Apollo Request Tracer

Extension for tracing GraphQL query resolution in ApolloServer

Primary motivation of this lib is tracking cold and warm start performance of GraphQL in serverless environments (AWS Lambda, Google Cloud Functions)

Install

yarn add [email protected]

Usage

// Create a new tracer
const Tracer = require('apollo-request-tracer');
const tracer = Tracer.start();

// Create a timer tracking how long node module import takes
let requireTimer = tracer.time('module_requires');
const Express = require('Express');
const {ApolloServer, gql} = require('apollo-server-express');
const Functions = require('firebase-functions');
const Models = require('./Models');
// Stop the timer
requireTimer.stop();

// Create a timer tracking how long the initial GraphQL setup takes
let setupTimer = tracer.time('graphql_setup');

const typeDefs = gql`
  type Query {
    hello(name: String): String
  }
`;

const resolvers = {
  Query: {
    hello: async (args, context)=> {
      // Request tracer gets added to resolver context and can be used
      // for adding timing information specific to that resolver
      const {tracer} = context;
      const timer = tracer.time('build_hello_message');
      const message = `Hello ${args.name}!`;
      timer.stop();
      return message;
    }
  }
};

// Create a new ApolloServer with tracer extension that tracks
// the graphql query resolution process
const server = new ApolloServer({
  typeDefs,
  resolvers,
  extensions: [tracer.request]
});

const app = Express();
server.applyMiddleware({app, path: '/'});

module.exports = {
  graphql: Functions.https.onRequest(app);
};

// Stop setup timer and tracer
setupTimer.stop();
tracer.stop();