installation-production.md

Install for Production

• Install for Production
  • Prerequisites
  • Installation
  • Configuration
  • Running Engine
    • Running with Systemd
    • Running with Supervisor
  • Logging
  • Read more

Prerequisites

Aura Engine runs on any modern Debian-based OS. It requires at least

• Python 3.7
• git

Additionally you'll need these system packages below.

sudo apt-get update
sudo apt-get install \
    supervisor \
    opam \
    redis-server \
    libsndfile1 \
    ffmpeg \
    quelcom \
    python3-pip \
    virtualenv \
    libssl-dev

Depending on the database management system you gonna use, you'll also need to install those packages.

In case of MariaDB this is:

sudo apt-get install \
    python-dev \
    default-libmysqlclient-dev \
    mariadb-server \
    libmariadbclient-dev

Create an user

While previous packages need superuser rights to be installed, the following ones are installed for the user which is executing the engine. In your development environment you can skip this step. In production you first need to create a user called engineuser.

    sudo adduser engineuser
    sudo adduser engineuser audio sudo

And switch to that user

  su engineuser

Liquidsoap Repository

Engine requires at least Liquidsoap 1.4.3 or newer, installed using OPAM (OCaml Package Manager).

Add the current Liquidsoap repository from this installation guide.

The other steps required for the Liquidsoap installation are handled by the install.sh script. If you experience any errors, carefully review them and consult the official documentation for installing Liquidsoap.

Cloning the project

Create the folder /opt/aura and clone the engine project from there:

  engineuser:/opt/aura/$  git clone https://gitlab.servus.at/autoradio/engine

Now you should have /opt/aura/engine/.

Let's move inside the home of engine:

  engineuser:/opt/aura/$ cd engine

Setup the database

The following installation script sets up the database. You either need to be logged in as root or have sudo rights.

  root:/opt/aura/engine/$ bash script/setup-db.sh

By default Aura Engine uses MariaDB for persistence. When starting this script, please ensure you have root access to your database instance. The installation script automatically creates a database plus an associated user with password. If you want to use your own database system, select "Other / Manually" during the database installation step.

If you have chosen to setup your database automatically, note the relevant credentials.

Initialize folders and permissions

Call this script to create the required log folders and update all permissions.

  root:/opt/aura/engine$ bash script/initialize.sh

Installation

The following installation script also sets up the database.

By default Aura Engine uses MariaDB for persistence. When starting the installation, please ensure you have root access to your database instance. The installation script automatically creates a database plus an associated user with password. If you want to use your own database system, select "Other / Manually" during the database installation step.

engineuser:/opt/aura/engine$  ./install.sh prod

This script does the following:

• Install Liquidsoap components using OPAM (script/install-opam-packages)
• Python Packages (requirements.txt)
• Creates a default Engine configuration file in /etc/aura/engine.ini

When this is completed, carefully check if any error occured. In case your database has been setup automatically, note the relevant credentials for later use in your engine.ini configuration.

Configuration

In your production environment edit following file to configure the engine:

engineuser:/opt/aura/engine$ nano /etc/aura/engine.ini

Now, specify at least following settings to get started:

    [database]
    db_user="aura"
    db_name="aura_engine"
    db_pass="---SECRET--PASSWORD---"

Set the URLs to the Steering, Tank and Engine API:

[api]

# The URL to get the health status 
api_steering_status = "http://aura.local:8000/api/v1/"
# The URL to get the Calendar via Steering
api_steering_calendar="http://aura.local:8000/api/v1/playout"
# The URL to get show details via Steering
api_steering_show="http://aura.local:8000/api/v1/shows/${ID}/"

## TANK ##

# The URL to get the health status 
api_tank_status = "http://aura.local:8040/healthz/"
# The URL to get playlist details via Tank
api_tank_playlist="http://aura.local:8040/api/v1/playlists/${ID}"

## ENGINE-API ##

# Engine ID (1 or 2)
api_engine_number = 1
# Engine API endpoint to store playlogs
api_engine_store_playlog = "http://localhost:8008/api/v1/playlog/store"
# Engine API endpoint to store clock information
api_engine_store_clock = "http://localhost:8008/api/v1/clock"
# Engine API endpoint to store health information
api_engine_store_health = "http://localhost:8008/api/v1/source/health/${ENGINE_NUMBER}"

Ensure that the Liquidsoap installation path is valid:

[lqs]
liquidsoap_path="/home/engineuser/.opam/4.08.0/bin/liquidsoap"

Configuring the Audio Store

Finally Engine needs to be able to access the audio folder, where all the tracks of the playlists are stored via Tank:

[audiofolder]
audiofolder="/var/audio"

There is some document on how to Setup the Audio Store.

If the audio device desired for playback is set as default, the Engine now should be ready to play sound. You can check the default audio hardware by executing aplay -L on the command line. If that's not the case you can set the default device in /etc/asound.conf. More advanced audio device settings can be looked up in the Configuration Guide.

Read about all other available settings in the Configuration Guide.

Running Engine

In production the process of starting the engine is slightly different compared to some development environment. This is due to the need of ensuring the engine's components are always running i.e. letting them to restart automatically after some system restart or crash has happened.

For this you can utilize either Systemd or Supervisor.

Running with Systemd

Copy the unit file /opt/aura/engine/configuration/systemd/aura-engine.service to /etc/systemd/system/.

This unit file starts engine-core and engine-liquidsoap within one command. Here Liquidsoap is started as as subprocess.

Please note not to use any other unit files in that directory yet. They are work in progress.

Now you'll need to reload the Systemd unit files

sudo systemctl daemon-reload

Start

sudo systemctl start aura-engine

Stop

sudo systemctl start aura-engine

Restart

sudo systemctl restart aura-engine

Status

sudo systemctl status aura-engine

Running with Supervisor

Now, given you are in the engine's home directory /opt/aura/engine/, simply type following to start the services:

supervisord

This picks up the supervisor configuration provided in the local supervisord.conf and the service configurations located in configuration/supervisor/*.conf.

Experience has shown it might be helpful to reload the supervisor configuration using sudo:

sudo supervisorctl reload

Note that the supervisor daemon starts all (both) services at once. If you want more fine-grained control for starting services individually, please check-out the next section.

Listing available Services

engineuser:/opt/aura/engine$ supervisorctl avail

You should get these all services with their actual state listed:

aura-engine                      in use    auto      666:666
aura-engine-api                  in use    auto      999:999

Maintanence using Supervisor

Please remember to call all supervisorctl commands from within your engine home directory (/opt/aura/engine/), to pickup the correct supervisord.conf.

Starting Services

    supervisorctl start <service-name>

Stopping Services

    supervisorctl stop <service-name>

Restarting Services

    supervisorctl restart <service-name>

Refresh after changing configurations

    supervisorctl restart <service-name>

In case you want to reload whole supervisor service

    sudo service supervisor restart

Logging

All Engine logs for production can be found under:

    `/var/log/aura`

and

    `/opt/aura/engine/logs`

Read more

• Overview
• Installation for Development
• Installation for Production
• Running with Docker
• Setup the Audio Store
• Developer Guide
• Engine Features
• Frequently Asked Questions (FAQ)