Rezilience

rezilience is a ZIO-native collection of policies for making asynchronous systems more resilient to failures, inspired by Polly, Resilience4J and Akka.

It consists of these policies:

Features / Design goals

• Type-safety: all errors that can result from any of the rezilience policies are encoded in the method signatures, so no unexpected RuntimeExceptions.
• Support for your own error types (the E in ZIO[R, E, A]) instead of requiring your effects to have Exception as error type
• Lightweight: rezilience uses only ZIO fibers and will not create threads or block
• Switchable at runtime with two transition modes
• Resource-safe: built on ZIO’s ZManaged, any allocated resources are cleaned up safely after use.
• Interrupt safe: interruptions of effects wrapped by rezilience policies are handled properly.
• Thread-safe: all policies are safe under concurrent use.
• ZIO integration: some policies take for example ZIO Schedules and rezilience tries to help type inference using variance annotations
• Metrics: all policies (will) provide usage metrics for monitoring purposes
• Composable: policies can be composed into one overall policy
• Discoverable: no syntax extensions or implicit conversions, just plain scala

Installation

Add to your build.sbt:

libraryDependencies += "nl.vroste" %% "rezilience" % "<version>"

Rezilience is available for ZIO 2 and Scala 2.13, Scala 3 and Scala.JS.

Usage example

Limit the rate of calls:

import zio._
import zio.duration._
import nl.vroste.rezilience._

def myCallToExternalResource(someInput: String): ZIO[Any, Throwable, Int] = ???

val rateLimiter: ZIO[Scope, Nothing, RateLimiter] = RateLimiter.make(max = 10, interval = 1.second)

ZIO.scoped {
  rateLimiter.flatMap { rateLimiter =>
    val result: ZIO[Any, Throwable, Int] =
      rateLimiter(myCallToExternalResource("some input"))

  }
}