coredns/plugin/metrics/setup.go
Miek Gieben 118b0c9408
plugin/metrcs: fix datarace on listeners (#2835)
This fixes a data race on the listener(s) that get started in the
metrics plugins.

It also restore pkg/uniq to its former glory and removes and state being
carried in there; this means for metrics that registry.go was to
replicate that behavior *with* locking (as pkg/uniq doesn't do, or need
that).

Also renamed uniqAddr to just u, to make it slightly shorter.

Signed-off-by: Miek Gieben <miek@miek.nl>
2019-05-18 18:34:46 +01:00

110 lines
2.6 KiB
Go

package metrics
import (
"net"
"runtime"
"github.com/coredns/coredns/core/dnsserver"
"github.com/coredns/coredns/coremain"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/metrics/vars"
clog "github.com/coredns/coredns/plugin/pkg/log"
"github.com/coredns/coredns/plugin/pkg/uniq"
"github.com/mholt/caddy"
)
var (
log = clog.NewWithPlugin("prometheus")
u = uniq.New()
registry = newReg()
)
func init() {
caddy.RegisterPlugin("prometheus", caddy.Plugin{
ServerType: "dns",
Action: setup,
})
}
func setup(c *caddy.Controller) error {
m, err := parse(c)
if err != nil {
return plugin.Error("prometheus", err)
}
m.Reg = registry.getOrSet(m.Addr, m.Reg)
c.OnStartup(func() error { m.Reg = registry.getOrSet(m.Addr, m.Reg); u.Set(m.Addr, m.OnStartup); return nil })
c.OnRestartFailed(func() error { m.Reg = registry.getOrSet(m.Addr, m.Reg); u.Set(m.Addr, m.OnStartup); return nil })
c.OnStartup(func() error { return u.ForEach() })
c.OnRestartFailed(func() error { return u.ForEach() })
c.OnStartup(func() error {
conf := dnsserver.GetConfig(c)
for _, h := range conf.ListenHosts {
addrstr := conf.Transport + "://" + net.JoinHostPort(h, conf.Port)
for _, p := range conf.Handlers() {
vars.PluginEnabled.WithLabelValues(addrstr, conf.Zone, p.Name()).Set(1)
}
}
return nil
})
c.OnRestartFailed(func() error {
conf := dnsserver.GetConfig(c)
for _, h := range conf.ListenHosts {
addrstr := conf.Transport + "://" + net.JoinHostPort(h, conf.Port)
for _, p := range conf.Handlers() {
vars.PluginEnabled.WithLabelValues(addrstr, conf.Zone, p.Name()).Set(1)
}
}
return nil
})
c.OnRestart(m.OnRestart)
c.OnRestart(func() error { vars.PluginEnabled.Reset(); return nil })
c.OnFinalShutdown(m.OnFinalShutdown)
// Initialize metrics.
buildInfo.WithLabelValues(coremain.CoreVersion, coremain.GitCommit, runtime.Version()).Set(1)
dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
m.Next = next
return m
})
return nil
}
func parse(c *caddy.Controller) (*Metrics, error) {
met := New(defaultAddr)
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"