56 lines
1.4 KiB
Go
56 lines
1.4 KiB
Go
package cluster
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import (
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log "github.com/Sirupsen/logrus"
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"github.com/cenkalti/backoff"
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"github.com/containous/traefik/safe"
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"github.com/containous/traefik/types"
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"github.com/docker/leadership"
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"time"
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)
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// Leadership allows leadership election using a KV store
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type Leadership struct {
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types.Cluster
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candidate *leadership.Candidate
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}
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// Participate tries to be a leader
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func (l *Leadership) Participate(pool *safe.Pool, isElected func(bool)) {
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pool.Go(func(stop chan bool) {
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l.candidate = leadership.NewCandidate(l.Store, l.Store.Prefix+"/leader", l.Node, 30*time.Second)
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backOff := backoff.NewExponentialBackOff()
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operation := func() error {
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return l.run(l.candidate, stop, isElected)
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}
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notify := func(err error, time time.Duration) {
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log.Errorf("Leadership election error %+v, retrying in %s", err, time)
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}
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err := backoff.RetryNotify(operation, backOff, notify)
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if err != nil {
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log.Errorf("Cannot elect leadership %+v", err)
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}
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})
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}
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// Resign resigns from being a leader
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func (l *Leadership) Resign() {
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if l.candidate != nil {
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l.candidate.Resign()
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}
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}
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func (l *Leadership) run(candidate *leadership.Candidate, stop chan bool, isElected func(bool)) error {
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electedCh, errCh := candidate.RunForElection()
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for {
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select {
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case elected := <-electedCh:
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isElected(elected)
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case err := <-errCh:
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return err
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case <-stop:
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return nil
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}
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}
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}
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