Python UDF를 사용하는 Cloud Storage Text to BigQuery(스트리밍) 템플릿

Cloud Storage Text to BigQuery 파이프라인은 Cloud Storage에 저장된 텍스트 파일을 스트리밍하고, 사용자가 제공한 Python 사용자 정의 함수(UDF)를 사용하여 변환하고, 결과를 BigQuery에 추가하는 스트리밍 파이프라인입니다.

파이프라인은 무한히 실행되며 드레이닝을 지원하지 않는 분할 가능한 DoFnWatch 변환 사용으로 인해 드레이닝이 아닌 취소를 통해 수동으로 종료되어야 합니다.

파이프라인 요구사항

  • BigQuery에서 출력 테이블의 스키마를 설명하는 JSON 파일을 만드세요.

    최상위 JSON 배열의 이름이 fields이고 해당 콘텐츠는 {"name": "COLUMN_NAME", "type": "DATA_TYPE"} 패턴을 따라야 합니다. 예를 들면 다음과 같습니다.

    {
      "fields": [
        {
          "name": "name",
          "type": "STRING"
        },
        {
          "name": "age",
          "type": "INTEGER"
        }
      ]
    }
  • 텍스트 줄을 변환하는 논리를 제공하는 UDF 함수를 사용하여 Python(.py) 파일을 만듭니다. 함수는 JSON 문자열을 반환해야 합니다.

    다음 예시에서는 CSV 파일의 각 줄을 분할하고, 값이 있는 JSON 객체를 만들고, JSON 문자열을 반환합니다.

    import json
    def process(value):
      data = value.split(',')
      obj = { 'name': data[0], 'age': int(data[1]) }
      return json.dumps(obj)

템플릿 매개변수

매개변수 설명
pythonExternalTextTransformGcsPath 사용할 사용자 정의 함수(UDF)를 정의하는 Python 코드 파일의 Cloud Storage URI입니다. 예를 들면 gs://my-bucket/my-udfs/my_file.py입니다.
pythonExternalTextTransformFunctionName 사용할 Python 사용자 정의 함수(UDF)의 이름입니다.
JSONPath JSON으로 설명된 BigQuery 스키마 파일의 Cloud Storage 위치입니다. 예를 들면 gs://path/to/my/schema.json입니다.
outputTable 정규화된 BigQuery 테이블입니다. 예를 들면 my-project:dataset.table입니다.
inputFilePattern 처리하려는 텍스트의 Cloud Storage 위치입니다. 예를 들면 gs://my-bucket/my-files/text.txt입니다.
bigQueryLoadingTemporaryDirectory BigQuery 로딩 프로세스를 위한 임시 디렉터리입니다. 예를 들면 gs://my-bucket/my-files/temp_dir입니다.
outputDeadletterTable 출력 테이블에 도달하지 못한 메시지 테이블입니다. 예를 들면 my-project:dataset.my-unprocessed-table입니다. 없으면 파이프라인 실행 중에 생성됩니다. 지정하지 않은 경우 <outputTableSpec>_error_records가 대신 사용됩니다.

사용자 정의 함수

이 템플릿에는 파이프라인 요구사항에 설명된 대로 입력 파일을 파싱하는 UDF가 필요합니다. 템플릿은 각 입력 파일의 모든 텍스트 줄에 대해 UDF를 호출합니다. UDF 만들기에 대한 자세한 내용은 Dataflow 템플릿에 대한 사용자 정의 함수 만들기를 참조하세요.

함수 사양

UDF의 사양은 다음과 같습니다.

  • 입력: 입력 파일의 텍스트 한 줄입니다.
  • 출력: BigQuery 대상 테이블의 스키마와 일치하는 JSON 문자열입니다.

템플릿 실행

콘솔gcloudAPI
  1. Dataflow 템플릿에서 작업 만들기 페이지로 이동합니다.
  2. 템플릿에서 작업 만들기로 이동
  3. 작업 이름 필드에 고유한 작업 이름을 입력합니다.
  4. (선택사항): 리전 엔드포인트의 드롭다운 메뉴에서 값을 선택합니다. 기본 리전은 us-central1입니다.

