Azure PostgreSQL for TypeScript (node-postgres)

Connect to Azure Database for PostgreSQL Flexible Server using the pg (node-postgres) package with support for password and Microsoft Entra ID (passwordless) authentication.

Installation

npm install pg @azure/identity
npm install -D @types/pg

Environment Variables

# Required
AZURE_POSTGRESQL_HOST=<server>.postgres.database.azure.com
AZURE_POSTGRESQL_DATABASE=<database>
AZURE_POSTGRESQL_PORT=5432

# For password authentication
AZURE_POSTGRESQL_USER=<username>
AZURE_POSTGRESQL_PASSWORD=<password>

# For Entra ID authentication
AZURE_POSTGRESQL_USER=<entra-user>@<server>   # e.g., user@contoso.com
AZURE_POSTGRESQL_CLIENTID=<managed-identity-client-id>  # For user-assigned identity

Authentication

Option 1: Password Authentication

import { Client, Pool } from "pg";

const client = new Client({
  host: process.env.AZURE_POSTGRESQL_HOST,
  database: process.env.AZURE_POSTGRESQL_DATABASE,
  user: process.env.AZURE_POSTGRESQL_USER,
  password: process.env.AZURE_POSTGRESQL_PASSWORD,
  port: Number(process.env.AZURE_POSTGRESQL_PORT) || 5432,
  ssl: { rejectUnauthorized: true }  // Required for Azure
});

await client.connect();

Option 2: Microsoft Entra ID (Passwordless) - Recommended

import { Client, Pool } from "pg";
import { DefaultAzureCredential } from "@azure/identity";

// For system-assigned managed identity
const credential = new DefaultAzureCredential();

// For user-assigned managed identity
// const credential = new DefaultAzureCredential({
//   managedIdentityClientId: process.env.AZURE_POSTGRESQL_CLIENTID
// });

// Acquire access token for Azure PostgreSQL
const tokenResponse = await credential.getToken(
  "https://ossrdbms-aad.database.windows.net/.default"
);

const client = new Client({
  host: process.env.AZURE_POSTGRESQL_HOST,
  database: process.env.AZURE_POSTGRESQL_DATABASE,
  user: process.env.AZURE_POSTGRESQL_USER,  // Entra ID user
  password: tokenResponse.token,             // Token as password
  port: Number(process.env.AZURE_POSTGRESQL_PORT) || 5432,
  ssl: { rejectUnauthorized: true }
});

await client.connect();

Core Workflows

1. Single Client Connection

import { Client } from "pg";

const client = new Client({
  host: process.env.AZURE_POSTGRESQL_HOST,
  database: process.env.AZURE_POSTGRESQL_DATABASE,
  user: process.env.AZURE_POSTGRESQL_USER,
  password: process.env.AZURE_POSTGRESQL_PASSWORD,
  port: 5432,
  ssl: { rejectUnauthorized: true }
});

try {
  await client.connect();
  
  const result = await client.query("SELECT NOW() as current_time");
  console.log(result.rows[0].current_time);
} finally {
  await client.end();  // Always close connection
}

2. Connection Pool (Recommended for Production)

import { Pool } from "pg";

const pool = new Pool({
  host: process.env.AZURE_POSTGRESQL_HOST,
  database: process.env.AZURE_POSTGRESQL_DATABASE,
  user: process.env.AZURE_POSTGRESQL_USER,
  password: process.env.AZURE_POSTGRESQL_PASSWORD,
  port: 5432,
  ssl: { rejectUnauthorized: true },
  
  // Pool configuration
  max: 20,                    // Maximum connections in pool
  idleTimeoutMillis: 30000,   // Close idle connections after 30s
  connectionTimeoutMillis: 10000  // Timeout for new connections
});

// Query using pool (automatically acquires and releases connection)
const result = await pool.query("SELECT * FROM users WHERE id = $1", [userId]);

// Explicit checkout for multiple queries
const client = await pool.connect();
try {
  const res1 = await client.query("SELECT * FROM users");
  const res2 = await client.query("SELECT * FROM orders");
} finally {
  client.release();  // Return connection to pool
}

// Cleanup on shutdown
await pool.end();

3. Parameterized Queries (Prevent SQL Injection)

// ALWAYS use parameterized queries - never concatenate user input
const userId = 123;
const email = "user@example.com";

// Single parameter
const result = await pool.query(
  "SELECT * FROM users WHERE id = $1",
  [userId]
);

// Multiple parameters
const result = await pool.query(
  "INSERT INTO users (email, name, created_at) VALUES ($1, $2, NOW()) RETURNING *",
  [email, "John Doe"]
);

// Array parameter
const ids = [1, 2, 3, 4, 5];
const result = await pool.query(
  "SELECT * FROM users WHERE id = ANY($1::int[])",
  [ids]
);

4. Transactions

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