Heroku CI with Postgres postgis extension - heroku

Question

I'm using a postgis extension to my database on Heroku. In production this works just fine; I'm mapping like a boss.
But, I can't get my app to build on HerokuCI because the database addon in the test environment doesn't have GDAL installed (part of the postgis extension):
django.core.exceptions.ImproperlyConfigured: Could not find the GDAL library (tried "gdal", "GDAL", "gdal2.3.0", "gdal2.2.0", "gdal2.1.0", "gdal2.0.0", "gdal1.11.0"). Is GDAL installed? If it is, try setting GDAL_LIBRARY_PATH in your settings.
-----> test command `python manage.py migrate --noinput && python manage.py test` failed with exit status 1
I can't find out how to create extensions in the heroku CI environment. Heroku's app json schema say nothing about how to create extensions on the test databases.
I know that I can't use in-dyno database for CI, as postgis is not an available extension for that, but I'm not using an in-dyno one, I'm using a plan...
Here's my app schema:
{
"name": "mymegaapp",
"scripts": {
"heroku-prebuild": "create extension postgis",
"heroku-postbuild": "echo heroku-postbuild script runs here."
},
"env": {
},
"formation": {
},
"addons": [
],
"buildpacks": [
{
"url": "heroku/python"
},
{
"url": "heroku/nodejs"
}
],
"environments": {
"test": {
"scripts": {
"test": "python manage.py migrate --noinput && python manage.py test"
},
"env": {
"DJANGO_DEBUG": "1"
},
"addons":[
{
"plan": "heroku-postgresql",
"options": {
"version": "11"
}
},
"heroku-redis:hobby-dev"
]
}
}
}
Note that I've tried to create the postgis extension in the prebuild script, which doesn't make a difference.
I've also tried invoking the creation before the test script:
"scripts": {
"test": "heroku create extension postgis && python manage.py migrate --noinput && python manage.py test"
},
which doesn't work because the heroku cli isn't installed in the dyno.
The key questions:
How can I create extensions in HerokuCI?
Is postgis an allowable extension at all in HerokuCI?

Answer 1

You've almost got it. There's no first class support for creating pg extensions directly from the CLI. However, you can pass a statement into psql.
Try this in your postdeploy or test setup script:
psql -c "create extension postgis" $DATABASE_URL As you're aware, you'll need to do this with a real database, not in-dyno. If you've attached the database as something other than DATABASE_URL, you will need to update that in the script.
[Edit by OP to add useful info] In this case, GDAL libraries will also be needed, which can be installed by setting the BUILD_WITH_GEO_LIBRARIES environment variable to 1. The final working solution in app.json will be:
"environments": {
"test": {
"scripts": {
"postdeploy": "psql -c \"create extension postgis\" $DATABASE_URL",
"test": "python manage.py migrate --noinput && python manage.py test"
},
"env": {
"DJANGO_DEBUG": "1",
"BUILD_WITH_GEO_LIBRARIES": "1"
},
"addons":[
{
"plan": "heroku-postgresql",
"options": {
"version": "11"
}
}
]
}
}

Answer 2

Here a 2021 update as the setting BUILD_WITH_GEO_LIBRARIES is now deprecated and unsupported by Heroku:
This app.json worked for my CI setup with Django / Heroku:
{
"buildpacks": [
{
"url": "https://github.com/heroku/heroku-geo-buildpack.git"
},
{
"url": "heroku/python"
}
],
"environments": {
"test": {
"scripts": {
"test": "python3 manage.py migrate --noinput && python3 manage.py test --keepdb"
},
"env": {
"DJANGO_DEBUG": "1"
}
}
}
}