database connection.md
Connect Postgres for Django
Summary
Connect a Django app to PostgreSQL on Ample. Read DATABASE_URL at runtime with dj-database-url with psycopg: when you supply one with --env it is delivered encrypted and takes precedence; when you supply none and the app needs PostgreSQL, Ample auto-provisions a managed PostgreSQL 16 database and injects its connection string.
Infrastructure requirements
- Compute: verified (Apps run in isolated x86_64 Firecracker microVMs that auto-pause when idle and wake on request; sizes are the priced VM sizes.)
- Postgres: verified (Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.)
Prerequisites
- dj-database-url with psycopg reading the DATABASE_URL environment variable at runtime
- Either a production DATABASE_URL to pass with --env, or nothing (auto-provision)
- An Ample account token with servers:write and databases:read
Exact tested configuration
- template:
python-3.12 - runtime:
python - size:
s-1vcpu-1gb - install:
python3 -m pip install --target .ample/python -r requirements.txt - start:
PYTHONPATH=.ample/python:${PYTHONPATH:-} python3 run.py
Steps
- Read the URL at runtime. Open connections from the DATABASE_URL environment variable inside the app; never commit credentials and never connect at build time.
- Choose the source of the database. Pass --env DATABASE_URL=... for an existing database, or omit it to let Ample provision a managed one on first deploy and reuse it on redeploys.
ample deploy . --name <app-name> --public --start "python3 run.py"
- Test the connection through the app. Expose a route (/db) that runs a trivial query and returns postgres=ok.
- Verify. Fetch the live URL and run the success checks below. On failure read the build log, then the runtime log, fix the cause and deploy again; do not blind-retry.
ample logs <deployment_id> --kind build
Tested examples
- Django + PostgreSQL canary (tests/deploy-canaries/django-postgres): Auto-provisioned managed database with a real query.
Success checks
- database route reports a live connection (
/dbon the live URL, expect postgres=ok)
Limitations
- Verified on the node-22 template at s-1vcpu-1gb; other templates and sizes are not verified by this recipe.
- Region, compliance attestations and request-duration limits are unknown and not claimed.
- Apps auto-pause when idle and wake on the next request; always-on is an operator setting, not a plan feature.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures are not verified.
- Apps and their managed databases are placed together; cross-node shared databases are unsupported.
Cost estimate
Estimated 10.00 USD per month (size prices from pricing.toml at build revision a1b8c38919e59cd035ebabaced73cf84ece24371).
- app server x1
s-1vcpu-1gb: 5.00 USD - managed PostgreSQL database x1
s-1vcpu-1gb: 5.00 USD
Apps and managed databases auto-pause when idle; the estimate is the always-on monthly price of the tested sizes. Plan quotas and budgets apply.
Verification evidence
- canary_run on 2026-09-20T01:42:25Z at revision
199ff1dfd52683832ae75d3f98b53a7a4bff7f96-dirty (CLI e3181f5): Django 5 project with dj-database-url and psycopg: the managed PostgreSQL database was auto-provisioned, python3 manage.py migrate ran as the release command, and /db and /migrated reported postgres=ok and the migrated marker. (expires 2027-03-19T01:42:25Z) - canary_run on 2026-09-19T23:55:33Z at revision
1764076-tls-account-903d345: Node app needing PostgreSQL with no DATABASE_URL: a managed database was auto-provisioned and /db reported postgres=ok. (expires 2027-03-18T23:55:33Z)
Last verified: 2026-09-20T01:42:25Z
Execution binding
MCP tool ample_deploy (registry mcp:ample_deploy), schema hash 876465fce906da0c observed 2026-09-20T01:55:48.667900+00:00 at revision 199ff1dfd526, binding state current, required scopes: servers:write, databases:read.