coredns/plugin/log/log.go
Francois Tur 94c9aae323 plugin/log - Support for Metadata (#2251)
* - add metadata support to Log

* - adapt ctx after rebase
2018-11-13 11:20:49 -08:00

89 lines
2.7 KiB
Go

// Package log implements basic but useful request (access) logging plugin.
package log
import (
"context"
"time"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/metrics/vars"
"github.com/coredns/coredns/plugin/pkg/dnstest"
clog "github.com/coredns/coredns/plugin/pkg/log"
"github.com/coredns/coredns/plugin/pkg/rcode"
"github.com/coredns/coredns/plugin/pkg/replacer"
"github.com/coredns/coredns/plugin/pkg/response"
"github.com/coredns/coredns/request"
"github.com/miekg/dns"
)
// Logger is a basic request logging plugin.
type Logger struct {
Next plugin.Handler
Rules []Rule
ErrorFunc func(context.Context, dns.ResponseWriter, *dns.Msg, int) // failover error handler
}
// ServeDNS implements the plugin.Handler interface.
func (l Logger) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
state := request.Request{W: w, Req: r}
for _, rule := range l.Rules {
if !plugin.Name(rule.NameScope).Matches(state.Name()) {
continue
}
rrw := dnstest.NewRecorder(w)
rc, err := plugin.NextOrFailure(l.Name(), l.Next, ctx, rrw, r)
if rc > 0 {
// There was an error up the chain, but no response has been written yet.
// The error must be handled here so the log entry will record the response size.
if l.ErrorFunc != nil {
l.ErrorFunc(ctx, rrw, r, rc)
} else {
answer := new(dns.Msg)
answer.SetRcode(r, rc)
state.SizeAndDo(answer)
vars.Report(ctx, state, vars.Dropped, rcode.ToString(rc), answer.Len(), time.Now())
w.WriteMsg(answer)
}
rc = 0
}
tpe, _ := response.Typify(rrw.Msg, time.Now().UTC())
class := response.Classify(tpe)
// If we don't set up a class in config, the default "all" will be added
// and we shouldn't have an empty rule.Class.
if rule.Class[response.All] || rule.Class[class] {
rep := replacer.New(ctx, r, rrw, CommonLogEmptyValue)
clog.Infof(rep.Replace(rule.Format))
}
return rc, err
}
return plugin.NextOrFailure(l.Name(), l.Next, ctx, w, r)
}
// Name implements the Handler interface.
func (l Logger) Name() string { return "log" }
// Rule configures the logging plugin.
type Rule struct {
NameScope string
Class map[response.Class]bool
Format string
}
const (
// CommonLogFormat is the common log format.
CommonLogFormat = `{remote}:{port} ` + CommonLogEmptyValue + ` {>id} "{type} {class} {name} {proto} {size} {>do} {>bufsize}" {rcode} {>rflags} {rsize} {duration}`
// CommonLogEmptyValue is the common empty log value.
CommonLogEmptyValue = "-"
// CombinedLogFormat is the combined log format.
CombinedLogFormat = CommonLogFormat + ` "{>opcode}"`
// DefaultLogFormat is the default log format.
DefaultLogFormat = CommonLogFormat
)