Cloud Storage Text to BigQuery template

The Cloud Storage Text to BigQuery pipeline is a batch pipeline that reads text files stored in Cloud Storage, transforms them using a JavaScript user-defined Function (UDF), and appends the result to a BigQuery table.

Pipeline requirements

  • Create a JSON file that describes your BigQuery schema.

    Ensure that there is a top-level JSON array titled BigQuery Schema and that its contents follow the pattern {"name": "COLUMN_NAME", "type": "DATA_TYPE"}.

    The Cloud Storage Text to BigQuery batch template doesn't support importing data into STRUCT (Record) fields in the target BigQuery table.

    The following JSON describes an example BigQuery schema:

    {
  "BigQuery Schema": [
    {
      "name": "name",
      "type": "STRING"
    },
    {
      "name": "age",
      "type": "INTEGER"
    },
  ]
}
  • Create a JavaScript (.js) file with your UDF function that supplies the logic to transform the lines of text. Your function must return a JSON string.

    For example, this function splits each line of a CSV file and returns a JSON string after transforming the values.

    function process(inJson) {
  val = inJson.split(",");

  const obj = { "name": val[0], "age": parseInt(val[1]) };
  return JSON.stringify(obj);
}

Template parameters

Required parameters

  • inputFilePattern : The gs:// path to the text in Cloud Storage you'd like to process. (Example: gs://your-bucket/your-file.txt).
  • JSONPath : The gs:// path to the JSON file that defines your BigQuery schema, stored in Cloud Storage. (Example: gs://your-bucket/your-schema.json).
  • outputTable : The location of the BigQuery table to use to store the processed data. If you reuse an existing table, it is overwritten. (Example: <PROJECT_ID>:<DATASET_NAME>.<TABLE_NAME>).
  • javascriptTextTransformGcsPath : The Cloud Storage URI of the .js file that defines the JavaScript user-defined function (UDF) you want to use. (Example: gs://your-bucket/your-transforms/*.js).
  • javascriptTextTransformFunctionName : The name of the JavaScript user-defined function (UDF) that you want to use. For example, if your JavaScript function code is myTransform(inJson) { /*...do stuff...*/ }, then the function name is myTransform. For sample JavaScript UDFs, see UDF Examples (https://github.com/GoogleCloudPlatform/DataflowTemplates#udf-examples) (Example: transform_udf1).
  • bigQueryLoadingTemporaryDirectory : Temporary directory for BigQuery loading process. (Example: gs://your-bucket/your-files/temp-dir).

Optional parameters

User-defined function

Optionally, you can extend this template by writing a user-defined function (UDF). The template calls the UDF for each input element. Element payloads are serialized as JSON strings. For more information, see Create user-defined functions for Dataflow templates.

Function specification

The UDF has the following specification:

  • Input: a line of text from a Cloud Storage input file.
  • Output: a JSON string that matches the schema of the BigQuery destination table.

Run the template

Console

  1. Go to the Dataflow Create job from template page.
    2. 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 region 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 Text Files on Cloud Storage to BigQuery (Batch) template.
  5. In the provided parameter fields, enter your parameter values.
  6. Click Run job.

gcloud

In your shell or terminal, run the template:

gcloud dataflow flex-template run JOB_NAME \
    --template-file-gcs-location gs://dataflow-templates-REGION_NAME/VERSION/flex/GCS_Text_to_BigQuery_Flex \
    --region REGION_NAME \
    --parameters \
javascriptTextTransformFunctionName=JAVASCRIPT_FUNCTION,\
JSONPath=PATH_TO_BIGQUERY_SCHEMA_JSON,\
javascriptTextTransformGcsPath=PATH_TO_JAVASCRIPT_UDF_FILE,\
inputFilePattern=PATH_TO_TEXT_DATA,\
outputTable=BIGQUERY_TABLE,\
bigQueryLoadingTemporaryDirectory=PATH_TO_TEMP_DIR_ON_GCS

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:

  • REGION_NAME: the region where you want to deploy your Dataflow job—for example, us-central1
  • JAVASCRIPT_FUNCTION: the name of the JavaScript user-defined function (UDF) that you want to use

    For example, if your JavaScript function code is myTransform(inJson) { /*...do stuff...*/ }, then the function name is myTransform. For sample JavaScript UDFs, see UDF Examples.

  • PATH_TO_BIGQUERY_SCHEMA_JSON: the Cloud Storage path to the JSON file containing the schema definition
  • PATH_TO_JAVASCRIPT_UDF_FILE: the Cloud Storage URI of the .js file that defines the JavaScript user-defined function (UDF) you want to use—for example, gs://my-bucket/my-udfs/my_file.js
  • PATH_TO_TEXT_DATA: your Cloud Storage path to your text dataset
  • BIGQUERY_TABLE: your BigQuery table name
  • PATH_TO_TEMP_DIR_ON_GCS: your Cloud Storage path to the temp directory

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/flexTemplates:launch
{
   "launch_parameter": {
      "jobName": "JOB_NAME",
      "parameters": {
        "javascriptTextTransformFunctionName": "JAVASCRIPT_FUNCTION",
        "JSONPath": "PATH_TO_BIGQUERY_SCHEMA_JSON",
        "javascriptTextTransformGcsPath": "PATH_TO_JAVASCRIPT_UDF_FILE",
        "inputFilePattern":"PATH_TO_TEXT_DATA",
        "outputTable":"BIGQUERY_TABLE",
        "bigQueryLoadingTemporaryDirectory": "PATH_TO_TEMP_DIR_ON_GCS"
      },
      "containerSpecGcsPath": "gs://dataflow-templates-LOCATION/VERSION/flex/GCS_Text_to_BigQuery_Flex",
   }
}

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:

  • LOCATION: the region where you want to deploy your Dataflow job—for example, us-central1
  • JAVASCRIPT_FUNCTION: the name of the JavaScript user-defined function (UDF) that you want to use

    For example, if your JavaScript function code is myTransform(inJson) { /*...do stuff...*/ }, then the function name is myTransform. For sample JavaScript UDFs, see UDF Examples.

  • PATH_TO_BIGQUERY_SCHEMA_JSON: the Cloud Storage path to the JSON file containing the schema definition
  • PATH_TO_JAVASCRIPT_UDF_FILE: the Cloud Storage URI of the .js file that defines the JavaScript user-defined function (UDF) you want to use—for example, gs://my-bucket/my-udfs/my_file.js
  • PATH_TO_TEXT_DATA: your Cloud Storage path to your text dataset
  • BIGQUERY_TABLE: your BigQuery table name
  • PATH_TO_TEMP_DIR_ON_GCS: your Cloud Storage path to the temp directory

What's next