recorder.js

/* eslint-env browser */
const {
  BatchRecorder,
  jsonEncoder: {JSON_V2}
} = require('zipkin');
const {HttpLogger} = require('zipkin-transport-http');

const debug = 'undefined' !== typeof window
  ? window.location.search.indexOf('debug') !== -1
  : process.env.DEBUG;

// Send spans to Zipkin asynchronously over HTTP
const zipkinBaseUrl = 'http://localhost:9411';

const httpLogger = new HttpLogger({
  endpoint: `${zipkinBaseUrl}/api/v2/spans`,
  jsonEncoder: JSON_V2
});

function recorder(serviceName) {
  return debug ? debugRecorder(serviceName) : new BatchRecorder({logger: httpLogger});
}

function debugRecorder(serviceName) {
  // This is a hack that lets you see the data sent to Zipkin!
  const logger = {
    logSpan: (span) => {
      const json = JSON_V2.encode(span);
      console.log(`${serviceName} reporting: ${json}`);
      httpLogger.logSpan(span);
    }
  };

  const batchRecorder = new BatchRecorder({logger});

  // This is a hack that lets you see which annotations become which spans
  return ({
    record: (rec) => {
      const {spanId, traceId} = rec.traceId;
      console.log(`${serviceName} recording: ${traceId}/${spanId} ${rec.annotation.toString()}`);
      batchRecorder.record(rec);
    }
  });
}

module.exports.recorder = recorder;