OpenTelemetry笔记(5)-Instrumentation

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概念

Instrumentation 表示对一种特定组件交互的跟踪封装，比如 MQ，HTTP，方法调用等

接口定义

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public class Instrumenter<REQUEST, RESPONSE> {

    boolean shouldStart(Context parentContext, REQUEST request);
    Context start(Context parentContext, REQUEST request);
    void end(
      Context context, REQUEST request, @Nullable RESPONSE response, @Nullable Throwable error);

其定义了 start 和 end 方法来代替手动创建 Span 的过程

  • request 表示输入端的参数
  • response 表示输出结果，error 表示输出结果是否有异常

构造 Instrumenter

Instrumenter 的要素比较多，其构建时使用 InstrumenterBuilder 进行构造

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public class Instrumenter<REQUEST, RESPONSE> {
    public static <REQUEST, RESPONSE> InstrumenterBuilder<REQUEST, RESPONSE> builder(
          OpenTelemetry openTelemetry,
          String instrumentationName,
          SpanNameExtractor<? super REQUEST> spanNameExtractor);
}

调用示例

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Instrumenter instrumenter =
    Instrumenter.builder(openTelemetry, INSTRUMENTATION_NAME, WithSpanAspect::spanName)
        .addAttributesExtractor(
            MethodSpanAttributesExtractor.newInstance(
                JoinPointRequest::method,
                parameterAttributeNamesExtractor,
                JoinPointRequest::args))
        .newInstrumenter(WithSpanAspect::spanKind);

Extractor

Instrumentation 接口中存在着非常多的 Extractor,其对对象的某一些属性进行抽取，可以理解为内容过滤器，如下定义

  • SpanKeyExtractor
  • SpanKindExtractor
  • SpanLinksExtractor
  • SpanNameExtractor
  • SpanStatusExtractor
  • AttributesExtractor
  • TimeExtractor

AttributesExtractor

  • MethodSpanAttributesExtractor
  • MethodExtractor
  • ParameterAttributeNamesExtractor
  • MethodArgumentsExtractor