Method autoJoin

ring/lifecycler.go:912–946

autoJoin selects random tokens & moves state to targetState

(ctx context.Context, targetState InstanceState)

// autoJoin selects random tokens & moves state to targetState
func (i *Lifecycler) autoJoin(ctx context.Context, targetState InstanceState) error {
	err := i.waitBeforeJoining(ctx)
	if err != nil {
		return err
	}

	var ringDesc *Desc
	err = i.KVStore.CAS(ctx, i.RingKey, func(in interface{}) (out interface{}, retry bool, err error) {
		ringDesc = GetOrCreateRingDesc(in)

		// At this point, we should not have any tokens, and we should be in PENDING state.
		myTokens, takenTokens := ringDesc.TokensFor(i.ID)
		if len(myTokens) > 0 {
			level.Error(i.logger).Log("msg", "tokens already exist for this instance - wasn't expecting any!", "num_tokens", len(myTokens), "ring", i.RingName)
		}

		newTokens := i.tokenGenerator.GenerateTokens(i.cfg.NumTokens-len(myTokens), takenTokens)
		i.setState(targetState)

		myTokens = append(myTokens, newTokens...)
		sort.Sort(myTokens)
		i.setTokens(myTokens)

		ro, rots := i.GetReadOnlyState()
		ringDesc.AddIngester(i.ID, i.Addr, i.Zone, i.getTokens(), i.GetState(), i.getRegisteredAt(), ro, rots, nil)
		return ringDesc, true, nil
	})

	// Update counters
	if err == nil {
		i.updateCounters(ringDesc)
	}

	return err
}

// updateConsul updates our entries in consul, heartbeating and dealing with
// consul restarts.