multitasking 0.0.13

✨ What’s New in v0.0.12

• 🎯 Full Type Hint Support: Complete type annotations for better IDE support and code safety

• 📚 Enhanced Documentation: Comprehensive docstrings and inline comments for better maintainability

• 🔧 Improved Error Handling: More robust exception handling with specific error types

• 🚀 Better Performance: Optimized task creation and management logic

• 🛡️ Code Quality: PEP8 compliant, linter-friendly codebase

Quick Start

import multitasking
import time

@multitasking.task
def fetch_data(url_id):
    # Simulate API call or I/O operation
    time.sleep(1)
    return f"Data from {url_id}"

# These run concurrently, not sequentially!
for i in range(5):
    fetch_data(i)

# Wait for all tasks to complete
multitasking.wait_for_tasks()
print("All data fetched!")

Basic Example

# example.py
import multitasking
import time
import random
import signal

# Kill all tasks on ctrl-c (recommended for development)
signal.signal(signal.SIGINT, multitasking.killall)

# Or, wait for tasks to finish gracefully on ctrl-c:
# signal.signal(signal.SIGINT, multitasking.wait_for_tasks)

@multitasking.task  # <== this is all it takes! 🎉
def hello(count):
    sleep_time = random.randint(1, 10) / 2
    print(f"Hello {count} (sleeping for {sleep_time}s)")
    time.sleep(sleep_time)
    print(f"Goodbye {count} (slept for {sleep_time}s)")

if __name__ == "__main__":
    # Launch 10 concurrent tasks
    for i in range(10):
        hello(i + 1)

    # Wait for all tasks to complete
    multitasking.wait_for_tasks()
    print("All tasks completed!")

Output:

$ python example.py

Hello 1 (sleeping for 0.5s)
Hello 2 (sleeping for 1.0s)
Hello 3 (sleeping for 5.0s)
Hello 4 (sleeping for 0.5s)
Hello 5 (sleeping for 2.5s)
Hello 6 (sleeping for 3.0s)
Hello 7 (sleeping for 0.5s)
Hello 8 (sleeping for 4.0s)
Hello 9 (sleeping for 3.0s)
Hello 10 (sleeping for 1.0s)
Goodbye 1 (slept for 0.5s)
Goodbye 4 (slept for 0.5s)
Goodbye 7 (slept for 0.5s)
Goodbye 2 (slept for 1.0s)
Goodbye 10 (slept for 1.0s)
Goodbye 5 (slept for 2.5s)
Goodbye 6 (slept for 3.0s)
Goodbye 9 (slept for 3.0s)
Goodbye 8 (slept for 4.0s)
Goodbye 3 (slept for 5.0s)
All tasks completed!

Real-World Examples

Web Scraping with Concurrent Requests:

import multitasking
import requests
import signal

signal.signal(signal.SIGINT, multitasking.killall)

@multitasking.task
def fetch_url(url):
    try:
        response = requests.get(url, timeout=10)
        print(f"✅ {url}: {response.status_code}")
        return response.text
    except Exception as e:
        print(f"❌ {url}: {str(e)}")
        return None

# Fetch multiple URLs concurrently
urls = [
    "https://httpbin.org/delay/1",
    "https://httpbin.org/delay/2",
    "https://httpbin.org/status/200",
    "https://httpbin.org/json"
]

for url in urls:
    fetch_url(url)

multitasking.wait_for_tasks()
print(f"Processed {len(urls)} URLs concurrently!")

Database Operations:

import multitasking
import sqlite3
import time

@multitasking.task
def process_batch(batch_id, data_batch):
    # Simulate database processing
    conn = sqlite3.connect(f'batch_{batch_id}.db')
    # ... database operations ...
    conn.close()
    print(f"Processed batch {batch_id} with {len(data_batch)} records")

# Process multiple data batches concurrently
large_dataset = list(range(1000))
batch_size = 100

for i in range(0, len(large_dataset), batch_size):
    batch = large_dataset[i:i + batch_size]
    process_batch(i // batch_size, batch)

multitasking.wait_for_tasks()

Pool Management

MultiTasking uses execution pools to manage concurrent tasks. You can create and configure multiple pools for different types of operations:

import multitasking

# Create a pool for API calls (higher concurrency)
multitasking.createPool("api_pool", threads=20, engine="thread")

# Create a pool for CPU-intensive tasks (lower concurrency)
multitasking.createPool("cpu_pool", threads=4, engine="process")

# Switch between pools
multitasking.use_tag("api_pool")  # Future tasks use this pool

@multitasking.task
def api_call(endpoint):
    # This will use the api_pool
    pass

