a72f3a161c
Reload didn't take proper care to protect the fields from use in different goroutines. Add a mutex and add helpers for usage and interval. Signed-off-by: Miek Gieben <miek@miek.nl>
95 lines
2 KiB
Go
95 lines
2 KiB
Go
package reload
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import (
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"fmt"
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"math/rand"
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"sync"
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"time"
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"github.com/coredns/coredns/plugin"
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clog "github.com/coredns/coredns/plugin/pkg/log"
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"github.com/mholt/caddy"
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)
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var log = clog.NewWithPlugin("reload")
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func init() {
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caddy.RegisterPlugin("reload", caddy.Plugin{
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ServerType: "dns",
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Action: setup,
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})
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}
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// the info reload is global to all application, whatever number of reloads.
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// it is used to transmit data between Setup and start of the hook called 'onInstanceStartup'
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// channel for QUIT is never changed in purpose.
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// WARNING: this data may be unsync after an invalid attempt of reload Corefile.
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var (
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r = reload{dur: defaultInterval, u: unused, quit: make(chan bool)}
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once, shutOnce sync.Once
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)
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func setup(c *caddy.Controller) error {
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c.Next() // 'reload'
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args := c.RemainingArgs()
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if len(args) > 2 {
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return plugin.Error("reload", c.ArgErr())
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}
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i := defaultInterval
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if len(args) > 0 {
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d, err := time.ParseDuration(args[0])
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if err != nil {
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return plugin.Error("reload", err)
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}
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i = d
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}
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if i < minInterval {
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return plugin.Error("reload", fmt.Errorf("interval value must be greater or equal to %v", minInterval))
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}
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j := defaultJitter
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if len(args) > 1 {
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d, err := time.ParseDuration(args[1])
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if err != nil {
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return plugin.Error("reload", err)
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}
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j = d
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}
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if j < minJitter {
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return plugin.Error("reload", fmt.Errorf("jitter value must be greater or equal to %v", minJitter))
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}
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if j > i/2 {
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j = i / 2
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}
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jitter := time.Duration(rand.Int63n(j.Nanoseconds()) - (j.Nanoseconds() / 2))
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i = i + jitter
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// prepare info for next onInstanceStartup event
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r.setInterval(i)
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r.setUsage(used)
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once.Do(func() {
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caddy.RegisterEventHook("reload", hook)
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})
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// re-register on finalShutDown as the instance most-likely will be changed
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shutOnce.Do(func() {
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c.OnFinalShutdown(func() error {
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r.quit <- true
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return nil
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})
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})
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return nil
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}
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const (
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minJitter = 1 * time.Second
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minInterval = 2 * time.Second
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defaultInterval = 30 * time.Second
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defaultJitter = 15 * time.Second
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)
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