Go and Node.js: a comparison

Transcript

1. Go and Node.js A comparison
2. Nathan Youngman Web developer
 > 21 years
4. • Go microservices • gorilla/mux • sqlx, gocql • Node.js • Feathers • Objection
5. • Vue.js • Shape Detection API • Elixir + Erlang NIF (C) account.alberta.ca
6. • Vue.js • Node.js • GraphQL with Apollo
7. Nathan Youngman Author
8. Edmonton Go edmontongo.org
10. – Brendan Eich “It was also an incredible rush job… I knew there would be mistakes, and there would be gaps, so I made it very malleable as a language.” “a language that was approachable, that you could put directly in the web page”
11. – Ryan Dahl “JavaScript plus asynchronous IO plus some HTTP server stuff would be a cool thing. And I was so excited about that idea that I just worked on it non- stop for the next four years.”
13. – Ryan Dahl, creator of Node.js “if you’re building a server, I can’t imagine using anything other than Go”
14. – TJ Holowaychuk, creator of Express.js “If you’re doing distributed work then you’ll find Go’s expressive concurrency primitives very helpful.”
15. Go origins • Unix • grep • UTF-8 encoding Ken Thompson Robert Griesemer • Strongtalk VM • Java HotSpot VM • Codegen for V8 Rob Pike • First window system for Unix • Newsqueak, Limbo (CSP)
16. – Rob Pike “We wanted a language with the safety and performance of statically compiled languages such as C++ and Java, but the lightness and fun of dynamically typed interpreted languages such as Python.”
17. • GCC toolchain Ian Lance Taylor Early gophers Brad Fitzpatrick Russ Cox • Memcached • OpenID • Bell Labs • Tech lead
18. Asynchronous I/O Promises
19. Async/Await const axios = require("axios");
 
 async function fetchHumans(url) {
 const response = await axios.get(url);
 return response.data;
 }
20. Calling an async function const express = require("express");
 const app = express();
 const url = “https://www.google.com/humans.txt";
 const port = 3000; 
 app.get("/", async (req, res) => {
 const data = await fetchHumans(url);
 res.send(data);
 });
 
 app.listen(port, () => {
 console.info(`Listening on ${port}`);
 });
21. Promises all the way down Whoops!
 app.get("/", async (req, res) => {
 const data = await fetchHumans(url);
 res.send(data);
 }); The result: Promise { <pending> }
22. Multiple promises const urls = [
 "https://www.google.com/humans.txt",
 "https://www.netflix.com/humans.txt",
 "https://medium.com/humans.txt",
 ];
 
 app.get("/", async (req, res) => {
 const promises = urls.map((url) => fetchHumans(url));
 const data = await Promise.all(promises);
 res.setHeader("content-type", "text/plain");
 res.send(data.join("\n\n"));
 });
23. We need error handling const url = "https://www.moogle.com/humans.txt"; The result: UnhandledPromiseRejectionWarning
 Error: connect ECONNREFUSED
24. Try/Catch app.get("/", async (req, res) => {
 try {
 const data = await fetchHumans(url);
 res.send(data);
 } catch (err) {
 console.error(err.message);
 res.status(502).send("Bad gateway");
 }
 });
25. First error app.get("/", async (req, res) => {
 try {
 const promises = urls.map((url) => fetchHumans(url));
 const data = await Promise.all(promises);
 res.setHeader("content-type", "text/plain");
 res.send(data.join("\n\n"));
 } catch (err) {
 console.error(err.message);
 res.status(502).send("Bad gateway");
 }
 });
26. Asynchronous I/O You may not see it, but it’s there.
27. It looks synchronous package main
 
 import (
 "io"
 "log"
 "net/http"
 )
 
 func fetch(url string) (string, error) {
 r, err := http.Get(url)
 if err != nil {
 return "", err
 }
 defer r.Body.Close()
 b, err := ioutil.ReadAll(r.Body)
 if err != nil {
 return "", err
 }
 return string(b), nil
 }
28. Response writer const url = "https://www.google.com/humans.txt"
 
 func handler(w http.ResponseWriter, req *http.Request) {
 data, err := fetch(url)
 if err != nil {
 log.Print(err)
 w.WriteHeader(http.StatusBadGateway)
 io.WriteString(w, "Bad gateway")
 return
 }
 io.WriteString(w, data)
 }
29. Listen and serve func main() {
 http.HandleFunc("/", handler)
 
 const addr = ":3000"
 log.Printf("Listening on %v", addr)
 log.Fatal(http.ListenAndServe(addr, nil))
 }

