io.axual.connect.plugins.http.headerselection.BasicHeaderSelectorConfig Maven / Gradle / Ivy

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This connector is used to call an HTTP service for each record on a topic
There is a newer version: 1.1.0-RC1
package io.axual.connect.plugins.http.headerselection;

/*-
 * ========================LICENSE_START=================================
 * HTTP Sink Connector for Kafka Connect
 * %%
 * Copyright (C) 2020 Axual B.V.
 * %%
 * 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.
 * =========================LICENSE_END==================================
 */

import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import org.apache.kafka.common.config.AbstractConfig;
import org.apache.kafka.common.config.ConfigDef;
import org.apache.kafka.common.config.ConfigDef.Importance;
import org.apache.kafka.common.config.ConfigDef.NonEmptyStringWithoutControlChars;
import org.apache.kafka.common.config.ConfigDef.Type;
import org.apache.kafka.common.config.ConfigException;

/**
 * Provides the configuration and validation definitions for the {@link BasicHeaderSelector}
 * Because of the dynamic nature of the configuration properties the definitions are created
 * with
 * the {@link #enrichConfig(Map)} method.
 */
public class BasicHeaderSelectorConfig extends AbstractConfig {

  public static final String HEADER_ALIAS_CONFIG = "headers";
  private static final String HEADER_ALIAS_DEFAULT = "";
  private static final String HEADER_ALIAS_DOC = "This is a comma separated list of header alias for the header. Example headers=ab,cd would need configurations headers.ab.key=Custom-Header1 and headers.cd=Another-Header";

  public static final String HEADER_KEY_CONFIG_FORMAT = HEADER_ALIAS_CONFIG + ".%s.key";
  private static final String HEADER_KEY_DOC = "The actual Kafka Header name to use";

  /**
   * Creates the Configuration Definition based on the configuration properties provided.
 When
   * the {@link #HEADER_ALIAS_CONFIG} is set it will use the aliases to create the additional
   * configuration definitions per alias
   *
   * @param configs The map with configuration properties
   * @return The configuration definition enriched according to the contents of the provided
   * properties
   */
  public static ConfigDef enrichConfig(Map configs) {
    Object headerAliases = ConfigDef
        .parseType(HEADER_ALIAS_CONFIG, configs.get(HEADER_ALIAS_CONFIG), Type.LIST);
    ConfigDef newDef = new ConfigDef()
        .define(HEADER_ALIAS_CONFIG, Type.LIST, HEADER_ALIAS_DEFAULT, Importance.HIGH,
            HEADER_ALIAS_DOC);

    if (!(headerAliases instanceof List)) {
      // happens when HEADER_ALIAS_CONFIG is not set
      return newDef;
    }

    LinkedHashSet uniqueHeaderAliases = new LinkedHashSet<>((List) headerAliases);
    for (Object aliasElement : uniqueHeaderAliases) {
      if (!(aliasElement instanceof String)) {
        throw new ConfigException(
            "All elements of " + HEADER_ALIAS_CONFIG + " property should be of type String");
      }

      final String alias = ((String) aliasElement).trim();
      if (((String) aliasElement).isEmpty()) {
        throw new ConfigException(
            "An element of " + HEADER_ALIAS_CONFIG + " property is an empty String");
      }

      final String keyConfig = String.format(HEADER_KEY_CONFIG_FORMAT, alias);
      newDef.define(keyConfig, Type.STRING, ConfigDef.NO_DEFAULT_VALUE,
          new NonEmptyStringWithoutControlChars(), Importance.HIGH, HEADER_KEY_DOC);
    }

    return newDef;
  }

  public BasicHeaderSelectorConfig(Map originals) {
    super(enrichConfig(originals), originals);
  }

  /**
   * @return Returns the list of aliases defined in the properties
   */
  public List getHeaderAliases() {
    return getList(HEADER_ALIAS_CONFIG);
  }

  /**
   * Returns the header key for a specific alias. 
 This key is the exact name of the required
   * Kafka Header
   *
   * @param alias the alias to retrieve the Kafka Header key for
   * @return the exact name of the required Kafka Header the alias refers to
   */
  public String getHeaderKey(String alias) {
    return getString(String.format(HEADER_KEY_CONFIG_FORMAT, alias));
  }
}