@Override
public PCollection<T> apply(PInput input) {
if (filepattern == null) {
throw new IllegalStateException(
"need to set the filepattern of an AvroIO.Read transform");
}
if (schema == null) {
throw new IllegalStateException("need to set the schema of an AvroIO.Read transform");
}
if (validate) {
try {
checkState(
!IOChannelUtils.getFactory(filepattern).match(filepattern).isEmpty(),
"Unable to find any files matching %s",
filepattern);
} catch (IOException e) {
throw new IllegalStateException(String.format("Failed to validate %s", filepattern), e);
}
}
@SuppressWarnings("unchecked")
Bounded<T> read =
type == GenericRecord.class
? (Bounded<T>)
com.google.cloud.dataflow.sdk.io.Read.from(
AvroSource.from(filepattern).withSchema(schema))
: com.google.cloud.dataflow.sdk.io.Read.from(
AvroSource.from(filepattern).withSchema(type));
PCollection<T> pcol = input.getPipeline().apply("Read", read);
// Honor the default output coder that would have been used by this PTransform.
pcol.setCoder(getDefaultOutputCoder());
return pcol;
}
public static void main(String[] args) {
PipelineOptionsFactory.register(KafkaStreamingWordCountOptions.class);
KafkaStreamingWordCountOptions options =
PipelineOptionsFactory.fromArgs(args).as(KafkaStreamingWordCountOptions.class);
options.setJobName("KafkaExample - WindowSize: " + options.getWindowSize() + " seconds");
options.setStreaming(true);
options.setCheckpointingInterval(1000L);
options.setNumberOfExecutionRetries(5);
options.setExecutionRetryDelay(3000L);
options.setRunner(FlinkPipelineRunner.class);
System.out.println(
options.getKafkaTopic()
+ " "
+ options.getZookeeper()
+ " "
+ options.getBroker()
+ " "
+ options.getGroup());
Pipeline pipeline = Pipeline.create(options);
Properties p = new Properties();
p.setProperty("zookeeper.connect", options.getZookeeper());
p.setProperty("bootstrap.servers", options.getBroker());
p.setProperty("group.id", options.getGroup());
// this is the Flink consumer that reads the input to
// the program from a kafka topic.
FlinkKafkaConsumer08<String> kafkaConsumer =
new FlinkKafkaConsumer08<>(options.getKafkaTopic(), new SimpleStringSchema(), p);
PCollection<String> words =
pipeline
.apply(Read.from(new UnboundedFlinkSource<>(kafkaConsumer)).named("StreamingWordCount"))
.apply(ParDo.of(new ExtractWordsFn()))
.apply(
Window.<String>into(
FixedWindows.of(Duration.standardSeconds(options.getWindowSize())))
.triggering(AfterWatermark.pastEndOfWindow())
.withAllowedLateness(Duration.ZERO)
.discardingFiredPanes());
PCollection<KV<String, Long>> wordCounts = words.apply(Count.<String>perElement());
wordCounts.apply(ParDo.of(new FormatAsStringFn())).apply(TextIO.Write.to("./outputKafka.txt"));
pipeline.run();
}
