rate-limiter-flexible
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Flexible rate limiter and anti-DDoS protector works in process Memory, Cluster, MongoDB, MySQL, PostgreSQL or Redis allows to control requests rate in single process or distributed environment.
It uses fixed window as it is much faster than rolling window. See comparative benchmarks with other libraries here
:star: It is STARving, don't forget to feed the beast! :star:
Advantages:
get, block, penalty and reward methodsconst opts = {
points: 6, // 6 points
duration: 1, // Per second
};
const rateLimiter = new RateLimiterMemory(opts);
rateLimiter.consume(remoteAddress, 2) // consume 2 points
.then((rateLimiterRes) => {
// 2 points consumed
})
.catch((rateLimiterRes) => {
// Not enough points to consume
});
Average latency during test pure NodeJS endpoint in cluster of 4 workers with everything set up on one server.
1000 concurrent clients with maximum 2000 requests per sec during 30 seconds.
1. Memory 0.34 ms
2. Cluster 0.69 ms
3. Redis 2.45 ms
4. Mongo 4.75 ms
500 concurrent clients with maximum 1000 req per sec during 30 seconds
5. PostgreSQL 7.48 ms (with connection pool max 100)
6. MySQL 14.59 ms (with connection pool 100)
npm i rate-limiter-flexible
yarn add rate-limiter-flexible
keyPrefix Default: 'rlflx' If you need to create several limiters for different purpose.
Note: for some limiters it should correspond to Storage requirements for tables or collections name,
as keyPrefix may be used as their name.
points Default: 4 Maximum number of points can be consumed over duration
duration Default: 1 Number of seconds before consumed points are reset
execEvenly Default: false Delay action to be executed evenly over duration
First action in duration is executed without delay.
All next allowed actions in current duration are delayed by formula msBeforeDurationEnd / (remainingPoints + 2)
It allows to cut off load peaks.
Note: it isn't recommended to use it for long duration, as it may delay action for too long
blockDuration Default: 0 If positive number and consumed more than points in current duration,
block for blockDuration seconds.
It sets consumed points more than allowed points for blockDuration seconds, so actions are rejected.
storeClient Required Have to be redis, ioredis, mongodb, pg, mysql2, mysql or any other related pool or connection.
inmemoryBlockOnConsumed Default: 0 Against DDoS attacks. Blocked key isn't checked by requesting Redis, MySQL or Mongo.
In-memory blocking works in current process memory.
inmemoryBlockDuration Default: 0 Block key for inmemoryBlockDuration seconds,
if inmemoryBlockOnConsumed or more points are consumed
insuranceLimiter Default: undefined Instance of RateLimiterAbstract extended object to store limits,
when database comes up with any error.
All data from insuranceLimiter is NOT copied to parent limiter, when error gone
Note: insuranceLimiter automatically setup blockDuration and execEvenly
to same values as in parent to avoid unexpected behaviour
tableName Default: equals to 'keyPrefix' option By default, limiter creates table for each unique keyPrefix.
All limits for all limiters are stored in one table if custom name is set.
storeType Default: storeClient.constructor.name It is required only for Knex and have to be set to 'knex'
dbName Default: 'rtlmtrflx' Database where limits are stored. It is created during creating a limitertimeoutMs Default: 5000 Timeout for communication between worker and master over IPC.
If master doesn't response in time, promise is rejected with ErrorBoth Promise resolve and reject returns object of RateLimiterRes class if there is no any error.
Object attributes:
RateLimiterRes = {
msBeforeNext: 250, // Number of milliseconds before next action can be done
remainingPoints: 0, // Number of remaining points in current duration
consumedPoints: 5, // Number of consumed points in current duration
isFirstInDuration: false, // action is first in current duration
}
Returns Promise, which:
RateLimiterRes when point(s) is consumed, so action can be doneinsuranceLimiter isn't setup: when some error happened, where reject reason rejRes is Error objectinsuranceLimiter isn't setup: when timeoutMs exceeded, where reject reason rejRes is Error objectrejRes is RateLimiterRes objectrejRes is RateLimiterRes objectArguments:
key is usually IP address or some unique client idpoints number of points consumed. default: 1Get RateLimiterRes in current duration.
Returns Promise, which:
RateLimiterRes if key is setnull if key is NOT set or expiredinsuranceLimiter isn't setup: when some error happened, where reject reason rejRes is Error objectinsuranceLimiter isn't setup: when timeoutMs exceeded, where reject reason rejRes is Error objectArguments:
key is usually IP address or some unique client idFine key by points number of points for one duration.
Note: Depending on time penalty may go to next durations
Returns Promise, which:
RateLimiterResinsuranceLimiter isn't setup: when some error happened, where reject reason rejRes is Error objectinsuranceLimiter isn't setup: when timeoutMs exceeded, where reject reason rejRes is Error objectReward key by points number of points for one duration.
Note: Depending on time reward may go to next durations
Returns Promise, which:
RateLimiterResinsuranceLimiter isn't setup: when some error happened, where reject reason rejRes is Error objectinsuranceLimiter isn't setup: when timeoutMs exceeded, where reject reason rejRes is Error objectBlock key for secDuration seconds
Returns Promise, which:
RateLimiterResinsuranceLimiter isn't setup: when some error happened, where reject reason rejRes is Error objectinsuranceLimiter isn't setup: when timeoutMs exceeded, where reject reason rejRes is Error objectRedis >=2.6.12
It supports both redis and ioredis clients.
