Typescript API Server

Installation

To download and install dependencies run npm install

Running

To run the API server run npm start

Testing

To run tests run npm run test

Development

To commit new code run npm run commit

Configuration

Rabbi may be configured in several ways depending on the needs of your environment.

Environment Variables
Configuration Files
Command Line Arguments

The same variables are used in all three options, however in configuration files and command line arguments all variables are strictly lower case, whereas in environment variables they may be upper case or lower case.

Environment Variables

Variable	Description	Default	Required
HTTP_API_ENABLED	Serve JSON API.	true	false
AMQP_ENABLED	Communicate between components via RabbitMQ. Require by some features under src/actors/	true	false
POSTGRES_ENABLED	Will automatically begin logging events to postgres	true	true
DATABASE_URL	Postgres connection Url in the form `postgres://user:password@host:port/database		true
HTTP_API_HOST	IP address to bind when serving. Set to 127.0.0.1 or localhost for local-only access	0.0.0.0	false
HTTP_API_PORT	Port to bind when accepting new API client connections.	5200	false
PROMETHEUS_ENABLED	Expose /metrics endpoint to allow prometheus to scrape default and your custom metrics.	true	false
LOKI_ENABLED	Stream logs from the application to a loki log aggregation server.	false	false

Configuration Files

The app loads files from a hierarchy each overriding the previous. First the system level config files are loaded, then user level config file, finally the local config file for development purposes

/etc/rabbi/rabbi.json
~/.rabbi/rabbi.json
.config/rabbi.json

Config files are JSON objects containing key value pairs where the key is the config variable and the value is the value of the variable. Numbers and booleans will be parsed and made available. Variable names can be either upper or lower case.

{
	"database_url": "postgres://postgres:12321423fekrefk@mydb.example.com:5432/boostpow",
	"http_api_port": 3000,
	"loki_enabled": true,
	"loki_url": "https://loki.example.com",
	"prometheus_enabled": false
}

System Events

When using AMQP you may bind the following events as routingkeys to receive delivery of these messages to your application. You may also choose to receive these events via Webhook by configuring the WEBHOOK_URL and WEBHOOKS_ENABLED variables.

Event	Description
prometheus.metrics.scraped	Every time prometheus scrapes
http.request	When a client makes a request to the HTTP API

Additional events can be published and listened to using rabbi

import { events } from 'rabbi'

events.publish('game.ended', { winner: 'nobody' })

Then in another component or process, or app connected to the same AMQP:

import { events } from 'rabbi'

events.on('game.ended', (message: Buffer, json?: any) => {

  console.log('---- GAME OVER ----')

  if (json && json.winner === 'nobody') {

    console.log('nobody wins')

  }

})

pow-co/gradeyourteacher-app