219bfd0493
* middleware/metrics: add more metrics middleware/cache: Add metrics for number of elements in the cache. Also export the total size. Update README to detail the new metrics. middleware/metrics Move metrics into subpackage called "vars". This breaks the import cycle and is cleaner. This allows vars.Report to be used in the the dnsserver to log refused queries. middleware/metrics: tests Add tests to the metrics framework. The metrics/test subpackage allows scraping of the local server. Do a few test scrape of the metrics that are defined in the metrics middleware. This also allows metrics integration tests to check if the caching and dnssec middleware export their metrics correctly. * update README * typos * fix tests
109 lines
2.9 KiB
Go
109 lines
2.9 KiB
Go
// Package errors implements an HTTP error handling middleware.
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package errors
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import (
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"fmt"
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"log"
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"runtime"
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"strings"
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"time"
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"github.com/miekg/coredns/middleware"
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"github.com/miekg/coredns/request"
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"github.com/miekg/dns"
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"golang.org/x/net/context"
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)
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// errorHandler handles DNS errors (and errors from other middleware).
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type errorHandler struct {
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Next middleware.Handler
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LogFile string
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Log *log.Logger
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Debug bool // if true, errors are written out to client rather than to a log
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}
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// ServeDNS implements the middleware.Handler interface.
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func (h errorHandler) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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defer h.recovery(ctx, w, r)
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rcode, err := h.Next.ServeDNS(ctx, w, r)
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if err != nil {
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state := request.Request{W: w, Req: r}
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errMsg := fmt.Sprintf("%s [ERROR %d %s %s] %v", time.Now().Format(timeFormat), rcode, state.Name(), state.Type(), err)
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if h.Debug {
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// Write error to response as a txt message instead of to log
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answer := debugMsg(rcode, r)
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txt, _ := dns.NewRR(". IN 0 TXT " + errMsg)
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answer.Answer = append(answer.Answer, txt)
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state.SizeAndDo(answer)
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w.WriteMsg(answer)
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return 0, err
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}
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h.Log.Println(errMsg)
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}
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return rcode, err
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}
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func (h errorHandler) Name() string { return "errors" }
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func (h errorHandler) recovery(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) {
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rec := recover()
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if rec == nil {
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return
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}
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state := request.Request{W: w, Req: r}
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// Obtain source of panic
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// From: https://gist.github.com/swdunlop/9629168
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var name, file string // function name, file name
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var line int
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var pc [16]uintptr
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n := runtime.Callers(3, pc[:])
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for _, pc := range pc[:n] {
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fn := runtime.FuncForPC(pc)
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if fn == nil {
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continue
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}
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file, line = fn.FileLine(pc)
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name = fn.Name()
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if !strings.HasPrefix(name, "runtime.") {
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break
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}
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}
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// Trim file path
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delim := "/coredns/"
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pkgPathPos := strings.Index(file, delim)
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if pkgPathPos > -1 && len(file) > pkgPathPos+len(delim) {
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file = file[pkgPathPos+len(delim):]
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}
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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)
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if h.Debug {
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// Write error and stack trace to the response rather than to a log
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var stackBuf [4096]byte
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stack := stackBuf[:runtime.Stack(stackBuf[:], false)]
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answer := debugMsg(dns.RcodeServerFailure, r)
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// add stack buf in TXT, limited to 255 chars for now.
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txt, _ := dns.NewRR(". IN 0 TXT " + string(stack[:255]))
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answer.Answer = append(answer.Answer, txt)
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state.SizeAndDo(answer)
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w.WriteMsg(answer)
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} else {
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// Currently we don't use the function name, since file:line is more conventional
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h.Log.Printf(panicMsg)
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}
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}
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// debugMsg creates a debug message that gets send back to the client.
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func debugMsg(rcode int, r *dns.Msg) *dns.Msg {
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answer := new(dns.Msg)
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answer.SetRcode(r, rcode)
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return answer
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}
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const timeFormat = "02/Jan/2006:15:04:05 -0700"
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