commit 3aa422f3283c7234a92baac8355e2e29af8ea056
Author: dave <dave@davepedu.com>
Date:   Tue Sep 5 00:22:24 2017 -0700

    initial commit

diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..5ad8eb6
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,2 @@
+pkg-resources==0.0.0
+pyzmq==16.0.2
diff --git a/server.py b/server.py
new file mode 100644
index 0000000..a8140bc
--- /dev/null
+++ b/server.py
@@ -0,0 +1,379 @@
+import asyncio
+from time import time
+import zmq.asyncio
+from contextlib import closing
+# from concurrent.futures import ThreadPoolExecutor
+from random import randint
+zmq.asyncio.install()
+
+
+def exewrap(func):
+    async def wrapped(*args, **kwargs):
+        try:
+            await func(*args, **kwargs)
+        except:
+            print("EXCEPTIN")
+            import traceback
+            traceback.print_exc()
+    return wrapped
+
+
+class MsgBusServerPeer(object):
+    """
+    A link to another msgbus server that we share messages with and get messages from.
+
+    Peering process:
+    - Another node sends, to our sub port, a __peer_request message with a server name
+    - We send a __peer_response message with two port numbers
+    - We start listening pub/sub on those two ports
+    - Anything we receive goes out to all our clients and peers EXCEPT this one
+    """
+    def __init__(self, server, name, pub_port, sub_port, bind=True):
+        self.alive = False
+        self.server = server
+        self.name = name
+        self.pub_port = pub_port
+        self.sub_port = sub_port
+        self.bind = bind
+
+        self.protocol = 'tcp'
+        self.sub_sock = None
+        self.sub_sock_addr = '{}://127.0.0.1:{}'.format(self.protocol, self.sub_port)
+        self.pub_sock = None
+        self.pub_sock_addr = '{}://127.0.0.1:{}'.format(self.protocol, self.pub_port)
+
+        self.last_keepalive = time()
+
+        self.confpeer = None
+
+        print("New peer on {}, {}".format(self.pub_port, self.sub_port))
+
+    async def run(self):
+        # Wait for messages
+        # On recv, pass it to the server for transmission to all peers but the sender
+        with closing(self.server.ctx.socket(zmq.SUB)) as self.sub_sock:
+            with closing(self.server.ctx.socket(zmq.PUB)) as self.pub_sock:
+                if self.bind:
+                    self.pub_sock.bind(self.pub_sock_addr)
+                    self.sub_sock.bind(self.sub_sock_addr)
+                else:
+                    self.pub_sock.connect(self.pub_sock_addr)
+                    self.sub_sock.connect(self.sub_sock_addr)
+                self.sub_sock.subscribe(b'')
+                self.alive = True
+                await asyncio.wait([self.listen(),
+                                    self.keep_alive_listener(),
+                                    self.keep_alive_sender()], loop=self.server.loop)
+
+    async def listen(self):
+        while self.alive:
+            # __peer_msg <origin> <topic> <data>
+            # print("peer recv")
+            msg = await self.sub_sock.recv()
+            topic, msg = msg.decode('utf-8').split(' ', 1)
+            # print('peer received topic:"{}" data:"{}"'.format(topic, msg))
+            if topic == "__peer_msg":
+                sender, data = msg.split(' ', 1)
+                self.server.counter_remote_messages += 1
+                await asyncio.wait([self.server.pub_sock.send(data.encode("utf-8")),
+                                    self.server.send_to_peers(data, exclude=sender)],
+                                   loop=self.server.loop)
+                # print("Sent!")
