# Using the gRPC API gRPC is the main API for interfacing with CORE. ## HTTP Proxy Since gRPC is HTTP2 based, proxy configurations can cause issue. Clear out your proxy when running if needed. ## Python Client A python client wrapper is provided at **core.api.grpc.client.CoreGrpcClient**. Below is a small example using it. ```python import logging from builtins import range from core.api.grpc import client, core_pb2 def log_event(event): logging.info("event: %s", event) def main(): core = client.CoreGrpcClient() with core.context_connect(): # create session response = core.create_session() logging.info("created session: %s", response) # handle events session may broadcast session_id = response.session_id core.events(session_id, log_event) # change session state response = core.set_session_state(session_id, core_pb2.SessionState.CONFIGURATION) logging.info("set session state: %s", response) # create switch node switch = core_pb2.Node(type=core_pb2.NodeType.SWITCH) response = core.add_node(session_id, switch) logging.info("created switch: %s", response) switch_id = response.node_id # helper to create interfaces interface_helper = client.InterfaceHelper(ip4_prefix="10.83.0.0/16") for i in range(2): # create node position = core_pb2.Position(x=50 + 50 * i, y=50) node = core_pb2.Node(position=position) response = core.add_node(session_id, node) logging.info("created node: %s", response) node_id = response.node_id # create link interface_one = interface_helper.create_interface(node_id, 0) response = core.add_link(session_id, node_id, switch_id, interface_one) logging.info("created link: %s", response) # change session state response = core.set_session_state(session_id, core_pb2.SessionState.INSTANTIATION) logging.info("set session state: %s", response) if __name__ == "__main__": logging.basicConfig(level=logging.DEBUG) main() ```