PyBackground 0.1.2

A lightweight scheduler that runs tasks in the background

PyBackground

PyBackground is

• a lightweight scheduler that runs tasks in the background
• written in Python (3.7+) Standard Library

PyBackground supports to

• execute tasks using thread pool
• run in the background (or foreground)
• use @task decorator to define task

Quickstart

Define your functions:

import time

def now(cost=1):
    time.sleep(cost)
    print( time.strftime('%Y-%m-%d %H:%M:%S %Z', time.localtime()) )

def utcnow(cost=1):
    time.sleep(cost)
    print( time.strftime('%Y-%m-%d %H:%M:%S %Z', time.gmtime()) )

Create a PyBackground scheduler and start executing your functions:

import pybackground

sched = pybackground.BackgroundScheduler()
sched.start(now, args=(1,))
sched.start(utcnow, args=(1,))

Shutdown the scheduler:

sched.shutdown(wait=True)

Handle with the infinite loops

Let's work based on now(cost) as an example:

import pybackground

sched = pybackground.BackgroundScheduler()
print(sched.stopped)

def timer(interval=3):
    while not sched.stopped:
        now()

sched.start(timer, args=(3,))

timer(interval) then runs forever in a seperate thread. When you'd like to terminate it, shutdown the scheduler as usual:

sched.shutdown(wait=True)

Play with the @task decorator

Use @task decorator to define your functions and start executing them, scheduling now(cost) and utcnow(cost) as an example:

import pybackground

sched = pybackground.BackgroundScheduler()

import time

@pybackground.task(sched)
def now(cost=1):
    time.sleep(cost)
    print( time.strftime('%Y-%m-%d %H:%M:%S %Z', time.localtime()) )

now.start(cost=1)

@pybackground.task(sched)
def utcnow(cost=1):
    time.sleep(cost)
    print( time.strftime('%Y-%m-%d %H:%M:%S %Z', time.gmtime()) )

utcnow.start(cost=1)

Shutdown the scheduler in normal way:

sched.shutdown(wait=True)

Install PyBackground

$ pip install pybackground

Documentation

BackgroundScheduler/BlockingScheduler

class pybackground.BackgroundScheduler/BlockingScheduler(max_worker=<num_cpu_cores>)

max_worker is set for ThreadPoolExecutor, default value is the number of CPU cores.

• stopped

  The scheduler is stopped or not, True (default) or False.

• latest_id

  The latest task id, which may be useful for pybackground.BlockingScheduler.

• task

  The task id, Task object (collections.namedtuple('Task', 'fn, args, kwargs')) dictionary, {} as default.

• future

  The task id, Future object dictionary, {} as default.

• start(fn, args=(), kwargs={})

  Let scheduler start executing your function using thread pool in the background (or foreground). It returns corresponding task id.

• shutdown(wait=True)

  Shutdown the scheduler.

task

class pybackground.task(scheduler)

• Use @task decorator to define your functions and start executing them:

  @task(scheduler)
  def fn(args, kwargs):
      pass
  
  fn.start(*args, **kwargs)
  

  fn.start(*args, **kwargs) is equivaluent to sheduler.start(fn, args, kwargs) using normal function definition.

Related Projects

• APScheduler (apscheduler.readthedocs.org)