Connect a Node.js 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.

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Install the Postgres client

npm install pg dotenv

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Add the connection string

DATABASE_URL='postgresql://<USERNAME>:<PASSWORD>@<HOST>:5432/postgres?sslmode=verify-full'

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Connect and run a query

require('dotenv').config()

const { Client } = require('pg')

const client = new Client({
  connectionString: process.env.DATABASE_URL,
})

async function main() {
  await client.connect()

  const result = await client.query(
    'SELECT current_database() AS database, current_user AS role, NOW() AS time'
  )

  console.log(result.rows[0])
  await client.end()
}

main().catch((error) => {
  console.error(error)
  process.exit(1)
})

node index.js

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Apply schema changes

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);

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