👀 Views: 73 💬 Answers: 1 📅 Created: 2025-06-26

gcp dataflow pubsub Java

Hey everyone, I'm running into an issue that's driving me crazy... I'm sure I'm missing something obvious here, but I'm running a Google Cloud Dataflow job to process streaming data from a Pub/Sub topic, but I keep working with a `NoSuchElementException` during execution. My Dataflow pipeline is designed to read messages from Pub/Sub, process them, and then write the results to BigQuery. The scenario arises intermittently and seems to be tied to how I handle the incoming Pub/Sub messages. Below is a simplified version of the code I’m using: ```java import com.google.cloud.pubsub.v1.MessageReceiver; import com.google.cloud.pubsub.v1.PubSubSubscriber; import com.google.cloud.dataflow.sdk.Pipeline; import com.google.cloud.dataflow.sdk.options.PipelineOptionsFactory; import com.google.cloud.dataflow.sdk.transforms.ParDo; import com.google.cloud.dataflow.sdk.transforms.DoFn; public class PubSubToBigQuery { public static void main(String[] args) { PipelineOptions options = PipelineOptionsFactory.create(); Pipeline p = Pipeline.create(options); p .apply("ReadFromPubSub", PubsubIO.read().topic("projects/my-project/topics/my-topic")) .apply("ProcessMessages", ParDo.of(new DoFn<String, MyResult>() { @ProcessElement public void processElement(ProcessContext c) { String message = c.element(); // Process message MyResult result = processMessage(message); c.output(result); } })) .apply("WriteToBigQuery", BigQueryIO.writeTableRows() .to("my-project:dataset.table") .withSchema(mySchema) .withWriteDisposition(WriteDisposition.WRITE_APPEND)); p.run().waitUntilFinish(); } private static MyResult processMessage(String message) { // Simulate processing logic if (message.isEmpty()) { throw new NoSuchElementException("Received empty message"); } return new MyResult(message); } } ``` I have added behavior handling to catch any exceptions in the `processMessage` method, but the `NoSuchElementException` is still not caught when it occurs. Instead, it causes the entire Dataflow job to unexpected result. I’ve also tried using side inputs to handle default cases, but that didn’t resolve the scenario either. My Dataflow job is running on version 2.30.0, and I’ve ensured that the Pub/Sub messages are being formatted correctly before being sent. Is there a recommended approach for dealing with this exception in the context of streaming Dataflow jobs? Any insights on improving behavior handling for this scenario would be greatly appreciated. I'm working on a application that needs to handle this. Am I missing something obvious? This is part of a larger application I'm building. Any ideas how to fix this?