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golimiter

import "github.com/Bose/golimiter"

Overview

Index

Package files

context.go golimiter.go inmemory.go janitor.go options.go rate.go store.go

Variables

var (
    // ErrNoCentralStore - no central store for the rate limiter was initialized
    ErrNoCentralStore = errors.New("no central limiter store initialized")
)

func EntrySyncInfo

func EntrySyncInfo(e goCache.GenericCacheEntry) (currentCount int, lastSyncCount int, delta uint64)

EntrySyncInfo - delta between last sync count

type Context

type Context struct {
    Limit     int64
    Count     int64
    Remaining int64
    Reset     int64
    Reached   bool
    Delay     int64
}

Context is the limit context.

func GetContextFromState

func GetContextFromState(now time.Time, rate Rate, expiration time.Time, count int64) Context

GetContextFromState generate a new Context from given state.

type Limiter

type Limiter struct {
    Store Store
    Rate  Rate
}

Limiter is the limiter instance.

func New

func New(store Store, rate Rate) *Limiter

New returns an instance of Limiter.

func (*Limiter) Get

func (l *Limiter) Get(ctx context.Context, key string) (Context, error)

Get returns the limit for given identifier.

func (*Limiter) Peek

func (l *Limiter) Peek(ctx context.Context, key string) (Context, error)

Peek returns the limit for given identifier, without modification on current values.

type LimiterStore

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

LimiterStore - encapsulate the limiterStore

func NewInMemoryLimiterStore

func NewInMemoryLimiterStore(maxEntries int, opt ...Option) *LimiterStore

NewInMemoryLimiterStore creates a new instance of memory store with defaults.

func (LimiterStore) CentralStorePeek

func (store LimiterStore) CentralStorePeek(key string) (uint64, error)

CentralStorePeek - peek at a value in the distributed central store

func (LimiterStore) CentralStoreSync

func (store LimiterStore) CentralStoreSync() error

CentralStoreSync - orchestrator for keeping the stores in sync that uses concurrency to get stuff done this syncs every entry, every time... see CentralStoreUpdates() which is far more efficient

func (LimiterStore) CentralStoreUpdates

func (store LimiterStore) CentralStoreUpdates() error

CentralStoreUpdates is used by the janitor.Run to "do" the updates via background workers

func (LimiterStore) EntryCentralStoreExpiresIn

func (store LimiterStore) EntryCentralStoreExpiresIn(key string) (int64, error)

EntryCentralStoreExpiresIn retrieves the entries TTL from the central store (if the limiter has one)

func (*LimiterStore) Get

func (store *LimiterStore) Get(ctx context.Context, key string, rate Rate) (lContext Context, err error)

Get returns the limit for given identifier. (and increments the limiter's counter) if it's drifted too far from the central store, it will sync to the central store

func (*LimiterStore) Peek

func (store *LimiterStore) Peek(ctx context.Context, key string, rate Rate) (lContext Context, err error)

Peek returns the limit for given identifier, without modification on current values.

func (*LimiterStore) StopCentralStoreUpdates

func (store *LimiterStore) StopCentralStoreUpdates() bool

StopCentralStoreUpdates - stop the janitor

func (LimiterStore) SyncEntryWithCentralStore

func (store LimiterStore) SyncEntryWithCentralStore(key string, opt ...Option) (updatedInMemoryCounter interface{})

SyncEntryWithCentralStore - figures out what to sync for one entry and sets the in memory TTL to match the central store TTL

type Option

type Option func(*options)

Option - defines a func interface for passing in options to the NewInMemoryLimiterStore()

func WithIncrement

func WithIncrement(i int) Option

WithIncrement passes an optional increment

func WithLimiterExpiration

func WithLimiterExpiration(exp time.Duration) Option

WithLimiterExpSeconds sets the limiter's expiry in seconds

func WithRate

func WithRate(r Rate) Option

WithRate passes an optional rate

func WithUnsyncCounterLimit

func WithUnsyncCounterLimit(deltaLimit uint64) Option

WithUnsyncCounterLimit - allows you to override the default limit to how far the in memory counter can drift from the central store

func WithUnsyncTimeLimit

func WithUnsyncTimeLimit(timeLimit uint64) Option

WithUnsyncTimeLimit - allows you to override the default time limit (milliseconds) between syncs to the central store. this cannot be 0 or it will default to defaultUnsyncTimeLimit

func WithWorkerNumber

func WithWorkerNumber(worker int) Option

WithWorkerNumber passes an optional worker number

type Rate

type Rate struct {
    Formatted string
    Period    time.Duration
    Limit     int64
    Delay     int64
}

Rate is the rate == 1-1-S-50

func NewRateFromFormatted

func NewRateFromFormatted(formatted string) (Rate, error)

NewRateFromFormatted - returns the rate from the formatted version ()

type Store

type Store interface {
    // Get increments the limit for a given identtfier and returns its context
    Get(ctx context.Context, key string, rate Rate) (Context, error)
    // Peek returns the limit for given identifier, without modification on current values.
    Peek(ctx context.Context, key string, rate Rate) (Context, error)
    // CentrailStorePeek - Peek at an entry in the central store
    CentralStorePeek(key string) (uint64, error)
    // CentralStoreSync - syncs all the keys from in memory with the central store
    CentralStoreSync() error
    // CentralStoreUpdates - just sync the updated keys from in memory with the central store
    CentralStoreUpdates() error
    // SyncEntryWithCentralStore - sync just one key from in memory with the central store and return the new entry IF it's updated
    SyncEntryWithCentralStore(key string, opt ...Option) interface{}
    // StopCentralStoreUpdates - stop all janitor syncing to central store and return whether or not the message to stop as successfully sent
    StopCentralStoreUpdates() bool
}

Store is the common interface for limiter stores.

type StoreEntry

type StoreEntry struct {
    CurrentCount    int
    LastSyncedCount int
}

StoreEntry - represent the entry in the store

type StoreOptions

type StoreOptions struct {
    // Prefix is the prefix to use for the key.
    Prefix string

    // MaxRetry is the maximum number of retry under race conditions.
    MaxRetry int

    // CleanUpInterval is the interval for cleanup.
    CleanUpInterval time.Duration
}

StoreOptions are options for store.

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