Reply by email

GitLab can be set up to allow users to comment on issues and merge requests by replying to notification emails.

Get a mailbox

Reply by email requires an IMAP-enabled email account, with a provider or server that supports email sub-addressing. Sub-addressing is a feature where any email to user+some_arbitrary_tag@example.com will end up in the mailbox for user@example.com, and is supported by providers such as Gmail, Yahoo! Mail, Outlook.com and iCloud, as well as the Postfix mail server which you can run on-premises.

If you want to use Gmail with Reply by email, make sure you have IMAP access enabled and allow less secure apps to access the account.

To set up a basic Postfix mail server with IMAP access on Ubuntu, follow these instructions.

Set it up

Omnibus package installations

Find the incoming_email section in /etc/gitlab/gitlab.rb, enable the feature, enter the email address including a placeholder for the key that references the item being replied to and fill in the details for your specific IMAP server and email account:

# Postfix mail server, assumes mailbox incoming@gitlab.example.com
gitlab_rails['incoming_email_enabled'] = true
gitlab_rails['incoming_email_address'] = "incoming+%{key}@gitlab.example.com"
gitlab_rails['incoming_email_host'] = "gitlab.example.com" # IMAP server host
gitlab_rails['incoming_email_port'] = 143 # IMAP server port
gitlab_rails['incoming_email_ssl'] = false # Whether the IMAP server uses SSL
gitlab_rails['incoming_email_email'] = "incoming"  # Email account username. Usually the full email address.
gitlab_rails['incoming_email_password'] = "[REDACTED]" # Email account password
gitlab_rails['incoming_email_mailbox_name'] = "inbox" # The name of the mailbox where incoming mail will end up. Usually "inbox".

# Gmail / Google Apps, assumes mailbox gitlab-incoming@gmail.com
gitlab_rails['incoming_email_enabled'] = true
gitlab_rails['incoming_email_address'] = "gitlab-incoming+%{key}@gmail.com"
gitlab_rails['incoming_email_host'] = "imap.gmail.com" # IMAP server host
gitlab_rails['incoming_email_port'] = 993 # IMAP server port
gitlab_rails['incoming_email_ssl'] = true # Whether the IMAP server uses SSL
gitlab_rails['incoming_email_email'] = "gitlab-incoming@gmail.com"  # Email account username. Usually the full email address.
gitlab_rails['incoming_email_password'] = "[REDACTED]" # Email account password
gitlab_rails['incoming_email_mailbox_name'] = "inbox" # The name of the mailbox where incoming mail will end up. Usually "inbox".

As mentioned, the part after + in the address is ignored, and any email sent here will end up in the mailbox for incoming@gitlab.example.com/gitlab-incoming@gmail.com.

Reconfigure GitLab for the changes to take effect:
```
sudo gitlab-ctl reconfigure
```
Verify that everything is configured correctly:
```
sudo gitlab-rake gitlab:incoming_email:check
```
Reply by email should now be working.

Installations from source

Go to the GitLab installation directory:
```
cd /home/git/gitlab
```

Find the incoming_email section in config/gitlab.yml, enable the feature and enter the email address including a placeholder for the key that references the item being replied to:

sudo editor config/gitlab.yml

# Postfix mail server, assumes mailbox incoming@gitlab.example.com
incoming_email:
  enabled: true
  address: "incoming+%{key}@gitlab.example.com"

# Gmail / Google Apps, assumes mailbox gitlab-incoming@gmail.com
incoming_email:
  enabled: true
  address: "gitlab-incoming+%{key}@gmail.com"

As mentioned, the part after + in the address is ignored, and any email sent here will end up in the mailbox for incoming@gitlab.example.com/gitlab-incoming@gmail.com.

Copy config/mail_room.yml.example to config/mail_room.yml:

sudo cp config/mail_room.yml.example config/mail_room.yml

Uncomment the configuration options in config/mail_room.yml and fill in the details for your specific IMAP server and email account:

sudo editor config/mail_room.yml

# Postfix mail server
:mailboxes:
  -
    # IMAP server host
    :host: "gitlab.example.com"
    # IMAP server port
    :port: 143
    # Whether the IMAP server uses SSL
    :ssl: false
    # Whether the IMAP server uses StartTLS
    :start_tls: false
    # Email account username. Usually the full email address.
    :email: "incoming"
    # Email account password
    :password: "[REDACTED]"

    # The name of the mailbox where incoming mail will end up. Usually "inbox".
    :name: "inbox"

    # Always "sidekiq".
    :delivery_method: sidekiq
    # Always true.
    :delete_after_delivery: true
    :delivery_options:
      # The URL to the Redis server used by Sidekiq. Should match the URL in config/resque.yml.
      :redis_url: redis://localhost:6379
      # Always "resque:gitlab".
      :namespace: resque:gitlab
      # Always "incoming_email".
      :queue: incoming_email
      # Always "EmailReceiverWorker"
      :worker: EmailReceiverWorker

    # Always "redis".
    :arbitration_method: redis
    :arbitration_options:
      # The URL to the Redis server. Should match the URL in config/resque.yml.
      :redis_url: redis://localhost:6379
      # Always "mail_room:gitlab".
      :namespace: mail_room:gitlab

# Gmail / Google Apps
:mailboxes:
  -
    # IMAP server host
    :host: "imap.gmail.com"
    # IMAP server port
    :port: 993
    # Whether the IMAP server uses SSL
    :ssl: true
    # Whether the IMAP server uses StartTLS
    :start_tls: false
    # Email account username. Usually the full email address.
    :email: "gitlab-incoming@gmail.com"
    # Email account password
    :password: "[REDACTED]"

    # The name of the mailbox where incoming mail will end up. Usually "inbox".
    :name: "inbox"

    # Always "sidekiq".
    :delivery_method: sidekiq
    # Always true.
    :delete_after_delivery: true
    :delivery_options:
      # The URL to the Redis server used by Sidekiq. Should match the URL in config/resque.yml.
      :redis_url: redis://localhost:6379
      # Always "resque:gitlab".
      :namespace: resque:gitlab
      # Always "incoming_email".
      :queue: incoming_email
      # Always "EmailReceiverWorker"
      :worker: EmailReceiverWorker

    # Always "redis".
    :arbitration_method: redis
    :arbitration_options:
      # The URL to the Redis server. Should match the URL in config/resque.yml.
      :redis_url: redis://localhost:6379
      # Always "mail_room:gitlab".
      :namespace: mail_room:gitlab

Edit the init script configuration at /etc/default/gitlab to enable mail_room:

sudo mkdir -p /etc/default
echo 'mail_room_enabled=true' | sudo tee -a /etc/default/gitlab

Restart GitLab:
```
sudo service gitlab restart
```

Verify that everything is configured correctly:

sudo -u git -H bundle exec rake gitlab:incoming_email:check RAILS_ENV=production

Reply by email should now be working.

Development

Go to the GitLab installation directory.
Find the incoming_email section in config/gitlab.yml, enable the feature and enter the email address including a placeholder for the key that references the item being replied to:
```
# Gmail / Google Apps, assumes mailbox gitlab-incoming@gmail.com
incoming_email:
  enabled: true
  address: "gitlab-incoming+%{key}@gmail.com"
```
As mentioned, the part after + is ignored, and this will end up in the mailbox for gitlab-incoming@gmail.com.