forked from coredns/coredns
/
reload.go
75 lines (65 loc) · 1.68 KB
/
reload.go
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package reload
import (
"crypto/md5"
"time"
"github.com/mholt/caddy"
)
// reload periodically checks if the Corefile has changed, and reloads if so
const (
unused = 0
maybeUsed = 1
used = 2
)
type reload struct {
interval time.Duration
usage int
quit chan bool
}
func hook(event caddy.EventName, info interface{}) error {
if event != caddy.InstanceStartupEvent {
return nil
}
// if reload is removed from the Corefile, then the hook
// is still registered but setup is never called again
// so we need a flag to tell us not to reload
if r.usage == unused {
return nil
}
// this should be an instance. ok to panic if not
instance := info.(*caddy.Instance)
md5sum := md5.Sum(instance.Caddyfile().Body())
log.Infof("Running configuration MD5 = %x\n", md5sum)
go func() {
tick := time.NewTicker(r.interval)
for {
select {
case <-tick.C:
corefile, err := caddy.LoadCaddyfile(instance.Caddyfile().ServerType())
if err != nil {
continue
}
s := md5.Sum(corefile.Body())
if s != md5sum {
// Let not try to restart with the same file, even though it is wrong.
md5sum = s
// now lets consider that plugin will not be reload, unless appear in next config file
// change status iof usage will be reset in setup if the plugin appears in config file
r.usage = maybeUsed
_, err := instance.Restart(corefile)
if err != nil {
log.Errorf("Corefile changed but reload failed: %s\n", err)
continue
}
// we are done, if the plugin was not set used, then it is not.
if r.usage == maybeUsed {
r.usage = unused
}
return
}
case <-r.quit:
return
}
}
}()
return nil
}