An easy to use Flask wrapper for concurrent.futures
Project description
Flask-Executor
Sometimes you need a simple task queue without the overhead of separate worker processes or powerful-but-complex libraries beyond your requirements. Flask-Executor is an easy to use wrapper for the concurrent.futures
module that lets you initialise and configure executors via common Flask application patterns. It's a great way to get up and running fast with a lightweight in-process task queue.
Installation
Flask-Executor is available on PyPI and can be installed with:
pip install flask-executor
Quick start
Here's a quick example of using Flask-Executor inside your Flask application:
from flask import Flask
from flask_executor import Executor
app = Flask(__name__)
executor = Executor(app)
def send_email(recipient, subject, body):
# Magic to send an email
return True
@app.route('/signup')
def signup():
# Do signup form
executor.submit(send_email, recipient, subject, body)
Contexts
When calling submit()
or map()
Flask-Executor will wrap ThreadPoolExecutor
callables with a
copy of both the current application context and current request context. Code that must be run in
these contexts or that depends on information or configuration stored in flask.current_app
,
flask.request
or flask.g
can be submitted to the executor without modification.
Note: due to limitations in Python's default object serialisation and a lack of shared memory space between subprocesses, contexts cannot be pushed to ProcessPoolExecutor()
workers.
Futures
You may want to preserve access to Futures returned from the executor, so that you can retrieve the results in a different part of your application. Flask-Executor allows Futures to be stored within the executor itself and provides methods for querying and returning them in different parts of your app::
@app.route('/start-task')
def start_task():
executor.submit_stored('calc_power', pow, 323, 1235)
return jsonify({'result':'success'})
@app.route('/get-result')
def get_result():
if not executor.futures.done('calc_power'):
return jsonify({'status': executor.futures._state('calc_power')})
future = executor.futures.pop('calc_power')
return jsonify({'status': done, 'result': future.result()})
Decoration
Flask-Executor lets you decorate methods in the same style as distributed task queues like Celery:
@executor.job
def fib(n):
if n <= 2:
return 1
else:
return fib(n-1) + fib(n-2)
@app.route('/decorate_fib')
def decorate_fib():
fib.submit(5)
fib.submit_stored('fibonacci', 5)
fib.map(range(1, 6))
return 'OK'
Default Callbacks
Future objects can have callbacks attached by using Future.add_done_callback
. Flask-Executor
lets you specify default callbacks that will be applied to all new futures created by the executor:
def some_callback(future):
# do something with future
executor.add_default_done_callback(some_callback)
# Callback will be added to the below task automatically
executor.submit(pow, 323, 1235)
Propagate Exceptions
Normally any exceptions thrown by background threads or processes will be swallowed unless explicitly checked for. To instead surface all exceptions thrown by background tasks, Flask-Executor can add a special default callback that raises any exceptions thrown by tasks submitted to the executor::
app.config['EXECUTOR_PROPAGATE_EXCEPTIONS'] = True
Documentation
Check out the full documentation at flask-executor.readthedocs.io!
Project details
Release history Release notifications | RSS feed
Download files
Download the file for your platform. If you're not sure which to choose, learn more about installing packages.
Source Distribution
Built Distribution
File details
Details for the file Flask-Executor-1.0.0.tar.gz
.
File metadata
- Download URL: Flask-Executor-1.0.0.tar.gz
- Upload date:
- Size: 8.5 kB
- Tags: Source
- Uploaded using Trusted Publishing? No
- Uploaded via: twine/4.0.1 CPython/3.10.5
File hashes
Algorithm | Hash digest | |
---|---|---|
SHA256 | 4bc113def5d9f1c7ff272ff7ba09f843468eab80469bdbd21625a111b2c8ae7b |
|
MD5 | 74fe23ed41b323fb712760315e70d7be |
|
BLAKE2b-256 | 689d48200aa3211148e1a250882e68be5a97a6a6995ff6d63aa1f9b32b5c6e35 |
File details
Details for the file Flask_Executor-1.0.0-py3-none-any.whl
.
File metadata
- Download URL: Flask_Executor-1.0.0-py3-none-any.whl
- Upload date:
- Size: 9.3 kB
- Tags: Python 3
- Uploaded using Trusted Publishing? No
- Uploaded via: twine/4.0.1 CPython/3.10.5
File hashes
Algorithm | Hash digest | |
---|---|---|
SHA256 | c044dc6393326a83351e69e4ddf3686270abffeac2b599260cebf0ea5d1e93de |
|
MD5 | 11e062696323360755f7d897497fd719 |
|
BLAKE2b-256 | ff2661bc021698eaaf8dc58861f3f88feabbe2bd2fb1bcec6402dd2b9a59cb96 |