PostgREST/postgrest-heroku

README

PostgREST on Heroku

The best way to build an API, now for Heroku. Updated for PostgREST >= v9.0.0

Free and hobby Heroku PostgreSQL add-on do not support having multiple database roles (e.g. read-only or read-write roles).

Heroku Postgres paid tiers do support multiple database roles, though you'll have to create them through Heroku Postgres Credentials as explained below.

To Deploy PostgREST on Heroku

Log into Heroku using the Heroku CLI:

# If you have multiple Heroku accounts, use flag '--interactive' to switch between them
heroku login --interactive

Create a new Heroku app using this Heroku buildpack:

mkdir ${YOUR_APP_NAME}
cd ${YOUR_APP_NAME}
git init .

heroku apps:create ${YOUR_APP_NAME} --buildpack https://github.com/PostgREST/postgrest-heroku.git
heroku git:remote -a ${YOUR_APP_NAME}

Create a new Heroku Postgres add-on attached to the app and keep notes of the assigned add-on name (e.g. postgresql-curly-58902) referred later as ${HEROKU_PG_DB_NAME}
```
heroku addons:create heroku-postgresql:standard-0 -a ${YOUR_APP_NAME}
# wait until the add-on is available
heroku pg:wait -a ${YOUR_APP_NAME}
```

Create the necessary user roles according to the PostgREST documentation:

heroku pg:credentials:create --name api_user -a ${YOUR_APP_NAME}
# use the following command to ensure the new credential state is active before attaching it
heroku pg:credentials -a ${YOUR_APP_NAME}

heroku addons:attach ${HEROKU_PG_DB_NAME} --credential api_user -a ${YOUR_APP_NAME}

Connect to the Postgres database and create some sample data:

heroku psql -a ${YOUR_APP_NAME}

# from the psql command prompt execute the following commands:
create schema api;

create table api.todos (
id serial primary key,
done boolean not null default false,
task text not null,
due timestamptz
);

insert into api.todos (task) values
('finish tutorial 0'), ('pat self on back');

grant usage on schema api to api_user;
grant select on api.todos to api_user;

Create the Procfile:
```
web: PGRST_SERVER_HOST=0.0.0.0 PGRST_SERVER_PORT=${PORT} PGRST_DB_URI=${PGRST_DB_URI:-${DATABASE_URL}} ./postgrest-${POSTGREST_VER}
```
Set the following environment variables on Heroku:
```
heroku config:set POSTGREST_VER=10.0.0
heroku config:set PGRST_DB_SCHEMA=api
heroku config:set PGRST_DB_ANON_ROLE=api_user
```
PGRST_DB_URI can be set if an external database is used or if it's different from the default Heroku DATABASE_URL. This latter is used if nothing is provided.
POSTGREST_VER is mandatory to select and build the required PostgREST release.

See https://postgrest.org/en/stable/configuration.html#environment-variables for the full list of environment variables.
Build and deploy your app:
```
git add Procfile
git commit -m "PostgREST on Heroku"
git push heroku master
```
Your Heroku app should be live at ${YOUR_APP_NAME}.herokuapp.com
Test your app

From a terminal display the application logs:
```
heroku logs -t
```
From a different terminal retrieve with curl the records previously created:
```
curl https://${YOUR_APP_NAME}.herokuapp.com/todos
```
and test that any attempt to modify the table via a read-only user is not allowed:
```
curl https://${YOUR_APP_NAME}.herokuapp.com/todos -X POST \
 -H "Content-Type: application/json" \
 -d '{"task": "do bad thing"}'
```