Jeff M lovejavaee

How to connect an iOS device to your computer via a SOCKS proxy

Say you're running a virtual machine on your work computer. Say this machine, for whatever reason, can only connect to the internet over NAT - as in, it does not get it's own IP address. Say this VM is running a webserver, and you need a device outside of your computer to connect to it.

If only there was a way to get your work computer to 'share' it's network, so that you could get at that VM… Here's how you do it!

For all instructions, I assume your work computer is a mac

Get your computer's IP address:

Introduction to Kafka

Kafka acts as a kind of write-ahead log (WAL) that records messages to a persistent store (disk) and allows subscribers to read and apply these changes to their own stores in a system appropriate time-frame.

Terminology:

Producers send messages to brokers
Consumers read messages from brokers
Messages are sent to a topic

Adding 2 nodes to an existing 3-node ZooKeeper ensemble without losing the Quorum

Since many deployments may start out with 3 nodes and so little is known about how to grow a cluster from 3 memebrs to 5 members without losing the existing Quorum, here is an example of how this might be achieved.

In this example, all 5 nodes will be running on the same Vagrant host for the purpose of illustration, running on distinct configurations (ports and data directories) without the actual load of clients.

YMMV. Caveat usufructuarius.

Step 1: Have a healthy 3-node ensemble

##ss-redir 的 iptables 配置(透明代理)

透明代理指对客户端透明，客户端不需要进行任何设置就使用了网管设置的代理规则

创建 /etc/ss-redir.json 本地监听 7777 运行ss-redir -v -c /etc/ss-redir.json

iptables -t nat -N SHADOWSOCKS
# 在 nat 表中创建新链
iptables -t nat -A SHADOWSOCKS -p tcp --dport 23596 -j RETURN
# 23596 是 ss 代理服务器的端口，即远程 shadowsocks 服务器提供服务的端口，如果你有多个 ip 可用,但端口一致，就设置这个

Often referred to as the "swiss army of knife" for TCP/IP networking, [Netcat][1] is an extremely versatile Linux utility that allows you to do anything under the sun using TCP/UDP sockets. It is one of the most favorite tools for system admins when they need to do networking related troubleshooting and experimentation.

In this tutorial, I am sharing a few useful netcat examples, although the sky is the limit when it comes to possible netcat use cases. If you are using netcat regularly, feel free to share your use case.

Note that when you are binding to well-known ports (0-1023) with nc, you need root privilege. Otherwise, run nc as a normal user.

1. Test if a particular TCP port of a remote host is open.

$ nc -vn 192.168.233.208 5000

	package testng.samples;

	import java.util.ArrayList;
	import java.util.HashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.Random;

	import org.testng.ITestContext;
	import org.testng.TestNG;

	@ControllerAdvice
	public class CustomResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {

	@Override
	protected ResponseEntity<Object> handleMethodArgumentNotValid(MethodArgumentNotValidException ex, HttpHeaders headers, HttpStatus status, WebRequest request) {
	List<FieldError> fieldErrors = ex.getBindingResult().getFieldErrors();
	List<ObjectError> globalErrors = ex.getBindingResult().getGlobalErrors();
	List<String> errors = new ArrayList<>(fieldErrors.size() + globalErrors.size());
	String error;
	for (FieldError fieldError : fieldErrors) {

	##
	# Creates an alias called "git hist" that outputs a nicely formatted git log.
	# Usage is just like "git log"
	# Examples:
	# git hist
	# git hist -5
	# git hist <branch_name>
	# git hist <tag_name> -10
	##
	git config --global alias.hist "log --pretty=format:'%C(yellow)[%ad]%C(reset) %C(green)[%h]%C(reset) \| %C(red)%s %C(bold red){{%an}}%C(reset) %C(blue)%d%C(reset)' --graph --date=short"

	$ mvn verify
	[INFO] Scanning for projects...
	[INFO]
	[INFO] ------------------------------------------------------------------------
	[INFO] Building maven-tests-config 1.0-SNAPSHOT
	[INFO] ------------------------------------------------------------------------
	[INFO]
	[INFO] --- maven-resources-plugin:2.5:resources (default-resources) @ maven-tests-config ---
	[debug] execute contextualize
	[INFO] Using 'UTF-8' encoding to copy filtered resources.

	public class ClhSpinLock {
	private final ThreadLocal<Node> pred;
	private final ThreadLocal<Node> node;
	private final AtomicReference<Node> tail = new AtomicReference<Node>(new Node());

	public ClhSpinLock() {
	this.node = new ThreadLocal<Node>() {
	protected Node initialValue() {
	return new Node();
	}