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|
package main
import (
"flag"
"fmt"
"html/template"
"net/http"
"os"
"runtime"
"runtime/debug"
"time"
"blitiri.com.ar/go/dnss/internal/nettrace"
"blitiri.com.ar/go/log"
)
var (
Version = ""
SourceDate = time.Time{}
)
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
}
}
SourceDate, _ = time.Parse(time.RFC3339, gitTime)
Version = SourceDate.Format("20060102")
if gitRev != "" {
Version += fmt.Sprintf("-%.9s", gitRev)
}
if dirty {
Version += "-dirty"
}
}
func monitoringServer(addr string) {
log.Infof("Monitoring HTTP server listening on %s", addr)
http.HandleFunc("/", debugRoot())
nettrace.RegisterHandler(http.DefaultServeMux)
go http.ListenAndServe(addr, nil)
}
func debugRoot() http.HandlerFunc {
hostname, _ := os.Hostname()
fSet, fUnset := flagsLists()
indexData := struct {
Hostname string
Version string
GoVersion string
SourceDate time.Time
StartTime time.Time
Args []string
Env []string
FlagsSet []string
FlagsUnset []string
}{
Hostname: hostname,
Version: Version,
GoVersion: runtime.Version(),
SourceDate: SourceDate,
StartTime: time.Now(),
Args: os.Args,
Env: os.Environ(),
FlagsSet: fSet,
FlagsUnset: fUnset,
}
return 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)
}
}
}
var tmplFuncs = template.FuncMap{
"since": time.Since,
"roundDuration": func(d time.Duration) time.Duration {
return d.Round(time.Second)
},
}
// Static index for the monitoring 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>dnss @{{.Hostname}}</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>dnss @{{.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>
<ul>
<li><a href="/debug/traces">traces</a>
<li><a href="/debug/dnsserver/cache/dump">cache dump</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>
<li><a href="/debug/flags">flags</a>
<li><a href="/debug/vars">public variables</a>
</ul>
<details>
<summary>flags</summary>
<ul>
{{range .FlagsSet}}<li><tt>{{.}}</tt>{{end}}
{{range .FlagsUnset}}<li><i><tt>{{.}}</tt></i>{{end}}
</ul>
</details>
<p>
<details>
<summary>env</summary>
<ul> {{range .Env}}<li><tt>{{.}}</tt>{{end}} </ul>
</details>
</body>
</html>
`))
func flagsLists() (set, unset []string) {
visited := make(map[string]bool)
// Print set flags first, then the rest.
flag.Visit(func(f *flag.Flag) {
set = append(set, fmt.Sprintf("-%s=%s", f.Name, f.Value.String()))
visited[f.Name] = true
})
flag.VisitAll(func(f *flag.Flag) {
if visited[f.Name] {
return
}
unset = append(unset, fmt.Sprintf("-%s=%s", f.Name, f.Value.String()))
})
return set, unset
}
|
