kubernetes/vendor/go.etcd.io/etcd/raft/v3/confchange/confchange.go

type Changer …

// EnterJoint verifies that the outgoing (=right) majority config of the joint
// config is empty and initializes it with a copy of the incoming (=left)
// majority config. That is, it transitions from
//
//	(1 2 3)&&()
//
// to
//
//	(1 2 3)&&(1 2 3).
//
// The supplied changes are then applied to the incoming majority config,
// resulting in a joint configuration that in terms of the Raft thesis[1]
// (Section 4.3) corresponds to `C_{new,old}`.
//
// [1]: https://github.com/ongardie/dissertation/blob/master/online-trim.pdf
func (c Changer) EnterJoint(autoLeave bool, ccs ...pb.ConfChangeSingle) (tracker.Config, tracker.ProgressMap, error) { … }

// LeaveJoint transitions out of a joint configuration. It is an error to call
// this method if the configuration is not joint, i.e. if the outgoing majority
// config Voters[1] is empty.
//
// The outgoing majority config of the joint configuration will be removed,
// that is, the incoming config is promoted as the sole decision maker. In the
// notation of the Raft thesis[1] (Section 4.3), this method transitions from
// `C_{new,old}` into `C_new`.
//
// At the same time, any staged learners (LearnersNext) the addition of which
// was held back by an overlapping voter in the former outgoing config will be
// inserted into Learners.
//
// [1]: https://github.com/ongardie/dissertation/blob/master/online-trim.pdf
func (c Changer) LeaveJoint() (tracker.Config, tracker.ProgressMap, error) { … }

// Simple carries out a series of configuration changes that (in aggregate)
// mutates the incoming majority config Voters[0] by at most one. This method
// will return an error if that is not the case, if the resulting quorum is
// zero, or if the configuration is in a joint state (i.e. if there is an
// outgoing configuration).
func (c Changer) Simple(ccs ...pb.ConfChangeSingle) (tracker.Config, tracker.ProgressMap, error) { … }

// apply a change to the configuration. By convention, changes to voters are
// always made to the incoming majority config Voters[0]. Voters[1] is either
// empty or preserves the outgoing majority configuration while in a joint state.
func (c Changer) apply(cfg *tracker.Config, prs tracker.ProgressMap, ccs ...pb.ConfChangeSingle) error { … }

// makeVoter adds or promotes the given ID to be a voter in the incoming
// majority config.
func (c Changer) makeVoter(cfg *tracker.Config, prs tracker.ProgressMap, id uint64) { … }

// makeLearner makes the given ID a learner or stages it to be a learner once
// an active joint configuration is exited.
//
// The former happens when the peer is not a part of the outgoing config, in
// which case we either add a new learner or demote a voter in the incoming
// config.
//
// The latter case occurs when the configuration is joint and the peer is a
// voter in the outgoing config. In that case, we do not want to add the peer
// as a learner because then we'd have to track a peer as a voter and learner
// simultaneously. Instead, we add the learner to LearnersNext, so that it will
// be added to Learners the moment the outgoing config is removed by
// LeaveJoint().
func (c Changer) makeLearner(cfg *tracker.Config, prs tracker.ProgressMap, id uint64) { … }

// remove this peer as a voter or learner from the incoming config.
func (c Changer) remove(cfg *tracker.Config, prs tracker.ProgressMap, id uint64) { … }

// initProgress initializes a new progress for the given node or learner.
func (c Changer) initProgress(cfg *tracker.Config, prs tracker.ProgressMap, id uint64, isLearner bool) { … }

// checkInvariants makes sure that the config and progress are compatible with
// each other. This is used to check both what the Changer is initialized with,
// as well as what it returns.
func checkInvariants(cfg tracker.Config, prs tracker.ProgressMap) error { … }

// checkAndCopy copies the tracker's config and progress map (deeply enough for
// the purposes of the Changer) and returns those copies. It returns an error
// if checkInvariants does.
func (c Changer) checkAndCopy() (tracker.Config, tracker.ProgressMap, error) { … }

// checkAndReturn calls checkInvariants on the input and returns either the
// resulting error or the input.
func checkAndReturn(cfg tracker.Config, prs tracker.ProgressMap) (tracker.Config, tracker.ProgressMap, error) { … }

// err returns zero values and an error.
func (c Changer) err(err error) (tracker.Config, tracker.ProgressMap, error) { … }

// nilAwareAdd populates a map entry, creating the map if necessary.
func nilAwareAdd(m *map[uint64]struct{ … }

// nilAwareDelete deletes from a map, nil'ing the map itself if it is empty after.
func nilAwareDelete(m *map[uint64]struct{ … }

// symdiff returns the count of the symmetric difference between the sets of
// uint64s, i.e. len( (l - r) \union (r - l)).
func symdiff(l, r map[uint64]struct{ … }

func joint(cfg tracker.Config) bool { … }

func incoming(voters quorum.JointConfig) quorum.MajorityConfig      { … }

func outgoing(voters quorum.JointConfig) quorum.MajorityConfig      { … }

func outgoingPtr(voters *quorum.JointConfig) *quorum.MajorityConfig { … }

// Describe prints the type and NodeID of the configuration changes as a
// space-delimited string.
func Describe(ccs ...pb.ConfChangeSingle) string { … }