io.opentracing.contrib.aws.TracingRequestHandler.java Source code

Introduction

Here is the source code for io.opentracing.contrib.aws.TracingRequestHandler.java

Source

/*
 * Copyright 2017-2019 The OpenTracing Authors
 *
 * 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 io.opentracing.contrib.aws;

import com.amazonaws.Request;
import com.amazonaws.Response;
import com.amazonaws.handlers.HandlerContextKey;
import com.amazonaws.handlers.RequestHandler2;
import io.opentracing.Span;
import io.opentracing.SpanContext;
import io.opentracing.Tracer;
import io.opentracing.propagation.Format;
import io.opentracing.propagation.TextMapAdapter;
import io.opentracing.tag.Tags;
import io.opentracing.util.GlobalTracer;

/**
 * Tracing Request Handler
 */
public class TracingRequestHandler extends RequestHandler2 {

    private final HandlerContextKey<Span> contextKey = new HandlerContextKey<>("span");
    private final SpanContext parentContext; // for Async Client
    private final Tracer tracer;

    public TracingRequestHandler(Tracer tracer) {
        this.parentContext = null;
        this.tracer = tracer;
    }

    /**
     * GlobalTracer is used to get tracer
     */
    public TracingRequestHandler() {
        this(GlobalTracer.get());
    }

    /**
     * In case of Async Client:  beforeRequest runs in separate thread therefore we need to inject
     * parent context to build chain
     *
     * @param parentContext parent context
     */
    public TracingRequestHandler(SpanContext parentContext, Tracer tracer) {
        this.parentContext = parentContext;
        this.tracer = tracer;
    }

    /**
     * GlobalTracer is used to get tracer
     */
    public TracingRequestHandler(SpanContext parentContext) {
        this(parentContext, GlobalTracer.get());
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void beforeRequest(Request<?> request) {
        Tracer.SpanBuilder spanBuilder = tracer.buildSpan(request.getOriginalRequest().getClass().getSimpleName())
                .withTag(Tags.SPAN_KIND.getKey(), Tags.SPAN_KIND_CLIENT);

        if (parentContext != null) {
            spanBuilder.asChildOf(parentContext);
        }

        Span span = spanBuilder.start();
        SpanDecorator.onRequest(request, span);

        tracer.inject(span.context(), Format.Builtin.HTTP_HEADERS, new TextMapAdapter(request.getHeaders()));

        request.addHandlerContext(contextKey, span);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void afterResponse(Request<?> request, Response<?> response) {
        Span span = request.getHandlerContext(contextKey);
        SpanDecorator.onResponse(response, span);
        span.finish();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void afterError(Request<?> request, Response<?> response, Exception e) {
        Span span = request.getHandlerContext(contextKey);
        SpanDecorator.onError(e, span);
        span.finish();
    }
}