30. Concurrency in Go Goroutines and channels
31. Fetch multiple humans.txt package main
 
 import (
 "io"
 "io/ioutil"
 "log"
 "net/http"
 "strings"
 "sync"
 )
 
 var urls = []string{
 "https://www.google.com/humans.txt",
 "https://www.netflix.com/humans.txt",
 "https://medium.com/humans.txt",
 }

32. A synchronous API func handler(w http.ResponseWriter, req *http.Request) {
 data, err := fetchHumans(urls)
 if err != nil {
 log.Print(err)
 w.WriteHeader(http.StatusBadGateway)
 io.WriteString(w, "Bad gateway")
 return
 } 
 w.Header().Set("Content-Type", "text/plain; charset=utf-8")
 io.WriteString(w, strings.Join(data, "\n\n"))
 }

33. Concurrency primitives func fetchHumans(urls []string) ([]string, error) {
 var m sync.Mutex
 var wg sync.WaitGroup
 errChan := make(chan error, 1) 
 resp := make([]string, len(urls))
34. for index, url := range urls {
 wg.Add(1)
 go func(index int, url string) {
 defer wg.Done()
 
 s, err := fetch(url)
 if err != nil {
 select {
 case errChan <- err:
 default:
 }
 return
 }
 m.Lock()
 resp[index] = s
 m.Unlock()
 }(index, url)
 }
 wg.Wait()
 
 select {
 case err := <-errChan:
 return nil, err
 default:
 }
 return resp, nil
 }
35. JavaScript Go Promises Channels Single-threaded* event loop Multiplexed goroutines async/await Appears synchronous Async and Concurrency
36. Language [mis]Features
37. Destructuring const data = {
 latitude: 53.5458874,
 longitude: -113.5034304,
 timezone: "America/Edmonton",
 currently: {
 summary: "Light Snow",
 temperature: 20.33,
 },
 };
 
 const {
 currently: {summary, temperature},
 } = data;
 
 console.info(`${summary} and ${temperature}ºF`);

38. – Brendan Eich on early feature requests “I’d like to compare a number to a string that contains that numeral. And I don’t want to have to change my code to convert the string to a number, or the number to a string. I just want it to work. Can you please make the equals operator just say, Oh this looks like a two, and this looks like a string number two. They’re equal enough.”
39. Language [mis]Features
40. Incomparable if "2" == 2 {
 //
 } The result: invalid operation: "2" == 2 (mismatched types string and int)
41. – Go brand book “Go is an open source programming language that enables the production of simple, efficient, and reliable software at scale.”
42. Mutable iteration variables for index, url := range urls {
 go func(index int, url string) {
 // ..
 }(index, url)
 }
43. JavaScript Go Dynamically typed Statically typed Lenient Strict compiler Prototypes, Classes, Inheritance Types, methods, interfaces First-class functions First-class functions Language
44. Node.js Go prettier gofmt eslint go lint, go vet Babel, TypeScript go build Jest, Chai, Mocha, Jasmine go test Tooling
45. Node.js Go ES6 modules packages NPM packages Go modules Ecosystem
46. Node.js Go HTTP/2 HTTP/2 TLS 1.3 with OpenSSL 1.1.1 TLS 1.3 in Go 1.12 Modern Web
47. Node.js Go Full stack Server-only* Ecosystem Batteries included Small projects* Large projects, large teams I/O bound CPU bound and I/O bound Malleable language Reliability, security Use when
48. programminggo.com
49. Nathan Youngman • nathany.com • hello@nathany.com • @nathany