Connecting to Heroku Postgres Databases from Outside of Heroku
Last updated 03 November 2016
Heroku Postgres databases are designed to be used with a Heroku app. However, they are accessible from anywhere and may be used from any application using standard Postgres clients.
To make effective use of Heroku Postgres databases outside of a Heroku application, keep in mind the following:
All Heroku Postgres databases have a corresponding Heroku application. You can find the application name on the database page at data.heroku.com. You do not have to use the Heroku app for application code, but your database is attached to it and holds a config var containing the database URL. This variable is managed by Heroku, and is the primary way we tell you about your database’s network location and credentials.
Do not copy and paste database credentials to a separate environment or into your application’s code. The database URL is managed by Heroku and will change under some circumstances such as:
- User initiated database credential rotations using
heroku pg:credentials --reset.
- Catastrophic hardware failure leading to Heroku Postgres staff recovering your database on new hardware.
- Automated failover events on HA enabled plans.
It is best practice to always fetch the database URL config var from the corresponding Heroku app when your application starts. For example, you may follow 12Factor application configuration principles by using the Heroku CLI and invoke your process like so:
DATABASE_URL=$(heroku config:get DATABASE_URL -a your-app) your_process
This way, you ensure your process or application always has correct database credentials.
Other Heroku Apps
If you need to connect to a database from other Heroku apps, you can now attach a database addon directly to multiple applications. This ensures that any changes to the database’s URL will automatically propagate to your other apps.
Connecting to a Heroku Postgres database from outside of the Heroku network requires SSL. Your client or application must support and enable SSL to connect to a Heroku Postgres database. Most clients will connect over SSL by default, but on occasion it is necessary to set the
sslmode=require parameter on a Postgres connection. Note: it is important to add this paramater in code rather than editing the config var directly. Various automated events such as failover can change the config var, and edits there would be lost.
You can use Heroku Postgres Backups on the enclosing Heroku app in order to get automated backups on your database. Heroku Postgres Backups takes backups of the database pointed at by
DATABASE_URL in the Heroku app, so make sure you promote your database:
heroku pg:promote HEROKU_POSTGRESQL_VIOLET --app your-app