In a previous blog I described a simple echo bot, that echoes back anything you say to it. This time I will talk about a bot that generates traffic for the chat server, that can be used for load-testing both the chat server as well as any chat clients connected to it.

I’ve dubbed it JumperBot - it jumps between chat rooms, saying a few random phrases in each room, then jumping to the next one. This bot builds on the same framework as the EchoBot - refer to the previous blog if you are interested in the details. The source lives on GitHub: https://github.com/snorristurluson/xmpp-chatbot

Configure the server

In an earlier blog I described the setup of Prosody as the chat server to run against. Before we can connect bots to the server we have to make sure they can log in, either by creating accounts for them:

prosodyctl register jumperbot_0 localhost jumperbot
prosodyctl register jumperbot_1 localhost jumperbot
...

or by setting the authentication up so that anyone can log in.

We also need to enable multi-room chat - do this by adding this to the Prosody configuration file (near the bottom of the file, in the Components section):

Component "conference.localhost" "muc"

JumperBot

The Jumperbot is similar to the EchoBot, but rather than handling incoming messages we set up an asyncio task as this bot is proactive where the echo bot was reactive. The task is created when the connection is made:

    self.task = asyncio.get_event_loop().create_task(self.run())

The run method looks like this:

    async def run(self):
        while True:
            self.join_random_room()
            n = random.randint(5, 10)
            for i in range(n):
                if self.transport.is_closing():
                    return
                self.say_random_phrase()
                try:
                    await asyncio.sleep(random.random() * 10.0 + 5.0)
                except asyncio.CancelledError:
                    return

This implements the bot behavior as described above - joins a random room, says a few random phrases, then repeats the process in the next room. The asyncio.sleep command is very important - this allows other tasks to run concurrently with this loop.

BotManager

Running a single JumperBot doesn’t really generate much traffic and rather than running multiple processes, let’s make use of asyncio and create multiple bots as tasks. For that, we set up a BotManager to create and monitor bots:

    manager = BotManager()

    manager.create_bots(args)
    loop = asyncio.get_event_loop()

    loop.create_task(manager.monitor_status(args.monitor))

The bot manager looks like this:

class BotManager(object):
    def __init__(self):
        self.bots_running = {}
        self.bots_logged_in = {}
        self.args = None

    def create_bot(self, botname, args):
        bot = JumperBot(self, args.host_name, botname, "jumperbot",
                        args.num_rooms)
        if args.listener:
            bot.listener = True

        self.connect_bot(bot, args)

        return bot

    def connect_bot(self, bot, args):
        loop = asyncio.get_event_loop()
        handler = loop.create_connection(lambda: bot, args.server_name, 5222)
        loop.create_task(handler)

    def create_bots(self, args):
        self.args = args
        for i in range(args.num_bots):
            botname = "jumperbot_{0}".format(i)
            bot = self.create_bot(botname, args)
            self.bots_running[bot.username] = bot

Each bot is a protocol instance associated with its connection and gets a callback, data_received whenever something is received from the server. The bot also runs its own task for initiating its chattiness, as described above.

There is one more task - the monitor:

    async def monitor_status(self, display_stats):
        blinkers = [" ", ".", ":", "."]
        blinker_index = 0
        template = "{2} bots running, {3} logged in {4}"
        while True:
            await asyncio.sleep(1)
            if display_stats:
                print(template.format(
                    len(self.bots_running),
                    len(self.bots_logged_in),
                    blinkers[blinker_index]),
                    end="\r"
                )
            blinker_index += 1
            blinker_index %= len(blinkers)

            if len(self.bots_running) == 0:
                asyncio.get_event_loop().stop()
                return

If no bots are running, the loop is stopped.

Trying it out

The bots do their chatter in rooms named bot_room_0 through bot_room_9. Connect to the server with Swift (or your favorite chat client) and join one or more of those rooms to listen in. You can also run the jumperbot with a --verbose flag to see all the XMPP traffic in the log.