AbstractLogAppender.java

/*
 * Copyright 2014-2016 CyberVision, 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 org.kaaproject.kaa.server.common.log.shared.appender;

import org.apache.avro.generic.GenericRecord;
import org.apache.avro.specific.SpecificRecordBase;
import org.kaaproject.kaa.common.avro.AvroByteArrayConverter;
import org.kaaproject.kaa.common.avro.GenericAvroConverter;
import org.kaaproject.kaa.common.dto.logs.LogAppenderDto;
import org.kaaproject.kaa.common.dto.logs.LogEventDto;
import org.kaaproject.kaa.common.dto.logs.LogHeaderStructureDto;
import org.kaaproject.kaa.server.common.log.shared.avro.gen.RecordHeader;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


public abstract class AbstractLogAppender<T extends SpecificRecordBase> implements LogAppender {

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

  private static final int LOG_HEADER_VERSION = 1;
  private final Class<T> configurationClass;

  private Map<String, GenericAvroConverter<GenericRecord>> converters = new HashMap<>();

  private String appenderId;

  private String name;

  private String applicationToken;

  private List<LogHeaderStructureDto> header;
  private int minSchemaVersion;
  private int maxSchemaVersion;
  private boolean confirmDelivery;

  public AbstractLogAppender(Class<T> configurationClass) {
    this.configurationClass = configurationClass;
  }

  /**
   * Log in <code>LogAppender</code> specific way.
   *
   * @param logEventPack the pack of Log Events
   * @param header       the header
   * @param listener     the listener
   */
  public abstract void doAppend(LogEventPack logEventPack, RecordHeader header,
                                LogDeliveryCallback listener);

  @Override
  public void doAppend(LogEventPack logEventPack, LogDeliveryCallback listener) {
    if (logEventPack != null) {
      doAppend(logEventPack, generateHeader(logEventPack), listener);
    } else {
      LOG.warn("Can't append log events. LogEventPack object is null.");
    }
  }

  /**
   * Change parameters of log appender.
   *
   * @param appender      the appender
   * @param configuration the configuration
   */
  protected abstract void initFromConfiguration(LogAppenderDto appender, T configuration);

  /**
   * Change parameters of log appender.
   *
   * @param appender      the appender
   */
  public void initLogAppender(LogAppenderDto appender) {
    this.minSchemaVersion = appender.getMinLogSchemaVersion();
    this.maxSchemaVersion = appender.getMaxLogSchemaVersion();
    this.confirmDelivery = appender.isConfirmDelivery();
    byte[] rawConfiguration = appender.getRawConfiguration();
    try {
      AvroByteArrayConverter<T> converter = new AvroByteArrayConverter<>(configurationClass);
      T configuration = converter.fromByteArray(rawConfiguration);
      initFromConfiguration(appender, configuration);
    } catch (IOException ex) {
      LOG.error("Unable to parse configuration for appender '" + getName() + "'", ex);
    }
  }

  @Override
  public String getName() {
    return name;
  }

  @Override
  public void setName(String name) {
    this.name = name;
  }

  @Override
  public String getAppenderId() {
    return appenderId;
  }

  @Override
  public void setAppenderId(String appenderId) {
    this.appenderId = appenderId;
  }

  /**
   * Gets the application token.
   *
   * @return the applicationToken
   */
  public String getApplicationToken() {
    return applicationToken;
  }

  @Override
  public void setApplicationToken(String applicationToken) {
    this.applicationToken = applicationToken;
  }

  /**
   * Gets the header.
   *
   * @return the header
   */
  public List<LogHeaderStructureDto> getHeader() {
    return header;
  }

  /**
   * Sets the header.
   *
   * @param header the new header
   */
  public void setHeader(List<LogHeaderStructureDto> header) {
    this.header = header;
  }

  @Override
  public void init(LogAppenderDto appender) {
    this.header = appender.getHeaderStructure();
    initLogAppender(appender);
  }



  @Override
  public boolean isSchemaVersionSupported(int version) {
    return minSchemaVersion <= version && version <= maxSchemaVersion;
  }

  @Override
  public boolean isDeliveryConfirmationRequired() {
    return confirmDelivery;
  }

  /**
   * Generate log event.
   *
   * @param logEventPack the log event pack
   * @param header       the header
   * @return the list
   * @throws IOException the io exception
   */
  protected List<LogEventDto> generateLogEvent(LogEventPack logEventPack, RecordHeader header)
      throws IOException {
    LOG.debug("Generate LogEventDto objects from LogEventPack [{}] and header [{}]",
        logEventPack, header);
    List<LogEventDto> events = new ArrayList<>(logEventPack.getEvents().size());
    GenericAvroConverter<GenericRecord> eventConverter = getConverter(
        logEventPack.getLogSchema().getSchema());
    GenericAvroConverter<GenericRecord> headerConverter = getConverter(
        header.getSchema().toString());
    try {
      for (LogEvent logEvent : logEventPack.getEvents()) {
        LOG.debug("Convert log events [{}] to dto objects.", logEvent);
        if (logEvent == null || logEvent.getLogData() == null) {
          continue;
        }
        LOG.trace("Avro record converter [{}] with log data [{}]",
            eventConverter, logEvent.getLogData());
        GenericRecord decodedLog = eventConverter.decodeBinary(logEvent.getLogData());
        LOG.trace("Avro header record converter [{}]", headerConverter);
        String encodedJsonLogHeader = headerConverter.encodeToJson(header);
        String encodedJsonLog = eventConverter.encodeToJson(decodedLog);
        events.add(new LogEventDto(encodedJsonLogHeader, encodedJsonLog));
      }
    } catch (IOException ex) {
      LOG.error("Unexpected IOException while decoding LogEvents", ex);
      throw ex;
    }
    return events;
  }

  /**
   * Gets the converter.
   *
   * @param schema the schema
   * @return the converter
   */
  private GenericAvroConverter<GenericRecord> getConverter(String schema) {
    LOG.trace("Get converter for schema [{}]", schema);
    GenericAvroConverter<GenericRecord> genAvroConverter = converters.get(schema);
    if (genAvroConverter == null) {
      LOG.trace("Create new converter for schema [{}]", schema);
      genAvroConverter = new GenericAvroConverter<>(schema);
      converters.put(schema, genAvroConverter);
    }
    LOG.trace("Get converter [{}] from map.", genAvroConverter);
    return genAvroConverter;
  }

  /**
   * Generate header.
   *
   * @param logEventPack the log event pack
   * @return the log header
   */
  private RecordHeader generateHeader(LogEventPack logEventPack) {
    RecordHeader logHeader = null;
    if (header != null) {
      logHeader = new RecordHeader();
      for (LogHeaderStructureDto field : header) {
        switch (field) {
          case KEYHASH:
            logHeader.setEndpointKeyHash(logEventPack.getEndpointKey());
            break;
          case TIMESTAMP:
            logHeader.setTimestamp(System.currentTimeMillis());
            break;
          case TOKEN:
            logHeader.setApplicationToken(applicationToken);
            break;
          case VERSION:
            logHeader.setHeaderVersion(LOG_HEADER_VERSION);
            break;
          case LSVERSION:
            logHeader.setLogSchemaVersion(logEventPack.getLogSchema().getVersion());
            break;
          default:
            if (LOG.isWarnEnabled()) {
              LOG.warn("Current header field [{}] doesn't support", field);
            }
            break;
        }
      }
    }
    return logHeader;
  }

}