Redis-Celery

Redis-Celery (Distributed Architecture)

This includes

• Redis
• Flower

Usage (docker-compose)

• start the system

  add ``` -d ``` run in background  
  * down the system   
  ctrl-c or  
  

  docker-compose down ```

Celery

Celery Documentation
Flower Documentation

install "celery"

### Starting the worker

shell celery -A proj worker

#### Options
Worker Options:
  * -n, --hostname HOSTNAME         Set custom hostname (e.g., 'w1@%%h').  
                                    Expands: %%h (hostname), %%n (name) and %%d, (domain).
  * -D, --detach                    Start worker as a background process.
  * -S, --statedb PATH              Path to the state database. The extension
                                  '.db' may be appended to the filename.
  * -l, --loglevel [DEBUG|INFO|WARNING|ERROR|CRITICAL|FATAL]
                                    Logging level.
  * -O, --optimization [default|fair]
                                    Apply optimization profile.
  * --prefetch-multiplier <prefetch multiplier>
                                    Set custom prefetch multiplier value for
                                    this worker instance.
Pool Options:
  * -c, --concurrency <concurrency> 
                                    Number of child processes processing the  
                                    queue.  The default is the number of CPUs  
                                    available on your system.  

celery worker --help ``` can get more infomation.

woker in Windows

add --pool=solo option

Calling the task

>>> from tasks import add
>>> add.hello()

If your celery app set rsult backend

>>> from tasks import add  
>>> result = add.hello()

The ready() method returns whether the task has finished processing or not:

>>> result.ready()
>>> False

You can wait for the result to complete, but this is rarely used since it turns the asynchronous call into a synchronous one:

>>> result.get(timeout=1)
>>> 'hello world'