futurist/doc/source/examples.rst

Examples

Creating and using a synchronous executor

# NOTE: enable printing timestamp for additional data

import sys import futurist import eventlet

def delayed_func():

print("started") eventlet.sleep(3) print("done")

#print(datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")) e = futurist.SynchronousExecutor() fut = e.submit(delayed_func) eventlet.sleep(1) print("Hello") eventlet.sleep(1) e.shutdown() #print(datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"))

Expected output:

started done Hello

Creating and using a green thread-based executor

# NOTE: enable printing timestamp for additional data

import sys import futurist import eventlet

def delayed_func():

print("started") eventlet.sleep(3) print("done")

#print(datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S")) e = futurist.GreenThreadPoolExecutor() fut = e.submit(delayed_func) eventlet.sleep(1) print("Hello") eventlet.sleep(1) e.shutdown() #print(datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"))

Expected output:

started Hello done

Creating and using a thread-based executor

import time

import futurist

def delayed_func():

time.sleep(0.1) return "hello"

e = futurist.ThreadPoolExecutor() fut = e.submit(delayed_func) print(fut.result()) e.shutdown()

Expected output:

hello

Creating and using a process-based executor

import time

import futurist

def delayed_func():
    time.sleep(0.1)
    return "hello"

e = futurist.ProcessPoolExecutor()
fut = e.submit(delayed_func)
print(fut.result())
e.shutdown()

Expected output:

hello

Running a set of functions periodically

import futurist from futurist import periodics

import time import threading

@periodics.periodic(1) def every_one(started_at): print("1: %s" % (time.time() - started_at))

@periodics.periodic(2) def every_two(started_at): print("2: %s" % (time.time() - started_at))

@periodics.periodic(4) def every_four(started_at): print("4: %s" % (time.time() - started_at))

@periodics.periodic(6) def every_six(started_at): print("6: %s" % (time.time() - started_at))

started_at = time.time() callables = [ # The function to run + any automatically provided positional and # keyword arguments to provide to it everytime it is activated. (every_one, (started_at,), {}), (every_two, (started_at,), {}), (every_four, (started_at,), {}), (every_six, (started_at,), {}), ] w = periodics.PeriodicWorker(callables)

# In this example we will run the periodic functions using a thread, it # is also possible to just call the w.start() method directly if you do # not mind blocking up the current program. t = threading.Thread(target=w.start) t.daemon = True t.start()

# Run for 10 seconds and then stop. while (time.time() - started_at) <= 10: time.sleep(0.1) w.stop() w.wait() t.join()

...

Running a set of functions periodically (using an executor)

import futurist from futurist import periodics

import time import threading

@periodics.periodic(1) def every_one(started_at): print("1: %s" % (time.time() - started_at)) time.sleep(0.5)

@periodics.periodic(2) def every_two(started_at): print("2: %s" % (time.time() - started_at)) time.sleep(1)

@periodics.periodic(4) def every_four(started_at): print("4: %s" % (time.time() - started_at)) time.sleep(2)

@periodics.periodic(6) def every_six(started_at): print("6: %s" % (time.time() - started_at)) time.sleep(3)

started_at = time.time() callables = [ # The function to run + any automatically provided positional and # keyword arguments to provide to it everytime it is activated. (every_one, (started_at,), {}), (every_two, (started_at,), {}), (every_four, (started_at,), {}), (every_six, (started_at,), {}), ]

# To avoid getting blocked up by slow periodic functions we can also # provide a executor pool to make sure that slow functions only block # up a thread (or green thread), instead of blocking other periodic # functions that need to be scheduled to run. executor_factory = lambda: futurist.ThreadPoolExecutor(max_workers=2) w = periodics.PeriodicWorker(callables, executor_factory=executor_factory)

# In this example we will run the periodic functions using a thread, it # is also possible to just call the w.start() method directly if you do # not mind blocking up the current program. t = threading.Thread(target=w.start) t.daemon = True t.start()

# Run for 10 seconds and then stop. while (time.time() - started_at) <= 10: time.sleep(0.1) w.stop() w.wait() t.join()

...