t.i.t.react(main, argv=(), _reactor=None) : function documentation

Call main and run the reactor until the Deferred it returns fires.

This is intended as the way to start up an application with a well-defined completion condition. Use it to write clients or one-off asynchronous operations. Prefer this to calling reactor.run directly, as this function will also:

• Take care to call reactor.stop once and only once, and at the right time.
• Log any failures from the Deferred returned by main.
• Exit the application when done, with exit code 0 in case of success and 1 in case of failure. If main fails with a SystemExit error, the code returned is used.

The following demonstrates the signature of a main function which can be used with react:

     def main(reactor, username, password):
         return defer.succeed('ok')

     task.react(main, ('alice', 'secret'))

Parameters	main	A callable which returns a Deferred. It should take the reactor as its first parameter, followed by the elements of argv.
	argv	A list of arguments to pass to main. If omitted the callable will be invoked with no additional arguments.
	_reactor	An implementation detail to allow easier unit testing. Do not supply this parameter.
Present Since	12.3