Python Worker Dispatcher

A flexible task dispatcher for Python with multiple threading or processing control

Features

• Tasks Dispatching to managed workers

• Elegant Interface for setup and use

• Various modes to choose from

---

OUTLINE

• Demonstration
• Introduction
• Installation
• Usage
  • Options
    • task.callback
    • task.result_callback
  • Other Methods
    • get_results()
    • get_logs()
    • get_result_info()
    • get_tps()
  • Scenarios
    • Stress Test

---

DEMONSTRATION

Just write your own callback functions using the library, then run it and collect the result details:

$ python3 main.py

Worker Dispatcher Configutation:
- Local CPU core: 10
- Tasks Count: 100
- Runtime: Unlimited
- Dispatch Mode: Fixed Workers (Default)
- Workers Info:
  └ Worker Type: Processing
  └ Number of Workers : 10
  └ Max Worker: 10

--- Start to dispatch workers at 2024-06-14T17:46:30.996685+08:00 ---

...(User-defined output)...

--- End of worker dispatch at 2024-06-14T17:46:41.420888+08:00---

Spend Time: 10.424203 sec
Completed Tasks Count: 100
Uncompleted Tasks Count: 0
Undispatched Tasks Count: 0

Use 20 theads concurrently to dispatch tasks for HTTP reqeusts

import worker_dispatcher
import requests

def each_task(id: int, config, task, log):
    response = requests.get(config['my_endpoint'] + task)
    return response

responses = worker_dispatcher.start({
    'task': {
        'list': ['ORD_AH001', 'ORD_KL502', '...' , 'ORD_GR393'],
        'callback': each_task,
        'config': {
            'my_endpoint': 'https://your.name/order-handler/'
        },
    },
    'worker': {
        'number': 20,
    }
})

Utilizes all CPU cores on the machine to compute tasks.

import worker_dispatcher

def each_task(id: int, config, task, log):
    result = sum(id * i for i in range(10**9))
    return result

if __name__ == '__main__':
    results = worker_dispatcher.start({
        'task': {
            'list': 10,
            'callback': each_task,
        },
        'worker': {   
            'use_processing': True
        }
    })

---

INTRODUCTION

This library helps to efficiently consume tasks by using multiple threading or processing and returns all results jointly.

---

INSTALLATION

To install the current release:

$ pip install worker-dispatcher

---

USAGE

By calling the start() methid with the configuration parameter, the package will begin dispatching tasks while managing threading or processing based on the provided settings. Once the tasks are completed, the package will return all the results.

An example configuration setting with all options is as follows:

import worker_dispatcher 

results = worker_dispatcher.start({
    'debug': False,
    'task': {
        'list': [],                     # Support list and integer. Integer represent the number of tasks to be generated.
        'callback': callback_sample,
        'config': {},
        'result_callback': False
    },
    'worker': {
        'number': 8,
        'frequency_mode': {             # Changing from assigning tasks to a fixed number of workers once, to assigning tasks and workers frequently.
            'enabled': False, 
            'interval': 1,              # The second(s) of interval
            'accumulated_workers': 0,   # Accumulate the number of workers for each interval for next dispatch.
            'max_workers': None,        # limit the maximum number of workers to prevent system exhaustion.
        },
        'use_processing': False,        # To break GIL, workers will be based on processing pool.
        'parallel_processing': {        # To break GIL and require a number of workers greater than the number of CPU cores.
            'enabled': False,           # `worker.use_processing` setting will be ignored when enabled. The actual number of workers will be adjusted to a multiple of the CPU core count.
            'use_queue': False,         # Enable a task queue to specify the number of workers without adjustment, though the maximum may be limited by your device.
        },   
    },
    'runtime': None,                    # Dispatcher max runtime in seconds
    'verbose': True
})

Options

Option	Type	Deafult	Description
debug	bool	False	Debug mode
task.list	multitype	list	The tasks for dispatching to each worker. * - List: Each value will be passed as a parameter to your callback function. - Integer: The number of tasks to be generated.
task.callback	callable	(sample)	The callback function called by each worker runs
task.config	multitype	list	The custom variable to be passed to the callback function
task.result_callback	callable	Null	The callback function called when each task processes the result
worker.number	int	(auto)	The number of workers to fork. (The default value is the number of local CPU cores)
worker.frequency_mode.enabled	bool	False	Changing from assigning tasks to a fixed number of workers once, to assigning tasks and workers frequently.
worker.frequency_mode.interval	float	1	The second(s) of interval.
worker.frequency_mode.accumulated_workers	int	0	Accumulate the number of workers for each interval for next dispatch.
worker.frequency_mode.max_workers	int	None	limit the maximum number of workers to prevent system exhaustion.
worker.use_processing	boolean	False	To break GIL, workers will be based on processing pool.
worker.parallel_processing.enabled	bool	False	worker.use_processing setting will be ignored when enabled. The actual number of workers will be adjusted to a multiple of the CPU core count.
worker.parallel_processing.use_queue	bool	False	Enable the use of a task queue instead of task dispatch, which allows specifying the number of workers but may be limited by your device.
runtime	float	None	Dispatcher max runtime in seconds.
verbose	bool	True	Enables or disables verbose mode for detailed output.

task.callback

The callback function called by each worker runs

callback_function (id: int, config, task, log: dict)

Argument	Type	Deafult	Description
id	int	(auto)	The sequence number generated by each task starting from 1
config	multitype	{}	The custom variable to be passed to the callback function
task	multitype	(custom)	Each value from the task.list
log	dict	{}	The log from each task written by this callback function.

task.result_callback

The callback function called when each task processes the result

result_callback_function (id: int, config, result, log: dict)

Argument	Type	Deafult	Description
id	int	(auto)	The sequence number generated by each task starting from 1
config	multitype	{}	The custom variable to be passed to the callback function
result	multitype	(custom)	Each value returned back from task.callback
log	dict	(auto)	Reference: get_logs()

Other Methods

• get_results()

  Get all results in list type after completing start()

• get_logs()

  Get all logs in list type after completing start()

  Each log is of type dict, containing the results of every task processed by the worker:

  • task_id
  • started_at
  • ended_at
  • duration
  • result

• get_result_info()

  Get a dict with the whole spending time and started/ended timestamps after completing start()

• get_tps()

  Get TPS report in dict type after completing start() or by passing a list data.

  def get_tps(logs: dict=None, debug: bool=False, interval: float=0, reverse_interval: bool = False, display_intervals: bool = False) -> dict:

  The log dict matches the format of the get_logs() and refers to it by default. Each result of a log will be considered valid if it meets one of the following conditions:

  • It is a requests.Response object with a status code of 200
  • It is a valid value other than the aforementioned object

Scenarios

Stress Test

Perform a stress test scenario with 10 requests per second.

import worker_dispatcher, requests

def each_task(id, config, task, log):
    response = None
    try:
        response = requests.get(config['my_endpoint'], timeout=(5, 10))
    except requests.exceptions.RequestException as e:
        print("An error occurred:", e)
    return response

responses = worker_dispatcher.start({
    'task': {
        'list': 5000,
        'callback': each_task,
        'config': {
            'my_endpoint': 'https://your.name/api'
        },
    },
    'worker': {
        'number': 10,
        'frequency_mode': {
            'enabled': True, 
            'interval': 1,
        },
    }
})

print(worker_dispatcher.get_logs())
print(worker_dispatcher.get_tps())