Bigtable to Cloud Storage Avro template

The Bigtable to Cloud Storage Avro template is a pipeline that reads data from a Bigtable table and writes it to a Cloud Storage bucket in Avro format. You can use the template to move data from Bigtable to Cloud Storage.

Pipeline requirements

• The Bigtable table must exist.
• The output Cloud Storage bucket must exist before running the pipeline.

Template parameters

Parameter	Description
bigtableProjectId	The ID of the Google Cloud project of the Bigtable instance that you want to read data from.
bigtableInstanceId	The ID of the Bigtable instance that contains the table.
bigtableTableId	The ID of the Bigtable table to export.
outputDirectory	The Cloud Storage path where data is written. For example, gs://mybucket/somefolder.
filenamePrefix	The prefix of the Avro filename. For example, output-.

Run the template

Console

1. Go to the Dataflow Create job from template page.
Go to Create job from template
2. In the Job name field, enter a unique job name.
3. Optional: For Regional endpoint, select a value from the drop-down menu. The default regional endpoint is us-central1.

   For a list of regions where you can run a Dataflow job, see Dataflow locations.

4. From the Dataflow template drop-down menu, select the Cloud Bigtable to Avro Files on Cloud Storage template .
5. In the provided parameter fields, enter your parameter values.
6. Click Run job.

gcloud

Note: To use the Google Cloud CLI to run classic templates, you must have Google Cloud CLI version 138.0.0 or later.

In your shell or terminal, run the template:

gcloud dataflow jobs run JOB_NAME \
    --gcs-location gs://dataflow-templates-REGION_NAME/VERSION/Cloud_Bigtable_to_GCS_Avro \
    --region REGION_NAME \
    --parameters \
bigtableProjectId=BIGTABLE_PROJECT_ID,\
bigtableInstanceId=INSTANCE_ID,\
bigtableTableId=TABLE_ID,\
outputDirectory=OUTPUT_DIRECTORY,\
filenamePrefix=FILENAME_PREFIX

Replace the following:

• JOB_NAME: a unique job name of your choice
• VERSION: the version of the template that you want to use

  You can use the following values:

  • latest to use the latest version of the template, which is available in the non-dated parent folder in the bucket— gs://dataflow-templates-REGION_NAME/latest/
  • the version name, like 2023-04-18-00_RC00, to use a specific version of the template, which can be found nested in the respective dated parent folder in the bucket— gs://dataflow-templates-REGION_NAME/
  Caution: The latest version of templates might update with breaking changes. Your production environments should use templates kept in the most recent dated parent folder to prevent these breaking changes from affecting your production workflows.
• REGION_NAME: the regional endpoint where you want to deploy your Dataflow job—for example, us-central1
• BIGTABLE_PROJECT_ID: the ID of the Google Cloud project of the Bigtable instance that you want to read data from
• INSTANCE_ID: the ID of the Bigtable instance that contains the table
• TABLE_ID: the ID of the Bigtable table to export
• OUTPUT_DIRECTORY: the Cloud Storage path where data is written, for example, gs://mybucket/somefolder
• FILENAME_PREFIX: the prefix of the Avro filename, for example, output-

API

To run the template using the REST API, send an HTTP POST request. For more information on the API and its authorization scopes, see projects.templates.launch.

POST https://dataflow.googleapis.com/v1b3/projects/PROJECT_ID/locations/LOCATION/templates:launch?gcsPath=gs://dataflow-templates-LOCATION/VERSION/Cloud_Bigtable_to_GCS_Avro
{
   "jobName": "JOB_NAME",
   "parameters": {
       "bigtableProjectId": "BIGTABLE_PROJECT_ID",
       "bigtableInstanceId": "INSTANCE_ID",
       "bigtableTableId": "TABLE_ID",
       "outputDirectory": "OUTPUT_DIRECTORY",
       "filenamePrefix": "FILENAME_PREFIX",
   },
   "environment": { "zone": "us-central1-f" }
}

Replace the following:

• PROJECT_ID: the Google Cloud project ID where you want to run the Dataflow job
• JOB_NAME: a unique job name of your choice
• VERSION: the version of the template that you want to use

  You can use the following values:

