failover: enable retries for the LiveKit Cloud API hosts

Author: u9g

livekit-api/livekit/api/_failover.py

@@ -44,11 +44,11 @@ def failover_attempts(
     timeout: Optional[float] = None,
 ) -> int:
     """Total request attempts for a host; 1 means no failover. Failover only
-    engages when enabled, the host is a LiveKit Cloud domain, and the request
-    timeout is long enough to retry. ``force`` bypasses the cloud-host check and
-    is for internal testing only.
+    engages when enabled, the host is a LiveKit Cloud project or Cloud API
+    domain, and the request timeout is long enough to retry. ``force`` bypasses
+    the cloud-host check and is for internal testing only.
     """
-    if not (enabled and (force or (host is not None and is_cloud(host)))):
+    if not (enabled and (force or (host is not None and (is_cloud(host) or is_cloud_api(host))))):
         return 1
     if timeout is not None and 0 < timeout < MIN_FAILOVER_TIMEOUT:
         return 1
@@ -60,6 +60,11 @@ def is_cloud(host: str) -> bool:
     return host.endswith(".livekit.cloud")
 
 
+def is_cloud_api(host: str) -> bool:
+    # cloud-api.livekit.io or a cloud-api.<env>.livekit.io variant.
+    return host.startswith("cloud-api.") and host.endswith(".livekit.io")
+
+
 def to_http(url: str) -> str:
     """Normalizes a region URL to an http(s) scheme (ws -> http, wss -> https)."""
     if url.startswith("ws"):

tests/api/test_failover_unit.py

@@ -25,6 +25,7 @@
 from aiohttp.test_utils import TestServer
 
 from livekit.api import CreateRoomRequest, Room, ServerError
+from livekit.api._failover import FAILOVER_MAX_ATTEMPTS, failover_attempts
 from livekit.api.twirp_client import TwirpClient
 
 Handler = Callable[[int, web.Request], "web.StreamResponse | None"]
@@ -87,3 +88,22 @@ def behave(attempt: int, request: web.Request):
         asyncio.run(_call_single_host(behave, attempts))
     assert exc.value.status == 502
     assert len(attempts) == 1
+
+
+@pytest.mark.parametrize(
+    "host, expected",
+    [
+        ("myproject.livekit.cloud", FAILOVER_MAX_ATTEMPTS),
+        ("myproject.region.livekit.cloud", FAILOVER_MAX_ATTEMPTS),
+        ("myproject.livekit.io", 1),
+        # The LiveKit Cloud API hosts fail over too (same-host retry).
+        ("cloud-api.livekit.io", FAILOVER_MAX_ATTEMPTS),
+        ("cloud-api.staging.livekit.io", FAILOVER_MAX_ATTEMPTS),
+        ("cloud-api.example.com", 1),
+        ("example.com", 1),
+        ("127.0.0.1", 1),
+        ("notlivekit.cloud", 1),
+    ],
+)
+def test_failover_attempts(host: str, expected: int):
+    assert failover_attempts(True, host) == expected