forked from coredns/coredns
/
setup.go
88 lines (70 loc) · 1.63 KB
/
setup.go
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package metrics
import (
"net"
"runtime"
"github.com/coredns/coredns/core/dnsserver"
"github.com/coredns/coredns/coremain"
"github.com/coredns/coredns/plugin"
clog "github.com/coredns/coredns/plugin/pkg/log"
"github.com/mholt/caddy"
)
var log = clog.NewWithPlugin("prometheus")
func init() {
caddy.RegisterPlugin("prometheus", caddy.Plugin{
ServerType: "dns",
Action: setup,
})
uniqAddr = newAddress()
}
func setup(c *caddy.Controller) error {
m, err := prometheusParse(c)
if err != nil {
return plugin.Error("prometheus", err)
}
dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
m.Next = next
return m
})
c.OncePerServerBlock(func() error {
c.OnStartup(func() error {
return uniqAddr.forEachTodo()
})
return nil
})
c.OnRestart(m.OnRestart)
c.OnFinalShutdown(m.OnFinalShutdown)
// Initialize metrics.
buildInfo.WithLabelValues(coremain.CoreVersion, coremain.GitCommit, runtime.Version()).Set(1)
return nil
}
func prometheusParse(c *caddy.Controller) (*Metrics, error) {
var met = New(defaultAddr)
defer func() {
uniqAddr.setAddress(met.Addr, met.OnStartup)
}()
i := 0
for c.Next() {
if i > 0 {
return nil, plugin.ErrOnce
}
i++
for _, z := range c.ServerBlockKeys {
met.AddZone(plugin.Host(z).Normalize())
}
args := c.RemainingArgs()
switch len(args) {
case 0:
case 1:
met.Addr = args[0]
_, _, e := net.SplitHostPort(met.Addr)
if e != nil {
return met, e
}
default:
return met, c.ArgErr()
}
}
return met, nil
}
// defaultAddr is the address the where the metrics are exported by default.
const defaultAddr = "localhost:9153"