bucket

Documentation

Overview

Package bucket implements a rolling bucket system.

Index

• Constants
• Variables
• type Channel
• type Controller
• type EvictFn
• type OnAddRecentFn
• type Queue
  • func NewQueue(l *logger.Logger, size int, maxSize int, scheduler *timestamp.Scheduler, ...) (Queue, error)
• type Reporter
  • func NewTimeBasedReporter(name string, timeRange timestamp.TimeRange, clock timestamp.Clock, ...) Reporter
• type Status
• type Strategy
  • func NewStrategy(ctrl Controller, options ...StrategyOptions) (*Strategy, error)
  • func (s *Strategy) Close()
  • func (s *Strategy) Run()
  • func (s *Strategy) String() string
• type StrategyOptions
  • func WithLogger(logger *logger.Logger) StrategyOptions
  • func WithNextThreshold(r ratio) StrategyOptions

Constants

const (
	// QueueName is identity of the queue.
	QueueName = "block-queue-cleanup"
)

Variables

var (
	// ErrInvalidParameter denotes input parameters are invalid.
	ErrInvalidParameter = errors.New("parameters are invalid")
	// ErrNoMoreBucket denotes the bucket volume reaches the limitation.
	ErrNoMoreBucket = errors.New("no more buckets")
)

var (

	// DummyReporter is a special Reporter to avoid nil errors.
	DummyReporter = &dummyReporter{}
)

Types

type Channel

type Channel chan Status

Channel reports the status of a Reporter.

type Controller

type Controller interface {
	Current() (Reporter, error)
	Next() (Reporter, error)
	OnMove(prev, next Reporter)
}

Controller defines the provider of a Reporter.

type EvictFn

type EvictFn func(ctx context.Context, id interface{}) error

EvictFn is a closure executed on evicting an item.

type OnAddRecentFn

type OnAddRecentFn func() error

OnAddRecentFn is a notifier on adding an item into the recent queue.

type Queue

type Queue interface {
	Touch(id fmt.Stringer) bool
	Push(ctx context.Context, id fmt.Stringer, fn OnAddRecentFn) error
	Remove(id fmt.Stringer)
	Len() int
	Volume() int
	All() []fmt.Stringer
}

Queue is a LRU queue.

func NewQueue

func NewQueue(l *logger.Logger, size int, maxSize int, scheduler *timestamp.Scheduler, evictFn EvictFn) (Queue, error)

NewQueue return a Queue for blocks eviction.

type Reporter

type Reporter interface {
	// TODO: refactor Report to return a status. It's too complicated to return a channel
	Report() (Channel, error)
	String() string
}

Reporter allows reporting status to its supervisor.

func NewTimeBasedReporter

func NewTimeBasedReporter(name string, timeRange timestamp.TimeRange, clock timestamp.Clock, scheduler *timestamp.Scheduler) Reporter

NewTimeBasedReporter returns a Reporter which sends report based on time.

type Status

type Status struct {
	Capacity int
	Volume   int
}

Status is a sample of the Reporter's status.

type Strategy

type Strategy struct {
	// contains filtered or unexported fields
}

Strategy controls Reporters with Controller's help.

func NewStrategy

func NewStrategy(ctrl Controller, options ...StrategyOptions) (*Strategy, error)

NewStrategy returns a Strategy.

func (*Strategy) Close

func (s *Strategy) Close()

Close the Strategy running in the background.

func (*Strategy) Run

func (s *Strategy) Run()

Run the Strategy in the background.

func (*Strategy) String

func (s *Strategy) String() string

type StrategyOptions

type StrategyOptions func(*Strategy)

StrategyOptions sets how to create a Strategy.

func WithLogger

func WithLogger(logger *logger.Logger) StrategyOptions

WithLogger sets a logger.Logger.

func WithNextThreshold

func WithNextThreshold(r ratio) StrategyOptions

WithNextThreshold sets a ratio to creat the next Reporter.