holmberd

SSH Welcome banner with FIGlet

• sudo apt-get install figlet
• sudo touch /etc/update-motd.d/10-my-banner
• sudo chmod +x /etc/update-motd.d/10-my-banner

10-my-banner.sh:

#!/bin/sh

holmberd

/**
 * Binds a component to one or more decorator functions.
 * @param {Object} component
 * @param {[function]} decorators
 * @returns {Object}
 * @throws {Error}
 */
function Decorator(component, decorators) {
  if (!component || !decorators) {
    throw new Error('Failed to create decorator, arguments invalid.');

holmberd

Responses

POST /api/v1/products

success-status: 201

failure-status: 400 (bad request), 500

{
  id: 1,

holmberd

Kill user tty/pts sessions in Linux

Commands

• w: show who is logged on and what they are doing
• who: show who is logged on
• tty: show current users pseudo terminal
• ps -ft pts/1: get process id for the pseudo terminal
• pkill: signal process based on name and other attributes

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Debug Nginx access log

log_format debug_format '$remote_addr - $remote_user [$time_local] "$request" $status $body_bytes_sent "$http_referer" "$http_user_agent" "$http_x_forwarded_for" host:"$host"';
access_log /var/log/nginx/access.log debug_format;

sudo service nginx reload

holmberd

Move MySQL data to new EBS volume (/mnt/data-01)

• mysql -u root -p
• mysql> select @@datadir;
• sudo service mysql stop
• sudo service mysql status
• Move files: sudo rsync -av /var/lib/mysql /mnt/data-01
• Create backup: sudo mv /var/lib/mysql /var/lib/mysql.bak
• Change datadir to point to the new volume:
  • sudo vim /etc/mysql/mysql.conf.d/mysqld.cnf
• datadir=/mnt/data-01/mysql

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Move Redis data to new EBS volume (/mnt/data-01)

• sudo vim /etc/systemd/system/redis.service
  

• Set ReadWriteDirectories=-/mnt/data-01

• sudo mkdir /mnt/data-01/redis

• Set chown and chmod
  The permissons on /var/lib/redis are 755 and it's owned by redis:redis.
  The permissons on /var/lib/redis/dump.rdb are 644 and it's owned by redis:redis.

• Switch configurations while redis is running

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/**
 * Retries a async function recursively n times.
 *
 * @param {function} fn
 * @param {Number} [retries=3]
 * @returns {Promise}
 */
function retry(fn, retries=3, err=null) {
  if (retries === 0) {
    return Promise.reject(err);

holmberd

Setup Automatic Security Updates On Ubuntu

Install unattended-upgrade pkg

• (Might already be installed depending on your Ubuntu release)

sudo apt update
sudo apt install unattended-upgrades

Configure unattended-upgrade for security updates only

holmberd

/** Quick and dirty Cart pub/sub example */

class CartStore {
  add(item) {}
  remove(index) {}
  update(index, item) {}
  get(index) {}
  getAll() {}
}