cacheable

Table of Contents

High Performance Layer 1 / Layer 2 Caching with Keyv Storage

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cacheable is a high performance layer 1 / layer 2 caching engine that is focused on distributed caching with enterprise features such as CacheSync (coming soon). It is built on top of the robust storage engine Keyv and provides a simple API to cache and retrieve data.

  • Simple to use with robust API
  • Not bloated with additional modules
  • Scalable and trusted storage engine by Keyv
  • Memory Caching with LRU and Expiration CacheableMemory
  • Resilient to failures with try/catch and offline
  • Wrap / Memoization for Sync and Async Functions with Stampede Protection
  • Hooks and Events to extend functionality
  • Shorthand for ttl in milliseconds (1m = 60000) (1h = 3600000) (1d = 86400000)
  • Non-blocking operations for layer 2 caching
  • Distributed Caching Sync via Pub/Sub (coming soon)
  • Comprehensive testing and code coverage
  • ESM and CommonJS support with Typescript
  • Maintained and supported regularly

Table of Contents

Getting Started

cacheable is primarily used as an extension to your caching engine with a robust storage backend Keyv, Memoization (Wrap), Hooks, Events, and Statistics.

npm install cacheable

Basic Usage

import { Cacheable } from 'cacheable';

const cacheable = new Cacheable();
await cacheable.set('key', 'value', 1000);
const value = await cacheable.get('key');

This is a basic example where you are only using the in-memory storage engine. To enable layer 1 and layer 2 caching you can use the secondary property in the options:

import { Cacheable } from 'cacheable';
import KeyvRedis from '@keyv/redis';

const secondary = new KeyvRedis('redis://user:pass@localhost:6379');
const cache = new Cacheable({secondary});

In this example, the primary store we will use lru-cache and the secondary store is Redis. You can also set multiple stores in the options:

import { Cacheable } from 'cacheable';
import { Keyv } from 'keyv';
import KeyvRedis from '@keyv/redis';
import { LRUCache } from 'lru-cache'

const primary = new Keyv({store: new LRUCache()});
const secondary = new KeyvRedis('redis://user:pass@localhost:6379');
const cache = new Cacheable({primary, secondary});

This is a more advanced example and not needed for most use cases.

Hooks and Events

The following hooks are available for you to extend the functionality of cacheable via CacheableHooks enum:

  • BEFORE_SET: This is called before the set() method is called.
  • AFTER_SET: This is called after the set() method is called.
  • BEFORE_SET_MANY: This is called before the setMany() method is called.
  • AFTER_SET_MANY: This is called after the setMany() method is called.
  • BEFORE_GET: This is called before the get() method is called.
  • AFTER_GET: This is called after the get() method is called.
  • BEFORE_GET_MANY: This is called before the getMany() method is called.
  • AFTER_GET_MANY: This is called after the getMany() method is called.
  • BEFORE_SECONDARY_SETS_PRIMARY: This is called when the secondary store sets the value in the primary store.

An example of how to use these hooks:

import { Cacheable, CacheableHooks } from 'cacheable';

const cacheable = new Cacheable();
cacheable.onHook(CacheableHooks.BEFORE_SET, (data) => {
  console.log(`before set: ${data.key} ${data.value}`);
});

Here is an example of how to use BEFORE_SECONDARY_SETS_PRIMARY hook:

import { Cacheable, CacheableHooks } from 'cacheable';
import KeyvRedis from '@keyv/redis';
const secondary = new KeyvRedis('redis://user:pass@localhost:6379');
const cache = new Cacheable({secondary});
cache.onHook(CacheableHooks.BEFORE_SECONDARY_SETS_PRIMARY, (data) => {
  console.log(`before secondary sets primary: ${data.key} ${data.value} ${data.ttl}`);
});

This is called when the secondary store sets the value in the primary store. This is useful if you want to do something before the value is set in the primary store such as manipulating the ttl or the value.