+            elif topic == "__peer_keepalive":
+                self.last_keepalive = time()
+
+    async def local_send(self, msg):
+        # Send a raw message to peers
+        if self.alive:
+            await self.pub_sock.send('__peer_msg {} {}'.format(self.server.name, msg).encode('utf-8'))
+
+    async def keep_alive_sender(self):
+        interval = self.server.conf.get("peer_keepalive_interval", 1)
+        try:
+            while self.alive:
+                await self.pub_sock.send("__peer_keepalive ping".encode('utf-8'))
+                await asyncio.sleep(interval)
+        except:
+            import traceback
+            traceback.print_exc()
+
+    async def keep_alive_listener(self):
+        interval = self.server.conf.get("peer_keepalive_timeout", 5)
+        try:
+            while self.alive:
+                if time() - self.last_keepalive > interval:
+                    print("Peer {} is lost!".format(self.name))
+                    self.server.disconnect_peer(self.name)
+                    break
+                await asyncio.sleep(1)
+        except:
+            import traceback
+            traceback.print_exc()
+
+    def shutdown(self):
+        self.alive = False
+        self.sub_sock.close()
+        self.pub_sock.close()
+
+
+class MsgBusServer(object):
+    def __init__(self, loop, ctx, subport, pubport, port_range, peers):
+        assert subport != pubport
+        self.alive = True  # TODO move this?
+
+        self.loop = loop
+        self.ctx = ctx
+        self.subport = subport
+        self.pubport = pubport
+
+        self.protocol = 'tcp'
+        self.sub_sock = None
+        self.sub_sock_addr = '{}://127.0.0.1:{}'.format(self.protocol, self.subport)
+        self.pub_sock = None
+        self.pub_sock_addr = '{}://127.0.0.1:{}'.format(self.protocol, self.pubport)
+
+        self.seed_peers = peers
+        self.peers = {}
+
+        self.name = "randomname_{}".format(randint(0, 420000))
+
+        self.port_range = port_range
+
+        self.counter_local_messages = 0
+        self.counter_remote_messages = 0
+
+        self.conf = {}
+
+        self.inprogress_connects = []
+
+    async def run(self):
+        with closing(self.ctx.socket(zmq.SUB)) as self.sub_sock:
+            with closing(self.ctx.socket(zmq.PUB)) as self.pub_sock:
+
+                self.sub_sock.bind(self.sub_sock_addr)
+                self.sub_sock.subscribe(b'')
+                self.pub_sock.bind(self.pub_sock_addr)
+                await asyncio.wait([self.reciever(),
+                                    self.heartbeat(),
+                                    self.peer_monitor(),
+                                    self.stats_monitor()], loop=self.loop)
+
+    async def stats_monitor(self):
+        """
+        Print out stats on an interval (messages/s etc)
+        """
+        start = time()
+        interval = self.conf.get("stats_interval", 5)
+        show_idle_stats = self.conf.get("show_idle_stats", True)
+        counter_local_total = 0
+        counter_remote_total = 0
+        while True:
+            await asyncio.sleep(interval)
+            if show_idle_stats or self.counter_local_messages > 0 or self.counter_remote_messages > 0:
+                counter_local_total += self.counter_local_messages
+                counter_remote_total += self.counter_remote_messages
+                print("Last {}s i delivered {} messages locally ({}/s)"
+                      .format(interval, self.counter_local_messages, round(self.counter_local_messages / interval, 2)))
+                print("Last {}s i delivered {} messages remotely ({}/s)"
+                      .format(interval, self.counter_remote_messages, round(self.counter_remote_messages / interval, 2)))
+                total = self.counter_local_messages + self.counter_remote_messages
+                print("Last {}s total {} messages ({}/s)".format(interval, total, round(total / interval, 2)))
+                uptime = round(time() - start, 2)
+                print("Lifetime {}s i delivered {} messages locally ({}/s)"
+                      .format(uptime, counter_local_total, round(counter_local_total / uptime, 2)))
+                print("Lifetime {}s i delivered {} messages remotely ({}/s)"
+                      .format(uptime, counter_remote_total, round(counter_remote_total / uptime, 2)))
+                total = counter_local_total + counter_remote_total
