coredns/middleware/log/log.go
2016-03-19 11:16:08 +00:00

68 lines
2 KiB
Go

// Package log implements basic but useful request (access) logging middleware.
package log
import (
"log"
"golang.org/x/net/context"
"github.com/miekg/coredns/middleware"
"github.com/miekg/dns"
)
// Logger is a basic request logging middleware.
type Logger struct {
Next middleware.Handler
Rules []Rule
ErrorFunc func(dns.ResponseWriter, *dns.Msg, int) // failover error handler
}
func (l Logger) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
state := middleware.State{W: w, Req: r}
for _, rule := range l.Rules {
if middleware.Name(state.Name()).Matches(rule.NameScope) {
responseRecorder := middleware.NewResponseRecorder(w)
rcode, err := l.Next.ServeDNS(ctx, responseRecorder, r)
if rcode > 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(responseRecorder, r, rcode)
} else {
// Default failover error handler
answer := new(dns.Msg)
answer.SetRcode(r, rcode)
w.WriteMsg(answer)
}
rcode = 0
}
rep := middleware.NewReplacer(r, responseRecorder, CommonLogEmptyValue)
rule.Log.Println(rep.Replace(rule.Format))
return rcode, err
}
}
return l.Next.ServeDNS(ctx, w, r)
}
// Rule configures the logging middleware.
type Rule struct {
NameScope string
OutputFile string
Format string
Log *log.Logger
Roller *middleware.LogRoller
}
const (
// DefaultLogFilename is the default log filename.
DefaultLogFilename = "query.log"
// CommonLogFormat is the common log format.
CommonLogFormat = `{remote} ` + CommonLogEmptyValue + ` [{when}] "{type} {name} {proto}" {rcode} {size}`
// 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
)