The following events are provided:

  • error: Emitted when an error occurs.
  • cache:hit: Emitted when a cache hit occurs.
  • cache:miss: Emitted when a cache miss occurs.

Here is an example of using the error event:

import { Cacheable, CacheableEvents } from 'cacheable';

const cacheable = new Cacheable();
cacheable.on(CacheableEvents.ERROR, (error) => {
  console.error(`Cacheable error: ${error.message}`);
});

We also offer cache:hit and cache:miss events. These events are emitted when a cache hit or miss occurs, respectively. Here is how to use them:

import { Cacheable, CacheableEvents } from 'cacheable';

const cacheable = new Cacheable();
cacheable.on(CacheableEvents.CACHE_HIT, (data) => {
  console.log(`Cache hit: ${data.key} ${data.value} ${data.store}`); // the store will say primary or secondary
});
cacheable.on(CacheableEvents.CACHE_MISS, (data) => {
  console.log(`Cache miss: ${data.key} ${data.store}`); // the store will say primary or secondary
});

Storage Tiering and Caching

cacheable is built as a layer 1 and layer 2 caching engine by default. The purpose is to have your layer 1 be fast and your layer 2 be more persistent. The primary store is the layer 1 cache and the secondary store is the layer 2 cache. By adding the secondary store you are enabling layer 2 caching. By default the operations are blocking but fault tolerant:

  • Setting Data: Sets the value in the primary store and then the secondary store.
  • Getting Data: Gets the value from the primary if the value does not exist it will get it from the secondary store and set it in the primary store.
  • Deleting Data: Deletes the value from the primary store and secondary store at the same time waiting for both to respond.
  • Clearing Data: Clears the primary store and secondary store at the same time waiting for both to respond.

When Getting Data if the value does not exist in the primary store it will try to get it from the secondary store. If the secondary store returns the value it will set it in the primary store. Because we use TTL Propagation the value will be set in the primary store with the TTL of the secondary store unless the time to live (TTL) is greater than the primary store which will then use the TTL of the primary store. An example of this is:

import { Cacheable } from 'cacheable';
import KeyvRedis from '@keyv/redis';
const secondary = new KeyvRedis('redis://user:pass@localhost:6379', { ttl: 1000 });
const cache = new Cacheable({secondary, ttl: 100});

await cache.set('key', 'value'); // sets the value in the primary store with a ttl of 100 ms and secondary store with a ttl of 1000 ms

await sleep(500); // wait for .5 seconds

const value = await cache.get('key'); // gets the value from the secondary store and now sets the value in the primary store with a ttl of 500 ms which is what is left from the secondary store

In this example the primary store has a ttl of 100 ms and the secondary store has a ttl of 1000 ms. Because the ttl is greater in the secondary store it will default to setting ttl value in the primary store.

import { Cacheable } from 'cacheable';
import {Keyv} from 'keyv';
import KeyvRedis from '@keyv/redis';
const primary = new Keyv({ ttl: 200 });
const secondary = new KeyvRedis('redis://user:pass@localhost:6379', { ttl: 1000 });
const cache = new Cacheable({primary, secondary});

await cache.set('key', 'value'); // sets the value in the primary store with a ttl of 100 ms and secondary store with a ttl of 1000 ms

await sleep(200); // wait for .2 seconds

const value = await cache.get('key'); // gets the value from the secondary store and now sets the value in the primary store with a ttl of 200 ms which is what the primary store is set with

TTL Propagation and Storage Tiering

Cacheable TTL propagation is a feature that allows you to set a time to live (TTL) for the cache. By default the TTL is set in the following order:

ttl = set at the function ?? storage adapter ttl ?? cacheable ttl

This means that if you set a TTL at the function level it will override the storage adapter TTL and the cacheable TTL. If you do not set a TTL at the function level it will use the storage adapter TTL and then the cacheable TTL. If you do not set a TTL at all it will use the default TTL of undefined which is disabled.

