koolay koolay

There are three easy to make mistakes in go. I present them here in the way they are often found in the wild, not in the way that is easiest to understand.

All three of these mistakes have been made in Kubernetes code, getting past code review at least once each that I know of.

Loop variables are scoped outside the loop.

What do these lines do? Make predictions and then scroll down.

func print(pi *int) { fmt.Println(*pi) }

This is a gist with a set of helpful performance tricks and best practices that I've found on the internet.

Network for LXC container

Host device as bridge

persisted in host's /etc/network/interfaces the container's veth virtual ethernet interface can share the network link on the physical interface of the host (eth0). So the container resides on the same ethernet segment and talks to the same dhcp server as the host does.

Additonal bridge device

setup manually with brctl

Juju 2.0 on Centos7

Configure epel repository

yum -y install epel-release
yum repolist

	map $http_origin $allow_origin {
	default "";
	"~^https?://(?:[^/]*\.)?(stevebuzonas\.(?:com\|local))(?::[0-9]+)?$" "$http_origin";
	}

	map $request_method $cors_method {
	default "allowed";
	"OPTIONS" "preflight";
	}

	#!/usr/bin/env python
	#-- coding: utf-8 --
	from Crypto.Cipher import PKCS1_v1_5
	from Crypto.PublicKey import RSA
	from Crypto.Hash import SHA
	from Crypto import Random
	import base64
	import StringIO

	# passphrase, random string => private key, public key pair

	// v2 of the great example of SSE in go by @ismasan.
	// includes fixes:
	// * infinite loop ending in panic
	// * closing a client twice
	// * potentially blocked listen() from closing a connection during multiplex step.
	package main

	import (
	"fmt"
	"log"

	curl -X POST -d http://master-host:6066/v1/submissions/create --header "Content-Type:application/json" --data '{
	"action": "CreateSubmissionRequest",
	"appResource": "hdfs://localhost:9000/user/spark-examples_2.11-2.0.0.jar",
	"clientSparkVersion": "2.0.0",
	"appArgs": [ "10" ],
	"environmentVariables" : {
	"SPARK_ENV_LOADED" : "1"
	},
	"mainClass": "org.apache.spark.examples.SparkPi",
	"sparkProperties": {

	#!/bin/sh
	# Userland mode (~$USER/), (~/).

	# ~/.fonts is now deprecated and that
	#FONT_HOME=~/.fonts
	# ~/.local/share/fonts should be used instead
	FONT_HOME=~/.local/share/fonts

	echo "installing fonts at $PWD to $FONT_HOME"
	mkdir -p "$FONT_HOME/adobe-fonts/source-code-pro"