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docs/src/backend/demo/management/commands/create_demo.py
Anthony LC f1227ed037 🚨(CI) fix linter backend
The linter in the CI was checking only the
impress directory. We were passing near some lint
issues. Now the linter checks the whole backend
directory.
2024-05-31 10:12:28 +02:00

160 lines
4.8 KiB
Python

# ruff: noqa: S311, S106
"""create_demo management command"""
import logging
import random
import time
from collections import defaultdict
from django import db
from django.conf import settings
from django.core.management.base import BaseCommand, CommandError
from faker import Faker
from core import models
fake = Faker()
logger = logging.getLogger("impress.commands.demo.create_demo")
def random_true_with_probability(probability):
"""return True with the requested probability, False otherwise."""
return random.random() < probability
class BulkQueue:
"""A utility class to create Django model instances in bulk by just pushing to a queue."""
BATCH_SIZE = 20000
def __init__(self, stdout, *args, **kwargs):
"""Define the queue as a dict of lists."""
self.queue = defaultdict(list)
self.stdout = stdout
def _bulk_create(self, objects):
"""Actually create instances in bulk in the database."""
if not objects:
return
objects[0]._meta.model.objects.bulk_create(objects, ignore_conflicts=False) # noqa: SLF001
# In debug mode, Django keeps query cache which creates a memory leak in this case
db.reset_queries()
self.queue[objects[0]._meta.model.__name__] = [] # noqa: SLF001
def push(self, obj):
"""Add a model instance to queue to that it gets created in bulk."""
objects = self.queue[obj._meta.model.__name__] # noqa: SLF001
objects.append(obj)
if len(objects) > self.BATCH_SIZE:
self._bulk_create(objects)
self.stdout.write(".", ending="")
def flush(self):
"""Flush the queue after creating the remaining model instances."""
for objects in self.queue.values():
self._bulk_create(objects)
class Timeit:
"""A utility context manager/method decorator to time execution."""
total_time = 0
def __init__(self, stdout, sentence=None):
"""Set the sentence to be displayed for timing information."""
self.sentence = sentence
self.start = None
self.stdout = stdout
def __call__(self, func):
"""Behavior on call for use as a method decorator."""
def timeit_wrapper(*args, **kwargs):
"""wrapper to trigger/stop the timer before/after function call."""
self.__enter__()
result = func(*args, **kwargs)
self.__exit__(None, None, None)
return result
return timeit_wrapper
def __enter__(self):
"""Start timer upon entering context manager."""
self.start = time.perf_counter()
if self.sentence:
self.stdout.write(self.sentence, ending=".")
def __exit__(self, exc_type, exc_value, exc_tb):
"""Stop timer and display result upon leaving context manager."""
if exc_type is not None:
raise exc_type(exc_value)
end = time.perf_counter()
elapsed_time = end - self.start
if self.sentence:
self.stdout.write(f" Took {elapsed_time:g} seconds")
self.__class__.total_time += elapsed_time
return elapsed_time
def create_demo(stdout):
"""
Create a database with demo data for developers to work in a realistic environment.
The code is engineered to create a huge number of objects fast.
"""
queue = BulkQueue(stdout)
with Timeit(stdout, "Creating Template"):
with open(
file="demo/data/template/code.txt", mode="r", encoding="utf-8"
) as text_file:
code_data = text_file.read()
with open(
file="demo/data/template/css.txt", mode="r", encoding="utf-8"
) as text_file:
css_data = text_file.read()
queue.push(
models.Template(
title="Demo Template",
description="This is the demo template",
code=code_data,
css=css_data,
is_public=True,
)
)
queue.flush()
class Command(BaseCommand):
"""A management command to create a demo database."""
help = __doc__
def add_arguments(self, parser):
"""Add argument to require forcing execution when not in debug mode."""
parser.add_argument(
"-f",
"--force",
action="store_true",
default=False,
help="Force command execution despite DEBUG is set to False",
)
def handle(self, *args, **options):
"""Handling of the management command."""
if not settings.DEBUG and not options["force"]:
raise CommandError(
(
"This command is not meant to be used in production environment "
"except you know what you are doing, if so use --force parameter"
)
)
create_demo(self.stdout)