Send email with Gitlab docker image - email

Question

Here's my goal, I would like to configure emails for my Gitlab server. I followed a lot of tutorials but I can't make it work.
My configuration is the following, I've got a reverse-proxy in a Docker container and my Gitlab server also in a Docker container.
About versions :
Docker version 17.09.0-ce, build afdb6d4
docker-compose version 1.16.1, build 6d1ac21
Here's my docker-compose.yml file
version: '3.3'
networks:
proxy:
external: true
internal:
external: false
services:
gitlab:
image: gitlab/gitlab-ce:latest
container_name: gitlab
environment:
- TZ=Europe/Paris
- GITLAB_TIMEZONE=Paris
- IMAP_USER=USER#GMAIL.COM
- IMAP_PASSWORD=MYGMAILPASS
- GITLAB_INCOMING_EMAIL_ADDRESS=USERGMAIL+%{key}#gmail.com
volumes:
- /srv/gitlab/config:/etc/gitlab
- /srv/gitlab/logs:/var/log/gitlab
- /srv/gitlab/data:/var/opt/gitlab
restart: always
labels:
- traefik.backend=gitlab
- traefik.frontend.rule=Host:git.domain.com
- traefik.docker.network=proxy
- traefik.port=80
- traefik.frontend.entryPoints=http,https
networks:
- internal
- proxy
I followed this tutorial which seems to be good :
https://github.com/sameersbn/docker-gitlab#available-configuration-parameters
I must miss something in my configuration but I can't figure out what is it ...
Does anyone can help me to configure email sending ? I don't know either the proper way to test email sending from GitLab.
Is the best way is to configure from docker-compose environment variables or directly from gitlab.rb file ?
Some help would be much appreciated

Answer 1

The instructions you followed are for a different docker image than the one you're actually using. You also set up IMAP, which is for receiving emails. In GitLab's case, it's for replying to issues by email.
What you want are the SMTP settings. The GitLab docker image does not come with sendmail installed, so you will have to follow the instructions here to set up SMTP in GitLab: https://docs.gitlab.com/omnibus/settings/smtp.html#example-configuration
You can dump gitlab.rb configuration right in your docker-compose under the environment section. My Fastmail setup for reference:
environment:
GITLAB_OMNIBUS_CONFIG: |
gitlab_rails['smtp_enable'] = true
gitlab_rails['smtp_address'] = "***"
gitlab_rails['smtp_port'] = 465
gitlab_rails['smtp_user_name'] = "***"
gitlab_rails['smtp_password'] = "***"
gitlab_rails['smtp_enable_starttls_auto'] = true
gitlab_rails['smtp_tls'] = true
gitlab_rails['smtp_openssl_verify_mode'] = 'peer'