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Add stime metric and improve commenting

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This commit is contained in:
Simon Marsh 2019-05-25 21:53:07 +01:00
parent 15c06c265e
commit 1a6a9190f3
Signed by: burble
GPG Key ID: 7B9FE8780CFB6593
1 changed files with 46 additions and 5 deletions
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51
dns.go
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@ -13,27 +13,36 @@ import (
log "github.com/sirupsen/logrus"
"math"
"strconv"
"time"
)
//////////////////////////////////////////////////////////////////////////
// data structures
// for holding the metrics
type DNSMetrics struct {
soa *prometheus.GaugeVec
rtt *prometheus.GaugeVec
valid *prometheus.GaugeVec
stime *prometheus.GaugeVec
label_map []prometheus.Labels
}
// for specifying DNS servers
type DNSServer struct {
role string
name string
ip uint8
addr string
soa uint
soa uint64
}
// hardcoded :( list of DNS servers to query
var dns_servers = []*DNSServer{
&DNSServer{"master", "master.delegation-servers.dn42", 6, "[fd42:180:3de0:10:5054:ff:fe87:ea39]:53", 0},
&DNSServer{"master", "j.master.delegation-servers.dn42", 6, "[fd42:180:3de0:10:5054:ff:fe87:ea39]:53", 0},
&DNSServer{"delegation", "b.delegation-servers.dn42", 4, "172.20.129.1:53", 0},
&DNSServer{"delegation", "b.delegation-servers.dn42", 6, "[fd42:4242:2601:ac53::1]:53", 0},
&DNSServer{"delegation", "j.delegation-servers.dn42", 4, "172.20.1.18:53", 0},
@ -56,6 +65,7 @@ var dns_servers = []*DNSServer{
}
//////////////////////////////////////////////////////////////////////////
// initialisation function to register metrics
func (m *DNSMetrics) Register() {
@ -77,6 +87,12 @@ func (m *DNSMetrics) Register() {
}, []string{"role", "name", "ip", "addr"})
prometheus.MustRegister(m.valid)
m.stime = prometheus.NewGaugeVec(prometheus.GaugeOpts{
Name: "dn42_dns_stime",
Help: "Returns the time between now and the SOA serial number",
}, []string{"role", "name", "ip", "addr"})
prometheus.MustRegister(m.stime)
// pre-populate the labels
m.label_map = make([]prometheus.Labels, len(dns_servers))
@ -92,28 +108,53 @@ func (m *DNSMetrics) Register() {
}
//////////////////////////////////////////////////////////////////////////
// collect metrics for all DNS servers
func (m *DNSMetrics) Collect() {
for ix, server := range dns_servers {
soa, rtt := server.Query()
server.soa = uint(soa)
now := uint64(time.Now().Unix())
// go through each server in turn
for ix, server := range dns_servers {
// query it
soa, rtt := server.Query()
server.soa = uint64(soa)
// SOA and RTT are direct metrics returned from the query
m.soa.With(m.label_map[ix]).Set(soa)
m.rtt.With(m.label_map[ix]).Set(rtt)
// check if the returned SOA matches j.master.delegation-servers.dn42
var valid uint = 0
if server.soa == 0 {
// didn't get a result, server issue
valid = 2
} else {
if server.soa != dns_servers[0].soa {
// SOA didn't match
valid = 1
} else {
valid = 0
}
}
// before setting whether the server is valid, calculate the stime
// (difference in time between now and the SOA, to allow checking that
// it is not stale)
// it's possible that the SOA could be in the future if there is a
// clock mismatch between monitor and DNS server, in which case this
// is flagged as a server error
if server.soa > now {
// server error
valid = 2
} else {
m.stime.With(m.label_map[ix]).Set(float64(now - server.soa))
}
// finally set the valid status
m.valid.With(m.label_map[ix]).Set(float64(valid))
}