mshRoR

PostgreSQL is Enough

• Simplify: move code into database functions
• Just Use Postgres for Everything
• PostgreSQL is the worlds’ best database
• Hacker News discussion

Background and Cron Jobs

• https://github.com/citusdata/pg_cron

mshRoR

# Call scopes directly from your URL params:
#
#     @products = Product.filter(params.slice(:status, :location, :starts_with))
module Filterable
  extend ActiveSupport::Concern

  module ClassMethods
    
    # Call the class methods with names based on the keys in <tt>filtering_params</tt>
    # with their associated values. For example, "{ status: 'delayed' }" would call 

mshRoR

# spin up our new (empty) database
docker compose up -d db_postgres_151

# login to postgres
$ psql -U postgres
$ CREATE DATABASE database_name

# dump our existing database
docker compose exec -it db_postgres_146 /bin/bash -c 'pg_dumpall -U $POSTGRES_USER > /backup/20230127.sql'

mshRoR

# Check server process is using jemalloc
# ref. [Japanese] https://tech.studyplus.co.jp/entry/2019/09/09/094140
class AppController < ActionController::Base
  def show
    r = `strings /proc/#{Process.pid}/maps | grep jemalloc`
    render plain: "<h1>#{ENV['LD_PRELOAD'].presence || 'empty'}</h1><pre>#{r}</pre>"
  end
end

mshRoR

# Refresh ubuntu keys server
$ sudo apt-key adv --refresh-keys --keyserver keyserver.ubuntu.com

# Group permission change
$ sudo chgrp -R root esdata

# Add current login User ID to .bashrc or .zshrc file
$ echo "export UID=$UID" >> ~/.bashrc
or
$ echo "export UID=$UID" >> ~/.zshrc

mshRoR

If you want to run docker as non-root user then you need to add it to the docker group.
1. Create the docker group if it does not exist
  $ sudo groupadd docker
2. Add your user to the docker group.
  $ sudo usermod -aG docker $USER
3. Run the following command or Logout and login again and run (that doesn't work you may need to reboot your machine first)
  $ newgrp docker
4. Check if docker can be run without root
  $ docker run hello-world
  

mshRoR

## Awesome Guidelines
https://github.com/Kristories/awesome-guidelines

## List of Free Learning Resources
https://github.com/EbookFoundation/free-programming-books

## Angular 2+ Components & Libraries
https://github.com/brillout/awesome-angular-components

## বাংলায় শেল ও শেলস্ক্রিপ্টিং শেখার কোর্স https://sh.howtocode.com.bd

mshRoR

MiniKube Setup:
1. https://kubernetes.io/docs/tasks/tools/install-minikube/
2. https://kubernetes.io/docs/tasks/tools/install-kubectl/

KOPS Setup for production:
http://github.com/kubernetes/kops

mshRoR

Then the code you write should have the following qualities. Code should be

• Transparent The consequences of change should be obvious in the code that is changing and in distant code that relies upon it
• Reasonable The cost of any change should be proportional to the benefits the change achieves
• Usable Existing code should be usable in new and unexpected contexts
• Exemplary The code itself should encourage those who change it to perpetuate these qualities

Code that is Transparent, Reasonable, Usable, and Exemplary (TRUE) not only meets today’s needs but can also be changed to meet the needs of the future. The first step in creating code that is TRUE is to ensure that each class has a single, well-defined responsibility.

mshRoR

## python 3.7 install
-> sudo apt update
-> sudo apt install build-essential zlib1g-dev libncurses5-dev libgdbm-dev libnss3-dev libssl-dev libreadline-dev libffi-dev wget
-> sudo apt install software-properties-common
-> sudo add-apt-repository ppa:deadsnakes/ppa
-> sudo apt update
-> sudo apt install python3.7
-> python3.7 --version

## pip3 install