celerity
v0.1.0
Published
celerity uses redis to do centralized rate limiting for applications running on multiple heroku dynos
Downloads
3
Readme
celerity
celerity uses redis to do centralized rate limiting for applications running on multiple heroku dynos (or processes).
install
npm install celerity
example
see example.js for a simple rate limited webserver using celerity
use
require
var celerity = require('celerity');
var redis = require('redis');
configure
var config = {
redis: redis.createClient(),
timespan: 10 * 1000,
bucketCount: 10
};
celerity keeps the rate for the last timespan
milliseconds.
timespan
is divided into bucketCount
buckets.
the rate is stored in the buckets.
buckets older than timespan
expire every timespan / bucketCount
milliseconds.
a higher bucketCount
increases the frequency and accuracy of the expires
but uses more memory and results in slower read operations.
if timespan
is several seconds long it is usually enough to have
a bucket for every second.
use the prefix
property to set a prefix for all redis keys used by celerity.
the default prefix is celerity:
.
increment(config, event, n, cb)
celerity.increment(config, 'event', 1, function(err) {
});
atomic. complexity: O(1).
read(config, event, cb)
celerity.read(config, 'event', function(err, rate) {
});
atomic. complexity: O(n) where n is bucketCount
.
incrementAndRead(config, event, n, cb)
celerity.incrementAndRead(config, 'event', 1, function(err, rate) {
});
atomic. complexity: O(n) where n is bucketCount
.