Connect a Django application to Neki

• A Neki database with a ready branch.
• An application role for that branch. Use pg_read_all_data for read traffic and add pg_write_all_data when the application writes rows. These inherited data roles do not grant CREATE or ALTER, so application credentials cannot change the schema.
• A separate migration role, if you run schema changes against the branch. DDL requires the postgres inherited role. Neki restricts execution of the cross-router DDL barrier function __neki.wait_for_ddl to its neki_viewer role, so add neki_viewer, which requires pg_read_all_data, to the same role. Keep the migration credentials out of the application’s runtime configuration.
• The Primary connection details from the database’s Connect page.

​

Install the Postgres driver

pip install "psycopg[binary]" python-dotenv

​

Add the connection details

DB_HOST=<HOST>
DB_PORT=5432
DB_NAME=postgres
DB_USER=<USERNAME>
DB_PASSWORD=<PASSWORD>
DB_SSLROOTCERT=<SYSTEM_CA_PATH>

​

Configure Django

import os

from dotenv import load_dotenv

load_dotenv()

DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.postgresql",
        "HOST": os.environ["DB_HOST"],
        "PORT": os.environ.get("DB_PORT", "5432"),
        "NAME": os.environ.get("DB_NAME", "postgres"),
        "USER": os.environ["DB_USER"],
        "PASSWORD": os.environ["DB_PASSWORD"],
        "OPTIONS": {
            "sslmode": "verify-full",
            "sslrootcert": os.environ["DB_SSLROOTCERT"],
        },
    }
}

python manage.py check --database default

psql "$MIGRATION_DATABASE_URL" -f <MIGRATION_FILE>

NOTICE: DDL is committed and the change is visible on this router; other routers may not see it yet. To wait until it is visible on every router, use __neki.wait_for_ddl(42, 7)

SELECT __neki.wait_for_ddl(42, 7);

​

Need help?