Shorthand for Time to Live (ttl)

By default Cacheable and CacheableMemory the ttl is in milliseconds but you can use shorthand for the time to live. Here are the following shorthand values:

  • ms: Milliseconds such as (1ms = 1)
  • s: Seconds such as (1s = 1000)
  • m: Minutes such as (1m = 60000)
  • h or hr: Hours such as (1h = 3600000)
  • d: Days such as (1d = 86400000)

Here is an example of how to use the shorthand for the ttl:

import { Cacheable } from 'cacheable';
const cache = new Cacheable({ ttl: '15m' }); //sets the default ttl to 15 minutes (900000 ms)
cache.set('key', 'value', '1h'); //sets the ttl to 1 hour (3600000 ms) and overrides the default

if you want to disable the ttl you can set it to 0 or undefined:

import { Cacheable } from 'cacheable';
const cache = new Cacheable({ ttl: 0 }); //sets the default ttl to 0 which is disabled
cache.set('key', 'value', 0); //sets the ttl to 0 which is disabled

If you set the ttl to anything below 0 or undefined it will disable the ttl for the cache and the value that returns will be undefined. With no ttl set the value will be stored indefinitely.

import { Cacheable } from 'cacheable';
const cache = new Cacheable({ ttl: 0 }); //sets the default ttl to 0 which is disabled
console.log(cache.ttl); // undefined
cache.ttl = '1h'; // sets the default ttl to 1 hour (3600000 ms)
console.log(cache.ttl); // '1h'
cache.ttl = -1; // sets the default ttl to 0 which is disabled
console.log(cache.ttl); // undefined

Retrieving raw cache entries

The get and getMany methods support a raw option, which returns the full stored metadata (StoredDataRaw) instead of just the value:

import { Cacheable } from 'cacheable';

const cache = new Cacheable();

// store a value
await cache.set('user:1', { name: 'Alice' });

// default: only the value
const user = await cache.get<{ name: string }>('user:1');
console.log(user); // { name: 'Alice' }

// with raw: full record including expiration
const raw = await cache.get<{ name: string }>('user:1', { raw: true });
console.log(raw.value);   // { name: 'Alice' }
console.log(raw.expires); // e.g. 1677628495000 or null

// getMany with raw option
await cache.set('a', 1);
await cache.set('b', 2);

const raws = await cache.getMany<number>(['a', 'b'], { raw: true });
raws.forEach((entry, idx) => {
  console.log(`key=${['a','b'][idx]}, value=${entry?.value}, expires=${entry?.expires}`);
});

Non-Blocking Operations

If you want your layer 2 (secondary) store to be non-blocking you can set the nonBlocking property to true in the options. This will make the secondary store non-blocking and will not wait for the secondary store to respond on setting data, deleting data, or clearing data. This is useful if you want to have a faster response time and not wait for the secondary store to respond. Here is a full list of what each method does in nonBlocking mode:

  • set - in non-blocking mode it will set at the primary storage and then in the background update secondary

  • get - in non-blocking mode it will only check the primary storage but then in the background look to see if there is a value in the secondary and update the primary

  • getMany - in non-blocking mode it will only check the primary storage but then in the background look to see if there is a value in the secondary and update the primary

  • getRaw - in non-blocking mode it will only check the primary storage but then in the background look to see if there is a value in the secondary and update the primary

  • getManyRaw - in non-blocking mode it will only check the primary storage but then in the background look to see if there is a value in the secondary and update the primary

Non-Blocking with @keyv/redis

@keyv/redis is one of the most popular storage adapters used with cacheable. It provides a Redis-backed cache store that can be used as a secondary store. It is a bit complicated to setup as by default it causes hangs and blocking with its default configuration. To get past this you will need to configure the following:

Construct your own Redis client via the createClient() method from @keyv/redis with the following options:

  • Set disableOfflineQueue to true
  • Set socket.reconnectStrategy to false In the KeyvRedis options:
  • Set throwOnConnectError to false In the Cacheable options:
  • Set nonBlocking to true

