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.
postgres_version	string	Yes		The version of PostgreSQL you wish to run. See PostgreSQL on Amazon RDS for the list of supported versions.
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.
storage_type	string	No	standard	The type of storage to use, whether magnetic or SSD. Allowed values: ‘standard’, ‘gp2’.
multi_az	boolean	No	false	Whether or not the deployed database should be Multi-AZ. Note: Using Multi-AZ increases the cost of your database.
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	Resource 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.

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
      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
<SERVICE_NAME>_ADDRESS	The DNS name of the PostgreSQL database address.
<SERVICE_NAME>_PORT	The port on which the PostgreSQL instance is listening.
<SERVICE_NAME>_DATABASE_NAME	The name of the database in your PostgreSQL instance.

See Environment Variable Names for information about how the service name is included in the environment variable name.

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

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

Note

The <parameter_prefix> section of the parameter name 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.

The <service_name> section of the parameter name should be replaced by the service name you gave your database in your Handel file.

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.