lazy ffi dlopen (#567)

Author: theomonnom

livekit-rtc/livekit/rtc/_ffi_client.py

@@ -34,22 +34,27 @@
 atexit.register(_resource_files.close)
 
 
+def _lib_name():
+    if platform.system() == "Linux":
+        return "liblivekit_ffi.so"
+    elif platform.system() == "Darwin":
+        return "liblivekit_ffi.dylib"
+    elif platform.system() == "Windows":
+        return "livekit_ffi.dll"
+    return None
+
+
 def get_ffi_lib():
     # allow to override the lib path using an env var
     libpath = os.environ.get("LIVEKIT_LIB_PATH", "").strip()
     if libpath:
         return ctypes.CDLL(libpath)
 
-    if platform.system() == "Linux":
-        libname = "liblivekit_ffi.so"
-    elif platform.system() == "Darwin":
-        libname = "liblivekit_ffi.dylib"
-    elif platform.system() == "Windows":
-        libname = "livekit_ffi.dll"
-    else:
+    libname = _lib_name()
+    if libname is None:
         raise Exception(
-            f"no ffi library found for platform {platform.system()}. \
-                Set LIVEKIT_LIB_PATH to specify a the lib path"
+            f"no ffi library found for platform {platform.system()}. "
+            "Set LIVEKIT_LIB_PATH to specify the lib path"
         )
 
     res = importlib.resources.files("livekit.rtc.resources") / libname
@@ -58,32 +63,8 @@ def get_ffi_lib():
     return ctypes.CDLL(str(path))
 
 
-ffi_lib = get_ffi_lib()
 ffi_cb_fnc = ctypes.CFUNCTYPE(None, ctypes.POINTER(ctypes.c_uint8), ctypes.c_size_t)
 
-# C function types
-ffi_lib.livekit_ffi_initialize.argtypes = [
-    ffi_cb_fnc,
-    ctypes.c_bool,
-    ctypes.c_char_p,
-    ctypes.c_char_p,
-]
-
-ffi_lib.livekit_ffi_request.argtypes = [
-    ctypes.POINTER(ctypes.c_ubyte),
-    ctypes.c_size_t,
-    ctypes.POINTER(ctypes.POINTER(ctypes.c_ubyte)),
-    ctypes.POINTER(ctypes.c_size_t),
-]
-ffi_lib.livekit_ffi_request.restype = ctypes.c_uint64
-
-ffi_lib.livekit_ffi_drop_handle.argtypes = [ctypes.c_uint64]
-ffi_lib.livekit_ffi_drop_handle.restype = ctypes.c_bool
-
-
-ffi_lib.livekit_ffi_dispose.argtypes = []
-ffi_lib.livekit_ffi_dispose.restype = None
-
 INVALID_HANDLE = 0
 
 
@@ -102,7 +83,7 @@ def disposed(self) -> bool:
     def dispose(self) -> None:
         if self.handle != INVALID_HANDLE and not self._disposed:
             self._disposed = True
-            assert ffi_lib.livekit_ffi_drop_handle(ctypes.c_uint64(self.handle))
+            assert FfiClient.instance._ffi_lib.livekit_ffi_drop_handle(ctypes.c_uint64(self.handle))
 
     def __repr__(self) -> str:
         return f"FfiHandle({self.handle})"
@@ -214,10 +195,39 @@ def __init__(self) -> None:
         self._lock = threading.RLock()
         self._queue = FfiQueue[proto_ffi.FfiEvent]()
 
-        ffi_lib.livekit_ffi_initialize(
+        try:
+            self._ffi_lib = get_ffi_lib()
+        except Exception as e:
+            libname = _lib_name() or "livekit_ffi"
+            raise ImportError(
+                "failed to load %s: %s\n"
+                "Install the livekit package with: pip install livekit\n"
+                "Or set LIVEKIT_LIB_PATH to the path of the native library." % (libname, e)
+            ) from None
+        self._ffi_lib.livekit_ffi_initialize.argtypes = [
+            ffi_cb_fnc,
+            ctypes.c_bool,
+            ctypes.c_char_p,
+            ctypes.c_char_p,
+        ]
+        self._ffi_lib.livekit_ffi_request.argtypes = [
+            ctypes.POINTER(ctypes.c_ubyte),
+            ctypes.c_size_t,
+            ctypes.POINTER(ctypes.POINTER(ctypes.c_ubyte)),
+            ctypes.POINTER(ctypes.c_size_t),
+        ]
+        self._ffi_lib.livekit_ffi_request.restype = ctypes.c_uint64
+        self._ffi_lib.livekit_ffi_drop_handle.argtypes = [ctypes.c_uint64]
+        self._ffi_lib.livekit_ffi_drop_handle.restype = ctypes.c_bool
+        self._ffi_lib.livekit_ffi_dispose.argtypes = []
+        self._ffi_lib.livekit_ffi_dispose.restype = None
+
+        self._ffi_lib.livekit_ffi_initialize(
             ffi_event_callback, True, b"python", __version__.encode("ascii")
         )
 
+        ffi_lib = self._ffi_lib
+
         @atexit.register
         def _dispose_lk_ffi():
             ffi_lib.livekit_ffi_dispose()
@@ -233,7 +243,7 @@ def request(self, req: proto_ffi.FfiRequest) -> proto_ffi.FfiResponse:
 
         resp_ptr = ctypes.POINTER(ctypes.c_ubyte)()
         resp_len = ctypes.c_size_t()
-        handle = ffi_lib.livekit_ffi_request(
+        handle = self._ffi_lib.livekit_ffi_request(
             data, proto_len, ctypes.byref(resp_ptr), ctypes.byref(resp_len)
         )
         assert handle != INVALID_HANDLE

livekit-rtc/livekit/rtc/participant.py

@@ -318,9 +318,7 @@ async def perform_rpc(
         queue = FfiClient.instance.queue.subscribe()
         try:
             resp = FfiClient.instance.request(req)
-            cb = await queue.wait_for(
-                lambda e: (e.perform_rpc.async_id == resp.perform_rpc.async_id)
-            )
+            cb = await queue.wait_for(lambda e: e.perform_rpc.async_id == resp.perform_rpc.async_id)
         finally:
             FfiClient.instance.queue.unsubscribe(queue)
 

tests/rtc/test_e2e.py

@@ -314,9 +314,11 @@ def on_room2_track_unpublished(
         await room1.connect(url, token1)
 
         await assert_eventually(
-            lambda: len(events["connection_state_changed"]) > 0
-            and events["connection_state_changed"][-1]
-            == f"room1-{rtc.ConnectionState.CONN_CONNECTED}",
+            lambda: (
+                len(events["connection_state_changed"]) > 0
+                and events["connection_state_changed"][-1]
+                == f"room1-{rtc.ConnectionState.CONN_CONNECTED}"
+            ),
             message="room1 connection_state_changed event not fired or did not reach CONN_CONNECTED state",
         )
 
@@ -370,9 +372,13 @@ def on_room2_track_unpublished(
         await room1.disconnect()
 
         await assert_eventually(
-            lambda: lambda: len(events["connection_state_changed"]) > 0
-            and events["connection_state_changed"][-1]
-            == f"room1-{rtc.ConnectionState.CONN_DISCONNECTED}",
+            lambda: (
+                lambda: (
+                    len(events["connection_state_changed"]) > 0
+                    and events["connection_state_changed"][-1]
+                    == f"room1-{rtc.ConnectionState.CONN_DISCONNECTED}"
+                )
+            ),
             message="room1 disconnected event not fired",
         )