We have also build a function to help with this called createKeyvNonBlocking inside the @keyv/redis package after version 4.6.0. Here is an example of how to use it:

import { Cacheable } from 'cacheable';
import { createKeyvNonBlocking } from '@keyv/redis';

const secondary = createKeyvNonBlocking('redis://user:pass@localhost:6379');

const cache = new Cacheable({ secondary, nonBlocking: true });

GetOrSet

The getOrSet method provides a convenient way to implement the cache-aside pattern. It attempts to retrieve a value from cache, and if not found, calls the provided function to compute the value and store it in cache before returning it.

import { Cacheable } from 'cacheable';

// Create a new Cacheable instance
const cache = new Cacheable();

// Use getOrSet to fetch user data
async function getUserData(userId: string) {
  return await cache.getOrSet(
    `user:${userId}`,
    async () => {
      // This function only runs if the data isn't in the cache
      console.log('Fetching user from database...');
      // Simulate database fetch
      return { id: userId, name: 'John Doe', email: '[email protected]' };
    },
    { ttl: '30m' } // Cache for 30 minutes
  );
}

// First call - will fetch from "database"
const user1 = await getUserData('123');
console.log(user1); // { id: '123', name: 'John Doe', email: '[email protected]' }

// Second call - will retrieve from cache
const user2 = await getUserData('123');
console.log(user2); // Same data, but retrieved from cache

import { Cacheable } from 'cacheable';
import {KeyvRedis} from '@keyv/redis';

const secondary = new KeyvRedis('redis://user:pass@localhost:6379');
const cache = new Cacheable({secondary, nonBlocking: true});

CacheSync - Distributed Updates

cacheable has a feature called CacheSync that is coming soon. This feature will allow you to have distributed caching with Pub/Sub. This will allow you to have multiple instances of cacheable running and when a value is set, deleted, or cleared it will update all instances of cacheable with the same value. Current plan is to support the following:

This feature should be live by end of year.

Cacheable Options

The following options are available for you to configure cacheable:

  • primary: The primary store for the cache (layer 1) defaults to in-memory by Keyv.
  • secondary: The secondary store for the cache (layer 2) usually a persistent cache by Keyv.
  • nonBlocking: If the secondary store is non-blocking. Default is false.
  • stats: To enable statistics for this instance. Default is false.
  • ttl: The default time to live for the cache in milliseconds. Default is undefined which is disabled.
  • namespace: The namespace for the cache. Default is undefined.

Cacheable Statistics (Instance Only)

If you want to enable statistics for your instance you can set the .stats.enabled property to true in the options. This will enable statistics for your instance and you can get the statistics by calling the stats property. Here are the following property statistics:

  • hits: The number of hits in the cache.
  • misses: The number of misses in the cache.
  • sets: The number of sets in the cache.
  • deletes: The number of deletes in the cache.
  • clears: The number of clears in the cache.
  • errors: The number of errors in the cache.
  • count: The number of keys in the cache.
  • vsize: The estimated byte size of the values in the cache.
  • ksize: The estimated byte size of the keys in the cache.

You can clear / reset the stats by calling the .stats.reset() method.

This does not enable statistics for your layer 2 cache as that is a distributed cache.

