Executar um modelo de amostra

O modelo WordCount é um pipeline em lote que lê textos do Cloud Storage, transforma linhas de texto em palavras individuais e executa uma contagem de frequência em cada palavra. Para mais informações sobre WordCount, consulte Pipeline de exemplo de WordCount.

Se o bucket do Cloud Storage estiver fora do perímetro do serviço, crie uma regra de saída que permita acesso ao bucket.

Parâmetros do modelo

Parâmetro	Descrição
inputFile	O caminho do arquivo de entrada do Cloud Storage.
outputFile	Caminho e prefixo do arquivo de saída do Cloud Storage.

Executar o modelo WordCount

Console

1. Acesse a página Criar job usando um modelo do Dataflow.
Acesse Criar job usando um modelo
2. No campo Nome do job, insira um nome exclusivo.
3. Opcional: em Endpoint regional, selecione um valor no menu suspenso. A região padrão é us-central1.

   Para ver uma lista de regiões em que é possível executar um job do Dataflow, consulte Locais do Dataflow.

4. No menu suspenso Modelo do Dataflow, selecione the WordCount template.
5. Nos campos de parâmetro fornecidos, insira os valores de parâmetro.
6. Cliquem em Executar job.

gcloud

Observação: para usar a Google Cloud CLI para executar modelos classic você precisa ter a Google Cloud CLI na versão 138.0.0 ou mais recente.

No shell ou no terminal, execute o modelo:

gcloud dataflow jobs run JOB_NAME \
    --gcs-location gs://dataflow-templates/latest/Word_Count \
    --region REGION_NAME \
    --parameters \
    inputFile=gs://dataflow-samples/shakespeare/kinglear.txt,output=gs://BUCKET_NAME/output/my_output

Substitua:

• JOB_NAME: um nome de job de sua escolha

• REGION_NAME: a região em que você quer implantar o job do Dataflow, por exemplo, us-central1

• BUCKET_NAME: o nome do bucket do Cloud Storage

API

Para executar o modelo usando a API REST, envie uma solicitação HTTP POST. Para mais informações sobre a API e os respectivos escopos de autorização, consulte projects.templates.launch.

POST https://dataflow.googleapis.com/v1b3/projects/PROJECT_ID/locations/LOCATION/templates:launch?gcsPath=gs://dataflow-templates/latest/Word_Count
{
    "jobName": "JOB_NAME",
    "parameters": {
       "inputFile" : "gs://dataflow-samples/shakespeare/kinglear.txt",
       "output": "gs://BUCKET_NAME/output/my_output"
    },
    "environment": { "zone": "us-central1-f" }
}

Substitua:

• PROJECT_ID: o ID do projeto do Google Cloud em que você quer executar o job do Dataflow

• JOB_NAME: um nome de job de sua escolha

• LOCATION: a região em que você quer implantar o job do Dataflow, por exemplo, us-central1

• BUCKET_NAME: o nome do bucket do Cloud Storage

Código-fonte do modelo

Java

/*
 * Copyright (C) 2016 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.cloud.teleport.templates;

import com.google.cloud.teleport.metadata.Template;
import com.google.cloud.teleport.metadata.TemplateCategory;
import com.google.cloud.teleport.metadata.TemplateParameter;
import com.google.cloud.teleport.templates.WordCount.WordCountOptions;
import org.apache.beam.sdk.Pipeline;
import org.apache.beam.sdk.io.TextIO;
import org.apache.beam.sdk.metrics.Counter;
import org.apache.beam.sdk.metrics.Metrics;
import org.apache.beam.sdk.options.PipelineOptions;
import org.apache.beam.sdk.options.PipelineOptionsFactory;
import org.apache.beam.sdk.options.ValueProvider;
import org.apache.beam.sdk.transforms.Count;
import org.apache.beam.sdk.transforms.DoFn;
import org.apache.beam.sdk.transforms.MapElements;
import org.apache.beam.sdk.transforms.PTransform;
import org.apache.beam.sdk.transforms.ParDo;
import org.apache.beam.sdk.transforms.SimpleFunction;
import org.apache.beam.sdk.values.KV;
import org.apache.beam.sdk.values.PCollection;

