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dns: track number of questions and which upstream was used

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This commit is contained in:
Michael Stapelberg 2018-06-18 09:35:14 +02:00
parent 24e2d5de00
commit c743091929
1 changed files with 26 additions and 2 deletions
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24
internal/dns/dns.go
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@ -26,6 +26,8 @@ type Server struct {
prom struct {
registry *prometheus.Registry
queries prometheus.Counter
upstream *prometheus.CounterVec
questions prometheus.Histogram
}
mu sync.Mutex
@ -47,11 +49,29 @@ func NewServer(addr, domain string) *Server {
ip: ip,
}
server.prom.registry = prometheus.NewRegistry()
server.prom.queries = prometheus.NewCounter(prometheus.CounterOpts{
Name: "dns_queries",
Help: "Number of DNS queries received",
})
server.prom.registry.MustRegister(server.prom.queries)
server.prom.upstream = prometheus.NewCounterVec(
prometheus.CounterOpts{
Name: "dns_upstream",
Help: "Which upstream answered which DNS query",
},
[]string{"upstream"},
)
server.prom.registry.MustRegister(server.prom.upstream)
server.prom.questions = prometheus.NewHistogram(prometheus.HistogramOpts{
Name: "dns_questions",
Help: "Number of questions in each DNS request",
Buckets: prometheus.LinearBuckets(0, 1, 10),
})
server.prom.registry.MustRegister(server.prom.questions)
server.prom.registry.MustRegister(prometheus.NewGoCollector())
server.initHostsLocked()
dns.HandleFunc(".", server.handleRequest)
@ -144,6 +164,7 @@ func isLocalInAddrArpa(q string) bool {
// TODO: require search domains to be present, then use HandleFunc("lan.", internalName)
func (s *Server) handleRequest(w dns.ResponseWriter, r *dns.Msg) {
s.prom.queries.Inc()
s.prom.questions.Observe(float64(len(r.Question)))
if len(r.Question) == 1 { // TODO: answer all questions we can answer
q := r.Question[0]
if q.Qtype == dns.TypeA && q.Qclass == dns.ClassINET {
@ -160,6 +181,7 @@ func (s *Server) handleRequest(w dns.ResponseWriter, r *dns.Msg) {
m.SetReply(r)
m.Answer = append(m.Answer, rr)
w.WriteMsg(m)
s.prom.upstream.WithLabelValues("local").Inc()
return
}
}
@ -175,6 +197,7 @@ func (s *Server) handleRequest(w dns.ResponseWriter, r *dns.Msg) {
m.SetReply(r)
m.Answer = append(m.Answer, rr)
w.WriteMsg(m)
s.prom.upstream.WithLabelValues("local").Inc()
return
}
}
@ -189,4 +212,5 @@ func (s *Server) handleRequest(w dns.ResponseWriter, r *dns.Msg) {
return // DNS has no reply for resolving errors
}
w.WriteMsg(in)
s.prom.upstream.WithLabelValues("DNS").Inc()
}