Cacheable - API

  • set(key, value, ttl?): Sets a value in the cache.
  • setMany([{key, value, ttl?}]): Sets multiple values in the cache.
  • get(key): Gets a value from the cache.
  • get(key, { raw: true }): Gets a raw value from the cache.
  • getMany([keys]): Gets multiple values from the cache.
  • getMany([keys], { raw: true }): Gets multiple raw values from the cache.
  • has(key): Checks if a value exists in the cache.
  • hasMany([keys]): Checks if multiple values exist in the cache.
  • take(key): Takes a value from the cache and deletes it.
  • takeMany([keys]): Takes multiple values from the cache and deletes them.
  • delete(key): Deletes a value from the cache.
  • deleteMany([keys]): Deletes multiple values from the cache.
  • clear(): Clears the cache stores. Be careful with this as it will clear both layer 1 and layer 2.
  • wrap(function, WrapOptions): Wraps an async function in a cache.
  • getOrSet(GetOrSetKey, valueFunction, GetOrSetFunctionOptions): Gets a value from cache or sets it if not found using the provided function.
  • disconnect(): Disconnects from the cache stores.
  • onHook(hook, callback): Sets a hook.
  • removeHook(hook): Removes a hook.
  • on(event, callback): Listens for an event.
  • removeListener(event, callback): Removes a listener.
  • hash(object: any, algorithm = 'sha256'): string: Hashes an object with the algorithm. Default is sha256.
  • primary: The primary store for the cache (layer 1) defaults to in-memory by Keyv.
  • secondary: The secondary store for the cache (layer 2) usually a persistent cache by Keyv.
  • namespace: The namespace for the cache. Default is undefined. This will set the namespace for the primary and secondary stores.
  • nonBlocking: If the secondary store is non-blocking. Default is false.
  • stats: The statistics for this instance which includes hits, misses, sets, deletes, clears, errors, count, vsize, ksize.

CacheableMemory - In-Memory Cache

cacheable comes with a built-in in-memory cache called CacheableMemory from @cacheable/memory. This is a simple in-memory cache that is used as the primary store for cacheable. You can use this as a standalone cache or as a primary store for cacheable. Here is an example of how to use CacheableMemory:

import { CacheableMemory } from 'cacheable';
const options = {
  ttl: '1h', // 1 hour
  useClones: true, // use clones for the values (default is true)
  lruSize: 1000, // the size of the LRU cache (default is 0 which is unlimited)
}
const cache = new CacheableMemory(options);
cache.set('key', 'value');
const value = cache.get('key'); // value

To learn more go to @cacheable/memory

Wrap / Memoization for Sync and Async Functions

Cacheable and CacheableMemory has a feature called wrap that comes from @cacheable/memoize and allows you to wrap a function in a cache. This is useful for memoization and caching the results of a function. You can wrap a sync or async function in a cache. Here is an example of how to use the wrap function:

import { Cacheable } from 'cacheable';
const asyncFunction = async (value: number) => {
  return Math.random() * value;
};

const cache = new Cacheable();
const options = {
  ttl: '1h', // 1 hour
  keyPrefix: 'p1', // key prefix. This is used if you have multiple functions and need to set a unique prefix.
}
const wrappedFunction = cache.wrap(asyncFunction, options);
console.log(await wrappedFunction(2)); // 4
console.log(await wrappedFunction(2)); // 4 from cache

With Cacheable we have also included stampede protection so that a Promise based call will only be called once if multiple requests of the same are executed at the same time. Here is an example of how to test for stampede protection:

import { Cacheable } from 'cacheable';
const asyncFunction = async (value: number) => {
  return value;
};

const cache = new Cacheable();
const options = {
  ttl: '1h', // 1 hour
  keyPrefix: 'p1', // key prefix. This is used if you have multiple functions and need to set a unique prefix.
}

const wrappedFunction = cache.wrap(asyncFunction, options);
const promises = [];
for (let i = 0; i < 10; i++) {
  promises.push(wrappedFunction(i));
}

const results = await Promise.all(promises); // all results should be the same

console.log(results); // [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

In this example we are wrapping an async function in a cache with a ttl of 1 hour. This will cache the result of the function for 1 hour and then expire the value. You can also wrap a sync function in a cache:

import { CacheableMemory } from 'cacheable';
const syncFunction = (value: number) => {
  return value * 2;
};

const cache = new CacheableMemory();
const wrappedFunction = cache.wrap(syncFunction, { ttl: '1h', key: 'syncFunction' });
console.log(wrappedFunction(2)); // 4
console.log(wrappedFunction(2)); // 4 from cache

In this example we are wrapping a sync function in a cache with a ttl of 1 hour. This will cache the result of the function for 1 hour and then expire the value. You can also set the key property in the wrap() options to set a custom key for the cache.

