Nachrichten mit benutzerdefinierten Attributen in Pub/Sub schreiben

Dataflow zum Schreiben von Nachrichten mit benutzerdefinierten Attributen in Pub/Sub verwenden

Weitere Informationen

Eine ausführliche Dokumentation, die dieses Codebeispiel enthält, finden Sie hier:

Codebeispiel

Java

Richten Sie die Standardanmeldedaten für Anwendungen ein, um sich bei Dataflow zu authentifizieren. Weitere Informationen finden Sie unter Authentifizierung für eine lokale Entwicklungsumgebung einrichten. 

import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import org.apache.beam.sdk.Pipeline;
import org.apache.beam.sdk.coders.DefaultCoder;
import org.apache.beam.sdk.extensions.avro.coders.AvroCoder;
import org.apache.beam.sdk.io.gcp.pubsub.PubsubIO;
import org.apache.beam.sdk.io.gcp.pubsub.PubsubMessage;
import org.apache.beam.sdk.options.Description;
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.options.PipelineOptionsFactory;
import org.apache.beam.sdk.transforms.Create;
import org.apache.beam.sdk.transforms.MapElements;
import org.apache.beam.sdk.values.TypeDescriptor;



public class PubSubWriteWithAttributes {
  public interface Options extends PipelineOptions {
    @Description("The Pub/Sub topic to write to. Format: projects/<PROJECT>/topics/<TOPIC>")
    String getTopic();

    void setTopic(String value);
  }

  // A custom datatype for the source data.
  @DefaultCoder(AvroCoder.class)
  static class ExampleData {
    public String name;
    public String product;
    public Long timestamp; // Epoch time in milliseconds

    public ExampleData() {}

    public ExampleData(String name, String product, Long timestamp) {
      this.name = name;
      this.product = product;
      this.timestamp = timestamp;
    }
  }

  // Write messages to a Pub/Sub topic.
  public static void main(String[] args) {
    // Example source data.
    final List<ExampleData> messages = Arrays.asList(
        new ExampleData("Robert", "TV", 1613141590000L),
        new ExampleData("Maria", "Phone", 1612718280000L),
        new ExampleData("Juan", "Laptop", 1611618000000L),
        new ExampleData("Rebeca", "Videogame", 1610000000000L)
    );

    // Parse the pipeline options passed into the application. Example:
    //   --runner=DirectRunner --topic=projects/MY_PROJECT/topics/MY_TOPIC"
    // For more information, see https://beam.apache.org/documentation/programming-guide/#configuring-pipeline-options
    var options = PipelineOptionsFactory.fromArgs(args).withValidation().as(Options.class);
    var pipeline = Pipeline.create(options);
    pipeline
        // Create some data to write to Pub/Sub.
        .apply(Create.of(messages))
        // Convert the data to Pub/Sub messages.
        .apply(MapElements
            .into(TypeDescriptor.of(PubsubMessage.class))
            .via((message -> {
              byte[] payload = message.product.getBytes(StandardCharsets.UTF_8);
              // Create attributes for each message.
              HashMap<String, String> attributes = new HashMap<String, String>();
              attributes.put("buyer", message.name);
              attributes.put("timestamp", Long.toString(message.timestamp));
              return new PubsubMessage(payload, attributes);
            })))
        // Write the messages to Pub/Sub.
        .apply(PubsubIO.writeMessages().to(options.getTopic()));
    pipeline.run().waitUntilFinish();
  }
}

Python

Richten Sie die Standardanmeldedaten für Anwendungen ein, um sich bei Dataflow zu authentifizieren. Weitere Informationen finden Sie unter Authentifizierung für eine lokale Entwicklungsumgebung einrichten. 

import argparse
from typing import Any, Dict, List

import apache_beam as beam
from apache_beam.io import PubsubMessage
from apache_beam.io import WriteToPubSub
from apache_beam.options.pipeline_options import PipelineOptions

from typing_extensions import Self


def item_to_message(item: Dict[str, Any]) -> PubsubMessage:
    # Re-import needed types. When using the Dataflow runner, this
    # function executes on a worker, where the global namespace is not
    # available. For more information, see:
    # https://cloud.google.com/dataflow/docs/guides/common-errors#name-error
    from apache_beam.io import PubsubMessage

    attributes = {"buyer": item["name"], "timestamp": str(item["ts"])}
    data = bytes(item["product"], "utf-8")

    return PubsubMessage(data=data, attributes=attributes)


def write_to_pubsub(argv: List[str] = None) -> None:
    # Parse the pipeline options passed into the application. Example:
    #     --topic=$TOPIC_PATH --streaming
    # For more information, see
    # https://beam.apache.org/documentation/programming-guide/#configuring-pipeline-options
    class MyOptions(PipelineOptions):
        @classmethod
        # Define a custom pipeline option to specify the Pub/Sub topic.
        def _add_argparse_args(cls: Self, parser: argparse.ArgumentParser) -> None:
            parser.add_argument("--topic", required=True)

    example_data = [
        {"name": "Robert", "product": "TV", "ts": 1613141590000},
        {"name": "Maria", "product": "Phone", "ts": 1612718280000},
        {"name": "Juan", "product": "Laptop", "ts": 1611618000000},
        {"name": "Rebeca", "product": "Video game", "ts": 1610000000000},
    ]
    options = MyOptions()

    with beam.Pipeline(options=options) as pipeline:
        (
            pipeline
            | "Create elements" >> beam.Create(example_data)
            | "Convert to Pub/Sub messages" >> beam.Map(item_to_message)
            | WriteToPubSub(topic=options.topic, with_attributes=True)
        )

    print("Pipeline ran successfully.")

Nächste Schritte

Wenn Sie nach Codebeispielen für andere Google Cloud -Produkte suchen und filtern möchten, können Sie den Google Cloud -Beispielbrowser verwenden.