memorystore

Documentation

Overview

Package memorystore defines an in-memory storage system for limiting.

Index

• func New(c *Config) (limiter.Store, error)
• type Config

Examples

• New

Functions

func New

func New(c *Config) (limiter.Store, error)

New creates an in-memory rate limiter that uses a bucketing model to limit the number of permitted events over an interval. It's optimized for runtime and memory efficiency.

Example

package main

import (
	"context"
	"log"
	"time"

	"github.com/sethvargo/go-limiter/memorystore"
)

func main() {
	ctx := context.Background()

	store, err := memorystore.New(&memorystore.Config{
		Tokens:   15,
		Interval: time.Minute,
	})
	if err != nil {
		log.Fatal(err)
	}
	defer store.Close(ctx)

	limit, remaining, reset, ok, err := store.Take(ctx, "my-key")
	if err != nil {
		log.Fatal(err)
	}
	_, _, _, _ = limit, remaining, reset, ok
}

Types

type Config

type Config struct {
	// Tokens is the number of tokens to allow per interval. The default value is
	// 1.
	Tokens uint64

	// Interval is the time interval upon which to enforce rate limiting. The
	// default value is 1 second.
	Interval time.Duration

	// SweepInterval is the rate at which to run the garabage collection on stale
	// entries. Setting this to a low value will optimize memory consumption, but
	// will likely reduce performance and increase lock contention. Setting this
	// to a high value will maximum throughput, but will increase the memory
	// footprint. This can be tuned in combination with SweepMinTTL to control how
	// long stale entires are kept. The default value is 6 hours.
	SweepInterval time.Duration

	// SweepMinTTL is the minimum amount of time a session must be inactive before
	// clearing it from the entries. There's no validation, but this should be at
	// least as high as your rate limit, or else the data store will purge records
	// before they limit is applied. The default value is 12 hours.
	SweepMinTTL time.Duration

	// InitialAlloc is the size to use for the in-memory map. Go will
	// automatically expand the buffer, but choosing higher number can trade
	// memory consumption for performance as it limits the number of times the map
	// needs to expand. The default value is 4096.
	InitialAlloc int
}

Config is used as input to New. It defines the behavior of the storage system.