check if it makes sense to add callbacks functionality

[dbarrosop]

on_error and on_success for the run method that is.

[dbarrosop]

Not sure how useful the on_success is:

Assuming:

def something_else(result):
    if result.changed:
        print("I feel different")
    else:
        print("I feel the same")

You could do either:

def my_task(task):
    r = do_something(...)
    do_something_else(r)

brigade.run(my_task)

Or

def my_task(task):
    r = do_something(...)
    return r

brigade.run(my_task, on_success=something_else)

And both would actually do the same. I actually feel on_success would be more rigid and hard to read. With a direct call I have full control of the arguments so I can do:

def reload_service(result, service):
   if result.changed:
          reload(service)

def deploy_apache(task):
    r = do_something(...)
    reload_service(r, service="apache")

def deploy_mysql(task):
    r = do_something(...)
    reload_service(r, service="mysql")


brigade.run(deploy_apache)
brigade.run(deploy_mysql)

I think on_error is more interesting though as it would let you handle tasks that failed in an uncontrolled manner. For example, you could log an error and print something on the screen or ask the user to cancel the execution or move forward ignoring the error.

[dbarrosop]

I don't think we need this.