  • latest to use the latest version of the template, which is available in the non-dated parent folder in the bucket— gs://dataflow-templates-REGION_NAME/latest/
  • the version name, like 2023-04-18-00_RC00, to use a specific version of the template, which can be found nested in the respective dated parent folder in the bucket— gs://dataflow-templates-REGION_NAME/
  Caution: The latest version of templates might update with breaking changes. Your production environments should use templates kept in the most recent dated parent folder to prevent these breaking changes from affecting your production workflows.
• LOCATION: the regional endpoint where you want to deploy your Dataflow job—for example, us-central1
• BIGTABLE_PROJECT_ID: the ID of the Google Cloud project of the Bigtable instance that you want to read data from
• INSTANCE_ID: the ID of the Bigtable instance that contains the table
• TABLE_ID: the ID of the Bigtable table to export
• OUTPUT_DIRECTORY: the Cloud Storage path where data is written, for example, gs://mybucket/somefolder
• FILENAME_PREFIX: the prefix of the Avro filename, for example, output-

Template source code

Java

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/*
 * Copyright (C) 2018 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.bigtable;

import com.google.bigtable.v2.Cell;
import com.google.bigtable.v2.Column;
import com.google.bigtable.v2.Family;
import com.google.bigtable.v2.Row;
import com.google.cloud.teleport.bigtable.BigtableToAvro.Options;
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.util.DualInputNestedValueProvider;
import com.google.cloud.teleport.util.DualInputNestedValueProvider.TranslatorInput;
import com.google.protobuf.ByteOutput;
import com.google.protobuf.ByteString;
import com.google.protobuf.UnsafeByteOperations;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import org.apache.beam.runners.dataflow.options.DataflowPipelineOptions;
import org.apache.beam.sdk.Pipeline;
import org.apache.beam.sdk.PipelineResult;
import org.apache.beam.sdk.io.AvroIO;
import org.apache.beam.sdk.io.FileSystems;
import org.apache.beam.sdk.io.fs.ResolveOptions.StandardResolveOptions;
import org.apache.beam.sdk.io.gcp.bigtable.BigtableIO;
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.MapElements;
import org.apache.beam.sdk.transforms.SerializableFunction;
import org.apache.beam.sdk.transforms.SimpleFunction;

/**
 * Dataflow pipeline that exports data from a Cloud Bigtable table to Avro files in GCS. Currently,
 * filtering on Cloud Bigtable table is not supported.
 *
 * <p>Check out <a
 * href="https://github.com/GoogleCloudPlatform/DataflowTemplates/blob/main/v1/README_Cloud_Bigtable_to_GCS_Avro.md">README</a>
 * for instructions on how to use or modify this template.
 */
@Template(
    name = "Cloud_Bigtable_to_GCS_Avro",
    category = TemplateCategory.BATCH,
    displayName = "Cloud Bigtable to Avro Files in Cloud Storage",
    description =
        "A pipeline which reads in Cloud Bigtable table and writes it to Cloud Storage in Avro"
            + " format.",
    optionsClass = Options.class,
    documentation =
        "https://cloud.google.com/dataflow/docs/guides/templates/provided/bigtable-to-avro",
    contactInformation = "https://cloud.google.com/support")
public class BigtableToAvro {

  /** Options for the export pipeline. */
  public interface Options extends PipelineOptions {
    @TemplateParameter.ProjectId(
        order = 1,
        description = "Project ID",
        helpText =
            "The ID of the Google Cloud project of the Cloud Bigtable instance that you want to"
                + " read data from")
    ValueProvider<String> getBigtableProjectId();

    @SuppressWarnings("unused")
    void setBigtableProjectId(ValueProvider<String> projectId);

    @TemplateParameter.Text(
        order = 2,
        regexes = {"[a-z][a-z0-9\\-]+[a-z0-9]"},
        description = "Instance ID",
        helpText = "The ID of the Cloud Bigtable instance that contains the table")
    ValueProvider<String> getBigtableInstanceId();

    @SuppressWarnings("unused")
    void setBigtableInstanceId(ValueProvider<String> instanceId);

    @TemplateParameter.Text(
        order = 3,
        regexes = {"[_a-zA-Z0-9][-_.a-zA-Z0-9]*"},
        description = "Table ID",
        helpText = "The ID of the Cloud Bigtable table to read")
    ValueProvider<String> getBigtableTableId();

    @SuppressWarnings("unused")
    void setBigtableTableId(ValueProvider<String> tableId);

    @TemplateParameter.GcsWriteFolder(
        order = 4,
        description = "Output file directory in Cloud Storage",
        helpText =
            "The path and filename prefix for writing output files. Must end with a slash. DateTime"
                + " formatting is used to parse directory path for date & time formatters.",
        example = "gs://your-bucket/your-path")
    ValueProvider<String> getOutputDirectory();