Redis client must be created with offline queue switched off.
const redis = require('redis');
const redisClient = redis.createClient({ enable_offline_queue: false });
const Redis = require('ioredis');
const redisClient = new Redis({
options: {
enableOfflineQueue: false
}
});
const { RateLimiterRedis, RateLimiterMemory } = require('rate-limiter-flexible');
// It is recommended to process Redis errors and setup some reconnection strategy
redisClient.on('error', (err) => {
});
const opts = {
// Basic options
storeClient: redisClient,
points: 5, // Number of points
duration: 5, // Per second(s)
// Custom
execEvenly: false, // Do not delay actions evenly
blockDuration: 0, // Do not block if consumed more than points
keyPrefix: 'rlflx', // must be unique for limiters with different purpose
// Database limiters specific
inmemoryBlockOnConsumed: 10, // If 10 points consumed in current duration
inmemoryBlockDuration: 30, // block for 30 seconds in current process memory
};
const rateLimiterRedis = new RateLimiterRedis(opts);
rateLimiterRedis.consume(remoteAddress)
.then((rateLimiterRes) => {
// ... Some app logic here ...
// Depending on results it allows to fine
rateLimiterRedis.penalty(remoteAddress, 3)
.then((rateLimiterRes) => {});
// or rise number of points for current duration
rateLimiterRedis.reward(remoteAddress, 2)
.then((rateLimiterRes) => {});
})
.catch((rejRes) => {
if (rejRes instanceof Error) {
// Some Redis error
// Never happen if `insuranceLimiter` set up
// Decide what to do with it in other case
} else {
// Can't consume
// If there is no error, rateLimiterRedis promise rejected with number of ms before next request allowed
const secs = Math.round(rejRes.msBeforeNext / 1000) || 1;
res.set('Retry-After', String(secs));
res.status(429).send('Too Many Requests');
}
});
Endpoint is pure NodeJS endpoint launched in node:10.5.0-jessie and redis:4.0.10-alpine Docker containers by PM2 with 4 workers
By bombardier -c 1000 -l -d 30s -r 2000 -t 5s http://127.0.0.1:8000
Test with 1000 concurrent requests with maximum 2000 requests per sec during 30 seconds
Statistics Avg Stdev Max
Reqs/sec 2015.20 511.21 14570.19
Latency 2.45ms 7.51ms 138.41ms
Latency Distribution
50% 1.95ms
75% 2.16ms
90% 2.43ms
95% 2.77ms
99% 5.73ms
HTTP codes:
1xx - 0, 2xx - 53556, 3xx - 0, 4xx - 6417, 5xx - 0
It manages limits in current process memory, so keep it in mind when use it in cluster
const rateLimiter = new RateLimiterMemory(
{
keyPrefix: 'rlflx',
points: 1, // 1 is fair if you have 5 workers and 1 cluster, all workers will limit it to 5 in sum
duration: 5,
execEvenly: false,
});
// Usage is the same as for RateLimiterRedis
// Except: it never rejects Promise with Error
Combine 2 or more rate limiters to act as single
Any rate limiters from this rate-limiter-flexible can be united
Useful for authorization, which must be protected from password brute force
For example, not more than once per second and only 5 points per minute
keyPrefix is necessary as resolved and rejected results depend on it
const limiter1 = new RateLimiterMemory({
keyPrefix: 'limit1',
points: 1,
duration: 1,
});
const limiter2 = new RateLimiterMemory({
keyPrefix: 'limit2',
points: 5,
duration: 60,
});
const rateLimiterUnion = new RateLimiterUnion(limiter1, limiter2);
rateLimiterUnion.consume(remoteAddress)
.then((res) => {
// Returns object with 2 RateLimiterRes objects
res['limit1'].remainingPoints;
res['limit2'].remainingPoints;
})
.catch((rej) => {
/* Returns object with RateLimiterRes objects only for rejected limiters
* For example:
* { limit1: RateLimiterRes { ... } }
*
* It may be Error if you use any limiter without insurance except Memory
* { limit2: Error }
*/
});
const rateLimiterMiddleware = (req, res, next) => {
rateLimiter.consume(req.connection.remoteAddress)
.then(() => {
next();
})
.catch((rejRes) => {
res.status(429).send('Too Many Requests');
});
};
app.use(async (ctx, next) => {
try {
await rateLimiter.consume(ctx.ip)
next()
} catch (rejRes) {
ctx.status = 429
ctx.body = 'Too Many Requests'
}
})
Appreciated, feel free!
Make sure you've launched npm run eslint before creating PR, all errors have to be fixed.
You can try to run npm run eslint-fix to fix some issues.
Any new limiter with storage have to be extended from RateLimiterStoreAbstract.
It has to implement at least 3 methods:
_getRateLimiterRes parses raw data from store to RateLimiterRes object_upsert inserts or updates limits data by key and returns raw data_get returns raw data by keyAll other methods depends on store. See RateLimiterRedis or RateLimiterPostgres for example.
FAQs
Node.js rate limiter by key and protection from DDoS and Brute-Force attacks in process Memory, Redis, MongoDb, Memcached, MySQL, PostgreSQL, Cluster or PM
The npm package rate-limiter-flexible receives a total of 410,201 weekly downloads. As such, rate-limiter-flexible popularity was classified as popular.
We found that rate-limiter-flexible demonstrated a healthy version release cadence and project activity because the last version was released less than a year ago. It has 1 open source maintainer collaborating on the project.
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