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.
You can read more about tick tuples here.
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.
You can find many examples in the GitHub repo.