lib/instrumentation/modules/ws.js

/*
 * Copyright Elasticsearch B.V. and other contributors where applicable.
 * Licensed under the BSD 2-Clause License; you may not use this file except in
 * compliance with the BSD 2-Clause License.
 */

'use strict';

var semver = require('semver');

var shimmer = require('../shimmer');

module.exports = function (ws, agent, { version, enabled }) {
  if (!enabled) return ws;
  if (!semver.satisfies(version, '>=1 <8')) {
    agent.logger.debug('ws version %s not supported - aborting...', version);
    return ws;
  }

  const ins = agent._instrumentation;

  agent.logger.debug('shimming ws.prototype.send function');
  shimmer.wrap(ws.prototype, 'send', wrapSend);

  return ws;

  function wrapSend(orig) {
    return function wrappedSend() {
      agent.logger.debug('intercepted call to ws.prototype.send');
      const span = ins.createSpan(
        'Send WebSocket Message',
        'websocket',
        'send',
        { exitSpan: true },
      );
      if (!span) {
        return orig.apply(this, arguments);
      }

      const args = Array.prototype.slice.call(arguments);
      let cb = args[args.length - 1];
      const onDone = function () {
        span.end();
        if (cb) {
          cb.apply(this, arguments);
        }
      };
      if (typeof cb === 'function') {
        args[args.length - 1] = ins.bindFunction(onDone);
      } else {
        cb = null;
        args.push(ins.bindFunction(onDone));
      }

      const spanRunContext = ins.currRunContext().enterSpan(span);
      return ins.withRunContext(spanRunContext, orig, this, ...args);
    };
  }
};