question Re: Storm Bolt throws an error when trying to read a field from a tuple in Archives of Support Questions (Read Only)

Storm Bolt throws an error when trying to read a field from a tuple

Alex_hardingrnd — Tue, 10 May 2016 11:14:47 GMT

I’m having an issue with my Storm topology. Everytime I process the tuple I get the following exception:

Caused by: java.lang.IllegalArgumentException: word does not exist
at backtype.storm.tuple.Fields.fieldIndex(Fields.java:78)
at backtype.storm.tuple.TupleImpl.fieldIndex(TupleImpl.java:100)
at backtype.storm.tuple.TupleImpl.getStringByField(TupleImpl.java:153)
at TickFail.WordCounterBolt.execute(WordCounterBolt.java:48)
at backtype.storm.daemon.executor$fn__3697$tuple_action_fn__3699.invoke(executor.clj:670)
at backtype.storm.daemon.executor$mk_task_receiver$fn__3620.invoke(executor.clj:429)
at backtype.storm.disruptor$clojure_handler$reify__3196.onEvent(disruptor.clj:58)
at backtype.storm.utils.DisruptorQueue.consumeBatchToCursor(DisruptorQueue.java:125)

I’m not sure whats happening, I think it has something to do with my tick tuple

Here is the code for my execute method in my bolt:

@Override
public void execute(Tuple tuple) {
String str = tuple.getStringByField("word");
if (isTickTuple(tuple)) {
emitCounters(tuple);
return;
}
..

Here is my tick tuple logic:

@Override
public Map<String, Object> getComponentConfiguration() {
Config conf = new Config();
conf.put(Config.TOPOLOGY_TICK_TUPLE_FREQ_SECS, 20);
return conf;
}
private boolean isTickTuple(Tuple tuple) {
String sourceComponent = tuple.getSourceComponent();
String sourceStreamId = tuple.getSourceStreamId();
return sourceComponent.equals(Constants.SYSTEM_COMPONENT_ID)
&& sourceStreamId.equals(Constants.SYSTEM_TICK_STREAM_ID);
}

Re: Storm Bolt throws an error when trying to read a field from a tuple

nismaily — Tue, 10 May 2016 11:17:32 GMT

The error you are getting has to do with the logic in your execute method, particularly:

String str = tuple.getStringByField("word");

The Tick Tuple your bolt receives is mixed in with the other normal tuples you are processing.

You are attempting to get the field with the name “word” before you are checking if the tuple is a Tick Tuple.

The Tick Tuple has 1 field, “rate_secs” that is a equal to the value set for TOPOLOGY_TICK_TUPLE_FREQ_SECS in your conf. When you receive this Tick Tuple, you are attempting to get a field that does not exist, “word”, and assign it to the String, str. This is the reason you get the IllegalArgumentException: word does not exist.

Move

String str = tuple.getStringByField("word");

After your check for the Tick Tuple.

Re: Storm Bolt throws an error when trying to read a field from a tuple

Alex_hardingrnd — Tue, 10 May 2016 11:36:03 GMT

that worked! thanks for the explanation