    Dataflow 작업을 실행할 수 있는 리전 목록은 Dataflow 위치를 참조하세요.

  5. Dataflow 템플릿 드롭다운 메뉴에서 the Cloud Storage Text to BigQuery (Stream) with Python UDF template을 선택합니다.
  6. 제공된 매개변수 필드에 매개변수 값을 입력합니다.
  7. 작업 실행을 클릭합니다.

셸 또는 터미널에서 템플릿을 실행합니다.

gcloud dataflow flex-template run JOB_NAME \
    --template-file-gcs-location gs://dataflow-templates-REGION_NAME/VERSION/flex/Stream_GCS_Text_to_BigQuery_Xlang \
    --region REGION_NAME \
    --staging-location STAGING_LOCATION \
    --parameters \
pythonExternalTextTransformGcsPath=PATH_TO_PYTHON_UDF_FILE,\
pythonExternalTextTransformFunctionName=PYTHON_FUNCTION,\
JSONPath=PATH_TO_BIGQUERY_SCHEMA_JSON,\
inputFilePattern=PATH_TO_TEXT_DATA,\
outputTable=BIGQUERY_TABLE,\
outputDeadletterTable=BIGQUERY_UNPROCESSED_TABLE,\
bigQueryLoadingTemporaryDirectory=PATH_TO_TEMP_DIR_ON_GCS

다음을 바꿉니다.

  • JOB_NAME: 선택한 고유한 작업 이름
  • REGION_NAME: Dataflow 작업을 배포할 리전(예: us-central1)
  • VERSION: 사용할 템플릿 버전

    다음 값을 사용할 수 있습니다.

  • STAGING_LOCATION: 로컬 파일의 스테이징 위치(예: gs://your-bucket/staging)
  • PYTHON_FUNCTION: 사용할 Python 사용자 정의 함수(UDF)의 이름
  • PATH_TO_BIGQUERY_SCHEMA_JSON: 스키마 정의가 포함된 JSON 파일의 Cloud Storage 경로
  • PATH_TO_PYTHON_UDF_FILE: 사용할 사용자 정의 함수(UDF)를 정의하는 Python 코드 파일의 Cloud Storage URI. 예를 들면 gs://my-bucket/my-udfs/my_file.py입니다.
  • PATH_TO_TEXT_DATA: 텍스트 데이터 세트의 Cloud Storage 경로
  • BIGQUERY_TABLE: BigQuery 테이블 이름
  • BIGQUERY_UNPROCESSED_TABLE: 처리되지 않은 메시지에 대한 BigQuery 테이블의 이름
  • PATH_TO_TEMP_DIR_ON_GCS: 임시 디렉터리의 Cloud Storage 경로

REST API를 사용하여 템플릿을 실행하려면 HTTP POST 요청을 전송합니다. API 및 승인 범위에 대한 자세한 내용은 projects.templates.launch를 참조하세요.

POST https://dataflow.googleapis.com/v1b3/projects/PROJECT_ID/locations/LOCATION/flexTemplates:launch
{
   "launch_parameter": {
      "jobName": "JOB_NAME",
      "parameters": {
       "pythonExternalTextTransformFunctionName": "PYTHON_FUNCTION",
       "JSONPath": "PATH_TO_BIGQUERY_SCHEMA_JSON",
       "pythonExternalTextTransformGcsPath": "PATH_TO_PYTHON_UDF_FILE",
       "inputFilePattern":"PATH_TO_TEXT_DATA",
       "outputTable":"BIGQUERY_TABLE",
       "outputDeadletterTable":"BIGQUERY_UNPROCESSED_TABLE",
       "bigQueryLoadingTemporaryDirectory": "PATH_TO_TEMP_DIR_ON_GCS"
      },
      "containerSpecGcsPath": "gs://dataflow-templates-LOCATION/VERSION/flex/Stream_GCS_Text_to_BigQuery_Xlang",
   }
}

다음을 바꿉니다.

