Using the gRPC API

By default the gRPC API is currently not turned on by default. There are a couple ways that this can be enabled to use.

Enabling gRPC

HTTP Proxy

Since gRPC is HTTP2 based, proxy configurations can cause issue. Clear out your proxy when running if needed.

Daemon Options

The gRPC API is enabled through options provided to the core-daemon.

usage: core-daemon [-h] [-f CONFIGFILE] [-p PORT] [-n NUMTHREADS] [--ovs]
                   [--grpc] [--grpc-port GRPCPORT]
                   [--grpc-address GRPCADDRESS]

CORE daemon v.5.3.0 instantiates Linux network namespace nodes.

optional arguments:
  -h, --help            show this help message and exit
  -f CONFIGFILE, --configfile CONFIGFILE
                        read config from specified file; default =
                        /etc/core/core.conf
  -p PORT, --port PORT  port number to listen on; default = 4038
  -n NUMTHREADS, --numthreads NUMTHREADS
                        number of server threads; default = 1
  --ovs                 enable experimental ovs mode, default is false
  --grpc                enable grpc api, default is false
  --grpc-port GRPCPORT  grpc port to listen on; default 50051
  --grpc-address GRPCADDRESS
                        grpc address to listen on; default localhost

Enabling in Service Files

Modify service files to append the --grpc options as desired.

For sysv services /etc/init.d/core-daemon

CMD="PYTHONPATH=/usr/lib/python3.6/site-packages python3 /usr/bin/$NAME --grpc"

For systemd service /lib/systemd/system/core-daemon.service

ExecStart=@PYTHON@ @bindir@/core-daemon --grpc

Enabling from Command Line

sudo core-daemon --grpc

Python Client

A python client wrapper is provided at core.api.grpc.client.CoreGrpcClient.

Below is a small example using it.

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()

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