go/src/cmd/trace/v2/main.go

137 lines
3.0 KiB
Go

// Copyright 2023 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package trace
import (
"fmt"
"internal/trace/traceviewer"
tracev2 "internal/trace/v2"
"io"
"log"
"net"
"net/http"
"os"
"internal/trace/v2/raw"
"cmd/internal/browser"
)
// Main is the main function for cmd/trace v2.
func Main(traceFile, httpAddr, pprof string, debug int) error {
tracef, err := os.Open(traceFile)
if err != nil {
return fmt.Errorf("failed to read trace file: %w", err)
}
defer tracef.Close()
// Debug flags.
switch debug {
case 1:
return debugProcessedEvents(tracef)
case 2:
return debugRawEvents(tracef)
}
ln, err := net.Listen("tcp", httpAddr)
if err != nil {
return fmt.Errorf("failed to create server socket: %w", err)
}
addr := "http://" + ln.Addr().String()
log.Print("Parsing trace...")
parsed, err := parseTrace(tracef)
if err != nil {
return err
}
// N.B. tracef not needed after this point.
// We might double-close, but that's fine; we ignore the error.
tracef.Close()
log.Print("Splitting trace...")
ranges, err := splitTrace(parsed)
if err != nil {
return err
}
log.Printf("Opening browser. Trace viewer is listening on %s", addr)
browser.Open(addr)
mux := http.NewServeMux()
mux.Handle("/", traceviewer.MainHandler(ranges))
mux.Handle("/trace", traceviewer.TraceHandler())
mux.Handle("/jsontrace", JSONTraceHandler(parsed))
mux.Handle("/static/", traceviewer.StaticHandler())
err = http.Serve(ln, mux)
return fmt.Errorf("failed to start http server: %w", err)
}
type parsedTrace struct {
events []tracev2.Event
}
func parseTrace(trace io.Reader) (*parsedTrace, error) {
r, err := tracev2.NewReader(trace)
if err != nil {
return nil, fmt.Errorf("failed to create trace reader: %w", err)
}
var t parsedTrace
for {
ev, err := r.ReadEvent()
if err == io.EOF {
break
} else if err != nil {
return nil, fmt.Errorf("failed to read event: %w", err)
}
t.events = append(t.events, ev)
}
return &t, nil
}
// splitTrace splits the trace into a number of ranges, each resulting in approx 100 MiB of
// json output (the trace viewer can hardly handle more).
func splitTrace(parsed *parsedTrace) ([]traceviewer.Range, error) {
// TODO(mknyszek): Split traces by generation by doing a quick first pass over the
// trace to identify all the generation boundaries.
s, c := traceviewer.SplittingTraceConsumer(100 << 20) // 100 MiB
if err := generateTrace(parsed, c); err != nil {
return nil, err
}
return s.Ranges, nil
}
func debugProcessedEvents(trace io.Reader) error {
tr, err := tracev2.NewReader(trace)
if err != nil {
return err
}
for {
ev, err := tr.ReadEvent()
if err == io.EOF {
return nil
} else if err != nil {
return err
}
fmt.Println(ev.String())
}
}
func debugRawEvents(trace io.Reader) error {
rr, err := raw.NewReader(trace)
if err != nil {
return err
}
for {
ev, err := rr.ReadEvent()
if err == io.EOF {
return nil
} else if err != nil {
return err
}
fmt.Println(ev.String())
}
}