com.uber.jaeger.samplers.HTTPSamplingManager Maven / Gradle / Ivy

Go to download
Show more of this group Show more artifacts with this name
Show all versions of jaeger-core Show documentation
Jaeger Java bindings for OpenTracing API
There is a newer version: 0.27.0
/*
 * 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.samplers;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.uber.jaeger.exceptions.SamplingStrategyErrorException;
import com.uber.jaeger.thrift.sampling_manager.ProbabilisticSamplingStrategy;
import com.uber.jaeger.thrift.sampling_manager.RateLimitingSamplingStrategy;
import com.uber.jaeger.thrift.sampling_manager.SamplingStrategyResponse;
import com.uber.jaeger.thrift.sampling_manager.SamplingStrategyType;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLEncoder;
import java.util.HashMap;

public class HTTPSamplingManager implements SamplingManager {
    private static final String defaultSamplingServerHostPort = "localhost:5778";
    private String hostPort = defaultSamplingServerHostPort;

    public HTTPSamplingManager(String hostPort) {
        if (hostPort != null) {
            this.hostPort = hostPort;
        }
    }

    private String makeGetRequest(String urlToRead) throws IOException {
        URL url = new URL(urlToRead);
        HttpURLConnection conn = (HttpURLConnection) url.openConnection();
        StringBuilder result = new StringBuilder();
        try {
            conn.setRequestMethod("GET");
            try (BufferedReader rd = new BufferedReader(new InputStreamReader(conn.getInputStream()))) {
                String line;
                while ((line = rd.readLine()) != null) {
                    result.append(line);
                }
            }
        } finally {
            conn.disconnect();
        }
        return result.toString();
    }

    private SamplingStrategyResponse jsonStringToSamplingStrategy(String jsonString) {
        HashMap result;
        try {
            result = new ObjectMapper().readValue(jsonString, HashMap.class);
        } catch (IOException e) {
            throw new SamplingStrategyErrorException("Invalid json received when fetching sampling strategy from local agent.", e);
        }

        SamplingStrategyType samplingType = SamplingStrategyType.findByValue((Integer) result.get("strategyType"));
        if (samplingType == SamplingStrategyType.PROBABILISTIC) {
            Double samplingRate;
            try {
                samplingRate = (Double) ((HashMap) result.get("probabilisticSampling")).get("samplingRate");
            } catch (Exception e) {
                throw new SamplingStrategyErrorException(String.format("Unexpected format %s for parsing probabilistic sampling strategy", jsonString));
            }

            return new SamplingStrategyResponse(samplingType)
                    .setProbabilisticSampling(new ProbabilisticSamplingStrategy(samplingRate));
        }

        if (samplingType == SamplingStrategyType.RATE_LIMITING) {
            int maxTracesPerSecond;
            try {
                maxTracesPerSecond = (Integer) ((HashMap) result.get("rateLimitingSampling")).get("maxTracesPerSecond");
            } catch (Exception e) {
                throw new SamplingStrategyErrorException(String.format("Unexpected format %s for parsing rateLimiting sampling strategy", jsonString));
            }

            return new SamplingStrategyResponse(samplingType)
                    .setRateLimitingSampling(new RateLimitingSamplingStrategy((short)maxTracesPerSecond));
        }

        throw new SamplingStrategyErrorException("Unrecognized sampling strategy type.");
    }

    @Override
    public SamplingStrategyResponse getSamplingStrategy(String serviceName) throws SamplingStrategyErrorException {
        String jsonString;
        try {
            jsonString = makeGetRequest("http://" + hostPort + "/?service=" + URLEncoder.encode(serviceName, "UTF-8"));
        } catch (IOException e) {
            throw new SamplingStrategyErrorException("http call to get sampling strategy from local agent failed.", e);
        }

        return jsonStringToSamplingStrategy(jsonString);
    }
}