  • PROJECT_ID: Dataflow 작업을 실행하려는 Google Cloud 프로젝트 ID
  • JOB_NAME: 선택한 고유한 작업 이름
  • LOCATION: Dataflow 작업을 배포할 리전(예: us-central1)
  • VERSION: 사용할 템플릿 버전

    다음 값을 사용할 수 있습니다.

  • STAGING_LOCATION: 로컬 파일의 스테이징 위치(예: gs://your-bucket/staging)
  • PYTHON_FUNCTION: 사용할 Python 사용자 정의 함수(UDF)의 이름
  • PATH_TO_BIGQUERY_SCHEMA_JSON: 스키마 정의가 포함된 JSON 파일의 Cloud Storage 경로
  • PATH_TO_PYTHON_UDF_FILE: 사용할 사용자 정의 함수(UDF)를 정의하는 Python 코드 파일의 Cloud Storage URI. 예를 들면 gs://my-bucket/my-udfs/my_file.py입니다.
  • PATH_TO_TEXT_DATA: 텍스트 데이터 세트의 Cloud Storage 경로
  • BIGQUERY_TABLE: BigQuery 테이블 이름
  • BIGQUERY_UNPROCESSED_TABLE: 처리되지 않은 메시지에 대한 BigQuery 테이블의 이름
  • PATH_TO_TEMP_DIR_ON_GCS: 임시 디렉터리의 Cloud Storage 경로
Java
/*
 * 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.v2.templates;

import com.google.api.client.json.JsonFactory;
import com.google.api.services.bigquery.model.TableRow;
import com.google.cloud.teleport.metadata.MultiTemplate;
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.v2.coders.FailsafeElementCoder;
import com.google.cloud.teleport.v2.common.UncaughtExceptionLogger;
import com.google.cloud.teleport.v2.options.BigQueryStorageApiStreamingOptions;
import com.google.cloud.teleport.v2.templates.TextToBigQueryStreaming.TextToBigQueryStreamingOptions;
import com.google.cloud.teleport.v2.transforms.BigQueryConverters.FailsafeJsonToTableRow;
import com.google.cloud.teleport.v2.transforms.ErrorConverters.WriteStringMessageErrors;
import com.google.cloud.teleport.v2.transforms.JavascriptTextTransformer.FailsafeJavascriptUdf;
import com.google.cloud.teleport.v2.transforms.PythonExternalTextTransformer;
import com.google.cloud.teleport.v2.transforms.PythonExternalTextTransformer.RowToStringFailsafeElementFn;
import com.google.cloud.teleport.v2.utils.BigQueryIOUtils;
import com.google.cloud.teleport.v2.utils.GCSUtils;
import com.google.cloud.teleport.v2.utils.ResourceUtils;
import com.google.cloud.teleport.v2.values.FailsafeElement;
import com.google.common.base.Strings;
import com.google.common.collect.ImmutableList;
import java.io.IOException;
import org.apache.beam.sdk.Pipeline;
import org.apache.beam.sdk.PipelineResult;
import org.apache.beam.sdk.coders.CoderRegistry;
import org.apache.beam.sdk.coders.StringUtf8Coder;
import org.apache.beam.sdk.extensions.gcp.util.Transport;
import org.apache.beam.sdk.io.TextIO;
import org.apache.beam.sdk.io.gcp.bigquery.BigQueryIO;
import org.apache.beam.sdk.io.gcp.bigquery.BigQueryIO.Write.CreateDisposition;
import org.apache.beam.sdk.io.gcp.bigquery.BigQueryIO.Write.WriteDisposition;
import org.apache.beam.sdk.io.gcp.bigquery.BigQueryInsertError;
import org.apache.beam.sdk.io.gcp.bigquery.InsertRetryPolicy;
import org.apache.beam.sdk.io.gcp.bigquery.WriteResult;
import org.apache.beam.sdk.options.Default;
import org.apache.beam.sdk.options.PipelineOptionsFactory;
import org.apache.beam.sdk.options.ValueProvider.StaticValueProvider;
import org.apache.beam.sdk.transforms.Flatten;
import org.apache.beam.sdk.transforms.MapElements;
import org.apache.beam.sdk.transforms.ParDo;
import org.apache.beam.sdk.transforms.Watch.Growth;
import org.apache.beam.sdk.values.PCollection;
import org.apache.beam.sdk.values.PCollectionList;
import org.apache.beam.sdk.values.PCollectionTuple;
import org.apache.beam.sdk.values.TupleTag;
import org.apache.beam.sdk.values.TupleTagList;
import org.apache.commons.lang3.StringUtils;
import org.joda.time.Duration;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * The {@link TextToBigQueryStreaming} is a streaming version of {@link TextIOToBigQuery} pipeline
 * that reads text files, applies a JavaScript UDF and writes the output to BigQuery. The pipeline
 * continuously polls for new files, reads them row-by-row and processes each record into BigQuery.
 * The polling interval is set at 10 seconds.
 *
 * <p>Check out <a
 * href="https://github.com/GoogleCloudPlatform/DataflowTemplates/blob/main/v2/googlecloud-to-googlecloud/README_Stream_GCS_Text_to_BigQuery_Flex.md">README</a>
 * for instructions on how to use or modify this template.
 */
@MultiTemplate({
  @Template(
      name = "Stream_GCS_Text_to_BigQuery_Flex",
      category = TemplateCategory.STREAMING,
      displayName = "Cloud Storage Text to BigQuery (Stream)",
      description = {
        "The Text Files on Cloud Storage to BigQuery pipeline is a streaming pipeline that allows you to stream text files stored in Cloud Storage, transform them using a JavaScript User Defined Function (UDF) that you provide, and append the result to BigQuery.\n",
        "The pipeline runs indefinitely and needs to be terminated manually via a\n"
            + "    <a href=\"https://cloud.google.com/dataflow/docs/guides/stopping-a-pipeline#cancel\">cancel</a> and not a\n"
            + "    <a href=\"https://cloud.google.com/dataflow/docs/guides/stopping-a-pipeline#drain\">drain</a>, due to its use of the\n"
            + "    <code>Watch</code> transform, which is a splittable <code>DoFn</code> that does not support\n"
            + "    draining."
      },
      skipOptions = {
        "pythonExternalTextTransfromGcsPath",
        "pythonExternalTextTransformFunctionName"
      },
      optionsClass = TextToBigQueryStreamingOptions.class,
      flexContainerName = "text-to-bigquery-streaming",
      documentation =
          "https://cloud.google.com/dataflow/docs/guides/templates/provided/text-to-bigquery-stream",
      contactInformation = "https://cloud.google.com/support",
      requirements = {
        "Create a JSON file that describes the schema of your output table in BigQuery.\n"
            + "    <p>\n"
            + "      Ensure that there is a top-level JSON array titled <code>fields</code> and that its\n"
            + "      contents follow the pattern <code>{\"name\": \"COLUMN_NAME\", \"type\": \"DATA_TYPE\"}</code>.\n"
            + "      For example:\n"
            + "    </p>\n"
            + "<pre class=\"prettyprint lang-json\">\n"
            + "{\n"
            + "  \"fields\": [\n"
            + "    {\n"
            + "      \"name\": \"location\",\n"
            + "      \"type\": \"STRING\"\n"
            + "    },\n"
            + "    {\n"
            + "      \"name\": \"name\",\n"
            + "      \"type\": \"STRING\"\n"
            + "    },\n"
            + "    {\n"
