An example showing how to use a GitHub action to automate backups of a Fly.io Postgres database as well as then uploading the backups to S3 (or another storage provider of your choosing).
Clone this repo and add your environment variables as secrets to your GitHub action.
- Control the cron frequency in the backup.yml file
This example is based on the following tutorial by advantch. However, there were certain steps which were unclear to me—as someone with relatively little python or bash knowledge.
I also find the Fly naming conventions confusing—particularly between the switching of hyphens and underscores in app names. This made the tutorial harder to follow and I thought it was worth sharing for others.
We proxy our Postgres app to port 5432 and then perform usual pg_dump commands.
Add the following environment variables to your GitHub action secrets.
For illustration purposes, assume my main fly app is called my-example-app and my attached Postgres fly app is called my-example-app-db.
💡 How to find some of these values is explained further down.
Fly.io specific variables
| Example | Explanation | |
|---|---|---|
| PG_PASSWORD | ||
| PG_USER | my_example_app | Note the underscores |
| PG_DATABASE | my_example_app | Note the underscores |
| APP_NAME | my-example-app | main fly app name |
| PROXY_APP_NAME | my-example-app-db | attached fly Postgres app name |
S3 specific variables
| Example | Explanation | |
|---|---|---|
| S3_ACCESS_KEY | ||
| S3_SECRET_ACCESS_KEY | ||
| S3_BUCKET | my-database-backups | |
| AWS_REGION | eu-west-1 |
Slack specific variables
For alerting a channel if the workflow fails. See here for more info.
| Example | Explanation | |
|---|---|---|
| SLACK_CHANNEL_ID | ||
| SLACK_BOT_TOKEN |
### How to retrieve certain environment values
Ensure that you are logged into your fly account:
flyctl auth login
flyctl list apps
fly postgres users list -a my-example-app-db
For your app name, do not use the Postgres app name; instead, it needs to be the app to which the PostGres app is attached. If you omit the -a flag it will use the app specified in your fly.toml file—which is usually what we want anyway.
flyctl ssh console -a my-example-app
echo $DATABASE_URL
You can also see all variables with
printenv
Again, assuming my main fly app is called my-example-app and my postgres fly app is called my-example-app-db.
Your DATABASE_URL should look something like: postgres://my_example_app:[email protected]:5432/my_example_app?sslmode=disable
💡 postgres://{username}:{password}@{hostname}:{port}/{database}?options
What is confusing is when to use hyphens and when to use underscores.
It helps to remember that "Fly Postgres is a regular app". So we need to differentiate between the naming of the Fly app hosting the Postgres database to that of the actual database itself.
Ensure Postgres is setup correctly (especially the path)
sudo mkdir -p /etc/paths.d && echo /Applications/Postgres.app/Contents/Versions/latest/bin | sudo tee /etc/paths.d/postgresapp
Create and activate a virtual environment.
Run the following lines of code in your terminal:
$ python3 -m venv .venv
$ source .venv/bin/activate
$ python3 -m pip install -r requirements.txt
The connection to DB often hangs when testing locally--so you may need to kill it.
lsof -i tcp:5432
kill xxx