Why is postgres password authentication failing in deno?

I am able to connect fine from psql and node.js, but not from deno using deno-postgres. Why is this?

I am running postgres 15 in docker using the official postgres:15 image. This is the composed service:

db:
  image: postgres:15
  ports:
    - 5432:5432
  environment:
    POSTGRES_PASSWORD: foo

I can connect to it without any problem using psql

psql postgres://postgres:foo@localhost:5432/postgres

and node.js

const { Client } = require('pg')
const client = new Client('postgres://postgres:foo@localhost:5432/postgres');
client.connect();

but from deno (1.29.2)

import { Client } from 'https://deno.land/x/postgres@v0.16.1/mod.ts';
const client = new Client('postgres://postgres:foo@localhost:5432/postgres');
client.connect();

I get this in the deno log

error: Uncaught (in promise) PostgresError: password authentication failed for user "postgres" throw new PostgresError(parseNoticeMessage(maybe_sasl_final));

And this in the db log

FATAL: password authentication failed for user "postgres"

Found 3 different solutions thanks to spyrospal

Upgrade the deno-postgres library to 0.17.0
Downgrade to the postgres:13 image which is configured to use md5 instead of scram-sha-256
Provide an extra environment variable when initializing the docker container for image version 14+ (POSTGRES_INITDB_ARGS: "--auth md5")

Solution

The usage seems correct.

You can verify the authentication error by inspecting the log of the db container. You should be able to see something like this:

FATAL:  password authentication failed for user "postgres"

Are you getting any more info from the logs?

The lib seems to have attempted a login using the scram-sha-256 authentication method. Use can see the configured auth methods by inspecting the contents of the pg_hba.conf.

docker exec -it db cat /var/lib/postgresql/data/pg_hba.conf

If the scram-sha-256 method is indeed enabled maybe changing to md5 can help. Finally, if all fails then you can try to update to v0.17.0 version of the deno-postgres.