How to run a simple load test on Geth Node

In this blog, I am going to share a simple code snippet that I have used to run a load tests on geth node. To get things done, I am using the locust python library, and to connect to get node, I am using web3 library. This piece of code finds 10 addresses at the initialization step. After initialization, it spawns a predefined number of users and tries to find the balance of 1 of those 10 addresses.

from functools import wraps
from time import time
from locust import events, task
from locust.user.users import User
from web3 import Web3
import random
def geth_locust_task(f):
    '''
    Simple timing wrapper which fires off the necessary
    success and failure events for locust.
    '''
    @wraps(f)
    def wrapped(*args, **kwargs):
        start_time = time()
        try:
            result = f(*args, **kwargs)
            print(result)
        except Exception as e:
            print('Exception in {}'.format(f.__name__))
            total_time = int((time() - start_time) * 1000)
            events.request_failure.fire(
                request_type="web3",
                name=f.__name__,
                response_time=total_time,
                exception=e)
            return False
        else:
            total_time = int((time() - start_time) * 1000)
            events.request_success.fire(
                request_type="web3",
                name=f.__name__,
                response_time=total_time,
                response_length=0)
        return result
    return wrapped
    
class GethUser(User):
    def __init__(self, *args, **kwargs):
        super(GethUser, self).__init__(*args, **kwargs)

        server = args[0].host
        self.client = Web3(Web3.HTTPProvider(server))



        c=1
        block='latest'
        self.addresses = []
        while c<10:
            
            tnx = self.client.eth.get_block(block)
            self.addresses.append(tnx.miner)
            block = tnx.parentHash
            c+=1

        print(self.addresses)
    @geth_locust_task
    @task
    def get_balance(self):
        target_addr = random.choice(self.addresses)
        bal = self.client.eth.get_balance(target_addr)
        return bal

Then you can run the tests using `locust -f locustfile.py`. It would run a server on port 8089. On browser you have to open localhost:8089 and then you have to provide the number of users you want to spawn, the spawn rate and the host of your geth node.

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