Enterprise ready rate limiter.
Some implementations:
To add a dependency on rate-limiter using Maven, use the following:
<dependency>
<groupId>io.github.poshjosh</groupId>
<artifactId>rate-limiter</artifactId>
<version>0.7.0</version>
</dependency>We want rate limiting to be adjusted dynamically based on specific conditions. See rate condition expression language
import io.github.poshjosh.ratelimiter.bandwidths.Bandwidths;
import io.github.poshjosh.ratelimiter.util.Matcher;
class DynamicRateLimiting {
static RateLimiter rateLimiter = RateLimiter.of(Bandwidths.ofSeconds(1));
static Matcher matchAfter2Seconds = Matcher.ofExpression("sys.time.elapsed>PT2S");
public static void main(String[] args) throws Exception {
final long startTime = System.currentTimeMillis();
for (int i = 0; i < 5; i++) {
final boolean matches = matchAfter2Seconds.matches(startTime);
System.out.println("Matches: " + matchesCondition + ", elapsed time: " + elapsedTime);
if (matchesCondition) {
final boolean acquired = rateLimiter.tryAcquire(1);
System.out.println("Within limit: " + acquired);
}
Thread.sleep(500);
}
}
}
// Output
// Matches: false, elapsed time: 0
// Matches: false, elapsed time: 504
// Matches: true, elapsed time: 1004
// Within limit: true
// Matches: true, elapsed time: 1505
// Within limit: true
// Matches: true, elapsed time: 2008
// Within limit: falseWe have a flexible expression language for example:
jvm.memory.available<500MB && sys.time.elapsed>PT1S
We have a list of tasks to execute, but we don't want to submit more than 2 per second.
class Throttling {
final RateLimiter rateLimiter = RateLimiter.of(Bandwidth.bursty(2.0)); // 2 permits per second
void submitTasks(List<Runnable> tasks, Executor executor) {
for (Runnable task : tasks) {
rateLimiter.acquire(); // may wait
executor.execute(task);
}
}
}We produce a stream of data, and we want to cap it at 5kb per second. This could be accomplished by requiring a permit per byte, and specifying a rate of 5000 permits per second.
class DataCap {
final RateLimiter rateLimiter = RateLimiter.of(Bandwidth.bursty(5000.0)); // 5000 permits per second
void submitPacket(byte[] packet) {
rateLimiter.acquire(packet.length);
networkService.send(packet);
}
}This is a maven based java project, so:
To package a jar file
mvn clean packageTo install, thus making it referencable in other project's pom.xm
mvn clean installEnjoy! 😉
The following depend on this library: