Setting up the database

Set up the OpenCue database

This page describes how to install and set up a PostgreSQL database for use with OpenCue.

OpenCue supports a single database per deployment, which serves as the single source of truth within your deployment.

System requirements

Cuebot servers are the only component that access the database directly. All other components, such as PyCue, interact with the database indirectly via the Cuebot’s gRPC API. For this reason, make sure Cuebot has a low-latency connection to the database, either by running both on the same machine or on the same local network.

OpenCue supports versions 9 or greater of the PostgreSQL database.

Before you begin

To follow the instructions in this guide, you’ll need the following software:

If you’re on macOS, you’ll also need Homebrew.

Installing Postgres

Before you set up the database, make sure you complete the steps to install PostgreSQL.

Installing on Docker

  1. First, pull the Postgres image from Docker hub:

    docker pull postgres
  2. Then, start your Postgres container:

    export PG_CONTAINER=postgres
    docker run -td --name $PG_CONTAINER postgres
  3. Create a superuser named after your current OS user, which is used for the rest of the admin commands in this guide.

    docker exec -it --user=postgres $PG_CONTAINER createuser -s $USER
  4. To make things easier, install a Postgres client:

    On yum-based Linux you can run

    yum install postgresql-contrib

    On macOS, the easiest way is with Homebrew:

    brew install postgresql
  5. Finally, export the DB_HOST environment variable, which is used in the rest of this guide by fetching the IP address of your Postgres container:

    export DB_HOST=$(docker inspect -f '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $PG_CONTAINER)

Installing on Linux

The following steps assume a yum-based Linux distribution, such as CentOS.

See the Postgres docs for instructions for other distributions.

  1. First, run yum to install the required Postgres packages:

    yum install postgresql-server postgresql-contrib
  2. Next, initialize your Postgres installation and configure it to run as a service:

    postgresql-setup initdb
    systemctl enable postgresql.service
    systemctl start postgresql.service
  3. Create a superuser named after your current OS user, which is used for the rest of the admin commands in this guide:

    su -c "createuser -s $USER" postgres
  4. Finally, export the DB_HOST environment variable, which is used in the rest of this guide:

    export DB_HOST=localhost

Installing on macOS

For macOS, we recommend installing PostgreSQL using Homebrew.

To install the database:

  1. Install PostgreSQL:

    brew install postgresql
  2. Then, start the PostgreSQL software:

    brew services start postgres
  3. Finally, export the DB_HOST environment variable, which is used in the rest of this guide:

    export DB_HOST=localhost

Creating the database

After you’ve installed PostgreSQL, you must create a database.

To create a database:

  1. Define and export the following shell variables for a database named cuebot_local:

    export DB_NAME=cuebot_local
    export DB_USER=cuebot
    export DB_PASS=<changeme>
  2. Create the database and the user that Cuebot uses to connect to it:

    createdb $DB_NAME
    createuser $DB_USER --pwprompt
    # Enter the password stored in DB_PASS when prompted
    psql -c "ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL PRIVILEGES ON TABLES TO $DB_USER" $DB_NAME

    If you are running Postgres in a Docker container, you will instead need to run the same commands from within that container:

    docker exec -it --user=postgres $PG_CONTAINER createdb $DB_NAME
    docker exec -it --user=postgres $PG_CONTAINER createuser $DB_USER --pwprompt
    # Enter the password stored in DB_PASS when prompted
    docker exec -it --user=postgres $PG_CONTAINER psql -c "ALTER DEFAULT PRIVILEGES IN SCHEMA public GRANT ALL PRIVILEGES ON TABLES TO $DB_USER" $DB_NAME

Populate the database

Option 1: Download the published schema

Visit https://github.com/AcademySoftwareFoundation/OpenCue/releases and download the SQL files from the latest release’s Assets. There should be two - a schema file and a demo_data file.

To populate the database:

  1. To populate the database schema and some initial data, run the psql command:

    psql -h $DB_HOST -f <path to schema SQL file> $DB_NAME

    To see a list of flags for the psql tool, run the psql --help command. For example, if your database is running on a remote host, specify the -h flag. If you need to specify a different username, specify the -U flag.

  2. The demo_data SQL file contains a series of SQL commands to insert some sample data into the Cuebot database, which helps demonstrate various features of the software. To execute the SQL statements, run the psql command:

    psql -h $DB_HOST -f <path to demo_data SQL file> $DB_NAME

Option 2: Apply migrations from source

The OpenCue source code stores its database schema as migrations, which are a sequence of SQL files which the database administrator can apply incrementally to construct the full database schema.

While not necessary for a demo environment, we recommend this method for most production deployments of OpenCue use. Any future changes to the PostgreSQL schema will be published as new migrations, which allows your database administrator to safely apply the schema changes without needing to do a full rebuild of the database.

You need to check out the source code. The rest of this section assumes your current directory is the root of the checked out source.

Migrations are published as raw SQL, so it should be possible to use your database management tool of choice for applying the migrations. This example uses Flyway.

To apply the migrations:

  1. On macOS, the easiest way to install Flyway is via Homebrew:

    brew install flyway

    For installation instructions for other platforms, see the the Flyway documentation.

  2. Run the flyway command to execute the migrations:

    flyway -url=jdbc:postgresql://$DB_HOST/$DB_NAME -user=$USER -n -locations=filesystem:cuebot/src/main/resources/conf/ddl/postgres/migrations migrate
  3. The OpenCue repository also includes the PostgreSQL demo_data.sql file. This file contains a series of SQL commands to insert some sample data into the Cuebot database, which helps demonstrate various features of the software. To execute the SQL statements, run the psql command:

    psql -h $DB_HOST -f cuebot/src/main/resources/conf/ddl/postgres/demo_data.sql $DB_NAME

    To see a list of flags for the psql tool, run the psql --help command. For example, if your database is running on a remote host, specify the -h flag. If you need to specify a different username, specify the -U flag.

What’s next?

Last modified Thursday, July 11, 2019: reformat to address comments (5f88b38)