flume自定義攔截器

下面看一下源碼中時間戳的攔截器apache

public class TimestampInterceptor implements Interceptor {

  private final boolean preserveExisting;

  /**
   * Only {@link TimestampInterceptor.Builder} can build me
   */
  private TimestampInterceptor(boolean preserveExisting) {
    this.preserveExisting = preserveExisting;
  }

  @Override
  public void initialize() {
    // no-op
  }

  /**
   * Modifies events in-place.
    *這個是對單個事件的處理
   */
  @Override
  public Event intercept(Event event) {
//得到事件中的全部頭信息,都是以key-value的形式存儲
    Map<String, String> headers = event.getHeaders();
    if (preserveExisting && headers.containsKey(TIMESTAMP)) {
      // we must preserve the existing timestamp
    } else {
      long now = System.currentTimeMillis();
    //把時間戳放到頭信息
      headers.put(TIMESTAMP, Long.toString(now));
    }
    return event;
  }

  /**
   * Delegates to {@link #intercept(Event)} in a loop.
   * @param events
    *這是對多個事件的處理
   * @return
   */
  @Override
  public List<Event> intercept(List<Event> events) {
    for (Event event : events) {
      intercept(event);
    }
    return events;
  }

  @Override
  public void close() {
    // no-op
  }

  /**
   * Builder which builds new instances of the TimestampInterceptor.
    *這個方法是必須實現的,這個接口Interceptor中註釋明確必須實現
   */
  public static class Builder implements Interceptor.Builder {

    private boolean preserveExisting = PRESERVE_DFLT;

    @Override
    public Interceptor build() {
      return new TimestampInterceptor(preserveExisting);
    }

    @Override
    public void configure(Context context) {
      preserveExisting = context.getBoolean(PRESERVE, PRESERVE_DFLT);
    }

  }

  public static class Constants {
    public static String TIMESTAMP = "timestamp";
    public static String PRESERVE = "preserveExisting";
    public static boolean PRESERVE_DFLT = false;
  }

}

你們能夠寫本身的過濾器,特別對於log4j的日誌處理,例如若是你的日誌每個小時生成一個文件,可是我要把它按照天來存儲,你們能夠按照這個這種形式實現. 把生成的包放到/app/apache-flume-1.7.0-bin/plugins.d/interceptor/lib下,若是/plugins.d不存在,本身就創建這個目錄就能夠. 在配置文件中添加:xxx.sources.r1.interceptors.i1.type = com.hc360.interceptor.DateTimeSuffixInterceptor$Builder就能夠。 如今想把本身作的一些東西記錄一下,堅持,堅持。。。。。。。。。。。。。。app

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