Manu Zhang manuzhang

Pull request #8373 implementing issue 333 (but please note differences).

Pull request description follows:

This PR adds a -Wconf compiler flag that allows filtering and configuring compiler warnings (silence them, or turn them into errors).

It also integrates the fantastic silencer compiler plugin by @ghik into the compiler, which allows suppressing warnings locally using the @nowarn annotation.

An interesting question

This morning, one of my colleagues asked me the following interesting question:

So, I have been wondering about this question (which is not necessarily applicable to Kudu): when certain software says they use a single hot replica for failover, how does it handle confusion caused by transient network failure which breaks the communication between the primary and second ? In other words, how can such configuration guarantee that both nodes won't think of itself as the primary? Do they usually fall back to some third party as an arbitrator ? However, that third party may itself suffer random network partition with one or either of the nodes

This led to my brain-dumping for 20 minutes on Slack, which I then figured I'd copy-paste into a "blog post" gist.

My brain-dump

How to install Hadoop on your local Kubernetes cluster

Okey this is not the easiest way of running Hadoop on your local computer and probably you should instead just install it locally.

However if you really insist doing this here's how:

Install kubectl, minikube and Docker if you don't already have it. I recommend using package-manager like Chocolatey. Minikube should install with VirtualBox as default driver which I recommend. When starting minikube we should increase its memory limit since our Hadoop node's pods need at least 2GB: minikube --memory 4096 --cpus 2 start (minikube's default is 1GB). NOTE: actually the Hadoop cluster by default uses about 10GB in memory limits and about 3GB running memory. From what I looked my k8s will overprovision to 300% of its capacity limits but use far less.
Install helm. Then run helm init.
Now you

introduction

ScalaCheck 1.14.0 was just released with support for deterministic testing using seeds. Some folks have asked for examples, so I wanted to produce a Gist to help people use this feature.

simple example

These examples will assume the following imports:

collapsible markdown?

CLICK ME

yes, even hidden code blocks!

print("hello world!")

	package org.bykn.list

	import cats.Applicative

	import cats.implicits._

	/**
	* Implementation of "Purely Functional Random Access Lists" by Chris Okasaki.
	* This gives O(1) cons and uncons, and 2 log_2 N lookup.
	*/

	<project>
	...
	<build>
	<plugins>
	<plugin>
	<groupId>org.apache.maven.plugins</groupId>
	<artifactId>maven-shade-plugin</artifactId>
	<executions>
	<execution>
	<phase>package</phase>

	package sbt_plugin_ranking

	import gigahorse._, support.okhttp.Gigahorse
	import gigahorse.github.Github
	import scala.concurrent._, duration._
	import ExecutionContext.Implicits._
	object Main extends App {
	val repo = """https:\/\/github.com\/([a-zA-Z0-9_\-]+)\/([a-zA-Z0-9_\-]+)""".r
	val url = "https://www.scala-sbt.org/1.x/docs/Community-Plugins.html"

	package hello

	import java.io.ByteArrayOutputStream

	import chisel3._
	import chisel3.iotesters.{Driver, PeekPokeTester}

	sealed trait Op
	object Op{
	case class GotoIfZero(dest: Byte, valueAddr: Byte) extends Op

	package demo

	import scala.tools.nsc.io.AbstractFile
	import scala.tools.nsc.{Global, Phase}
	import scala.tools.nsc.plugins.{Plugin, PluginComponent}

	class DemoPlugin(val global: Global) extends Plugin {
	import global._
	override def init(options: List[String], error: String => Unit): Boolean = true