp_path, self._refs_path)
+            os.replace(tmp_path, path)
         finally:
             if tmp_path and os.path.exists(tmp_path):
                 try:
@@ -576,12 +710,14 @@ class MSTeamsChannel(BaseChannel):
                 except OSError:
                     pass
 
-    def _save_refs(self, *, prune: bool = True) -> None:
+    def _save_refs_locked(self, *, prune: bool = True) -> None:
-        """Persist conversation references."""
+        """Persist conversation references (caller must hold _refs_guard)."""
         try:
+            with self._refs_file_lock():
+                self._merge_refs_from_disk_locked()
                 if prune:
                     self._prune_conversation_refs()
-            data = {
+                refs_data = {
                     key: {
                         "service_url": ref.service_url,
                         "conversation_id": ref.conversation_id,
@@ -589,14 +725,25 @@ class MSTeamsChannel(BaseChannel):
                         "activity_id": ref.activity_id,
                         "conversation_type": ref.conversation_type,
                         "tenant_id": ref.tenant_id,
-                    "updated_at": ref.updated_at,
                     }
                     for key, ref in self._conversation_refs.items()
                 }
-            self._write_refs_atomically(data)
+                refs_meta = {
+                    key: {
+                        "updated_at": self._safe_float(ref.updated_at),
+                    }
+                    for key, ref in self._conversation_refs.items()
+                }
+                self._write_json_atomically(self._refs_path, refs_data)
+                self._write_json_atomically(self._refs_meta_path, refs_meta)
         except Exception as e:
             logger.warning("Failed to save MSTeams conversation refs: {}", e)
 
+    def _save_refs(self, *, prune: bool = True) -> None:
+        """Persist conversation references."""
+        with self._refs_guard:
+            self._save_refs_locked(prune=prune)
+
     async def _get_access_token(self) -> str:
         """Fetch an access token for Bot Framework / Azure Bot auth."""
 

tests/test_msteams.py

@@ -115,7 +115,10 @@ async def test_handle_activity_personal_message_publishes_and_stores_ref(make_ch
     saved = json.loads((tmp_path / "state" / "msteams_conversations.json").read_text(encoding="utf-8"))
     assert saved["conv-123"]["conversation_id"] == "conv-123"
     assert saved["conv-123"]["tenant_id"] == "tenant-id"
-    assert float(saved["conv-123"]["updated_at"]) > 0
+    saved_meta = json.loads(
+        (tmp_path / "state" / msteams_module.MSTEAMS_REF_META_FILENAME).read_text(encoding="utf-8"),
+    )
+    assert float(saved_meta["conv-123"]["updated_at"]) > 0
 
 
 def test_init_prunes_stale_and_unsupported_conversation_refs(make_channel, tmp_path, monkeypatch):
@@ -125,6 +128,7 @@ def test_init_prunes_stale_and_unsupported_conversation_refs(make_channel, tmp_p
     state_dir = tmp_path / "state"
     state_dir.mkdir(parents=True, exist_ok=True)
     refs_path = state_dir / "msteams_conversations.json"
+    refs_meta_path = state_dir / msteams_module.MSTEAMS_REF_META_FILENAME
     refs_path.write_text(
         json.dumps(
             {
@@ -132,25 +136,21 @@ def test_init_prunes_stale_and_unsupported_conversation_refs(make_channel, tmp_p
                     "service_url": "https://smba.trafficmanager.net/amer/",
                     "conversation_id": "conv-valid",
                     "conversation_type": "personal",
-                    "updated_at": now - 60,
                 },
                 "conv-webchat": {
                     "service_url": "https://webchat.botframework.com/",
                     "conversation_id": "conv-webchat",
                     "conversation_type": "personal",
-                    "updated_at": now - 60,
                 },
                 "conv-group": {
                     "service_url": "https://smba.trafficmanager.net/amer/",
                     "conversation_id": "conv-group",
                     "conversation_type": "channel",
-                    "updated_at": now - 60,
                 },
                 "conv-stale": {
                     "service_url": "https://smba.trafficmanager.net/amer/",
                     "conversation_id": "conv-stale",
                     "conversation_type": "personal",
-                    "updated_at": now - msteams_module.MSTEAMS_REF_TTL_S - 1,
                 },
                 "conv-missing-ts": {
                     "service_url": "https://smba.trafficmanager.net/amer/",
@@ -162,14 +162,27 @@ def test_init_prunes_stale_and_unsupported_conversation_refs(make_channel, tmp_p
         ),
         encoding="utf-8",
     )
+    refs_meta_path.write_text(
+        json.dumps(
+            {
+                "conv-valid": {"updated_at": now - 60},
+                "conv-webchat": {"updated_at": now - 60},
+                "conv-group": {"updated_at": now - 60},
+                "conv-stale": {"updated_at": now - msteams_module.MSTEAMS_REF_TTL_S - 1},
+            },
+            indent=2,
+        ),
+        encoding="utf-8",
+    )
 
     ch = make_channel()
 
