com.uber.jaeger.httpclient.TracingRequestInterceptor.java Source code

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Here is the source code for com.uber.jaeger.httpclient.TracingRequestInterceptor.java

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/*
 * Copyright (c) 2016, Uber Technologies, Inc
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */
package com.uber.jaeger.httpclient;

import com.uber.jaeger.context.TraceContext;
import com.uber.jaeger.context.TracingUtils;
import io.opentracing.Span;
import io.opentracing.Tracer;
import io.opentracing.propagation.Format;
import io.opentracing.tag.Tags;
import org.apache.http.HttpException;
import org.apache.http.HttpHost;
import org.apache.http.HttpRequest;
import org.apache.http.HttpRequestInterceptor;
import org.apache.http.RequestLine;
import org.apache.http.client.protocol.HttpClientContext;
import org.apache.http.protocol.HttpContext;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import java.io.IOException;

/**
 * Apache http client request interceptor This is designed to be used along with
 * {@link TracingResponseInterceptor} to report tracing information.
 *
 * In most cases you shouldn't be using this directly. Use the appropriate client builder from
 * {@link TracingInterceptors}
 *
 */
public class TracingRequestInterceptor implements HttpRequestInterceptor {
    private final Tracer tracer;
    private final Logger logger = LoggerFactory.getLogger(TracingRequestInterceptor.class);

    public TracingRequestInterceptor(Tracer tracer) {
        this.tracer = tracer;
    }

    @Override
    public void process(HttpRequest httpRequest, HttpContext httpContext) throws HttpException, IOException {
        try {
            TraceContext parentContext = TracingUtils.getTraceContext();

            RequestLine requestLine = httpRequest.getRequestLine();
            Tracer.SpanBuilder clientSpanBuilder = tracer.buildSpan(getOperationName(httpRequest));
            if (!parentContext.isEmpty()) {
                clientSpanBuilder.asChildOf(parentContext.getCurrentSpan());
            }

            Span clientSpan = clientSpanBuilder.start();
            Tags.SPAN_KIND.set(clientSpan, Tags.SPAN_KIND_CLIENT);
            Tags.HTTP_URL.set(clientSpan, requestLine.getUri());

            if (httpContext instanceof HttpClientContext) {
                HttpHost host = ((HttpClientContext) httpContext).getTargetHost();
                Tags.PEER_HOSTNAME.set(clientSpan, host.getHostName());
                Tags.PEER_PORT.set(clientSpan, (short) host.getPort());
            }

            onSpanStarted(clientSpan, httpRequest, httpContext);

            tracer.inject(clientSpan.context(), Format.Builtin.HTTP_HEADERS, new ClientRequestCarrier(httpRequest));

            httpContext.setAttribute(Constants.CURRENT_SPAN_CONTEXT_KEY, clientSpan);
        } catch (Exception e) {
            logger.error("Could not start client tracing span.", e);
        }
    }

    /**
     * onSpanStarted will be called right after the span is created.
     * The subclasses can override this method to add additional information
     * to the span, including tags and logs.
     *
     * @param clientSpan - the span that's being created
     * @param httpRequest - the http request for the operation
     * @param httpContext - the context on which the operation is being executed
     */
    protected void onSpanStarted(Span clientSpan, HttpRequest httpRequest, HttpContext httpContext) {
        // no-op, can be overriden by subclasses
    }

    /**
     * Get the Span's operation name. Defaults to the HTTP method.
     *
     * @param httpRequest the request for the http operation being executed
     * @return the operation name
     */
    protected String getOperationName(HttpRequest httpRequest) {
        return httpRequest.getRequestLine().getMethod();
    }

}