ZIO Quartz H2 Examples

This repository contains example HTTP/2 server implementations using the ZIO Quartz H2 library. Both examples demonstrate how to create a high-performance HTTP/2 server with ZIO.

This implementation leverages Linux's IO-Uring interface for significantly improved I/O performance by reducing context switches and copy operations. It requires:

• Linux kernel 5.1 or newer for basic IO-Uring support
• Linux kernel 5.5+ recommended for better performance features

You can check your kernel version with uname -r.

3. Running the Root Project Example

To run the example in the root project:

sbt run

This runs a minimal HTTP/2 server that demonstrates a simple route function with just a GET / endpoint that returns an empty OK response. It's ideal for understanding the basic structure of a ZIO Quartz H2 server without additional complexity.

Switching Between NIO and IO-Uring

By default, the server runs using Java NIO. To enable the high-performance Linux IO-Uring implementation:

1. Open src/main/scala/Run.scala
2. Comment out the NIO line:

// exitCode <- new QuartzH2Server("localhost", 8443, 16000, ctx).startIO(R, filter, sync = false)

3. Uncomment the IO-Uring line:

exitCode <- new QuartzH2Server("localhost", 8443, 16000, ctx).startIO_linuxOnly(1, R, filter)

Note that IO-Uring is only available on Linux systems with kernel version 5.1 or newer, with 5.5+ recommended for optimal performance.

Key Concepts

WebFilter with Either.cond

All examples demonstrate the use of a powerful WebFilter pattern using Scala's Either.cond mechanism:

val filter: WebFilter[Any] = (r: Request) =>
  ZIO.succeed(
    Either.cond(condition, r, Response.Error(StatusCode.Forbidden))
  )

This pattern allows for elegant request filtering where:

• If the condition evaluates to true, the request passes through to your routes (Right(r))
• If the condition evaluates to false, the request is rejected with the specified error response (Left(response))

This functional approach enables clean implementation of access control, rate limiting, authentication, or any other request filtering logic.

SSL Configuration

All examples use SSL and require a keystore file named keystore.jks with password "password" in the appropriate directory.