Ivan Velichko iximiuz

$ kubectl label po green-5c8f858bbb-mqxrd app=blue pod-template-hash=5bc56d75b --overwrite

NAME                     READY   STATUS              RESTARTS   AGE   LABELS
blue-5bc56d75b-5j462     1/1     Running             0          15m   app=blue,pod-template-hash=5bc56d75b
blue-5bc56d75b-wwn8c     1/1     Terminating         0          27s   app=blue,pod-template-hash=5bc56d75b
green-5c8f858bbb-bsjwv   0/1     ContainerCreating   0          0s    app=green,pod-template-hash=5c8f858bbb
green-5c8f858bbb-mqxrd 1/1 Running 0 15m app=blue,pod-template-hash=5bc56d75b

Networking scenarios [Linux Only]

KIND runs Kubernetes cluster in Docker, and leverages Docker networking for all the network features: port mapping, IPv6, containers connectivity, etc.

Docker Networking

KIND uses a docker user defined network.

It creates a bridge named kind

Libuv and libev, two I/O libraries with similar names, recently had the privilege to use both libraries to write something. Now let's talk about my own subjective expression of common and different points.

The topic of high-performance network programming has been discussed. Asynchronous, asynchronous, or asynchronous. Whether it is epoll or kqueue, it is always indispensable to the asynchronous topic.

Libuv is asynchronous, and libev is synchronous multiplexing IO multiplexing.

Libev is a simple encapsulation of system I/O reuse. Basically, it solves the problem of different APIs between epoll and kqueuq. Ensure that programs written using livev's API can run on most *nix platforms. However, the disadvantages of libev are also obvious. Because it basically just encapsulates the Event Library, it is inconvenient to use. For example, accept(3) requires manual setnonblocking after connection. EAGAIN, EWOULDBLOCK, and EINTER need to be detected when reading from a socket. This is a

Be Careful with Table Driven Tests and `t.Parallel()`

We Gophers, love table-driven-tests, it makes our unittesting structured, and makes it easy to add different test cases with ease.

Let’s create our table driven test, for convenience, I chose to use t.Log as the test function. Notice that we don't have any assertion in this test, it is not needed to for the demonstration.

func TestTLog(t *testing.T) {
	t.Parallel()

	#define _GNU_SOURCE
	#include <errno.h>
	#include <sched.h>
	#include <signal.h>
	#include <stdio.h>
	#include <stdlib.h>
	#include <sys/mount.h>
	#include <sys/stat.h>
	#include <sys/syscall.h>
	#include <sys/types.h>

	# A tiny 16-bit guest "kernel" that infinitely prints an incremented number to the debug port

	#
	# Build it:
	#
	# as -32 guest.S -o guest.o
	# ld -m elf_i386 --oformat binary -N -e _start -Ttext 0x10000 -o guest guest.o
	#

	.globl _start

	var c = document.getElementById('canvas_wrap').children[0];
	var gl = c.getContext('webgl', { preserveDrawingBuffer: true });

	function getColor(pixels, y) {
	var color =
	decimalToHex(pixels[y * 4], 2) +
	decimalToHex(pixels[y * 4 + 1], 2) +
	decimalToHex(pixels[y * 4 + 2], 2);
	return color;
	}


	# Add apt.llvm.org repository and install clang
	wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key\|sudo apt-key add -
	sudo apt-add-repository "deb http://apt.llvm.org/stretch/ llvm-toolchain-stretch main"
	sudo apt-get update
	sudo apt-get install -y clang clang-format clang-tidy lldb libc++-8-dev libc++abi-8-dev

	# Check version
	clang --version
	clang++ --version

	SHELL=/bin/bash

	# to see all colors, run
	# bash -c 'for c in {0..255}; do tput setaf $c; tput setaf $c \| cat -v; echo =$c; done'
	# the first 15 entries are the 8-bit colors

	# define standard colors
	ifneq (,$(findstring xterm,${TERM}))
	BLACK := $(shell tput -Txterm setaf 0)
	RED := $(shell tput -Txterm setaf 1)

	import 'package:flutter/widgets.dart';

	class Annotation extends Comparable<Annotation> {
	Annotation({@required this.range, this.style});
	final TextRange range;
	final TextStyle style;

	@override
	int compareTo(Annotation other) {
	return range.start.compareTo(other.range.start);

Ivan Velichko iximiuz

Networking scenarios [Linux Only]

Docker Networking

Be Careful with Table Driven Tests and t.Parallel()

Be Careful with Table Driven Tests and `t.Parallel()`