Documentation
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Index ¶
- type Generation
- type WaitGroup
- func (wg *WaitGroup) Add(key uint64)
- func (wg *WaitGroup) Done(key uint64)
- func (wg *WaitGroup) DoneGeneration(key uint64, generation *Generation)
- func (wg *WaitGroup) Get(key uint64) int
- func (wg *WaitGroup) Join(key uint64) <-chan struct{}
- func (wg *WaitGroup) JoinGeneration(key uint64) (*Generation, bool)
- func (wg *WaitGroup) Regroup(key uint64, previous *Generation) (*Generation, bool)
- func (wg *WaitGroup) Wait(key uint64)
Constants ¶
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Variables ¶
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Functions ¶
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Types ¶
type Generation ¶ added in v1.7.4
type Generation struct {
// contains filtered or unexported fields
}
Generation is one immutable leadership generation for a key. Followers keep this token after it completes so Regroup can link every member of that cohort to the same next generation, even when the next leader finishes before a late follower wakes.
func (*Generation) Done ¶ added in v1.7.4
func (g *Generation) Done() <-chan struct{}
Done returns a channel closed when this generation's leader finishes or its bounded wait expires.
func (*Generation) Err ¶ added in v1.7.4
func (g *Generation) Err() error
Err reports why the generation ended. DeadlineExceeded distinguishes an abandoned/timed-out leader from a normal Done cancellation.
type WaitGroup ¶
type WaitGroup struct {
// contains filtered or unexported fields
}
WaitGroup waits for other same processes based key with timeout.
func (*WaitGroup) Add ¶
(*WaitGroup).Add add adds a new caller or if the caller exists increment dups with key.
func (*WaitGroup) Done ¶
(*WaitGroup).Done done cancels the group context or if the caller dups more then zero, decrements the dups with key.
func (*WaitGroup) DoneGeneration ¶ added in v1.7.4
func (wg *WaitGroup) DoneGeneration(key uint64, generation *Generation)
DoneGeneration completes generation and removes it only if it is still the current value for key. The identity check prevents an old, timed-out leader from deleting a newer regroup generation.
func (*WaitGroup) Join ¶
Join atomically decides leadership for key. It is the legacy key-only API; callers must not mix Join/Done with JoinGeneration/DoneGeneration for the same key. It returns nil and registers the caller as the leader (caller must call Done when finished). If a leader already exists, Join returns a channel that closes when the leader finishes; followers must NOT call Done — they never registered as a participant, so calling Done would either over-decrement the dup counter or cancel the leader's context out from under it.
This API closes the Wait-then-Add race in the older Wait/Add sequence: two simultaneous first callers both saw "no leader" and both became leaders, so the dedup didn't actually dedup.
func (*WaitGroup) JoinGeneration ¶ added in v1.7.4
func (wg *WaitGroup) JoinGeneration(key uint64) (*Generation, bool)
JoinGeneration atomically decides leadership for key and returns the exact generation token. The leader must call DoneGeneration with that same token; followers wait on Generation.Done and must not call DoneGeneration.
func (*WaitGroup) Regroup ¶ added in v1.7.4
func (wg *WaitGroup) Regroup(key uint64, previous *Generation) (*Generation, bool)
Regroup links every follower of previous to one common next generation for key. Callers must wait for previous.Done and must handle a timed-out generation without regrouping. The link is retained on previous, so a late follower cannot create a third generation merely because the shared next leader already completed.
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