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package reload
import (
"fmt"
"math/rand"
"sync"
"time"
"github.com/coredns/coredns/plugin"
"github.com/coredns/coredns/plugin/metrics"
clog "github.com/coredns/coredns/plugin/pkg/log"
"github.com/caddyserver/caddy"
)
var log = clog.NewWithPlugin("reload")
func init() { plugin.Register("reload", setup) }
// the info reload is global to all application, whatever number of reloads.
// it is used to transmit data between Setup and start of the hook called 'onInstanceStartup'
// channel for QUIT is never changed in purpose.
// WARNING: this data may be unsync after an invalid attempt of reload Corefile.
var (
r = reload{dur: defaultInterval, u: unused, quit: make(chan bool)}
once, shutOnce sync.Once
)
func setup(c *caddy.Controller) error {
c.Next() // 'reload'
args := c.RemainingArgs()
if len(args) > 2 {
return plugin.Error("reload", c.ArgErr())
}
i := defaultInterval
if len(args) > 0 {
d, err := time.ParseDuration(args[0])
if err != nil {
return plugin.Error("reload", err)
}
i = d
}
if i < minInterval {
return plugin.Error("reload", fmt.Errorf("interval value must be greater or equal to %v", minInterval))
}
j := defaultJitter
if len(args) > 1 {
d, err := time.ParseDuration(args[1])
if err != nil {
return plugin.Error("reload", err)
}
j = d
}
if j < minJitter {
return plugin.Error("reload", fmt.Errorf("jitter value must be greater or equal to %v", minJitter))
}
if j > i/2 {
j = i / 2
}
jitter := time.Duration(rand.Int63n(j.Nanoseconds()) - (j.Nanoseconds() / 2))
i = i + jitter
// prepare info for next onInstanceStartup event
r.setInterval(i)
r.setUsage(used)
once.Do(func() {
caddy.RegisterEventHook("reload", hook)
c.OnRestart(func() error {
metrics.MustRegister(c, reloadInfo)
return nil
})
})
// re-register on finalShutDown as the instance most-likely will be changed
shutOnce.Do(func() {
c.OnFinalShutdown(func() error {
r.quit <- true
return nil
})
})
return nil
}
const (
minJitter = 1 * time.Second
minInterval = 2 * time.Second
defaultInterval = 30 * time.Second
defaultJitter = 15 * time.Second
)
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