Mastering Apache Storm

Configuration setting at component level

This step is done when building the topology with TopologyBuilder in the main method of a topology. ComponentConfigurationDeclarer has a method called addConfiguration(String config, String value) that allows adding of custom configuration--that is, metadata. In our case, we add the type information using this method:

TopologyBuilder builder = new TopologyBuilder(); 
builder.setSpout("spout", new SampleSpout(), 1); builder.setBolt("bolt1", new ExampleBolt1(), 1).shuffleGrouping("spout"); 
builder.setBolt("bolt3", new SampleBolt2(), 1).shuffleGrouping("bolt2").addConfiguration("type", "GPU"); 

The preceding code shows that we have typed our bolt2 component with type as GPU.