logfile is erroniously written when there are many workers.

[clint-qrypt]

Prerequisites

• [X] I am using the latest version of Locust
• [X] I am reporting a bug, not asking a question

Description

When using processes = -1 in the locust.conf file and 12 or more workers are running, the logfile is getting crushed by all the simultaneous writes. Data is being inserted in the middle of writes from other workers, and a lot of missing newlines.

Command line

locust

Locustfile contents

self.client.post(
   "/api/v1/entropy",
   name="entropy" + "/" + TEST_CASE.name,
   headers=self.headers,
   json=TEST_CASE.value,
   timeout=90,
)

#conf file
host = http://localhost    # uncomment this for local dev env testing
users = 300
spawn-rate = 25
processes = -1
csv = results/300VUs-32B-Soak-Test
only-summary = true
run-time = 36h
headless = true

Python version

3.10

Locust version

2.31.8

Operating system

Ubuntu 22.04

[clint-qrypt]

[cyberw]

I'm guessing you wouldn't want workers to write to the csv file at all and only have the master do it? I've added a fix for that, feel free to try it out.