Fibers, yields and cooperative multitasking
But wait! If we launch it as shown above – self.respawn() – the function will be executed only once, just like all the other methods. But we need to execute respawn() every 60 seconds. Creating a fiber is the Tarantool way of making application logic work in the background at all times.
A fiber is a set of instructions that are executed with cooperative multitasking: the instructions contain yield signals, upon which control is passed to another fiber.
Let’s launch respawn() in a fiber to make it work in the background all the time. To do so, we’ll need to amend respawn():
respawn = function(self) -- let's give our fiber a name; -- this will produce neat output in fiber.info() fiber.name('Respawn fiber') while true do for _, tuple in box.space.pokemons.index.status:pairs( self.state.CAUGHT) do box.space.pokemons:update( tuple[self.ID], {{'=', self.STATUS, self.state.ACTIVE}} ) end fiber.sleep(self.respawn_time) end end and call it as a fiber in start():
start = function(self) -- create spaces and indexes <...> -- create models <...> -- compile models <...> -- start the game self.pokemon_model = compiled_pokemon self.player_model = compiled_player fiber.create(self.respawn, self) log.info('Started') -- errors if schema creation or compilation fails <...> end