package debug
import (
"fmt"
"html/template"
"net/http"
"os"
"runtime"
"runtime/debug"
"strconv"
"time"
// Remote profiling support.
_ "net/http/pprof"
"blitiri.com.ar/go/gofer/config"
"blitiri.com.ar/go/gofer/nettrace"
"blitiri.com.ar/go/log"
)
// Build information, overridden at build time using
// -ldflags="-X blitiri.com.ar/go/gofer/debug.Version=blah".
var (
Version = ""
SourceDateTs = ""
// Derived from SourceDateTs.
SourceDate = time.Time{}
SourceDateStr = ""
)
func init() {
bi, ok := debug.ReadBuildInfo()
if !ok {
panic("unable to read build info")
}
dirty := false
gitRev := ""
gitTime := ""
for _, s := range bi.Settings {
switch s.Key {
case "vcs.modified":
if s.Value == "true" {
dirty = true
}
case "vcs.time":
gitTime = s.Value
case "vcs.revision":
gitRev = s.Value
}
}
if SourceDateTs != "" {
sdts, err := strconv.ParseInt(SourceDateTs, 10, 0)
if err != nil {
panic(err)
}
SourceDate = time.Unix(sdts, 0)
} else {
SourceDate, _ = time.Parse(time.RFC3339, gitTime)
}
SourceDateStr = SourceDate.Format("2006-01-02 15:04:05 -0700")
if Version == "" {
Version = SourceDate.Format("20060102")
if gitRev != "" {
Version += fmt.Sprintf("-%.9s", gitRev)
}
if dirty {
Version += "-dirty"
}
}
}
func ServeDebugging(addr string, conf *config.Config) error {
hostname, _ := os.Hostname()
indexData := struct {
Hostname string
Version string
GoVersion string
SourceDate time.Time
StartTime time.Time
Args []string
}{
Hostname: hostname,
Version: Version,
GoVersion: runtime.Version(),
SourceDate: SourceDate,
StartTime: time.Now(),
Args: os.Args,
}
http.HandleFunc("/debug/config", DumpConfigFunc(conf))
nettrace.RegisterHandler(http.DefaultServeMux)
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
if r.URL.Path != "/" {
http.NotFound(w, r)
return
}
if err := htmlIndex.Execute(w, indexData); err != nil {
log.Infof("Monitoring handler error: %v", err)
}
})
log.Infof("debugging HTTP server listening on %q", addr)
err := http.ListenAndServe(addr, nil)
return log.Errorf("debugging HTTP server died: %v", err)
}
func DumpConfigFunc(conf *config.Config) http.HandlerFunc {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.Header().Set("Content-Type", "text/plain; charset=utf-8")
w.Write([]byte(conf.String()))
})
}
// Functions available inside the templates.
var tmplFuncs = template.FuncMap{
"since": time.Since,
"roundDuration": func(d time.Duration) time.Duration {
return d.Round(time.Second)
},
}
// Static index for the debugging website.
var htmlIndex = template.Must(
template.New("index").Funcs(tmplFuncs).Parse(
`<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>{{.Hostname}}: gofer debugging</title>
<style type="text/css">
body {
font-family: sans-serif;
}
@media (prefers-color-scheme: dark) {
body {
background: #121212;
color: #c9d1d9;
}
a { color: #44b4ec; }
}
</style>
</head>
<body>
<h1>gofer @{{.Hostname}}</h1>
version {{.Version}}<br>
source date {{.SourceDate.Format "2006-01-02 15:04:05 -0700"}}<br>
built with: {{.GoVersion}}<p>
started {{.StartTime.Format "Mon, 2006-01-02 15:04:05 -0700"}}<br>
up for {{.StartTime | since | roundDuration}}<br>
os hostname <i>{{.Hostname}}</i><br>
<p>
args: <tt>{{.Args}}</tt><p>
<ul>
<li><a href="/debug/config">configuration</a>
<li><a href="/debug/traces">traces</a>
<li><a href="/debug/pprof">pprof</a>
<small><a href="https://golang.org/pkg/net/http/pprof/">
(ref)</a></small>
<ul>
<li><a href="/debug/pprof/goroutine?debug=1">goroutines</a>
</ul>
</ul>
</body>
</html>
`))