Building Your Bot

This guide walks through the process of coding a bot, and assumes that you have gone through the setup steps that can be found in the README.md file on the main page of this project.

Once you've downloaded the git repository (see README.md) then you'll have a genghis_client directory, with some files inside:

• get_started.py - This script will register you with a genghis server, so that you can fight against the other bots on that server (you've already done this)
• config.json - Tells the server where to find your bot script (and other things)
• template_bot.py - This is where you code your bot!
• template_battleground.py - You can also customise a battleground, which defines the terrain that your bot will fight on.

So, to code your bot you need to edit the template_bot.py file. The Genghis server will run your bot (and others) over and over again, providing you with information about the game (like the battlegrounds available, where the other bots are, where the coins are, etc).

The Genghis Server expects your script to take this information, calculate a move, and then write that move to a file called move.json.

Making a simple bot

Create a new file called hello_genghis.py in the genghis_client directory, and open the file in a text editor. To start, we'll need the json python library for writing to a JSON file, and the random python library will let us choose a direction to move at random:

import json
import random

Next we're going to open our move.json file in w+ (write) mode:

with open('move.json',  'w+') as json_file:
    ...

Now create a python dictionary to hold our move:

    my_move_dictionary = {
        "action": "walk",        
        "direction": random.choice(['l', 'r', 'u', 'd'])    
    }

The 'action' item specifies if you're walking, attacking, etc. The 'direction' item specifies in which direction you want to walk, attack, etc. For now, just walk in a random direction, either left 'l', right 'r', up 'u' or down 'd'.

Finally, actually write our move to a json file (setting indent=2 gives it nice formatting):

    json.dump(my_move_dictionary, json_file, indent=2)

And that's it! The full code is here:

import json
import random
with open('move.json',  'w+') as json_file:
    my_move_dictionary = {
        "action": "walk",        
        "direction": random.choice(['l', 'r', 'u', 'd'])    
    }
    json.dump(my_move_dictionary, json_file, indent=2)

That's your bot done! Except the server doesn't know that the script exists yet. To fix this, we need to edit the file called config.json.

We want to add the path to hello_genghis.py inside config.json so that the server can read config.json, and then find our script. To do this, open config.json and change the file from looking something like this:

...
  "bots": [
    {
      "path": "template_bot.py",
      "name": "template bot"
    }
  ],
...

to look like this:

...
  "bots": [
    {
      "path": "template_bot.py",
      "name": "template bot"
    }, {
      "path": "hello_genghis.py",
      "name": "my first bot"
    }
  ],
...

So now the full config.json file looks something like this (yours might look slightly different):

{
  "bots": [
    {
      "path": "template_bot.py",
      "name": "template bot"
    }, {
      "path": "hello_genghis.py",
      "name": "my first bot"
    }
  ],
  "battlegrounds": [
    {
      "path": "template_battleground.txt",
      "name": "template battleground"
    }
  ],
  "username": "<MY USERNAME>",
  "abbreviations": [
    "a"
  ],
  "url": "https://people.cs.uct.ac.za/~<MY STUDENT NUMBER>/genghis_client",
  "server_url": "https://people.cs.uct.ac.za/~KNXBOY001/genghis_server/"
}

That's it! go to https://people.cs.uct.ac.za/~KNXBOY001/genghis_server/ to watch your bot in the next battle. Battles happen every 10 minutes, on the 10th minute (like at 10 past, 20 past, etc)

This is okay, but your bot isn't very smart. To get it doing something fancier, we need to learn about our options for what to put in move.json:

Options for bot actions

"action": "walk"

Causes your bot to walk into one of the 8 cells adjacent to it, as specified by 'direction' which can be one of l, r, u, d, ul, ur, dl, dr (order doesn't matter).

Attempting to move into a wall (#) or another bot (A through to Z) will result in a null move (nothing happening).

Walking into a port (1 through to 9) will cause your bot to be moved through the port to the battleground on the other side of the port. Every battleground can be reached from every other battleground, although some routes may be faster than others.

Walking into a coin (a through to z) will add that coin to your bots inventory. Coins are a measure of success, so collect them all.

"action": "attack"

Causes your bot to attack one of the 8 cells adjacent to it, as specified by 'direction' which can be one of l, r, u, d, ul, ur, dl, dr (order doesn't matter). You can only attack other bots (A through to Z), attempting to attack anything else will result in a null move (nothing happening).

When your bot makes a legal attack on a bot, the attack can either hit or miss (50% chance either way).

If an attack misses, nothing happens and your turn is over. If the attack hits, then your opponent will instantly drop one coin (chosen at random) onto an adjacent block to itself.

This block must either be another bot (such as yourself), or be an air block. If the block is a bot, then that coin is immediately added to that bot's inventory.

"action": "drop"

Causes your bot to drop a coin onto one of the 8 cells adjacent to it, as specified by 'direction' which can be one of l, r, u, d, ul, ur, dl, dr, and 'type' which defines which coin to drop, and must be one of a through z.

You may only drop coins you have, and you may only drop onto other bots (A through to Z) or onto empty air blocks ' '. Anything else will result in a null move (nothing happening).

A slightly improved hello_genghis.py

With our newfound knowledge, we can update hello_genghis.py to either make a random move, or a random attack, or randomly drop a coin:

import json
import random
with open('move.json',  'w+') as json_file:
    my_move_dictionary = {
        "action": random.choice(['walk', 'attack', 'drop']),        
        "direction": random.choice(['l', 'r', 'u', 'd', 'lu', 'ru', 'ld', 'rd'])    
        # 'type' will be ignored if action != 'drop'
        "type": random.choice([chr(i) for i in range(ord('a'), ord('z') + 1)])    
    }
    json.dump(my_move_dictionary, json_file, indent=2)

This is all well and good, but our bot still isn't smart. For this, we need to know about our surroundings, like where the other bots / coins / ports are, and how to get to them:

Figuring out your move