            + "      \"name\": \"age\",\n"
            + "      \"type\": \"STRING\"\n"
            + "    },\n"
            + "    {\n"
            + "      \"name\": \"color\",\n"
            + "      \"type\": \"STRING\",\n"
            + "      \"mode\": \"REQUIRED\"\n"
            + "    },\n"
            + "    {\n"
            + "      \"name\": \"coffee\",\n"
            + "      \"type\": \"STRING\",\n"
            + "      \"mode\": \"REQUIRED\"\n"
            + "    }\n"
            + "  ]\n"
            + "}\n"
            + "</pre>",
        "Create a JavaScript (<code>.js</code>) file with your UDF function that supplies the logic\n"
            + "    to transform the lines of text. Note that your function must return a JSON string.\n"
            + "    <p>For example, this function splits each line of a CSV file and returns a JSON string after\n"
            + "      transforming the values.</p>\n"
            + "<pre class=\"prettyprint\" suppresswarning>\n"
            + "function transform(line) {\n"
            + "var values = line.split(',');\n"
            + "\n"
            + "var obj = new Object();\n"
            + "obj.location = values[0];\n"
            + "obj.name = values[1];\n"
            + "obj.age = values[2];\n"
            + "obj.color = values[3];\n"
            + "obj.coffee = values[4];\n"
            + "var jsonString = JSON.stringify(obj);\n"
            + "\n"
            + "return jsonString;\n"
            + "}\n"
            + "</pre>"
      },
      streaming = true,
      supportsAtLeastOnce = true),
  @Template(
      name = "Stream_GCS_Text_to_BigQuery_Xlang",
      category = TemplateCategory.STREAMING,
      displayName = "Cloud Storage Text to BigQuery (Stream) with Python UDF",
      type = Template.TemplateType.XLANG,
      description = {
        "The Text Files on Cloud Storage to BigQuery pipeline is a streaming pipeline that allows you to stream text files stored in Cloud Storage, transform them using a Python User Defined Function (UDF) that you provide, and append the result to BigQuery.\n",
        "The pipeline runs indefinitely and needs to be terminated manually via a\n"
            + "    <a href=\"https://cloud.google.com/dataflow/docs/guides/stopping-a-pipeline#cancel\">cancel</a> and not a\n"
            + "    <a href=\"https://cloud.google.com/dataflow/docs/guides/stopping-a-pipeline#drain\">drain</a>, due to its use of the\n"
            + "    <code>Watch</code> transform, which is a splittable <code>DoFn</code> that does not support\n"
            + "    draining."
      },
      skipOptions = {
        "javascriptTextTransformGcsPath",
        "javascriptTextTransformFunctionName",
        "javascriptTextTransformReloadIntervalMinutes"
      },
      optionsClass = TextToBigQueryStreamingOptions.class,
      flexContainerName = "text-to-bigquery-streaming-xlang",
      documentation =
          "https://cloud.google.com/dataflow/docs/guides/templates/provided/text-to-bigquery-stream",
      contactInformation = "https://cloud.google.com/support",
      requirements = {
        "Create a JSON file that describes the schema of your output table in BigQuery.\n"
            + "    <p>\n"
            + "      Ensure that there is a top-level JSON array titled <code>fields</code> and that its\n"
            + "      contents follow the pattern <code>{\"name\": \"COLUMN_NAME\", \"type\": \"DATA_TYPE\"}</code>.\n"
            + "      For example:\n"
            + "    </p>\n"
            + "<pre class=\"prettyprint lang-json\">\n"
            + "{\n"
            + "  \"fields\": [\n"
            + "    {\n"
            + "      \"name\": \"location\",\n"
            + "      \"type\": \"STRING\"\n"
            + "    },\n"
            + "    {\n"
            + "      \"name\": \"name\",\n"
            + "      \"type\": \"STRING\"\n"
            + "    },\n"
            + "    {\n"
            + "      \"name\": \"age\",\n"
            + "      \"type\": \"STRING\"\n"
            + "    },\n"
            + "    {\n"
            + "      \"name\": \"color\",\n"
            + "      \"type\": \"STRING\",\n"
            + "      \"mode\": \"REQUIRED\"\n"
            + "    },\n"
            + "    {\n"
            + "      \"name\": \"coffee\",\n"
            + "      \"type\": \"STRING\",\n"
            + "      \"mode\": \"REQUIRED\"\n"
            + "    }\n"
            + "  ]\n"
            + "}\n"
            + "</pre>",
        "Create a Python (<code>.js</code>) file with your UDF function that supplies the logic\n"
            + "    to transform the lines of text. Note that your function must return a JSON string.\n"
            + "    <p>For example, this function splits each line of a CSV file and returns a JSON string after\n"
            + "      transforming the values.</p>\n"
            + "<pre class=\"prettyprint\" suppresswarning>\n"
            + "import json\n"
            + "def transform(line): \n"
            + "  values = line.split(',')\n"
            + "\n"
            + "  obj = {\n"
            + "     'location' : values[0],\n"
            + "     'name' : values[1],\n"
            + "     'age' : values[2],\n"
            + "     'color' : values[3],\n"
            + "     'coffee' : values[4]\n"
            + "  }\n"
            + "  jsonString = JSON.dumps(obj);\n"
            + "\n"
            + "  return jsonString;\n"
            + "\n"
            + "</pre>"
      },
      streaming = true,
      supportsAtLeastOnce = true)
})
public class TextToBigQueryStreaming {

