PostgreSQL (RDS)

This page contains information about using the PostgreSQL service in Handel. This service provides a PostgreSQL database via the RDS service.

Service Limitations

No Option Group Support

This service doesn’t allow you to specify any custom options in an option group. It does allow you specify custom parameters in a parameter group, however.

No Update Support

This service intentionally does not support updates. Once a database is created, certain updates to the database will cause a new database to be created and the old one deleted. In an effort to avoid unwanted data loss, we don’t update this service automatically. You can still modify the database and parameter group manually in the AWS console.

Warning

Make sure you know what you’re doing when you modify your RDS database in the AWS Console. Certain actions will cause database downtime, and some may even cause the database to be recreated.

Parameters

Parameter Type Required Default Description
type string Yes   This must always be postgresql for this service type.
database_name string yes   The name of your database in your PostgreSQL instance.
description string No Parameter group. The parameter group description.
instance_type string no db.t2.micro The size of database instance to run. See DB Instance Class for information on choosing an instance type.
storage_gb: number no 5 The number of Gigabytes (GB) of storage to allocate to your database.
postgres_version: string no 9.6.2 The version of PostgreSQL you wish to run. See PostgreSQL on Amazon RDS for the list of supported versions.
db_username string no handel The username for the user that will be created in your database. Your password will be automatically generated and securely stored in the EC2 Parameter Store for you to access.
storage_type string no standard The type of storage to use, whether magnetic or SSD. Allowed values: ‘standard’, ‘gp2’.
db_parameters map<string, string> no   A list of key/value PostgreSQL parameter group pairs to configure your database. You will need to look in the AWS Console to see the list of available parameters for PostgreSQL.
tags Tags No   Any tags you wish to apply to this PostgreSQL instance.

Warning

Be aware that large database instances are very expensive. The db.cr1.8xl instance type, for example, costs about $3,400/month. Make sure you check how much you will be paying!

You can use the excellent EC2Instances.info site to easily see pricing information for RDS databases.

Tags

The Tags element is defined by the following schema:

tags:
 <your_tag_name>: <your_tag_value>

Note

Handel automatically applies some tags for you. See Default Tags for information about these tags.

Example Handel File

version: 1

name: my-postgres-instance

environments:
  dev:
    database:
      type: postgresql
      database_name: mydb
      instance_type: db.t2.micro
      storage_gb: 5
      postgres_version: 9.6.2
      db_username: mydb
      storage_type: standard
      db_parameters:
        authentication_timeout: 600
      tags:
        mytag: myvalue

Depending on this service

The PostgreSQL service outputs the following environment variables:

Environment Variable Description
<ENV_PREFIX>_ADDRESS The DNS name of the PostgreSQL database address.
<ENV_PREFIX>_PORT The port on which the PostgreSQL instance is listening.
<ENV_PREFIX>_USERNAME The username you can use to access the database.
<ENV_PREFIX>_DATABASE_NAME The name of the database in your PostgreSQL instance.

The <ENV_PREFIX> is a consistent prefix applied to all information injected for service dependencies. See Environment Variable Prefix for information about the structure of this prefix.

In addition, the PostgreSQL service puts the following credentials into the EC2 parameter store:

Parameter Name Description
<parameter_prefix>.db_password The password for your database user.

The <parameter_prefix> is a consistent prefix applied to all parameters injected by services in the EC2 Parameter Store. See Parameter Store Prefix for information about the structure of this prefix.

Events produced by this service

The PostgreSQL service does not produce events for other Handel services to consume.

Events consumed by this service

The PostgreSQL service does not consume events from other Handel services.