Timing using tick tuples¶

Tick tuples are system generated tuples that Storm can send to your bolt if you need to perform some actions at a fixed interval.

You can use the module level function pyleus.storm.is_tick() to tell whether a tuple is a tick tuple or not.

Configure tick tuples interval for a component¶

You can activate and configure tick tuples interval for a component using the tick_freq_secs option in the topology definition YAML file:

- bolt:
    name: tick-bolt
    module: tick_topology.tick_bolt
    groupings:
        - shuffle_grouping: my-spout
    tick_freq_secs: 2.5

The specified value has to be float and it is intended as the interval in seconds between two tick tuples.

You can retrieve the frequency value from within a bolt using property self.conf.tick_tuple_freq.

SimpleBolt tick tuple API¶

SimpleBolt offers a nicer API for handling tick tuples. Method process_tick() will be called instead of process_tuple() any time the bolt receives a tick tuple. In this way you can easily separate the code you want to execute for “real” tuple from the one you want to executed at a fixed interval.