When an error occurs in the function it will not cache the value and will return the error. This is useful if you want to cache the results of a function but not cache the error. If you want it to cache the error you can set the cacheError property to true in the wrap() options. This is disabled by default.

import { CacheableMemory } from 'cacheable';
const syncFunction = (value: number) => {
  throw new Error('error');
};

const cache = new CacheableMemory();
const wrappedFunction = cache.wrap(syncFunction, { ttl: '1h', key: 'syncFunction', cacheError: true });
console.log(wrappedFunction()); // error
console.log(wrappedFunction()); // error from cache

If you would like to generate your own key for the wrapped function you can set the createKey property in the wrap() options. This is useful if you want to generate a key based on the arguments of the function or any other criteria.

  const cache = new Cacheable();
  const options: WrapOptions = {
    cache,
    keyPrefix: 'test',
    createKey: (function_, arguments_, options: WrapOptions) => `customKey:${options?.keyPrefix}:${arguments_[0]}`,
  };

  const wrapped = wrap((argument: string) => `Result for ${argument}`, options);

  const result1 = await wrapped('arg1');
  const result2 = await wrapped('arg1'); // Should hit the cache

  console.log(result1); // Result for arg1
  console.log(result2); // Result for arg1 (from cache)

We will pass in the function that is being wrapped, the arguments passed to the function, and the options used to wrap the function. You can then use these to generate a custom key for the cache.

To learn more visit @cacheable/memoize

Get Or Set Memoization Function

The getOrSet method that comes from @cacheable/memoize provides a convenient way to implement the cache-aside pattern. It attempts to retrieve a value from cache, and if not found, calls the provided function to compute the value and store it in cache before returning it. Here are the options:

export type GetOrSetFunctionOptions = {
	ttl?: number | string;
	cacheErrors?: boolean;
	throwErrors?: boolean;
};

Here is an example of how to use the getOrSet method:

import { Cacheable } from 'cacheable';
const cache = new Cacheable();
// Use getOrSet to fetch user data
const function_ = async () => Math.random() * 100;
const value = await cache.getOrSet('randomValue', function_, { ttl: '1h' });
console.log(value); // e.g. 42.123456789

You can also use a function to compute the key for the function:

import { Cacheable, GetOrSetOptions } from 'cacheable';
const cache = new Cacheable();

// Function to generate a key based on options
const generateKey = (options?: GetOrSetOptions) => {
  return `custom_key_:${options?.cacheId || 'default'}`;
};

const function_ = async () => Math.random() * 100;
const value = await cache.getOrSet(generateKey(), function_, { ttl: '1h' });

To learn more go to @cacheable/memoize

v1 to v2 Changes

cacheable is now using @cacheable/utils, @cacheable/memoize, and @cacheable/memory for its core functionality as we are moving to this modular architecture and plan to eventually have these modules across cache-manager and flat-cache. In addition there are some breaking changes:

  • get() and getMany() no longer have the raw option but instead we have built out getRaw() and getManyRaw() to use.
  • All get related functions now support nonBlocking which means if nonBlocking: true the primary store will return what it has and then in the background will work to sync from secondary storage for any misses. You can disable this by setting at the get function level the option nonBlocking: false which will look for any missing keys in the secondary.
  • Keyv v5.5+ is now the recommended supported version as we are using its native getMany* and getRaw*
  • Wrap and getOrSet have been updated with more robust options including the ability to use your own serialize function for creating the key in wrap.
  • hash has now been updated with robust options and also an enum for setting the algorithm.

How to Contribute

You can contribute by forking the repo and submitting a pull request. Please make sure to add tests and update the documentation. To learn more about how to contribute go to our main README https://github.com/jaredwray/cacheable. This will talk about how to Open a Pull Request, Ask a Question, or Post an Issue.

License and Copyright

MIT © Jared Wray