tailscale/control/controlclient/debug.go

70 lines
1.8 KiB
Go

// Copyright (c) 2021 Tailscale Inc & 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 controlclient
import (
"bytes"
"compress/gzip"
"context"
"fmt"
"log"
"net/http"
"regexp"
"runtime"
"strconv"
"time"
)
func dumpGoroutinesToURL(c *http.Client, targetURL string) {
ctx, cancel := context.WithTimeout(context.Background(), 15*time.Second)
defer cancel()
zbuf := new(bytes.Buffer)
zw := gzip.NewWriter(zbuf)
zw.Write(scrubbedGoroutineDump())
zw.Close()
req, err := http.NewRequestWithContext(ctx, "PUT", targetURL, zbuf)
if err != nil {
log.Printf("dumpGoroutinesToURL: %v", err)
return
}
req.Header.Set("Content-Encoding", "gzip")
t0 := time.Now()
_, err = c.Do(req)
d := time.Since(t0).Round(time.Millisecond)
if err != nil {
log.Printf("dumpGoroutinesToURL error: %v to %v (after %v)", err, targetURL, d)
} else {
log.Printf("dumpGoroutinesToURL complete to %v (after %v)", targetURL, d)
}
}
var reHexArgs = regexp.MustCompile(`\b0x[0-9a-f]+\b`)
// scrubbedGoroutineDump returns the list of all current goroutines, but with the actual
// values of arguments scrubbed out, lest it contain some private key material.
func scrubbedGoroutineDump() []byte {
buf := make([]byte, 1<<20)
buf = buf[:runtime.Stack(buf, true)]
saw := map[string][]byte{} // "0x123" => "v1%3" (unique value 1 and its value mod 8)
return reHexArgs.ReplaceAllFunc(buf, func(in []byte) []byte {
if string(in) == "0x0" {
return in
}
if v, ok := saw[string(in)]; ok {
return v
}
u64, err := strconv.ParseUint(string(in[2:]), 16, 64)
if err != nil {
return []byte("??")
}
v := []byte(fmt.Sprintf("v%d%%%d", len(saw)+1, u64%8))
saw[string(in)] = v
return v
})
}