    @SuppressWarnings("unused")
    void setOutputDirectory(ValueProvider<String> outputDirectory);

    @TemplateParameter.Text(
        order = 5,
        description = "Avro file prefix",
        helpText = "The prefix of the Avro file name. For example, \"table1-\"")
    ValueProvider<String> getFilenamePrefix();

    @SuppressWarnings("unused")
    void setFilenamePrefix(ValueProvider<String> filenamePrefix);
  }

  /**
   * Runs a pipeline to export data from a Cloud Bigtable table to Avro files in GCS.
   *
   * @param args arguments to the pipeline
   */
  public static void main(String[] args) {
    Options options = PipelineOptionsFactory.fromArgs(args).withValidation().as(Options.class);

    PipelineResult result = run(options);

    // Wait for pipeline to finish only if it is not constructing a template.
    if (options.as(DataflowPipelineOptions.class).getTemplateLocation() == null) {
      result.waitUntilFinish();
    }
  }

  public static PipelineResult run(Options options) {
    Pipeline pipeline = Pipeline.create(PipelineUtils.tweakPipelineOptions(options));

    BigtableIO.Read read =
        BigtableIO.read()
            .withProjectId(options.getBigtableProjectId())
            .withInstanceId(options.getBigtableInstanceId())
            .withTableId(options.getBigtableTableId());

    // Do not validate input fields if it is running as a template.
    if (options.as(DataflowPipelineOptions.class).getTemplateLocation() != null) {
      read = read.withoutValidation();
    }

    ValueProvider<String> filePathPrefix =
        DualInputNestedValueProvider.of(
            options.getOutputDirectory(),
            options.getFilenamePrefix(),
            new SerializableFunction<TranslatorInput<String, String>, String>() {
              @Override
              public String apply(TranslatorInput<String, String> input) {
                return FileSystems.matchNewResource(input.getX(), true)
                    .resolve(input.getY(), StandardResolveOptions.RESOLVE_FILE)
                    .toString();
              }
            });

    pipeline
        .apply("Read from Bigtable", read)
        .apply("Transform to Avro", MapElements.via(new BigtableToAvroFn()))
        .apply(
            "Write to Avro in GCS",
            AvroIO.write(BigtableRow.class).to(filePathPrefix).withSuffix(".avro"));

    return pipeline.run();
  }

  /** Translates Bigtable {@link Row} to Avro {@link BigtableRow}. */
  static class BigtableToAvroFn extends SimpleFunction<Row, BigtableRow> {
    @Override
    public BigtableRow apply(Row row) {
      ByteBuffer key = ByteBuffer.wrap(toByteArray(row.getKey()));
      List<BigtableCell> cells = new ArrayList<>();
      for (Family family : row.getFamiliesList()) {
        String familyName = family.getName();
        for (Column column : family.getColumnsList()) {
          ByteBuffer qualifier = ByteBuffer.wrap(toByteArray(column.getQualifier()));
          for (Cell cell : column.getCellsList()) {
            long timestamp = cell.getTimestampMicros();
            ByteBuffer value = ByteBuffer.wrap(toByteArray(cell.getValue()));
            cells.add(new BigtableCell(familyName, qualifier, timestamp, value));
          }
        }
      }
      return new BigtableRow(key, cells);
    }
  }

  /**
   * Extracts the byte array from the given {@link ByteString} without copy.
   *
   * @param byteString A {@link ByteString} from which to extract the array.
   * @return an array of byte.
   */
  protected static byte[] toByteArray(final ByteString byteString) {
    try {
      ZeroCopyByteOutput byteOutput = new ZeroCopyByteOutput();
      UnsafeByteOperations.unsafeWriteTo(byteString, byteOutput);
      return byteOutput.bytes;
    } catch (IOException e) {
      return byteString.toByteArray();
    }
  }

  private static final class ZeroCopyByteOutput extends ByteOutput {
    private byte[] bytes;

    @Override
    public void writeLazy(byte[] value, int offset, int length) {
      if (offset != 0 || length != value.length) {
        throw new UnsupportedOperationException();
      }
      bytes = value;
    }

    @Override
    public void write(byte value) {
      throw new UnsupportedOperationException();
    }

    @Override
    public void write(byte[] value, int offset, int length) {
      throw new UnsupportedOperationException();
    }

    @Override
    public void write(ByteBuffer value) {
      throw new UnsupportedOperationException();
    }

    @Override
    public void writeLazy(ByteBuffer value) {
      throw new UnsupportedOperationException();
    }
  }
}