[Streaming] Streaming Python API (#6755)

streaming/python/runtime/gateway_client.py

@@ -0,0 +1,67 @@
+# -*- coding: UTF-8 -*-
+"""Module to interact between java and python
+"""
+
+import msgpack
+import ray
+
+
+class GatewayClient:
+    """GatewayClient is used to interact with `PythonGateway` java actor"""
+
+    _PYTHON_GATEWAY_CLASSNAME = \
+        b"org.ray.streaming.runtime.python.PythonGateway"
+
+    def __init__(self):
+        self._python_gateway_actor = ray.java_actor_class(
+            GatewayClient._PYTHON_GATEWAY_CLASSNAME).remote()
+
+    def create_streaming_context(self):
+        call = self._python_gateway_actor.createStreamingContext.remote()
+        return deserialize(ray.get(call))
+
+    def with_config(self, conf):
+        call = self._python_gateway_actor.withConfig.remote(serialize(conf))
+        ray.get(call)
+
+    def execute(self, job_name):
+        call = self._python_gateway_actor.execute.remote(serialize(job_name))
+        ray.get(call)
+
+    def create_py_stream_source(self, serialized_func):
+        assert isinstance(serialized_func, bytes)
+        call = self._python_gateway_actor.createPythonStreamSource\
+            .remote(serialized_func)
+        return deserialize(ray.get(call))
+
+    def create_py_func(self, serialized_func):
+        assert isinstance(serialized_func, bytes)
+        call = self._python_gateway_actor.createPyFunc.remote(serialized_func)
+        return deserialize(ray.get(call))
+
+    def create_py_partition(self, serialized_partition):
+        assert isinstance(serialized_partition, bytes)
+        call = self._python_gateway_actor.createPyPartition\
+            .remote(serialized_partition)
+        return deserialize(ray.get(call))
+
+    def call_function(self, java_class, java_function, *args):
+        java_params = serialize([java_class, java_function] + list(args))
+        call = self._python_gateway_actor.callFunction.remote(java_params)
+        return deserialize(ray.get(call))
+
+    def call_method(self, java_object, java_method, *args):
+        java_params = serialize([java_object, java_method] + list(args))
+        call = self._python_gateway_actor.callMethod.remote(java_params)
+        return deserialize(ray.get(call))
+
+
+def serialize(obj) -> bytes:
+    """Serialize a python object which can be deserialized by `PythonGateway`
+    """
+    return msgpack.packb(obj, use_bin_type=True)
+
+
+def deserialize(data: bytes):
+    """Deserialize the binary data serialized by `PythonGateway`"""
+    return msgpack.unpackb(data, raw=False)