# Get pool information
pool_info = multitasking.getPool("api_pool")
print(f"Pool: {pool_info}")  # {'engine': 'thread', 'name': 'api_pool', 'threads': 20}

Task Monitoring

Monitor and control your tasks with built-in functions:

import multitasking
import time

@multitasking.task
def long_running_task(task_id):
    time.sleep(2)
    print(f"Task {task_id} completed")

# Start some tasks
for i in range(5):
    long_running_task(i)

# Monitor active tasks
while multitasking.get_active_tasks():
    active_count = len(multitasking.get_active_tasks())
    total_count = len(multitasking.get_list_of_tasks())
    print(f"Progress: {total_count - active_count}/{total_count} completed")
    time.sleep(0.5)

print("All tasks finished!")

Thread/Process Limits

The default maximum threads equals the number of CPU cores. You can customize this:

import multitasking

# Set maximum concurrent tasks
multitasking.set_max_threads(10)

# Scale based on CPU cores (good rule of thumb for I/O-bound tasks)
multitasking.set_max_threads(multitasking.config["CPU_CORES"] * 5)

# Unlimited concurrent tasks (use carefully!)
multitasking.set_max_threads(0)

Execution Engine Selection

Choose between threading and multiprocessing based on your use case:

import multitasking

# For I/O-bound tasks (default, recommended for most cases)
multitasking.set_engine("thread")

# For CPU-bound tasks (avoids GIL limitations)
multitasking.set_engine("process")

When to use threads vs processes:

• Threads (default): Best for I/O-bound tasks like file operations, network requests, database queries

• Processes: Best for CPU-intensive tasks like mathematical computations, image processing, data analysis

Advanced Pool Configuration

Create specialized pools for different workloads:

import multitasking

# Fast pool for quick API calls
multitasking.createPool("fast_api", threads=50, engine="thread")

# CPU pool for heavy computation
multitasking.createPool("compute", threads=2, engine="process")

# Unlimited pool for lightweight tasks
multitasking.createPool("unlimited", threads=0, engine="thread")

# Get current pool info
current_pool = multitasking.getPool()
print(f"Using pool: {current_pool['name']}")

Performance Tips

1. Choose the right engine: Use threads for I/O-bound tasks, processes for CPU-bound tasks

2. Tune thread counts: Start with CPU cores × 2-5 for I/O tasks, CPU cores for CPU tasks

3. Use pools wisely: Create separate pools for different types of operations

4. Monitor memory usage: Each thread/process consumes memory

5. Handle exceptions: Always wrap risky operations in try-catch blocks

Error Handling

import multitasking
import requests

@multitasking.task
def robust_fetch(url):
    try:
        response = requests.get(url, timeout=10)
        response.raise_for_status()
        return response.json()
    except requests.exceptions.Timeout:
        print(f"⏰ Timeout fetching {url}")
    except requests.exceptions.RequestException as e:
        print(f"❌ Error fetching {url}: {e}")
    except Exception as e:
        print(f"💥 Unexpected error: {e}")
    return None

Resource Management

import multitasking
import signal

# Graceful shutdown on interrupt
def cleanup_handler(signum, frame):
    print("🛑 Shutting down gracefully...")
    multitasking.wait_for_tasks()
    print("✅ All tasks completed")
    exit(0)

signal.signal(signal.SIGINT, cleanup_handler)

# Your application code here...

Common Issues

Tasks not running concurrently? Check if you’re calling wait_for_tasks() inside your task loop instead of after it.

High memory usage? Reduce the number of concurrent threads or switch to a process-based engine.

Tasks hanging? Ensure your tasks can complete (avoid infinite loops) and handle exceptions properly.

Import errors? Make sure you’re using Python 3.6+ and have installed the latest version.

Debugging

import multitasking

# Enable task monitoring
active_tasks = multitasking.get_active_tasks()
all_tasks = multitasking.get_list_of_tasks()

print(f"Active: {len(active_tasks)}, Total: {len(all_tasks)}")

# Get current pool configuration
pool_info = multitasking.getPool()
print(f"Current pool: {pool_info}")

Decorators

• @multitasking.task - Convert function to asynchronous task

Configuration Functions

• set_max_threads(count) - Set maximum concurrent tasks

• set_engine(type) - Choose “thread” or “process” engine

• createPool(name, threads, engine) - Create custom execution pool

Task Management

• wait_for_tasks(sleep=0) - Wait for all tasks to complete

• get_active_tasks() - Get list of running tasks

• get_list_of_tasks() - Get list of all tasks

• killall() - Emergency shutdown (force exit)

Pool Management

• getPool(name=None) - Get pool information

• createPool(name, threads=None, engine=None) - Create new pool