agents can't talk to each other

[yemregundogmus]

Greetings, first of all thanks for this excellent library you have created. I am a related person who is just trying to get into the Multi Agent Systems, but I got stuck somewhere and I cannot move forward. I got the code below piece by piece examples and issues.

I have 2 different computers. I want to make one of them a host and the other an agent sending information. I want to do this with osbrain. However, I am facing a problem.

Host Agent is opening the server. 2. My agent connects to the server, but I cannot communicate between the two. Can you help me?

Host_Agent.py

from osbrain import run_nameserver
from osbrain.proxy import locate_ns
from osbrain import run_agent
import osbrain
import time
import pickle

def log_message(agent, message):
    agent.log_info('Received: %s' % message)

if __name__ == '__main__':

    ns_sock = '127.0.0.1:1212'

    osbrain.config['TRANSPORT'] = 'tcp'

    ns_proxy = run_nameserver(ns_sock)
    ns_addr = locate_ns(ns_sock)
    # New Agent

    while True:
        time.sleep(5)
        agents_in_NS = osbrain.nameserver.NameServer.agents(ns_proxy)
        print('Current agents in Nameserver are: %s' %agents_in_NS)

New_Agent.py

from osbrain import NSProxy
from osbrain import run_agent
import osbrain
import Pyro4
import pickle
import time

if __name__ == '__main__':

    ns_addr = '127.0.0.1:1212'

    osbrain.config['TRANSPORT'] = 'tcp'

    ns_proxy = NSProxy(ns_addr)

    print('Registering Agent with server...')
    agent_proxy = run_agent('Agent3', ns_addr)
    address = agent_proxy.bind('PUSH', alias='main')
    time.sleep(5)
    print('I have joined the nameserver!')

    for i in range(1000):
        print("I try to say HEY!")
        agent_proxy.send('main',message='Hey')
        print("I tried")
        time.sleep(2)

    print("Done")

[ocaballeror]

Hi

The issue here is that your agent is not communicating with anybody. You are trying to send a message to the "main" channel, but there is nobody connected to it to receive it, so it will hang forever.

In order for your test to work, you will need a second agent that can listen for that message and then do something with it. Take a closer look at this example in the docs, it is very similar to what you are trying to achieve.

[Peque]

Also, note that you are binding to '127.0.0.1', which is the localhost.

I would suggest you to carefully read through the osBrain documentation to understand how to work with it. Read at least the first 5 sections (from "About osBrain" until "Timers"). Read the Distributed systems section too.

[yemregundogmus]

Hello! After reading the documents you mentioned in detail again, I updated my code a little more, but I still cannot connect the listener bob to name_server.

Host.py

from osbrain import run_nameserver
from osbrain.proxy import locate_ns
from osbrain import run_agent
import osbrain
import time
import pickle

def log_message(agent, message):
    agent.log_info('Received: %s' % message)

if __name__ == '__main__':

    ns_sock = '127.0.0.1:1125'

    osbrain.config['TRANSPORT'] = 'tcp'
    osbrain.config['SERIALIZER'] = 'json'

    ns_proxy = run_nameserver(ns_sock)
    ns_addr = locate_ns(ns_sock)

    # New Agent
    time.sleep(5)
    bob = run_agent('Bob', nsaddr=ns_addr, serializer='json')
    agent_proxy = ns_proxy.proxy('Bob')
    address = agent_proxy.addr('alias1')
    bob.connect(address, handler=log_message)

    while True:
        time.sleep(5)
        agents_in_NS = osbrain.nameserver.NameServer.agents(ns_proxy)
        print('Current agents in Nameserver are: %s' %agents_in_NS)

Agent.py

from osbrain import NSProxy
from osbrain import run_agent
import osbrain
import Pyro4
import pickle
import time

if __name__ == '__main__':

    ns_sock = '127.0.0.1:1125'
    osbrain.config['TRANSPORT'] = 'tcp'
    osbrain.config['SERIALIZER'] = 'json'

    ns_proxy = NSProxy(ns_addr)

    print('Registering Agent with server...')
    alice = run_agent('Alice', ns_addr, serializer='json')
    # Raw serialization will override json for this socket
    addr1 = alice.bind('PUB', 'alias1', serializer='json')
    print('I have joined the nameserver!')

    time.sleep(5)
    for i in range(1000):
        print("I try to say HEY!")
        alice.send('alias1','Hey')
        print("I tried")
        time.sleep(2)

    print("Done")

address = agent.bind('PULL', transport='tcp', addr='127.0.0.1:1234')

I also tried the method you mentioned in distributed systems. However, here I encounter 2 different errors.

• ValueError: This socket requires a handler! (When i try PULL & SUB)
• zmq.error.ZMQError: Address in use (When i try PUSH)

[Peque]

@yemregundogmus Couple of random thoughts:

• Try to share a minimal, reproducible example. The code you shared does not run:
  • In your Host.py, you are calling agent_proxy.addr('alias1'), but that alias does not exist
  • In your Agent.py you refer to the variable ns_addr, but it not previously declared
• Read the nameserver introduction documentation for a better way to list agents
• Read the documentation on agents and proxies to understand what run_agent() does and why you probably do not need to call ns_proxy.proxy()
• Read the documentation on serialization to understand why you probably do not need to set both the global and per-socket serialization configurations (if they are all configured with the same serialization method)
• Read the basic communication patterns documentation to understand what handlers are and why you got that "This socket requires a handler!" error
• You are binding to 127.0.0.1 (localhost), so that will only work while working in a single machine (that is a good idea until you get it to work)
• The "Address in use" error means you are probably trying to bind to the same address twice. That is something you cannot do (that is not an osBrain issue, but how sockets work)

[yemregundogmus]

Greetings,

first of all i'm sorry for throwing code that doesn't work. While working on the Jupyter notebook, I must have sent it with the variables left in memory.

I read the articles you sent, I set up the system as PULL-PUSH and decided to send the message in that way. In this context, I put Alice and Bob on the same network, one in PULL and the other in PUSH. But even if Alice sends a message, Bob cannot hear.

Thank you very much for your patience and support.

Note: I'm bind on localhost to try it right now. I am running 2 different scripts.

Host.py

from osbrain import run_nameserver
from osbrain.proxy import locate_ns
from osbrain import run_agent
import osbrain
import time
import pickle

def log_message(agent, message):
    agent.log_info('Received: %s' % message)

if __name__ == '__main__':

    ns_sock = '127.0.0.1:1129'

    osbrain.config['TRANSPORT'] = 'tcp'
    osbrain.config['SERIALIZER'] = 'json'

    ns_proxy = run_nameserver(ns_sock)
    ns_addr = locate_ns(ns_sock)

    # New Agent

    bob = run_agent('Bob', ns_sock)
    addr1 = bob.bind('SUB', alias='main', handler=log_message)

    print("Setups done, wait for message")

Agent.py

from osbrain import NSProxy
from osbrain import run_agent
import osbrain
import Pyro4
import pickle
import time

if __name__ == '__main__':

    ns_sock = '127.0.0.1:1129'
    osbrain.config['TRANSPORT'] = 'tcp'
    osbrain.config['SERIALIZER'] = 'json'

    print('Registering Agent with server...')
    alice = run_agent('Alice', ns_sock)
    # Raw serialization will override json for this socket
    address = alice.bind('PUB', alias='main')
    print('I have joined the nameserver!')

    for i in range(10):
        print("I try to say HEY!")
        alice.send('main','Hey')
        print("I tried")
        time.sleep(2)

    print("Done")

[Peque]

@yemregundogmus You have not connected those agents.

Read the basic communication patterns documentation to understand how to connect them (see the required .connect() call from one of them). Since you are using a distributed system, read the distributed systems documentation to know how to retrieve an already-running agent's address in order to connect to it.

The resulting code may look like this:

nameserver = NSProxy(ns_sock)
alice.connect(nameserver.proxy('Bob').addr('main'), alias='main')

[Peque]

To be honest, I would use a well-known address for your main communication pattern, instead of binding to a random port. This would allow you to bind after connecting, or recover the host from a crash without the clients even noticing. Otherwise it would be harder for you to handle possible failures.

So just declare your main socket address as a string literal in both scripts, just like you do with the nameserver address.

This is just a suggestion, you can of course go with the default random addresses.

[Peque]

Closing this for now. Feel free to comment/reopen if you need further help. :blush: