128 lines
2.9 KiB
Go
128 lines
2.9 KiB
Go
// Package reload periodically checks if the Corefile has changed, and reloads if so.
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package reload
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import (
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"bytes"
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"crypto/sha512"
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"encoding/hex"
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"encoding/json"
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"sync"
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"time"
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"github.com/coredns/caddy"
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"github.com/coredns/caddy/caddyfile"
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"github.com/prometheus/client_golang/prometheus"
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)
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const (
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unused = 0
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maybeUsed = 1
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used = 2
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)
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type reload struct {
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dur time.Duration
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u int
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mtx sync.RWMutex
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quit chan bool
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}
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func (r *reload) setUsage(u int) {
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r.mtx.Lock()
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defer r.mtx.Unlock()
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r.u = u
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}
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func (r *reload) usage() int {
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r.mtx.RLock()
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defer r.mtx.RUnlock()
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return r.u
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}
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func (r *reload) setInterval(i time.Duration) {
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r.mtx.Lock()
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defer r.mtx.Unlock()
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r.dur = i
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}
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func (r *reload) interval() time.Duration {
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r.mtx.RLock()
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defer r.mtx.RUnlock()
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return r.dur
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}
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func parse(corefile caddy.Input) ([]byte, error) {
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serverBlocks, err := caddyfile.Parse(corefile.Path(), bytes.NewReader(corefile.Body()), nil)
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if err != nil {
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return nil, err
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}
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return json.Marshal(serverBlocks)
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}
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func hook(event caddy.EventName, info interface{}) error {
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if event != caddy.InstanceStartupEvent {
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return nil
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}
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// if reload is removed from the Corefile, then the hook
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// is still registered but setup is never called again
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// so we need a flag to tell us not to reload
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if r.usage() == unused {
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return nil
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}
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// this should be an instance. ok to panic if not
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instance := info.(*caddy.Instance)
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parsedCorefile, err := parse(instance.Caddyfile())
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if err != nil {
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return err
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}
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sha512sum := sha512.Sum512(parsedCorefile)
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log.Infof("Running configuration SHA512 = %x\n", sha512sum)
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go func() {
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tick := time.NewTicker(r.interval())
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defer tick.Stop()
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for {
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select {
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case <-tick.C:
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corefile, err := caddy.LoadCaddyfile(instance.Caddyfile().ServerType())
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if err != nil {
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continue
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}
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parsedCorefile, err := parse(corefile)
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if err != nil {
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log.Warningf("Corefile parse failed: %s", err)
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continue
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}
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s := sha512.Sum512(parsedCorefile)
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if s != sha512sum {
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reloadInfo.Delete(prometheus.Labels{"hash": "sha512", "value": hex.EncodeToString(sha512sum[:])})
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// Let not try to restart with the same file, even though it is wrong.
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sha512sum = s
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// now lets consider that plugin will not be reload, unless appear in next config file
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// change status of usage will be reset in setup if the plugin appears in config file
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r.setUsage(maybeUsed)
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_, err := instance.Restart(corefile)
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reloadInfo.WithLabelValues("sha512", hex.EncodeToString(sha512sum[:])).Set(1)
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if err != nil {
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log.Errorf("Corefile changed but reload failed: %s", err)
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failedCount.Add(1)
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continue
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}
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// we are done, if the plugin was not set used, then it is not.
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if r.usage() == maybeUsed {
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r.setUsage(unused)
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}
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return
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}
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case <-r.quit:
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return
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}
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}
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}()
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return nil
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}
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