-    assert set(ch._conversation_refs.keys()) == {"conv-valid"}
+    assert set(ch._conversation_refs.keys()) == {"conv-valid", "conv-missing-ts"}
     assert ch._conversation_refs["conv-valid"].conversation_id == "conv-valid"
+    assert ch._conversation_refs["conv-missing-ts"].conversation_id == "conv-missing-ts"
 
     persisted = json.loads(refs_path.read_text(encoding="utf-8"))
-    assert set(persisted.keys()) == {"conv-valid"}
+    assert set(persisted.keys()) == {"conv-valid", "conv-missing-ts"}
 
 
 def test_save_prunes_unsupported_conversation_refs(make_channel, tmp_path, monkeypatch):
@@ -204,6 +217,10 @@ def test_save_prunes_unsupported_conversation_refs(make_channel, tmp_path, monke
 
     saved = json.loads((tmp_path / "state" / "msteams_conversations.json").read_text(encoding="utf-8"))
     assert set(saved.keys()) == {"conv-valid"}
+    saved_meta = json.loads(
+        (tmp_path / "state" / msteams_module.MSTEAMS_REF_META_FILENAME).read_text(encoding="utf-8"),
+    )
+    assert set(saved_meta.keys()) == {"conv-valid"}
 
 
 def test_init_respects_prune_toggle_flags(make_channel, tmp_path, monkeypatch):
@@ -248,6 +265,7 @@ def test_init_respects_custom_ref_ttl_days(make_channel, tmp_path, monkeypatch):
     state_dir = tmp_path / "state"
     state_dir.mkdir(parents=True, exist_ok=True)
     refs_path = state_dir / "msteams_conversations.json"
+    refs_meta_path = state_dir / msteams_module.MSTEAMS_REF_META_FILENAME
     refs_path.write_text(
         json.dumps(
             {
@@ -255,19 +273,27 @@ def test_init_respects_custom_ref_ttl_days(make_channel, tmp_path, monkeypatch):
                     "service_url": "https://smba.trafficmanager.net/amer/",
                     "conversation_id": "conv-fresh",
                     "conversation_type": "personal",
-                    "updated_at": now - 12 * 60 * 60,
                 },
                 "conv-old": {
                     "service_url": "https://smba.trafficmanager.net/amer/",
                     "conversation_id": "conv-old",
                     "conversation_type": "personal",
-                    "updated_at": now - 10 * 24 * 60 * 60,
                 },
             },
             indent=2,
         ),
         encoding="utf-8",
     )
+    refs_meta_path.write_text(
+        json.dumps(
+            {
+                "conv-fresh": {"updated_at": now - 12 * 60 * 60},
+                "conv-old": {"updated_at": now - 10 * 24 * 60 * 60},
+            },
+            indent=2,
+        ),
+        encoding="utf-8",
+    )
 
     ch = make_channel(refTtlDays=1)
 
@@ -276,6 +302,34 @@ def test_init_respects_custom_ref_ttl_days(make_channel, tmp_path, monkeypatch):
     assert set(persisted.keys()) == {"conv-fresh"}
 
 
+def test_init_without_meta_keeps_legacy_refs_alive(make_channel, tmp_path, monkeypatch):
+    now = 1_800_000_000.0
+    monkeypatch.setattr(msteams_module.time, "time", lambda: now)
+
+    state_dir = tmp_path / "state"
+    state_dir.mkdir(parents=True, exist_ok=True)
+    refs_path = state_dir / "msteams_conversations.json"
+    refs_path.write_text(
+        json.dumps(
+            {
+                "conv-legacy": {
+                    "service_url": "https://smba.trafficmanager.net/amer/",
+                    "conversation_id": "conv-legacy",
+                    "conversation_type": "personal",
+                }
+            },
+            indent=2,
+        ),
+        encoding="utf-8",
+    )
+
+    ch = make_channel(refTtlDays=1)
+
+    assert set(ch._conversation_refs.keys()) == {"conv-legacy"}
+    assert ch._conversation_refs["conv-legacy"].updated_at == now
+    assert not (state_dir / msteams_module.MSTEAMS_REF_META_FILENAME).exists()
+
+
 def test_save_uses_atomic_replace_and_keeps_existing_file_on_replace_error(make_channel, tmp_path, monkeypatch):
     ch = make_channel()
     refs_path = tmp_path / "state" / "msteams_conversations.json"
@@ -591,6 +645,33 @@ async def test_send_replies_to_activity_when_reply_in_thread_enabled(make_channe
     assert kwargs["json"]["replyToId"] == "activity-1"
 
 
+@pytest.mark.asyncio
+async def test_send_success_refreshes_updated_at_and_persists_meta(make_channel, tmp_path, monkeypatch):
+    now = {"value": 1_800_000_000.0}
+    monkeypatch.setattr(msteams_module.time, "time", lambda: now["value"])
+
+    ch = make_channel(refTouchIntervalS=0)
+    fake_http = FakeHttpClient()
+    ch._http = fake_http
+    ch._token = "tok"
+    ch._token_expires_at = 9_999_999_999
+    ch._conversation_refs["conv-123"] = ConversationRef(
+        service_url="https://smba.trafficmanager.net/amer/",
+        conversation_id="conv-123",
+        activity_id="activity-1",
+        updated_at=now["value"] - 100,
+    )
+
+    now["value"] += 5
+    await ch.send(OutboundMessage(channel="msteams", chat_id="conv-123", content="Reply text"))
+
+    assert ch._conversation_refs["conv-123"].updated_at == now["value"]
+    saved_meta = json.loads(
+        (tmp_path / "state" / msteams_module.MSTEAMS_REF_META_FILENAME).read_text(encoding="utf-8"),
+    )
+    assert saved_meta["conv-123"]["updated_at"] == now["value"]
+
+
 @pytest.mark.asyncio
 async def test_send_posts_to_conversation_when_thread_reply_disabled(make_channel):
     ch = make_channel(replyInThread=False)
@@ -756,6 +837,7 @@ def test_msteams_default_config_includes_restart_notify_fields():
     assert cfg["refTtlDays"] == msteams_module.MSTEAMS_REF_TTL_DAYS
     assert cfg["pruneWebChatRefs"] is True
     assert cfg["pruneNonPersonalRefs"] is True
+    assert cfg["refTouchIntervalS"] == msteams_module.MSTEAMS_REF_TOUCH_INTERVAL_S
     assert "restartNotifyEnabled" not in cfg
     assert "restartNotifyPreMessage" not in cfg
     assert "restartNotifyPostMessage" not in cfg