Artyom Nikolaev iRet

Setting up postfix on MacOS High Sierra

MacOS Sierra High comes with preinstalled postfix. Follow these steps to configure it on a local system:

1. Create a `sasl_passwd` file

sudo nano /etc/postfix/sasl_passwd

Add this to the file

How to create and setup a development virtual machine for old ruby/rails

Using VirtualBox and Vagrant

Install and create a virtual machine

Install virtualbox and Vagrant:

$ brew cask install virtualbox

Rails 5 and 6 Deployment with Ubuntu, Mina, Puma and Nginx

Based on this tutorial but simplified and inlined. Particularly removed any Rails and 3rd party services part, assumed you just need deployment to any Ubuntu machine.

Prerequisite

A functional Rails app
Hosted Git repository (Github, Bitbucket, Gitlab)
Cloud hosting account (Digital Ocean, Vultr, Linode, Lightsail)
Local SSH account

Add the following line in `/etc/dnsmasq.conf`

dhcp-script=/etc/detect_new_device.sh

Setup sendmail to send email to your text number.

Reference:

https://wiki.openwrt.org/doc/howto/smtp.client

Date and Time comparisons in ActiveSupport

Question: How do we safely compare a date to an unknown value within a Rails application? Example: params[:date_field] > 2.years.ago

Doing a bit of digging, it looks like 2.years.ago returns an instance of ActiveSupport::TimeWithZone. In ruby, whenever you do a comparison of any sort ruby will follow the rules outlined in the Comparable module of stdlib.

ActiveSupport::TimeWithZone will create a instance of Time in a UTC time zone when doing comparisons with ActiveSupport::TimeWithZone#<=>.

Chef Local Development Workflow with ChefDK, Vagrant, VirtualBox, and Test Kitchen

Overview

The following document is intended to be a quick guide to getting you setup for doing local development with Chef. This guide was created on my MacBook, but should work fine with Linux, and Windows workstations as well.

Quick review on fundamental tenets of Chef

Workstation - A workstation is a computer that is configured to run various Chef command-line tools that synchronize with a chef-repo, author cookbooks, interact with the Chef server, interact with nodes, or applications like Chef Delivery
Node - A node is any machine—physical, virtual, cloud, network device, etc.—that is under management by Chef.
Chef Server- The Chef server acts as a hub for configuration data. The Chef server stores cookbooks, the policies that are applied to nodes, and metadata that describes each registered

	#include <stdio.h>
	#include <stdlib.h>
	#include <string.h>

	#define B 4

	static unsigned char* ntb(unsigned char b[], unsigned int n) {
	b[0] = n >> 24;
	b[1] = n >> 16;
	b[2] = n >> 8;

	digitalocean_domain.example example.com
	digitalocean_record.example example.com,<DO ID>
	digitalocean_record.fd-gmail-txt example.com,<DO ID>
	digitalocean_record.fd-mx["alt1.aspmx.l.google.com."] example.com,<DO ID>
	digitalocean_record.fd-mx["alt2.aspmx.l.google.com."] example.com,<DO ID>
	digitalocean_record.fd-mx["aspmx.l.google.com."] example.com,<DO ID>
	digitalocean_record.fd-mx["aspmx2.googlemail.com."] example.com,<DO ID>
	digitalocean_record.fd-mx["aspmx3.googlemail.com."] example.com,<DO ID>
	digitalocean_record.fd-ns["1"] example.com,<DO ID>
	digitalocean_record.fd-ns["2"] example.com,<DO ID>

	upstream site {
	server unix:/home/site/web/site.com.ua/site/shared/sockets/puma.sock fail_timeout=0;
	}

	server {
	listen 80;
	server_name site.com.ua www.site.com.ua;
	rewrite ^(.+)$ https://site.com.ua$uri permanent;
	}

	INSTALL JAVA
	$ sudo apt-get update && sudo apt-get install default-jre

	INSTALL ELASTIC SEARCH https://www.elastic.co/guide/en/elasticsearch/reference/current/setup-repositories.html
	$ wget -qO - https://packages.elastic.co/GPG-KEY-elasticsearch \| sudo apt-key add -
	$ echo "deb https://packages.elastic.co/elasticsearch/2.x/debian stable main" \| sudo tee -a /etc/apt/sources.list.d/elasticsearch-2.x.list
	$ sudo apt-get update && sudo apt-get install elasticsearch
	$ sudo update-rc.d elasticsearch defaults 95 10
	$ sudo service elasticsearch restart
	$ sudo service elasticsearch status