gowthamshankar99

Apache Airflow

How does Apache Airflow work ?

DAG - Directed Acyclic Graph

• Blueprint for your workflow
• Tasks are executed in a specific order

What is an Airflow Operator

norsec0de

Install Pyenv & Pipenv on AWS EC2 (Amazon Linux)

Installation

Install Dependencies

Pyenv builds Python versions from source and therefore requires all the necessary build dependencies.

sudo yum install gcc zlib-devel bzip2 bzip2-devel patch readline-devel sqlite sqlite-devel openssl-devel tk-devel libffi-devel

yogthos

Introductory resources

• High level overview https://yogthos.github.io/ClojureDistilled.html
• An Animated Introduction to Clojure https://markm208.github.io/cljbook/
• Interactive tutorial in a browser https://tryclojure.org/
• Interactive exercises http://clojurescriptkoans.com/
• Clerk notebooks with introductory examples https://github.clerk.garden/anthonygalea/notes-on-clojure
• More interactive exercises https://4clojure.oxal.org/
• Lambda Island tutorials https://lambdaisland.com/
• Functional Programming with Clojure resources https://practicalli.github.io/

efrapp

Setup Sidekiq for Heroku

Install Heroku Redis Add-on

Option 1: Using the dashboard

Go to the Resources tab and in the Add-ons section type Heroku Redis in the search field. It will appear in the search list. Click on it and a modal will show up to install it, click in the Provision button to start the installation.

charlesroper

How to setup a practically free CDN using Backblaze B2 and Cloudflare

⚠️ Note 2023-01-21
Some things have changed since I originally wrote this in 2016. I have updated a few minor details, and the advice is still broadly the same, but there are some new Cloudflare features you can (and should) take advantage of. In particular, pay attention to Trevor Stevens' comment here from 22 January 2022, and Matt Stenson's useful caching advice. In addition, Backblaze, with whom Cloudflare are a Bandwidth Alliance partner, have published their own guide detailing how to use Cloudflare's Web Workers to cache content from B2 private buckets. That is worth reading,

lizthegrey

default['sshd']['sshd_config']['AuthenticationMethods'] = 'publickey,keyboard-interactive:pam'
default['sshd']['sshd_config']['ChallengeResponseAuthentication'] = 'yes'
default['sshd']['sshd_config']['PasswordAuthentication'] = 'no'

oseme-techguy

#!/usr/bin/env bash

# To fix the " gpg: WARNING: unsafe permissions on homedir '/home/path/to/user/.gnupg' " error
# Make sure that the .gnupg directory and its contents is accessibile by your user.
chown -R $(whoami) ~/.gnupg/

# Also correct the permissions and access rights on the directory
chmod 600 ~/.gnupg/*
chmod 700 ~/.gnupg

pervognsen

A quadratic space is a real vector space V with a quadratic form Q(x), e.g. V = R^n with Q as the squared length. The Clifford algebra Cl(V) of a quadratic space is the associative algebra that contains V and satisfies x^2 = Q(x) for all x in V. We're imposing by fiat that the square of a vector should be the quadratic form's value and seeing where it takes us. Treat x^2 = Q(x) as a symbolic rewriting rule that lets you replace x^2 or x x with Q(x) and vice versa whenever x is a vector. Beyond that Cl(V) satisfies the standard axioms of an algebra: it lets you multiply by scalars, it's associative and distributive, but not necessarily commutative.

Remarkably, this is all you need to derive everything about Clifford algebras.

Let me show you how easy it is to bootstrap the theory from nothing.

We know Cl(V) contains a copy of V. Since x^2 = Q(x) for all x, it must also contain a copy of some nonnegative reals.

axw

version: "2.1"
services:
  apm-server:
    image: docker.elastic.co/apm/apm-server:${STACK_VERSION:-6.5.0}
    ports:
      - "127.0.0.1:${APM_SERVER_PORT:-8200}:8200"
      - "127.0.0.1:${APM_SERVER_MONITOR_PORT:-6060}:6060"
    command: >
      apm-server -e
        -E apm-server.rum.enabled=true

fernandoaleman

For MacOS Catalina, visit Install mysql2 on MacOS Catalina

Problem

Installing mysql2 gem errors on MacOS Mojave.

Solution

Make sure openssl is installed on Mac via Homebrew.