  private static final Logger LOG = LoggerFactory.getLogger(TextToBigQueryStreaming.class);

  /** The tag for the main output for the UDF. */
  private static final TupleTag<FailsafeElement<String, String>> UDF_OUT =
      new TupleTag<FailsafeElement<String, String>>() {};

  /** The tag for the dead-letter output of the udf. */
  private static final TupleTag<FailsafeElement<String, String>> UDF_DEADLETTER_OUT =
      new TupleTag<FailsafeElement<String, String>>() {};

  /** The tag for the main output of the json transformation. */
  private static final TupleTag<TableRow> TRANSFORM_OUT = new TupleTag<TableRow>() {};

  /** The tag for the dead-letter output of the json to table row transform. */
  private static final TupleTag<FailsafeElement<String, String>> TRANSFORM_DEADLETTER_OUT =
      new TupleTag<FailsafeElement<String, String>>() {};

  /** The default suffix for error tables if dead letter table is not specified. */
  private static final String DEFAULT_DEADLETTER_TABLE_SUFFIX = "_error_records";

  /** Default interval for polling files in GCS. */
  private static final Duration DEFAULT_POLL_INTERVAL = Duration.standardSeconds(10);

  /** Coder for FailsafeElement. */
  private static final FailsafeElementCoder<String, String> FAILSAFE_ELEMENT_CODER =
      FailsafeElementCoder.of(StringUtf8Coder.of(), StringUtf8Coder.of());

  private static final JsonFactory JSON_FACTORY = Transport.getJsonFactory();

  /**
   * Main entry point for executing the pipeline. This will run the pipeline asynchronously. If
   * blocking execution is required, use the {@link
   * TextToBigQueryStreaming#run(TextToBigQueryStreamingOptions)} method to start the pipeline and
   * invoke {@code result.waitUntilFinish()} on the {@link PipelineResult}
   *
   * @param args The command-line arguments to the pipeline.
   */
  public static void main(String[] args) {
    UncaughtExceptionLogger.register();

    // Parse the user options passed from the command-line
    TextToBigQueryStreamingOptions options =
        PipelineOptionsFactory.fromArgs(args)
            .withValidation()
            .as(TextToBigQueryStreamingOptions.class);
    BigQueryIOUtils.validateBQStorageApiOptionsStreaming(options);

    run(options);
  }

  /**
   * Runs the pipeline with the supplied options.
   *
   * @param options The execution parameters to the pipeline.
   * @return The result of the pipeline execution.
   */
  public static PipelineResult run(TextToBigQueryStreamingOptions options) {

    // Create the pipeline
    Pipeline pipeline = Pipeline.create(options);

    // Register the coder for pipeline
    FailsafeElementCoder<String, String> coder =
        FailsafeElementCoder.of(StringUtf8Coder.of(), StringUtf8Coder.of());

    CoderRegistry coderRegistry = pipeline.getCoderRegistry();
    coderRegistry.registerCoderForType(coder.getEncodedTypeDescriptor(), coder);

    // Determine if we are using Python UDFs or JS UDFs based on the provided options.
    boolean useJavascriptUdf = !Strings.isNullOrEmpty(options.getJavascriptTextTransformGcsPath());
    boolean usePythonUdf = !Strings.isNullOrEmpty(options.getPythonExternalTextTransformGcsPath());
    if (useJavascriptUdf && usePythonUdf) {
      throw new IllegalArgumentException(
          "Either javascript or Python gcs path must be provided, but not both.");
    }

