- sheraf.transactions.attempt(function, attempts=5, commit=<function <lambda>>, log_exceptions=True, args=None, kwargs=None, also_except=None, on_failure=<function <lambda>>)
This method attemps to execute a function several times until no ConflictError is encountered.
function – The function to execute.
args – The positionnal arguments to pass to the function.
kwargs – The keyword arguments to pass to the function.
attempts – The number of attempts.
commit – An executable returning a boolean indicating wether to commit after executing function.
log_exceptions – A boolean indicating wether to log exceptions.
also_except – A tuple containing exception classes. If one of those exceptions is catched during the attempt, a new execution will be attempted.
on_failure – Callback called after each failed attempt except the last one. By default it waits a random time between 0 and attempts. The callback takes one argument
The return value of function.
>>> with sheraf.connection(): ... try: ... sheraf.attempt(do_amazing_stuff, attempts=5, args=("DANGER",)) ... except ZODB.POSException.ConflictError: ... print("Impossible to commit do_amazing_stuff after 5 attempts.") ... >>> with sheraf.connection(): ... try: ... sheraf.attempt(lambda: 1/0, also_except=(ZeroDivisionError,)) ... except ZeroDivisionError: ... print("This has very few chances to be successful ¯\\_(ツ)_/¯") This has very few chances to be successful ¯\_(ツ)_/¯
Wrapper shortcut for
>>> class Cowboy(sheraf.Model): ... table = "cowboy" ... dead = sheraf.BooleanAttribute(default=False) ... >>> @sheraf.commit ... def fight(winner, loser): ... loser.dead = True ... >>> with sheraf.connection(commit=True): ... winner = Cowboy.create() ... loser = Cowboy.create() ... >>> with sheraf.connection(): ... fight(winner, loser) ... >>> with sheraf.connection(): ... Cowboy.read(loser.id).dead True