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// Package errors implements an HTTP error handling plugin.
package errors
import (
"fmt"
"log"
"runtime"
"strings"
"time"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/request"
"context"
"github.com/miekg/dns"
)
// errorHandler handles DNS errors (and errors from other plugin).
type errorHandler struct {
Next plugin.Handler
LogFile string
Log *log.Logger
}
// ServeDNS implements the plugin.Handler interface.
func (h errorHandler) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
defer h.recovery(ctx, w, r)
rcode, err := plugin.NextOrFailure(h.Name(), h.Next, ctx, w, r)
if err != nil {
state := request.Request{W: w, Req: r}
errMsg := fmt.Sprintf("%s [ERROR %d %s %s] %v", time.Now().Format(timeFormat), rcode, state.Name(), state.Type(), err)
h.Log.Println(errMsg)
}
return rcode, err
}
func (h errorHandler) Name() string { return "errors" }
func (h errorHandler) recovery(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) {
rec := recover()
if rec == nil {
return
}
// Obtain source of panic
// From: https://gist.github.com/swdunlop/9629168
var name, file string // function name, file name
var line int
var pc [16]uintptr
n := runtime.Callers(3, pc[:])
for _, pc := range pc[:n] {
fn := runtime.FuncForPC(pc)
if fn == nil {
continue
}
file, line = fn.FileLine(pc)
name = fn.Name()
if !strings.HasPrefix(name, "runtime.") {
break
}
}
// Trim file path
delim := "/coredns/"
pkgPathPos := strings.Index(file, delim)
if pkgPathPos > -1 && len(file) > pkgPathPos+len(delim) {
file = file[pkgPathPos+len(delim):]
}
panicMsg := fmt.Sprintf("%s [PANIC %s %s] %s:%d - %v", time.Now().Format(timeFormat), r.Question[0].Name, dns.Type(r.Question[0].Qtype), file, line, rec)
// Currently we don't use the function name, since file:line is more conventional
h.Log.Printf(panicMsg)
}
const timeFormat = "02/Jan/2006:15:04:05 -0700"
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