lilac

Query Pattern	Feature Type	Comment
Point lookup (query)	Entity Feature Family	1 entity key → 1 row
Batch query by a context	Context Feature Family	N context keys → N rows
Recall candidates by a context	Candidate Feature Family	1 entity key → N rows

lilac

Intro

This is a Scala script that reads a hex string from the system clipboard and compute the length of it.

Use case

It's mainly a utility for blob. Our data is stored in Cassandra (or ScyllaDB) as blob, but sometimes we need to analyze the data.

Usage

1. Install scala-cli in your system.
2. Copy the hex string to your clipboard.
3. Run the script via scala-cli hex-length.scala.

lilac

apiVersion: apps/v1
kind: Deployment
metadata:
  name: coder
spec:
  replicas: 1
  strategy:
    type: Recreate
  template:
    spec:

lilac

Building a Minimal HTTP Server with Virtual Threads in Java

In the latest release of JDK 21, virtual threads have become a stable feature, revolutionizing the way we write concurrent programs in Java. With virtual threads, it is now easier than ever to create highly performant and scalable applications. In this blog post, we will explore how to build a minimal yet fully functional HTTP server from scratch using virtual threads.

Introduction to Virtual Threads

Virtual threads, also known as fibers, are lightweight threads that can be scheduled cooperatively by the JVM. Unlike traditional threads, which are managed by the operating system, virtual threads are managed at the application level, resulting in reduced overhead and improved scalability. By leveraging virtual threads, we can achieve higher concurrency without the need for complex thread management.

Setting Up the Project

lilac

.phony: run

run: thread.wasm
	wasmtime run --wasm-features threads --wasi-modules experimental-wasi-threads ./thread.wasm

thread.wasm: thread.wat
	wat2wasm --debug-names --enable-threads thread.wat

lilac

public class HelloWorld {

    public static void main(String[] args) {
        System.out.println("Hello, World!");
    }
}

lilac

Install Tailscale

1. Install go if it's not there.
2. Install tailscale commands.

   go install tailscale.com/cmd/[email protected]
   go install tailscale.com/cmd/[email protected]
   

Install service

Since this linux is an old version, it still use sysv scripts for service management. To run tailscaled as a daemon (service), follow the procedure below.

lilac

# builtin functions

# graph is a builtin module exposed by the host environment
# graph.nodes = {}
# graph.edges = []


def node(name, operation, conf={}, predicate=None):
    """
    :rtype: str the node name is returned

lilac

package example

import com.google.common.collect.{ImmutableCollection, ImmutableList, ImmutableMap}
import net.starlark.java.annot.{Param, StarlarkBuiltin, StarlarkMethod}
import net.starlark.java.eval.{Dict, EvalException, Module, Mutability, Starlark, StarlarkFunction, StarlarkInt, StarlarkList, StarlarkSemantics, StarlarkThread, Structure, Tuple}
import net.starlark.java.syntax.{FileOptions, ParserInput}

import scala.collection.mutable.ListBuffer

object StarlarkDemo extends App {

lilac

Playground

• Install wazero with the following commmand.

  go get github.com/tetratelabs/wazero@latest

• Download the wasm file of a Javascript interpreter. For simplicity, the following ways are listed.

  • If you have wapm installed, you could download one with