+                print("Lifetime {}s total {} messages ({}/s)\n".format(uptime, total, round(total / uptime, 2)))
+            self.counter_local_messages = 0
+            self.counter_remote_messages = 0
+
+    @exewrap
+    async def peer_monitor(self):
+        # ensure we stay connected to peers
+        while self.alive:
+            for peer_addr in self.seed_peers:
+                if not self.has_peer(peer_addr):
+                    print("connecting to {}".format(peer_addr))
+                    self.loop.call_soon(asyncio.ensure_future, self.connect_to_peer(peer_addr))
+            await asyncio.sleep(1)
+
+    def has_peer(self, peer_name):
+        if peer_name in self.inprogress_connects:
+            return True
+        if peer_name in [i.confpeer for k, i in self.peers.items()]:
+            return True
+        return False
+
+    @exewrap
+    async def connect_to_peer(self, peer_name):
+        try:
+            self.inprogress_connects.append(peer_name)
+            host, pub_port = peer_name.split(":")
+            peer_pub_addr = '{}://{}:{}'.format(self.protocol, host, pub_port)
+            with closing(self.ctx.socket(zmq.SUB)) as peer_pub_socket:
+                peer_pub_socket.connect(peer_pub_addr)
+                peer_pub_socket.subscribe(b'__msgbus_meta')
+                async def wait_for_cmd(cmd_name, timeout=10):
+                    start = time()
+                    while time() - start < timeout:
+                        try:
+                            msg = await peer_pub_socket.recv(flags=zmq.NOBLOCK)
+                            if msg:
+                                _, cmd, data = msg.decode("utf-8").split(" ", 2)  # only subscribed to __msgbus_meta
+                                if cmd == cmd_name:
+                                    return data
+                        except zmq.error.Again:
+                            await asyncio.sleep(0.1)
+
+                print("waiting for peer info")
+                peer_info = await wait_for_cmd("__my_info")
+
+                if not peer_info:
+                    print("peering failed for", peer_name)
+                    return
+
+                remote_name, subport, subproto, pubbport, pubproto = peer_info.split()
+                peer_sub_addr = '{}://{}:{}'.format(subproto, host, subport)
+                peer_response = []
+                print(peer_sub_addr)
+                with closing(self.ctx.socket(zmq.PUB)) as peer_sub_socket:
+                    peer_sub_socket.connect(peer_sub_addr)
+                    await asyncio.sleep(1)
+                    while True:
+                        await peer_sub_socket.send("__msgbus_meta __peer_request {}".format(self.name).encode('utf-8'))
+                        peer_response = await wait_for_cmd("__peer_response")
+                        if peer_response:
+                            print("got peer resp: ", peer_response)
+                            break
+                        await asyncio.sleep(1)
+
+                if not peer_response:
+                    # TODO RETRY
+                    print("peering failed for", peer_name)
+                    return
+
+                _, pubport, pubproto, subport, subproto = peer_response.split()
+                peer = self.get_peer(remote_name, pub_port=pubport, sub_port=subport, bind=False)
+                peer.confpeer = peer_name
+                print("Added peer", peer_name)
+        finally:
+            self.inprogress_connects.remove(peer_name)
+
+    async def heartbeat(self):
+        """
+        Send heartbeat messages every second. These messages, all under the __msgbus_meta topic, include:
+        * __my_ports: a listing of this nodes pub and sub ports and protocols
+        """
+        while True:
+            msg = '__msgbus_meta __my_info {} {} {} {} {}'.format(self.name, self.subport, self.protocol,
+                                                                  self.pubport, self.protocol)
+            self.pub_sock.send(msg.encode('utf-8'))
+            await asyncio.sleep(1)
+
+    async def reciever(self):
+        try:
+            while True:
+                # print("recv")
+                msg = await self.sub_sock.recv()
+                msg = msg.decode("utf-8")
+                topic, data = msg.split(' ', 1)
+                # print('received topic:"{}" data:"{}"'.format(topic, data))
+                if topic == "__msgbus_meta":
+                    await self.process_meta(data)
+                else:
+                    await asyncio.wait([self.pub_sock.send(msg.encode("utf-8")), self.send_to_peers(msg)],
+                                       loop=self.loop)
+                    self.counter_local_messages += 1
+        except:
+            import traceback
+            traceback.print_exc()
+
+    async def process_meta(self, data):
+        print("Got meta: {}".format(data))
+        command, rest = data.split(" ", 1)
+        if command == "__peer_request":
+            try:
+                await self.handle_peer_request(rest)
+            except:
+                import traceback
+                traceback.print_exc()
+
+    async def handle_peer_request(self, peer_name):
+        assert type(peer_name) is str
+        peer = self.get_peer(peer_name)
+        await self.pub_sock.send("__msgbus_meta __peer_response {} {} tcp {} tcp"
+                                 .format(peer_name, peer.pub_port, peer.sub_port)
+                                 .encode("utf-8"))
+
+    def get_peer(self, peer_name, pub_port=None, sub_port=None, bind=True):
+        if peer_name not in self.peers:
+            if pub_port is None:
+                pub_port = randint(*self.port_range)
+            if sub_port is None:
+                sub_port = pub_port + 1
+            peer_ports = (sub_port, pub_port)
+            self.peers[peer_name] = MsgBusServerPeer(self, peer_name, *peer_ports, bind=bind)
+            self.loop.call_soon(asyncio.ensure_future, self.peers[peer_name].run())  # seems to act like a fork
+        return self.peers[peer_name]
+
+    def disconnect_peer(self, peer_name):
+        if peer_name in self.peers:
+            peer = self.peers[peer_name]
+            peer.shutdown()
+            del self.peers[peer_name]
+
+    async def send_to_peers(self, msg, exclude=None):
+        for peer_name, peer in self.peers.items():
+            if peer_name == exclude:
+                continue
+            await peer.local_send(msg)
+
+
+def main():
+    import argparse
+    parser = argparse.ArgumentParser(description="msgbus server")
+    parser.add_argument("-p", "--port", default=7003, help="first listen port (tcp)")
+    parser.add_argument("-n", "--peers", nargs="+", help="connect to peer 1.2.3.4:5678")
+    parser.add_argument("-r", "--port-range", default=[7010, 7400], nargs=2, help="peer port range")
+    args = parser.parse_args()
+
+    with zmq.asyncio.Context() as ctx:
+        loop = asyncio.get_event_loop()
+        # loop.set_default_executor(ThreadPoolExecutor(max_workers=10))
+        loop.set_debug(True)
+        server = MsgBusServer(loop, ctx, int(args.port), int(args.port) + 1,
+                              port_range=args.port_range, peers=args.peers if args.peers else [])
+        loop.run_until_complete(server.run())
+
+
+if __name__ == '__main__':
+    main()
+
+"""
+More on peering:
+
+./server.py -p 7003  # start a node on port 7003 + 7004
+./server.py -p 7200 --peer 127.0.0.1:7004  # connect another node
+./server.py -p 7300 --peer 127.0.0.1:7201  # connect a third node, in a chain
+./server.py -p 7400 --peer 127.0.0.1:7201  # connect a third node, making 7200 a hub
+
+- This server has 2 ports for all normal clients
+- peers use this normal port to request peering. The existing server is the REMOTE, the other is CLIENT
+    - CLIENT: subscribe to the configured host and IP, it is a publishing port
+    - REMOTE: (periodically) sends and info heartbeat advertising the REMOTE's subscribing port
+    - CLIENT: waits for ^ msg, connects to REMOTE's sub port
+    - CLIENT: send a __peer_request, indicating our identity (name)
+    - REMOTE: (always upon receiving a __peer_request) create a MsgBusServerPeer if one doesnt exist for the requester's
+      identity. It would start listening now or already be. Send a __peer_response containing the peer's name and ports.
+    - CLIENT: wait for a __peer_response. retry or panic if doesnt come X seconds after the request. Create a
+      MsgBusServerPeer object (probably manually checking for dupe this time).
+
+    MsgBusServerPeer:
+        - Creates a pub/sub port pair for the peer
+        - In parallel:
+            - Listen for incoming messages from peers
+                - Upon recv, forward to all peers (besides the sender) and local clients
+            - When local clients send msgs, send to all peers
+
+"""