如何从 Cloud Functions 连接到 Google Cloud SQL (PostgreSQL)？

Question

I feel like I've tried everything. I have a cloud function that I am trying to connect to Cloud SQL (PostgreSQL engine). Before I do so, I pull connection string info from Secrets Manager, set that up in a credentials object, and call a pg (package) pool to run a database query.

Below is my code: Credentials:

import { Pool } from 'pg';

const credentials: sqlCredentials = {
   "host":"127.0.0.1",
   "database":"myFirstDatabase",
   "port":"5432",
   "user":"postgres",
   "password":"postgres1!"
}

const pool: Pool = new Pool(credentials);

await pool.query(`select CURRENT_DATE;`).catch(error => console.error(`error in pool.query: ${error}`));

Upon running the cloud function with this code, I get the following error:

error in pool.query: Error: connect ECONNREFUSED 127.0.0.1:5432

I have attempted to update the host to the private IP of the Cloud SQL instance, and also update the host to the Cloud SQL instance name on this environment, but that is to no avail. Any other ideas?

Answer 1

Through much tribulation, I figured out the answer. Given that there is NO documentation on how to solve this, I'm going to put the answer here in hopes that I can come back here in 2025 and see that it has helped hundreds. In fact, I'm setting a reminder in my phone right now to check this URL on November 24, 2025.

Solution: The host must be set as:

/cloudsql/<googleProjectName(notId)>:<region>:<sql instanceName>

Ending code:

import { Pool } from 'pg';

const credentials: sqlCredentials = {
   "host":"/cloudsql/my-first-project-191923:us-east1:my-first-cloudsql-inst",
   "database":"myFirstDatabase",
   "port":"5432",
   "user":"postgres",
   "password":"postgres1!"
}

const pool: Pool = new Pool(credentials);

await pool.query(`select CURRENT_DATE;`).catch(error => console.error(`error in pool.query: ${error}`));