Docker - Cannot talk to Postgres - docker

Question

I am using docker-compose to orchestrate two services but I am getting an error for one of those. Upon following the logs, this is my output:
2023/02/01 08:34:35 [INFO] version.go:13 versionPrint(): starting Commento
2023/02/01 08:34:35 [INFO] database_connect.go:20 dbConnect(): opening connection to postgres: postgres://postgres:redacted#db:5432/commento?sslmode=disable
2023/02/01 08:34:35 [ERROR] database_connect.go:31 dbConnect(): cannot talk to postgres, retrying in 10 seconds (4 attempts left): dial tcp 172.18.0.2:5432: connect: connection refused
2023/02/01 08:34:45 [INFO] database_connect.go:20 dbConnect(): opening connection to postgres: postgres://postgres:redacted#db:5432/commento?sslmode=disable
2023/02/01 08:34:45 [ERROR] database_connect.go:31 dbConnect(): cannot talk to postgres, retrying in 10 seconds (3 attempts left): pq: unknown authentication response: 10
2023/02/01 08:34:55 [INFO] database_connect.go:20 dbConnect(): opening connection to postgres: postgres://postgres:redacted#db:5432/commento?sslmode=disable
2023/02/01 08:34:55 [ERROR] database_connect.go:31 dbConnect(): cannot talk to postgres, retrying in 10 seconds (2 attempts left): pq: unknown authentication response: 10
2023/02/01 08:35:05 [INFO] database_connect.go:20 dbConnect(): opening connection to postgres: postgres://postgres:redacted#db:5432/commento?sslmode=disable
2023/02/01 08:35:06 [ERROR] database_connect.go:31 dbConnect(): cannot talk to postgres, retrying in 10 seconds (1 attempts left): pq: unknown authentication response: 10
2023/02/01 08:35:16 [INFO] database_connect.go:20 dbConnect(): opening connection to postgres: postgres://postgres:redacted#db:5432/commento?sslmode=disable
2023/02/01 08:35:16 [ERROR] database_connect.go:31 dbConnect(): cannot talk to postgres, retrying in 10 seconds (0 attempts left): pq: unknown authentication response: 10
2023/02/01 08:35:26 [INFO] database_connect.go:20 dbConnect(): opening connection to postgres: postgres://postgres:redacted#db:5432/commento?sslmode=disable
2023/02/01 08:35:26 [ERROR] database_connect.go:35 dbConnect(): cannot talk to postgres, last attempt failed: pq: unknown authentication response: 10
fatal error: pq: unknown authentication response: 10
I haven't tried any solutions yet because I don't know where to start. How do I fix this?
Steps to reproduce:
On a clean Ubuntu 22.04LTS Server, installed docker and docker-compose.
Created a directory for the service and used the following configuration for docker-compose.yml :
version: '3'
services:
server:
image: registry.gitlab.com/commento/commento:SET_VERSION
ports:
- 8080:8080
environment:
COMMENTO_ORIGIN: http://commento.example.com:8080
COMMENTO_PORT: 8080
COMMENTO_POSTGRES: postgres://postgres:postgres#db:5432/commento?sslmode=disable
depends_on:
- db
db:
image: postgres
environment:
POSTGRES_DB: commento
POSTGRES_USER: postgres
POSTGRES_PASSWORD: postgres
volumes:
- postgres_data_volume:/var/lib/postgresql/data
volumes:
postgres_data_volume:
Ran docker-compose up -d and after that I followed the logs for both the services. The service "commento_server_1" produced the output mentioned above.

Answer 1

First, using registry.gitlab.com/commento/commento:SET_VERSION leads to the bellow error:
Pulling server (registry.gitlab.com/commento/commento:SET_VERSION)...
ERROR: manifest for registry.gitlab.com/commento/commento:SET_VERSION not found: manifest unknown: manifest unknown
because there is no release SET_VERSION of commento.
So you must have done something different. Please, next time you ask a question, make sure the instructions you provide to reproduce your issue are minimal and complete. See https://stackoverflow.com/help/minimal-reproducible-example
Anyway, I was able to reproduce your issue switching from commento:SET_VERSION to commento:latest. The issue you are facing is due to the fact that the latest release of commento (at the time of writing) doesn't support the latest release of postgres (at the time of writing).
The solution is to downgrade the postgres version to 13:
version: '3'
services:
db:
image: postgres:13
(keep other lines of your docker-compose.yml as they are).
Also, as future versions of commento may no longer support postgres 13. So when writing a docker-compose.yml, I would recommend always specifying the versions of all services:
services:
server:
image: registry.gitlab.com/commento/commento:v1.4.0