content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you 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 org.apache.beam.examples.complete.cdap.zendesk;
  
  import static org.apache.beam.examples.complete.cdap.zendesk.transforms.FormatInputTransform.readFromCdapZendesk;
  
  import io.cdap.cdap.api.data.format.StructuredRecord;
  import java.util.Map;
  import org.apache.beam.examples.complete.cdap.utils.StructuredRecordUtils;
  import org.apache.beam.examples.complete.cdap.zendesk.options.CdapZendeskOptions;
  import org.apache.beam.examples.complete.cdap.zendesk.utils.PluginConfigOptionsConverter;
  import org.apache.beam.sdk.Pipeline;
  import org.apache.beam.sdk.PipelineResult;
  import org.apache.beam.sdk.coders.KvCoder;
  import org.apache.beam.sdk.coders.NullableCoder;
  import org.apache.beam.sdk.coders.SerializableCoder;
  import org.apache.beam.sdk.coders.StringUtf8Coder;
  import org.apache.beam.sdk.io.TextIO;
  import org.apache.beam.sdk.io.hadoop.WritableCoder;
  import org.apache.beam.sdk.options.PipelineOptionsFactory;
  import org.apache.beam.sdk.transforms.MapValues;
  import org.apache.beam.sdk.transforms.Values;
  import org.apache.beam.sdk.values.TypeDescriptors;
  import org.apache.hadoop.io.NullWritable;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * The {@link CdapZendeskToTxt} pipeline is a batch pipeline which ingests data in JSON format from
   * CDAP Zendesk, and outputs the resulting records to .txt file. Zendesk parameters and output txt
   * file path are specified by the user as template parameters. <br>
   *
   * <p><b>Example Usage</b>
   *
   * <pre>
   * # Gradle preparation
   *
   * To run this example your {@code build.gradle} file should contain the following task
   * to execute the pipeline:
   * {@code
   * task executeCdap (type:JavaExec) {
   *     mainClass = System.getProperty("mainClass")
   *     classpath = sourceSets.main.runtimeClasspath
   *     systemProperties System.getProperties()
   *     args System.getProperty("exec.args", "").split()
   * }
   * }
   *
   * This task allows to run the pipeline via the following command:
   * {@code
   * gradle clean executeCdap -DmainClass=org.apache.beam.examples.complete.cdap.zendesk.CdapZendeskToTxt \
   *      -Dexec.args="--<argument>=<value> --<argument>=<value>"
   * }
   *
   * # Running the pipeline
   * To execute this pipeline, specify the parameters in the following format:
   * {@code
   * --zendeskBaseUrl=your-url \
   * --adminEmail=your-email \
   * --apiToken=your-token \
   * --objectsToPull=Groups \
   * --referenceName=your-reference-name \
   * --outputTxtFilePathPrefix=your-path-to-output-folder-with-filename-prefix
   * }
   *
   * By default this will run the pipeline locally with the DirectRunner. To change the runner, specify:
   * {@code
   * --runner=YOUR_SELECTED_RUNNER
   * }
   * </pre>
   */
  public class CdapZendeskToTxt {
  
    /* Logger for class.*/
    private static final Logger LOG = LoggerFactory.getLogger(CdapZendeskToTxt.class);
  
    /**
     * Main entry point for pipeline execution.
     *
     * @param args Command line arguments to the pipeline.
     */
    public static void main(String[] args) {
      CdapZendeskOptions options =
          PipelineOptionsFactory.fromArgs(args).withValidation().as(CdapZendeskOptions.class);
  
      // Create the pipeline
      Pipeline pipeline = Pipeline.create(options);
      run(pipeline, options);
    }
  
    /**
     * Runs a pipeline which reads message from CDAP and writes it to .txt file.
     *
     * @param options arguments to the pipeline
     */
    public static PipelineResult run(Pipeline pipeline, CdapZendeskOptions options) {
      Map<String, Object> pluginConfigParams =
          PluginConfigOptionsConverter.zendeskOptionsToParamsMap(options);
      LOG.info("Starting Cdap-Zendesk-To-Txt pipeline with parameters: {}", pluginConfigParams);
  
      /*
       * Steps:
       *  1) Read messages in from Cdap Zendesk
       *  2) Extract values only
       *  3) Write successful records to .txt file
       */
  
      pipeline
          .apply("readFromCdapZendesk", readFromCdapZendesk(pluginConfigParams))
          .setCoder(
              KvCoder.of(
                  NullableCoder.of(WritableCoder.of(NullWritable.class)),
                  SerializableCoder.of(StructuredRecord.class)))
          .apply(
              MapValues.into(TypeDescriptors.strings())
                  .via(StructuredRecordUtils::structuredRecordToString))
          .setCoder(
              KvCoder.of(
                  NullableCoder.of(WritableCoder.of(NullWritable.class)), StringUtf8Coder.of()))
          .apply(Values.create())
          .apply("writeToTxt", TextIO.write().to(options.getOutputTxtFilePathPrefix()));
  
      return pipeline.run();
    }
  }
  