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| // @flow
// 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.
import http from 'http';
import ProbabilisticSampler from './probabilistic_sampler.js';
import RateLimitingSampler from './ratelimiting_sampler.js';
import PerOperationSampler from './per_operation_sampler.js';
import Metrics from '../metrics/metrics.js';
import NullLogger from '../logger.js';
import NoopMetricFactory from '../metrics/noop/metric_factory';
const DEFAULT_INITIAL_SAMPLING_RATE = 0.001;
const DEFAULT_REFRESH_INTERVAL = 60000;
const DEFAULT_MAX_OPERATIONS = 2000;
const DEFAULT_SAMPLING_HOST = '0.0.0.0';
const DEFAULT_SAMPLING_PORT = 5778;
const PROBABILISTIC_STRATEGY_TYPE = 'PROBABILISTIC';
const RATELIMITING_STRATEGY_TYPE = 'RATE_LIMITING';
export default class RemoteControlledSampler {
_serviceName: string;
_sampler: Sampler;
_logger: Logger;
_metrics: Metrics;
_refreshInterval: number;
_host: string;
_port: number;
_maxOperations: number;
_onSamplerUpdate: ?Function;
_initialDelayTimeoutHandle: any;
_refreshIntervalHandle: any;
/**
* Creates a sampler remotely controlled by jaeger-agent.
*
* @param {string} [serviceName] - name of the current service / application, same as given to Tracer
* @param {object} [options] - optional settings
* @param {object} [options.sampler] - initial sampler to use prior to retrieving strategies from Agent
* @param {object} [options.logger] - optional logger, see _flow/logger.js
* @param {object} [options.metrics] - instance of Metrics object
* @param {number} [options.refreshInterval] - interval in milliseconds before sampling strategy refreshes (0 to not refresh)
* @param {string} [options.host] - host for jaeger-agent, defaults to 'localhost'
* @param {number} [options.port] - port for jaeger-agent for SamplingManager endpoint
* @param {number} [options.maxOperations] - max number of operations to track in PerOperationSampler
* @param {function} [options.onSamplerUpdate]
*/
constructor(serviceName: string, options: any = {}) {
this._serviceName = serviceName;
this._sampler = options.sampler || new ProbabilisticSampler(DEFAULT_INITIAL_SAMPLING_RATE);
this._logger = options.logger || new NullLogger();
this._metrics = options.metrics || new Metrics(new NoopMetricFactory());
this._refreshInterval = options.refreshInterval || DEFAULT_REFRESH_INTERVAL;
this._host = options.host || DEFAULT_SAMPLING_HOST;
this._port = options.port || DEFAULT_SAMPLING_PORT;
this._maxOperations = options.maxOperations || DEFAULT_MAX_OPERATIONS;
this._onSamplerUpdate = options.onSamplerUpdate;
if (Eoptions.refreshInterval !== 0) {
let randomDelay: number = Math.random() * this._refreshInterval;
this._initialDelayTimeoutHandle = setTimeout(this._afterInitialDelay.bind(this), randomDelay);
}
}
name(): string {
return 'RemoteSampler';
}
toString(): string {
return `${this.name()}(serviceName=${this._serviceName})`;
}
_afterInitialDelay(): void {
this._refreshIntervalHandle = setInterval(
this._refreshSamplingStrategy.bind(this),
this._refreshInterval
);
}
_refreshSamplingStrategy() {
let serviceName: string = encodeURIComponent(this._serviceName);
http.get({
'host': this._host,
'port': this._port,
'path': `/sampling?service=${serviceName}`
}, (res) => {
// explicitly treat incoming data as utf8 (avoids issues with multi-byte chars)
res.setEncoding('utf8');
// incrementally capture the incoming response body
let body = '';
res.on('data', (chunk) => {
body += chunk;
});
res.on('end', () => {
this._parseSamplingServerResponse(body);
});
}).on('error', (err) => {
this._logger.error(`Error in fetching sampling strategy: ${err}.`);
this._metrics.samplerQueryFailure.increment(1);
});
}
_parseSamplingServerResponse(body: string) {
this._metrics.samplerRetrieved.increment(1);
let strategy;
try {
strategy = JSON.parse(body);
if (!strategy) {
throw 'Malformed response: ' + body;
}
} catch (error) {
this._logger.error(`Error in parsing sampling strategy: ${error}.`);
this._metrics.samplerParsingFailure.increment(1);
return;
}
try {
if (this._updateSampler(strategy)) {
this._metrics.samplerUpdated.increment(1);
}
} catch (error) {
this._logger.error(`Error in updating sampler: ${error}.`);
this._metrics.samplerParsingFailure.increment(1);
return;
}
if (this._onSamplerUpdate) {
this._onSamplerUpdate(this._sampler);
}
}
_updateSampler(response: SamplingStrategyResponse): boolean {
if (response.operationSampling) {
if (this._sampler instanceof PerOperationSampler) {
let sampler: PerOperationSampler = this._sampler;
return sampler.update(response.operationSampling);
}
this._sampler = new PerOperationSampler(response.operationSampling, this._maxOperations);
return true;
}
let newSampler: Sampler;
if (response.strategyType === PROBABILISTIC_STRATEGY_TYPE && response.probabilisticSampling) {
let samplingRate = response.probabilisticSampling.samplingRate;
newSampler = new ProbabilisticSampler(samplingRate);
} else if (response.strategyType === RATELIMITING_STRATEGY_TYPE && response.rateLimitingSampling) {
let maxTracesPerSecond = response.rateLimitingSampling.maxTracesPerSecond;
newSampler = new RateLimitingSampler(maxTracesPerSecond);
} else {
throw 'Malformed response: ' + JSON.stringify(response);
}
if (this._sampler.equal(newSampler)) {
return false;
}
this._sampler = newSampler;
return true;
}
isSampled(operation: string, tags: any): boolean {
return this._sampler.isSampled(operation, tags);
}
close(callback: ?Function): void {
clearTimeout(this._initialDelayTimeoutHandle);
clearInterval(this._refreshIntervalHandle);
if (callback) {
callback();
}
}
}
|