vinodMS / flask-redis-celery

flask-redis-celery

SETUP

1. Make sure you have docker installed on your computer
2. Pull the repository
3. Run docker-compose up from project directory
4. If all goes well, running docker ps should show all 3 containers up and running.
5. In your browser access http://127.0.0.1:5000/, if you see This is hello world, then you're all set.

DIRECTORY STRUCTURE & FILE CONTAINS

• api/ -- contains flask and celery app code.
  • app.py -- flask and celery app setup.
  • tasks.py -- simple celery tasks to demontrate some mathematical operations such as addition and subtraction.
  • batch_tasks.py -- advance celery tasks that demonstrates batch calculation tasks.
  • views.py -- contains flask routes that can be accessed via the api.
  • celeryconfig.py -- self explanatory.
  • calculator.py -- calculator class with some basic operations to be used by batch celery tasks.

FLASK ROUTES

	HTTP Methods	URL	Args	Celery Refs
1	GET	/		Check app status
2	POST	/basic-task	x:int, y:int	Signature
3	POST	/callback-task	x:int, y:int, z:int	Callback
4	POST	/chain-task	a:int, x:int, y:int, z:int	Chain
5	POST	/simple-chord-task	range:int	Chord
6	POST	/chord-task	range:int	Chord
7	POST	/batch-start		A route that performs a calculator operation in batches

TESTING

1. Use postman to test the API endpoints which will trigger the celery tasks.
2. Following screenshot shows an example postman session,

EXTEND & EXPERIMENT

Experimenting with a new celery task can be done in 3 steps.

Add a celery task

@celery.task()
def new_celery_task(a, b):
    return a + b

Add a route

@app.post('/new-task')
def new_route():
    x = 1
    y = 2
    result = new_celery_task.s(x, y).apply_async()
    return str(result.get())

Test task

1. Restart all three docker containers to make sure the new tasks and routes are registered.
2. Call the new route using postman.

TO:DO

1. Add an example of redis caching
2. Add an example of passing arguments that are not generic python data types
3. Add examples of other primitives (group, start, map, etc..)
4. Add unit and integration tests