Matrix invite: honor 429 retry_after_ms (3 attempts)

app/main.py

@@ -846,15 +846,26 @@ async def sync_matrix_space() -> dict:
         return {"skipped": True}
     H = {"Authorization": f"Bearer {MATRIX_BOT_TOKEN}", "Content-Type": "application/json"}
 
-    async def invite(mxid: str, room: str) -> None:
-        r = await client.post(
-            f"{MATRIX_HOMESERVER}/_matrix/client/v3/rooms/{room}/invite",
-            headers=H, json={"user_id": mxid},
-        )
-        # 200 = invited; 403 M_FORBIDDEN with 'already in room' is fine too
-        if r.status_code not in (200, 403) and "already" not in r.text:
+    async def invite(mxid: str, room: str) -> bool:
+        import asyncio as _aio
+        for attempt in range(3):
+            r = await client.post(
+                f"{MATRIX_HOMESERVER}/_matrix/client/v3/rooms/{room}/invite",
+                headers=H, json={"user_id": mxid},
+            )
+            if r.status_code == 200:
+                return True
+            if r.status_code == 429:
+                wait = (r.json().get("retry_after_ms", 1000) / 1000) + 0.2
+                await _aio.sleep(wait)
+                continue
+            # 403 with 'already in room' is fine
+            if "already" in r.text:
+                return True
             logger.warning("Matrix invite %s -> %s failed: %s %s",
                            mxid, room, r.status_code, r.text[:120])
+            return False
+        return False
 
     async with httpx.AsyncClient(timeout=30) as client:
         # current members of the space (to avoid duplicate invites)