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)    endend

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