Andy Chrzaszcz andy9775

Introduction

This article describes an implementation of multi-tenancy using Yii and MySQL. “Multi-tenancy” is but one (yet crucial) aspect of SaaS applications; refer to the IBM document Convert your web application to a multi-tenant SaaS solution for more information on what else makes a webapp a SaaS application.

Moreover, there are three main architectures for multi-tenant databases: separate database, separate schemas and a single database. Refer to the Microsoft document Multi-Tenant Data Architecture for more information.

As MySQL doesn’t have schemas (at least the same way MS SQL Server and Oracle do) the only choices are a separate database for each tenant and single database with “commingled” tenant data. SaaS applications with a relatively small number of tenants can be easily managed with a database for each one, but for large numbers of tenants its

The ConnectionAdapter defines two callbacks :checkout (connect) and :checkin (disconnect).

ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.set_callback :checkout, :after do
  raw_connection
end

Source.

Story: Writing Scripts with Go

This is a story about how I tried to use Go for scripting. In this story, I’ll discuss the need for a Go script, how we would expect it to behave and the possible implementations; During the discussion I’ll deep dive to scripts, shells, and shebangs. Finally, we’ll discuss solutions that will make Go scripts work.

Why Go is good for scripting?

While python and bash are popular scripting languages, C, C++ and Java are not used for scripts at all, and some languages are somewhere in between.

Transparent Git Encryption

This document has been modified from its [original format][m1], which was written by Ning Shang ([email protected]). It has been updated and reformatted into a [Markdown][m2] document by [Woody Gilk][m3] and [republished][m4].

Description

When working with a remote git repository which is hosted on a third-party storage server, data confidentiality sometimes becomes

	# first we download the list of IP ranges from CloudFlare
	wget https://www.cloudflare.com/ips-v4

	# iterate over the lines in the downloaded file
	# make sure to set `--group-id` and `--port`; more details at http://docs.aws.amazon.com/cli/latest/reference/ec2/authorize-security-group-ingress.html
	while read p; do aws ec2 authorize-security-group-ingress --group-id sg-e0000000 --protocol tcp --port 80 --cidr $p; done< ips-v4

	{
	"Statement": [
	{
	"Action": [
	"apigateway:*",
	"cloudformation:CancelUpdateStack",
	"cloudformation:ContinueUpdateRollback",
	"cloudformation:CreateChangeSet",
	"cloudformation:CreateStack",
	"cloudformation:CreateUploadBucket",

	package main

	import (
	"container/list"
	"fmt"
	)

	type CacheItem struct {
	key string // Key of item
	value interface{} // Value of item

	# Be aware to first setup a valid Python 3 environment with the proper requirements installed.
	# Also activate your Python installation/venv before executing those commands.

	VER=0.19.4

	PROGS?=app1 app2 app3 app4

	PROGS_PY:=$(addsuffix .py,$(PROGS))
	PROGS_EXE:=$(addsuffix .exe,$(PROGS))

	let UserContext = React.createContext();

	class App extends React.Component {
	state = {
	user: null,
	setUser: user => {
	this.setState({ user });
	}
	};

	-- Create a group
	CREATE ROLE readaccess;

	-- Grant access to existing tables
	GRANT USAGE ON SCHEMA public TO readaccess;
	GRANT SELECT ON ALL TABLES IN SCHEMA public TO readaccess;

	-- Grant access to future tables
	ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT SELECT ON TABLES TO readaccess;