在响应中注入跟踪标头

Question

INFO [AppName,5dd62861a751e1b0,5dd62861a751e1b0,true]

X-B3-TraceId
X-B3-SpanId

public class RequestResponseFilter implements Filter {

    private final Tracer tracer;
    private final Injector<HttpServletResponse> tracingInjector;
    
    public RequestResponseFilter(final Tracing tracing, final Tracer tracer) {
        this.tracer = tracer;
        this.tracingInjector = tracing.propagation().injector(HttpServletResponse::addHeader);
    }

    @Override
    public void doFilter(final ServletRequest request, final ServletResponse response,
        final FilterChain chain) throws IOException, ServletException {

        final HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        final HttpServletResponse httpServletResponse = (HttpServletResponse) response;

        ....

        // inject tracing header
        Span currentSpan = tracer.currentSpan();
        tracingInjector.inject(currentSpan.context(), httpServletResponse);

        chain.doFilter(httpServletRequest, httpServletResponse);
    }
}

b3: 5dd62861a751e1b0,5dd62861a751e1b0-1

怎么啦？

Answer 1

如果您查看它编写的如何自定义HTTP服务器的文档，span-https://docs.spring.io/spring-cloud-sleuth/docs/current/reference/html/howto.html#how-to-cutomize-http-server-spans，因为您可以访问HttpServletResponse和TraceContext，您可以检索跟踪id/span id并将其放在响应中。

侦探3.x

@Configuration(proxyBeanMethods = false)
public static class ServerParserConfiguration {

    @Bean(name = HttpServerRequestParser.NAME)
    HttpRequestParser myHttpRequestParser() {
        return (request, context, span) -> {
            // Span customization
            span.tag("ServerRequest", "Tag");
            Object unwrap = request.unwrap();
            if (unwrap instanceof HttpServletRequest) {
                HttpServletRequest req = (HttpServletRequest) unwrap;
                // Span customization
                span.tag("ServerRequestServlet", req.getMethod());
            }
        };
    }

    @Bean(name = HttpServerResponseParser.NAME)
    HttpResponseParser myHttpResponseParser() {
        return (response, context, span) -> {
            // Span customization
            span.tag("ServerResponse", "Tag");
            Object unwrap = response.unwrap();
            if (unwrap instanceof HttpServletResponse) {
                HttpServletResponse resp = (HttpServletResponse) unwrap;
                // Span customization
                span.tag("ServerResponseServlet", String.valueOf(resp.getStatus()));
            }
        };
    }

}

Sleuth 2.x（几乎完全相同）-https://docs.spring.io/spring-cloud-sleuth/docs/2.2.x/reference/html/#data-policy