Request Gateway Postgres - address restricting add-on for auth.

A Go IP address restriction backend utility which uses Postgres/GCP CloudSQL. Intended to be used in conjunction with auth.

What?

This is a fairly rudimentary backend client which persists a list of approved address names (IPs, hostnames, whatever you want to use to differentiate), and will provide a boolean check to indicate if a given address name is on the approved list.

Why?

This was written to augment a GCP Appengine service. Appengine already provides a firewall service which can be used to control incoming traffic, so this address restriction utility is useful where a appengine default service already exists serving a superset of incoming traffic. This can be plugged into middleware to permit access to a non-default service for a subset of traffic.

How?

The best place to start is probably with the examples and tests. Initialise the approval list table with the schema SQL scripts.

Examples

See examples for a http/appengine implementations which uses requestgateway and auth. This is written for appengine standard 2nd gen, but also works as a standalone.

Dependencies and services

This utilises the following fine pieces of work:

• GCP's CloudSQL and Storage Go client

Installation

If you want to run the example code, then install using

$ go get -u github.com/lidstromberg/examples

If you only want the requestgateway utility, then install with

$ go get -u github.com/lidstromberg/requestgatewaypg

Environment Variables

You will also need to export (linux/macOS) or create (Windows) some environment variables.

################################
# GCP DETAILS
################################
export GTWAY_GCP_PROJECT='{{PROJECTNAME}}'

################################
# GCP CREDENTIALS
################################
export GOOGLE_APPLICATION_CREDENTIALS="/PATH/TO/GCPCREDENTIALS.JSON"

(See Google Application Credentials)

If you are using CloudSQL you will also need to give IAM permissions to the account to which GCPCREDENTIALS.JSON belongs (Role: Cloud SQL Client)

Change GTWAYPG_DEBUGON to true/false if you want verbose logging on/off. The other variables don't need to be changed.

################################
# REQUEST GATEWAY
################################
export GTWAYPG_DEBUGON='true'
export GTWAYPG_SQLDST='cloudsqlpostgres'
export GTWAYPG_SQLCNX='host={{instancename}} dbname=gateway user=gatewayuser password={{password}} sslmode=disable'

Main Files

File	Purpose
requestgateway.go	Logic manager
requestgateway_test.go	Tests

Postgres Schema Files

File	Purpose
001_dbcreate.sql	Database/User create
002_schema.sql	Database schema
003_funcs.sql	Database functions

Ancillary Files

File	Purpose
config.go	Boot package parameters, environment var collection
entity.go	Package structs
env	Package environment variables for local/dev installation
gogets	Statements for go-getting required packages