noodles-v6

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

noodles-v6

#!/usr/bin/env perl
use 5.010;
use open qw(:locale);
use strict;
use utf8;
use warnings qw(all);

use Mojo::UserAgent;

# FIFO queue

noodles-v6

#!/bin/bash
redEcho()
{
    echo -e "\033[1;31m$@\033[0m"
}
pid=`pgrep java`
uuid=`date +%s`_${RANDOM}_$$
jstackFile=/tmp/${uuid}_${pid}

sudo -u tomcat jstack ${pid} > ${jstackFile}

noodles-v6

//This sample is how to use websocket of Tomcat.
package wsapp;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.util.ArrayList;
import org.apache.catalina.websocket.MessageInbound;
import org.apache.catalina.websocket.StreamInbound;
import org.apache.catalina.websocket.WebSocketServlet;

noodles-v6

#!/usr/bin/env perl
use 5.010;
use open qw(:locale);
use strict;
use utf8;
use warnings qw(all);

use Mojo::UserAgent;

# FIFO queue

noodles-v6

#echo 'export PATH=$HOME/local/bin:$PATH' >> ~/.bashrc
#. ~/.bashrc
#mkdir ~/local
#mkdir ~/node-latest-install
#cd ~/node-latest-install
#curl http://nodejs.org/dist/node-latest.tar.gz | tar xz --strip-components=1
#./configure --prefix=~/local
#make install # ok, fine, this step probably takes more than 30 seconds...
#curl https://npmjs.org/install.sh | sh

noodles-v6

# reference https://bitbucket.org/xuxiaodong/dotman/src/cb7f1e6fb338/.tmux.conf

set -g default-terminal "screen-256color"
set -g display-time 3000
set -g history-limit 65535
set -g base-index 1
set -g pane-base-index 1
set -s escape-time 0

# key bindings

noodles-v6

# Encoding file
perl -MMIME::Base64 -0777 -ne 'print encode_base64($_)' < file

# Decoding file
perl -MMIME::Base64 -ne 'print decode_base64($_)' < file.b64