--- stage: none group: unassigned info: To determine the technical writer assigned to the Stage/Group associated with this page, see https://about.gitlab.com/handbook/engineering/ux/technical-writing/#assignments --- # Working with email in development ## Ensuring compatibility with mailer Sidekiq jobs A Sidekiq job is enqueued whenever `deliver_later` is called on an `ActionMailer`. If a mailer argument needs to be added or removed, it is important to ensure both backward and forward compatibility. Adhere to the Sidekiq steps for [changing the arguments for a worker](sidekiq/compatibility_across_updates.md#changing-the-arguments-for-a-worker). The same applies to a new mailer method, or a new mailer. If you introduce either, follow the steps for [adding new workers](sidekiq/compatibility_across_updates.md#adding-new-workers). In the following example from [`NotificationService`](https://gitlab.com/gitlab-org/gitlab/-/blob/33ccb22e4fc271dbaac94b003a7a1a2915a13441/app/services/notification_service.rb#L74) adding or removing an argument in this mailer's definition may cause problems during deployment before all Rails and Sidekiq nodes have the updated code. ```ruby mailer.unknown_sign_in_email(user, ip, time).deliver_later ``` ## Sent emails To view rendered emails "sent" in your development instance, visit [`/rails/letter_opener`](http://localhost:3000/rails/letter_opener). [S/MIME signed](../administration/smime_signing_email.md) emails [cannot be currently previewed](https://github.com/fgrehm/letter_opener_web/issues/96) with `letter_opener`. ## Mailer previews Rails provides a way to preview our mailer templates in HTML and plaintext using sample data. The previews live in [`app/mailers/previews`](https://gitlab.com/gitlab-org/gitlab-foss/tree/master/app/mailers/previews) and can be viewed at [`/rails/mailers`](http://localhost:3000/rails/mailers). See the [Rails guides](https://guides.rubyonrails.org/action_mailer_basics.html#previewing-emails) for more information. ## Incoming email 1. Go to the GitLab installation directory. 1. Find the `incoming_email` section in `config/gitlab.yml`, enable the feature and fill in the details for your specific IMAP server and email account: Configuration for Gmail / Google Apps, assumes mailbox `gitlab-incoming@gmail.com`: ```yaml incoming_email: enabled: true # The email address including the %{key} placeholder that will be replaced to reference the # item being replied to. This %{key} should be included in its entirety within the email # address and not replaced by another value. # For example: emailadress+%{key}@gmail.com. # The placeholder must appear in the "user" part of the address (before the `@`). It can be omitted but some features, # including Service Desk, may not work properly. address: "gitlab-incoming+%{key}@gmail.com" # Email account username # With third party providers, this is usually the full email address. # With self-hosted email servers, this is usually the user part of the email address. user: "gitlab-incoming@gmail.com" # Email account password password: "[REDACTED]" # 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 # The mailbox where incoming mail will end up. Usually "inbox". mailbox: "inbox" # The IDLE command timeout. idle_timeout: 60 # Whether to expunge (permanently remove) messages from the mailbox when they are deleted after delivery expunge_deleted: false ``` As mentioned, the part after `+` is ignored, and this message is sent to the mailbox for `gitlab-incoming@gmail.com`. 1. Read the [MailRoom Gem updates](#mailroom-gem-updates) section for more details before you proceed to make sure you have the right version of MailRoom installed. In summary, you need to update the `gitlab-mail_room` version in the `Gemfile` to the latest `gitlab-mail_room` temporarily and run `bundle install`. **Do not commit** this change as it's a temporary workaround. 1. Run this command in the GitLab root directory to launch `mail_room`: ```shell bundle exec mail_room -q -c config/mail_room.yml ``` 1. Verify that everything is configured correctly: ```shell bundle exec rake gitlab:incoming_email:check RAILS_ENV=development ``` 1. Reply by email should now be working. ## Email namespace As of GitLab 11.7, we support a new format for email handler addresses. This was done to support catch-all mailboxes. If you need to implement a feature which requires a new email handler, follow these rules for the format of the email key: - Actions are always at the end, separated by `-`. For example `-issue` or `-merge-request` - If your feature is related to a project, the key begins with the project identifiers (project path slug and project ID), separated by `-`. For example, `gitlab-org-gitlab-foss-20` - Additional information, such as an author's token, can be added between the project identifiers and the action, separated by `-`. For example, `gitlab-org-gitlab-foss-20-Author_Token12345678-issue` - You register your handlers in `lib/gitlab/email/handler.rb` Examples of valid email keys: - `gitlab-org-gitlab-foss-20-Author_Token12345678-issue` (create a new issue) - `gitlab-org-gitlab-foss-20-Author_Token12345678-merge-request` (create a new merge request) - `1234567890abcdef1234567890abcdef-unsubscribe` (unsubscribe from a conversation) - `1234567890abcdef1234567890abcdef` (reply to a conversation) The action `-issue-` is used in GitLab as the handler for the Service Desk feature. ### Legacy format Although we continue to support the older legacy format, no new features should use a legacy format. These are the only valid legacy formats for an email handler: - `path/to/project+namespace` - `path/to/project+namespace+action` - `namespace` - `namespace+action` In GitLab, the handler for the Service Desk feature is `path/to/project`. ### MailRoom Gem updates We use [`gitlab-mail_room`](https://gitlab.com/gitlab-org/gitlab-mail_room), a fork of [`MailRoom`](https://github.com/tpitale/mail_room/), to ensure that we can make updates quickly to the gem if necessary. We try to upstream changes as soon as possible and keep the two projects in sync. Updating the `gitlab-mail_room` dependency in `Gemfile` is deprecated at the moment in favor of updating the version in [Omnibus](https://gitlab.com/gitlab-org/omnibus-gitlab/-/blob/master/config/software/mail_room.rb) (see [example merge request](https://gitlab.com/gitlab-org/omnibus-gitlab/-/merge_requests/5816)) and Helm Chart configuration (see [example merge request](https://gitlab.com/gitlab-org/build/CNG/-/merge_requests/854)). #### Rationale This was done because to avoid [thread deadlocks](https://github.com/ruby/net-imap/issues/14), `MailRoom` needs an updated version of the `net-imap` gem. However, this [version of the net-imap cannot be installed by an unprivileged user](https://github.com/ruby/net-imap/issues/14) due to [an error installing the digest gem](https://github.com/ruby/digest/issues/14). [This bug in the Ruby interpreter](https://bugs.ruby-lang.org/issues/17761) was fixed in Ruby 3.0.2. Updating the gem directly in the GitLab Rails `Gemfile` caused a [production incident](https://gitlab.com/gitlab-com/gl-infra/production/-/issues/4053) since Kubernetes pods do not run as privileged users. Note that Omnibus GitLab runs `/opt/gitlab/embedded/bin/mail_room` instead of `bundle exec rake` to avoid loading the older version. With a Kubernetes install, the MailRoom version has always been explicitly set in the Helm Chart configuration rather than the `Gemfile`. #### Preserving backwards compatibility Removing the `Gemfile` would break incoming e-mail processing for source installs. For now, source installs are advised to upgrade manually to the version specified in Omnibus and run `bin/mail_room` directly as done with Omnibus. We can reconsider this deprecation once we upgrade to Ruby 3.0. --- [Return to Development documentation](index.md)