co.cask.hydrator.plugin.Hasher Maven / Gradle / Ivy

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/*
 * Copyright © 2015 Cask Data, Inc.
 *
 * 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 co.cask.hydrator.plugin;

import co.cask.cdap.api.annotation.Description;
import co.cask.cdap.api.annotation.Name;
import co.cask.cdap.api.annotation.Plugin;
import co.cask.cdap.api.data.format.StructuredRecord;
import co.cask.cdap.api.data.schema.Schema;
import co.cask.cdap.api.plugin.PluginConfig;
import co.cask.cdap.etl.api.Emitter;
import co.cask.cdap.etl.api.PipelineConfigurer;
import co.cask.cdap.etl.api.Transform;
import co.cask.cdap.etl.api.TransformContext;
import org.apache.commons.codec.digest.DigestUtils;

import java.util.HashSet;
import java.util.List;
import java.util.Set;
import javax.annotation.Nullable;

/**
 * Hash field(s) values using one the the digest algorithms.
 */
@Plugin(type = "transform")
@Name("Hasher")
@Description("Encodes field values using one of the digest algorithms. MD2, MD5, SHA1, SHA256, " +
  "SHA384 and SHA512 are the supported message digest algorithms.")
public final class Hasher extends Transform {
  private final Config config;
  private Set fieldSet = new HashSet<>();


  // For testing purpose only.
  public Hasher(Config config) {
    this.config = config;
  }

  @Override
  public void initialize(TransformContext context) throws Exception {
    super.initialize(context);
    config.validate();
    // Split the fields to be hashed.
    String[] fields = config.fields.split(",");
    for (String field : fields) {
      fieldSet.add(field);
    }
  }

  @Override
  public void configurePipeline(PipelineConfigurer pipelineConfigurer) throws IllegalArgumentException {
    super.configurePipeline(pipelineConfigurer);
    config.validate();
    pipelineConfigurer.getStageConfigurer().setOutputSchema(pipelineConfigurer.getStageConfigurer().getInputSchema());
  }

  @Override
  public void transform(StructuredRecord in, Emitter emitter) throws Exception {
    StructuredRecord.Builder builder = StructuredRecord.builder(in.getSchema());
    
    List fields = in.getSchema().getFields();
    for (Schema.Field field : fields) {
      String name = field.getName();
      if (fieldSet.contains(name) && field.getSchema().getType() == Schema.Type.STRING) {
        String value = in.get(name);
        String digest = value;
        switch(config.hash.toLowerCase()) {
          case "md2":
            digest = DigestUtils.md2Hex(value);
            break;
          case "md5":
            digest = DigestUtils.md5Hex(value);
            break;
          case "sha1":
            digest = DigestUtils.sha1Hex(value);
            break;
          case "sha256":
            digest = DigestUtils.sha256Hex(value);
            break;
          case "sha384":
            digest = DigestUtils.sha384Hex(value);
            break;
          case "sha512":
            digest = DigestUtils.sha512Hex(value);
            break;
        }
        builder.set(name, digest);
      } else {
        builder.set(name, in.get(name));
      }
    }
    emitter.emit(builder.build());
  }

  /**
   * Hasher Plugin Config.
   */
  public static class Config extends PluginConfig {
    @Name("hash")
    @Description("Specifies the Hash method for hashing fields.")
    @Nullable
    private final String hash;
    
    @Name("fields")
    @Description("List of fields to hash. Only string fields are allowed")
    private final String fields;
    
    public Config(String hash, String fields) {
      this.hash = hash;
      this.fields = fields;
    }

    private void validate() {
      // Checks if hash specified is one of the supported types.
      if (!hash.equalsIgnoreCase("md2") && !hash.equalsIgnoreCase("md5") &&
        !hash.equalsIgnoreCase("sha1") && !hash.equalsIgnoreCase("sha256") &&
        !hash.equalsIgnoreCase("sha384") && !hash.equalsIgnoreCase("sha512")) {
        throw new IllegalArgumentException("Invalid hasher '" + hash + "' specified. Allowed hashers are md2, " +
                                             "md5, sha1, sha256, sha384 and sha512");
      }
    }
  }
}