My Favorite Talks at GopherCon 2019

Transcript

1. 1 My Favorite Talks at GopherCon 2019 Yuki ITO

2. Table of Contents !2 Observability in Go Socket to Me:

   Where do Sockets Live in Go? Day 0 (Pre-Conference Workshop): Day 2:

3. Table of Contents !3 Observability in Go Socket to Me:

   Where do Sockets Live in Go? Day 0 (Pre-Conference Workshop): Day 2:

4. Observability in Go !4 https://github.com/freeformz/go-observability-workshop/ Repository

5. Observability in Go !5 Log Trace Metric 3 Pillars for

   Observability

6. Observability in Go !6 Log Trace Metric 3 Pillars for

   Observability

7. Logs !7 log package func handler(w http.ResponseWriter, r *http.Request) {

   status := http.StatusOK // net/http returns 200 by default defer func(t time.Time) { log.Printf( "%s %q => %d (%2.3fs)\n", r.Method, r.URL.String(), status, time.Since(t).Seconds(), ) }(time.Now()) // … }

8. Logs !8 log package func main() { log.SetFlags(log.Flags() | log.Lshortfile)

   log.Println("Listening at: http://localhost:" + port) http.ListenAndServe(":"+port, nil) // ... } 2019/08/20 19:00:00 server.go:54: Listening at: http://localhost:8080

9. Logs !9 Structured Logs github.com/sirupsen/logrus 2019/08/20 19:00:00 server.go:54: Listening at:

   http://localhost:8080 { “level”:"info", "msg":"Listening at: http://localhost:8080”, “time":"2019-07-17T21:26:08-07:00" }

10. !10 Log Trace Metric How should we log? If the

    only observability tool we have is logs, then we should log everything.

11. !11 Log Trace Metric How should we log? If we

    have metrics and traces, then reduce logging to important events meant largely for human consumption.

12. Observability in Go !12 Log Trace Metric 3 Pillars for

    Observability

13. Metrics !13 expvar package import ( "expvar" // ... )

    func main() { // ... // Expose the port value ep := expvar.NewString("Port") ep.Set(port) http.ListenAndServe(":"+port, nil) //... }

14. Metrics !14 expvar package package expvar // ... func init()

    { http.HandleFunc("/debug/vars", expvarHandler) Publish("cmdline", Func(cmdline)) Publish("memstats", Func(memstats)) }

15. Metrics !15 expvar package $ curl -s http://localhost:8080/debug/vars | jq

    .Port "8080"

16. Metrics !16 expvar makes us be able to expose metrics

    We can recognize only `current status` of system. Hoever…

17. Metrics !17 Prometheus Time Series Database

18. Metrics !18 import ( // ... "github.com/prometheus/client_golang/prometheus/promhttp" ) func main()

    { // ... http.Handle("/metrics", promhttp.Handler()) // … http.ListenAndServe(":"+port, nil) // ... }

19. Metrics !19 Pull Model Prometheus Scrape `/metrics` Application server

20. Metrics !20

21. Observability in Go !21 Log Trace Metric 3 Pillars for

    Observability

22. Traces !22 Microservices ServiceB ServiceA

23. Traces !23 Distributed Tracing Jaeger

24. Traces !24 import ( // ... "contrib.go.opencensus.io/exporter/jaeger" "go.opencensus.io/trace" ) func

    main() { je, err := jaeger.NewExporter(jaeger.Options{ CollectorEndpoint: "http://localhost:14268/api/traces", Process: jaeger.Process{ ServiceName: "servicea", Tags: []jaeger.Tag{ jaeger.StringTag("server", "1"), jaeger.StringTag("port", port), jaeger.BoolTag("demo", true), }, }, }) trace.RegisterExporter(je) }

25. Traces !25 func queryServiceBHandler(c *http.Client, url string) http.HandlerFunc { return

    func(w http.ResponseWriter, r *http.Request) { ctx, span := trace.StartSpan( r.Context(), "queryServiceBHandler", ) defer span.End() // ... } }

26. Traces !26

27. Traces !27

28. Observability in Go !28 Log Trace Metric 3 Pillars for

    Observability

29. Table of Contents !29 Observability in Go Socket to Me:

    Where do Sockets Live in Go? Day 0 (Pre-Conference Workshop): Day 2:

30. !30 System calls under net.Listen & Accept https://about.sourcegraph.com/go/gophercon-2019-socket-to-me-where-do-sockets-live-in-go

31. !31 System calls under net.Listen & Accept https://about.sourcegraph.com/go/gophercon-2019-socket-to-me-where-do-sockets-live-in-go

32. !32 func (srv *Server) Serve(l net.Listener) error { // ...

    for { rw, e := l.Accept() // ... c := srv.newConn(rw) go c.serve(ctx) } } Socket to me net/http/server.go

33. !33 System calls under net.Listen & Accept https://about.sourcegraph.com/go/gophercon-2019-socket-to-me-where-do-sockets-live-in-go

34. Socket Options in Go !34 ListenConfig.Listen() ListenConfig.Control RawConn.Control() Callback to

    set socket options

35. Socket Options in Go !35 https://github.com/110y/sockoptgo/ Example Implementation

36. Socket Options in Go !36 ListenConfig.Listen() ListenConfig.Control RawConn.Control() Callback to

    set socket options

37. !37 func Listen(network, address string) (Listener, error) { var lc

    ListenConfig return lc.Listen(context.Background(), network, address) } net.Listen() Socket Options in Go

38. !38 Socket Options in Go lc := net.ListenConfig{ Control: listenControler,

    } lis, err := lc.Listen(ctx, "tcp4", addr)

39. Socket Options in Go !39 ListenConfig.Listen() ListenConfig.Control RawConn.Control() Callback to

    set socket options

40. !40 func listenControler(network, address string, c syscall.RawConn) error { return

    c.Control(func(fd uintptr) { syscall.SetsockoptInt( int(fd), syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1, ) }) } Socket Options in Go

41. !41 func listenControler(network, address string, c syscall.RawConn) error { return

    c.Control(func(fd uintptr) { syscall.SetsockoptInt( int(fd), syscall.SOL_SOCKET, syscall.SO_REUSEADDR, 1, ) }) } Socket Options in Go

42. Table of Contents !42 Observability in Go Socket to Me:

    Where do Sockets Live in Go? Day 0 (Pre-Conference Workshop): Day 2: