appdynamics/lib/probes/grpc-entry-probe.js

Performance Profiler and Monitor

/*
Copyright (c) AppDynamics, Inc., and its affiliates
2015
All Rights Reserved
*/
'use strict';

function GrpcEntryProbe(agent) {
  this.agent = agent;
}

exports.GrpcEntryProbe = GrpcEntryProbe;
GrpcEntryProbe.prototype.init = function () {
};

GrpcEntryProbe.prototype.attach = function (obj) {
  var self = this;

  self.agent.proxy.after(obj.Server.prototype, ['register'], function (obj, args) {
    var serviceName = args[0];
    var type = args[4];

    if (!serviceName || !type) return;
    var handlerSet = obj.handlers.get(serviceName);
    if (!handlerSet) return;

    var original = handlerSet.func;
    handlerSet.func = self.createWrapperFunc(original, serviceName, type);
  });
};

GrpcEntryProbe.prototype.createWrapperFunc = function(original, serviceName, type) {
  var self = this;
  return function() {
    var args = arguments;
    self.agent.context.runGeneric(handlerFunc, args);

    function handlerFunc() {
      var call = arguments[0];
      if(!call) return;

      self.agent.context.bindEmitter(call);

      var profiler = self.agent.profiler;
      var time = profiler.time(true);

      var req = {url: serviceName, method: null, headers: {}, type: 'GRPC', metadata: call.metadata};
      var transaction = profiler.startTransaction(time, req, 'NODEJS_WEB');
      self.agent.context.set('threadId', transaction.threadId);

      switch(type) {
      case 'unary':
      case 'clientStream':
      case 'client_stream':
        self.agent.proxy.callback(arguments, -1, self._clientStreamAndUnaryHandler.bind(self, time, transaction));
        break;
      case 'serverStream':
      case 'server_stream':
      case 'bidi':
        self._serverStreamAndBidiHandler(time, transaction, call);
        break;
      }
      return original.apply(this, arguments);
    }
  };
};

GrpcEntryProbe.prototype._clientStreamAndUnaryHandler = function(time, transaction, cbCtxt, cbArgs) {
  var self = this;
  var profiler = self.agent.profiler;
  var error = cbArgs[0];
  if (error) {
    if(error.code) {
      var errorObject = { message: error.message, name: "GRPC Error code " + error.code };
      transaction.error = errorObject;
    }
  }
  profiler.endTransaction(time, transaction);
};

GrpcEntryProbe.prototype._serverStreamAndBidiHandler = function(time, transaction, call) {
  var self = this;
  var profiler = self.agent.profiler;
  var spanEnded = false;
  
  const endSpan = (time, tx) => {
    if (!spanEnded) {
      spanEnded = true;
      profiler.endTransaction(time, tx);
    }
  };
  
  call.on('finish', () => {
    endSpan(time, transaction);
  });

  call.on('error', (err) => {
    if (err) {
      if(err.code) {
        var errorObject = { message: err.message, name: "GRPC Error code " + err.code };
        transaction.error = errorObject;
      }
    }
    endSpan(time, transaction);
  });
};