NPE in WARCHdfsBolt on cleanup()

When a (local) topology is killed and no tuples have been passed to the WARCHdfsBolt, the cleanup() will raise a NPE:

68227 [Thread-91-warc-executor[36 36]] INFO  o.a.s.util - Async loop interrupted!
68227 [Thread-89-disruptor-executor[36 36]-send-queue] INFO  o.a.s.util - Async loop interrupted!
68227 [SLOT_1024] INFO  c.d.s.w.GzipHdfsBolt - Cleanup called on bolt
68227 [SLOT_1024] ERROR o.a.s.d.s.Slot - Error when processing event
java.lang.NullPointerException: null
        at com.digitalpebble.stormcrawler.warc.GzipHdfsBolt.cleanup(GzipHdfsBolt.java:187) ~[storm-crawler-fight-2.0-SNAPSHOT.jar:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_181]
        ...
        at org.apache.storm.ProcessSimulator.killProcess(ProcessSimulator.java:67) ~[storm-core-1.2.2.jar:1.2.2]
        at org.apache.storm.daemon.supervisor.LocalContainer.kill(LocalContainer.java:69) ~[storm-core-1.2.2.jar:1.2.2]
        ...

Of course, it’s a minor issue (the topology is shut down anyway) but should either check always initialize the output stream or check whether it is initialized.

[jnioche]

Did you specify the config key for the bolt?

      - name: "withConfigKey"
        args:
          - "warc"

[jnioche]

Merged, thanks @sebastian-nagel