    /*
     * Steps:
     *  1) Read from the text source continuously.
     *  2) Convert to FailsafeElement.
     *  3) Apply Javascript udf transformation.
     *    - Tag records that were successfully transformed and those
     *      that failed transformation.
     *  4) Convert records to TableRow.
     *    - Tag records that were successfully converted and those
     *      that failed conversion.
     *  5) Insert successfully converted records into BigQuery.
     *    - Errors encountered while streaming will be sent to deadletter table.
     *  6) Insert records that failed into deadletter table.
     */

    PCollection<String> sourceRead =
        pipeline.apply(
            TextIO.read()
                .from(options.getInputFilePattern())
                .watchForNewFiles(DEFAULT_POLL_INTERVAL, Growth.never()));
    PCollectionTuple transformedOutput;
    if (usePythonUdf) {
      transformedOutput =
          sourceRead
              .apply(
                  "MapToRecord",
                  PythonExternalTextTransformer.FailsafeRowPythonExternalUdf
                      .stringMappingFunction())
              .setRowSchema(PythonExternalTextTransformer.FailsafeRowPythonExternalUdf.ROW_SCHEMA)
              .apply(
                  "InvokeUDF",
                  PythonExternalTextTransformer.FailsafePythonExternalUdf.newBuilder()
                      .setFileSystemPath(options.getPythonExternalTextTransformGcsPath())
                      .setFunctionName(options.getPythonExternalTextTransformFunctionName())
                      .build())
              .apply(
                  ParDo.of(new RowToStringFailsafeElementFn(UDF_OUT, UDF_DEADLETTER_OUT))
                      .withOutputTags(UDF_OUT, TupleTagList.of(UDF_DEADLETTER_OUT)));

    } else {
      transformedOutput =
          pipeline

              // 1) Read from the text source continuously.
              .apply(
                  "ReadFromSource",
                  TextIO.read()
                      .from(options.getInputFilePattern())
                      .watchForNewFiles(DEFAULT_POLL_INTERVAL, Growth.never()))

              // 2) Convert to FailsafeElement.
              .apply(
                  "ConvertToFailsafeElement",
                  MapElements.into(FAILSAFE_ELEMENT_CODER.getEncodedTypeDescriptor())
                      .via(input -> FailsafeElement.of(input, input)))

              // 3) Apply Javascript udf transformation.
              .apply(
                  "ApplyUDFTransformation",
                  FailsafeJavascriptUdf.<String>newBuilder()
                      .setFileSystemPath(options.getJavascriptTextTransformGcsPath())
                      .setFunctionName(options.getJavascriptTextTransformFunctionName())
                      .setReloadIntervalMinutes(
                          options.getJavascriptTextTransformReloadIntervalMinutes())
                      .setSuccessTag(UDF_OUT)
                      .setFailureTag(UDF_DEADLETTER_OUT)
                      .build());
    }

    PCollectionTuple convertedTableRows =
        transformedOutput

            // 4) Convert records to TableRow.
            .get(UDF_OUT)
            .apply(
                "ConvertJSONToTableRow",
                FailsafeJsonToTableRow.<String>newBuilder()
                    .setSuccessTag(TRANSFORM_OUT)
                    .setFailureTag(TRANSFORM_DEADLETTER_OUT)
                    .build());

    WriteResult writeResult =
        convertedTableRows

            // 5) Insert successfully converted records into BigQuery.
            .get(TRANSFORM_OUT)
            .apply(
                "InsertIntoBigQuery",
                BigQueryIO.writeTableRows()
                    .withJsonSchema(GCSUtils.getGcsFileAsString(options.getJSONPath()))
                    .to(options.getOutputTable())
                    .withExtendedErrorInfo()
                    .withoutValidation()
                    .withCreateDisposition(CreateDisposition.CREATE_IF_NEEDED)
                    .withWriteDisposition(WriteDisposition.WRITE_APPEND)
                    .withFailedInsertRetryPolicy(InsertRetryPolicy.retryTransientErrors())
                    .withCustomGcsTempLocation(
                        StaticValueProvider.of(options.getBigQueryLoadingTemporaryDirectory())));

