README.md

datarouter-rate-limiter

datarouter-rate-limiter keeps a rolling window of counters for specific actions so that they can be rejected after a quota. Rate-limiters utilize the TallyStorage interface, which is implemented by datarouter-memcached and datarouter-redis.

Installation with Maven

<dependency>
	<groupId>io.datarouter</groupId>
	<artifactId>datarouter-rate-limiter</artifactId>
	<version>0.0.126</version>
</dependency>

Installation with Datarouter

You can install this module by adding its plugin to the WebappBuilder.

.addPlugin(new DatarouterRateLimiterPluginBuilder(...)
		...
		.build()

Tally

The Tally databean holds a running tally of increments and decrements. It's suitable for a generic counter or something more specific like a rate limiter.

The serialization format of the Long tally field is compatible with the Memcached or Redis increment operation, meaning the resulting value will be consistent in the face of concurrent access.

To use, extend BaseTallyDao, specifying the Node parameters, then write and read with these DAO methods:

Long incrementAndGetCount(String key, int delta, Duration ttl, Duration timeout)
Map<String,Long> getMultiTallyCount(Collection<String> keys, Duration ttl, Duration timeout)

Local Testing

To build this module locally, add rate-limiter.properties to /etc/datarouter/test.

License

This library is licensed under the Apache License, Version 2.0 - see LICENSE for details.