/**
 * A template that counts words in text files.
 *
 * <p>Check out <a
 * href="https://github.com/GoogleCloudPlatform/DataflowTemplates/blob/main/v1/README_Word_Count.md">README</a>
 * for instructions on how to use or modify this template.
 */
@Template(
    name = "Word_Count",
    category = TemplateCategory.GET_STARTED,
    displayName = "Word Count",
    description =
        "Batch pipeline. Reads text from Cloud Storage, tokenizes text lines into individual words,"
            + " and performs frequency count on each of the words.",
    optionsClass = WordCountOptions.class,
    contactInformation = "https://cloud.google.com/support")
public class WordCount {

  static class ExtractWordsFn extends DoFn<String, String> {
    private final Counter emptyLines = Metrics.counter(ExtractWordsFn.class, "emptyLines");

    @ProcessElement
    public void processElement(ProcessContext c) {
      // Check if the line is empty.
      if (c.element().trim().isEmpty()) {
        emptyLines.inc();
        return;
      }

      // Split the line into words.
      String[] words = c.element().split("[^a-zA-Z']+");

      // Output each word encountered into the output PCollection.
      for (String word : words) {
        if (!word.isEmpty()) {
          c.output(word);
        }
      }
    }
  }

  /** A SimpleFunction that converts a Word and Count into a printable string. */
  public static class FormatAsTextFn extends SimpleFunction<KV<String, Long>, String> {
    @Override
    public String apply(KV<String, Long> input) {
      return input.getKey() + ": " + input.getValue();
    }
  }

  /**
   * A PTransform that converts a PCollection containing lines of text into a PCollection of
   * formatted word counts.
   */
  public static class CountWords
      extends PTransform<PCollection<String>, PCollection<KV<String, Long>>> {
    @Override
    public PCollection<KV<String, Long>> expand(PCollection<String> lines) {

      // Convert lines of text into individual words.
      PCollection<String> words = lines.apply(ParDo.of(new ExtractWordsFn()));

      // Count the number of times each word occurs.
      PCollection<KV<String, Long>> wordCounts = words.apply(Count.<String>perElement());

      return wordCounts;
    }
  }

  /**
   * Options supported by {@link com.google.cloud.teleport.templates.WordCount}.
   *
   * <p>Inherits standard configuration options.
   */
  public interface WordCountOptions extends PipelineOptions {

    @TemplateParameter.GcsReadFile(
        order = 1,
        description = "Input file(s) in Cloud Storage",
        helpText =
            "The input file pattern Dataflow reads from. Use the example file "
                + "(gs://dataflow-samples/shakespeare/kinglear.txt) or enter the path to your own "
                + "using the same format: gs://your-bucket/your-file.txt")
    ValueProvider<String> getInputFile();

    void setInputFile(ValueProvider<String> value);

    @TemplateParameter.GcsWriteFolder(
        order = 2,
        description = "Output Cloud Storage file prefix",
        helpText = "Path and filename prefix for writing output files. Ex: gs://your-bucket/counts")
    ValueProvider<String> getOutput();

    void setOutput(ValueProvider<String> value);
  }

  public static void main(String[] args) {
    WordCountOptions options =
        PipelineOptionsFactory.fromArgs(args).withValidation().as(WordCountOptions.class);
    Pipeline p = Pipeline.create(options);
    p.apply("ReadLines", TextIO.read().from(options.getInputFile()))
        .apply(new CountWords())
        .apply(MapElements.via(new FormatAsTextFn()))
        .apply("WriteCounts", TextIO.write().to(options.getOutput()));

    p.run();
  }
}