    // Elements that failed inserts into BigQuery are extracted and converted to FailsafeElement
    PCollection<FailsafeElement<String, String>> failedInserts =
        BigQueryIOUtils.writeResultToBigQueryInsertErrors(writeResult, options)
            .apply(
                "WrapInsertionErrors",
                MapElements.into(FAILSAFE_ELEMENT_CODER.getEncodedTypeDescriptor())
                    .via(TextToBigQueryStreaming::wrapBigQueryInsertError));

    // 6) Insert records that failed transformation or conversion into deadletter table
    PCollectionList.of(
            ImmutableList.of(
                transformedOutput.get(UDF_DEADLETTER_OUT),
                convertedTableRows.get(TRANSFORM_DEADLETTER_OUT),
                failedInserts))
        .apply("Flatten", Flatten.pCollections())
        .apply(
            "WriteFailedRecords",
            WriteStringMessageErrors.newBuilder()
                .setErrorRecordsTable(
                    StringUtils.isNotEmpty(options.getOutputDeadletterTable())
                        ? options.getOutputDeadletterTable()
                        : options.getOutputTable() + DEFAULT_DEADLETTER_TABLE_SUFFIX)
                .setErrorRecordsTableSchema(ResourceUtils.getDeadletterTableSchemaJson())
                .build());

    return pipeline.run();
  }

  /**
   * Method to wrap a {@link BigQueryInsertError} into a {@link FailsafeElement}.
   *
   * @param insertError BigQueryInsert error.
   * @return FailsafeElement object.
   * @throws IOException
   */
  static FailsafeElement<String, String> wrapBigQueryInsertError(BigQueryInsertError insertError) {

    FailsafeElement<String, String> failsafeElement;
    try {

      String rowPayload = JSON_FACTORY.toString(insertError.getRow());
      String errorMessage = JSON_FACTORY.toString(insertError.getError());

      failsafeElement = FailsafeElement.of(rowPayload, rowPayload);
      failsafeElement.setErrorMessage(errorMessage);

    } catch (IOException e) {
      throw new RuntimeException(e);
    }

    return failsafeElement;
  }

  /**
   * The {@link TextToBigQueryStreamingOptions} class provides the custom execution options passed
   * by the executor at the command-line.
   */
  public interface TextToBigQueryStreamingOptions
      extends TextIOToBigQuery.Options, BigQueryStorageApiStreamingOptions {
    @TemplateParameter.BigQueryTable(
        order = 1,
        optional = true,
        description = "The dead-letter table name to output failed messages to BigQuery",
        helpText =
            "Table for messages that failed to reach the output table. If a table doesn't exist, it is created during "
                + "pipeline execution. If not specified, `<outputTableSpec>_error_records` is used.",
        example = "<PROJECT_ID>:<DATASET_NAME>.<TABLE_NAME>")
    String getOutputDeadletterTable();

    void setOutputDeadletterTable(String value);

    // Hide the UseStorageWriteApiAtLeastOnce in the UI, because it will automatically be turned
    // on when pipeline is running on ALO mode and using the Storage Write API
    @TemplateParameter.Boolean(
        order = 2,
        optional = true,
        parentName = "useStorageWriteApi",
        parentTriggerValues = {"true"},
        description = "Use at at-least-once semantics in BigQuery Storage Write API",
        helpText =
            "This parameter takes effect only if `Use BigQuery Storage Write API` is enabled. If"
                + " enabled the at-least-once semantics will be used for Storage Write API, otherwise"
                + " exactly-once semantics will be used.",
        hiddenUi = true)
    @Default.Boolean(false)
    @Override
    Boolean getUseStorageWriteApiAtLeastOnce();

    void setUseStorageWriteApiAtLeastOnce(Boolean value);
  }
}

다음 단계