Introduce common incoming email setup doc and new issue by email doc

doc/administration/index.md

@@ -89,18 +89,24 @@ created in snippets, wikis, and repos.
 - [Authentication/Authorization](../topics/authentication/index.md#gitlab-administrators): Enforce 2FA, configure external authentication with LDAP, SAML, CAS and additional Omniauth providers.
   - **(Starter/Premium)** [Sync LDAP](auth/ldap-ee.md)
   - **(Starter/Premium)** [Kerberos authentication](../integration/kerberos.md)
-- [Reply by email](reply_by_email.md): Allow users to comment on issues and merge requests by replying to notification emails.
-  - [Postfix for Reply by email](reply_by_email_postfix_setup.md): Set up a basic Postfix mail
-server with IMAP authentication on Ubuntu, to be used with Reply by email.
 - **(Starter/Premium)** [Email users](../tools/email.md): Email GitLab users from within GitLab.
 - [User Cohorts](../user/admin_area/user_cohorts.md): Display the monthly cohorts of new users and their activities over time.
 - **(Starter/Premium)** [Audit logs and events](audit_events.md): View the changes made within the GitLab server.
 - **(Premium)** [Auditor users](auditor_users.md): Users with read-only access to all projects, groups, and other resources on the GitLab instance.
-- [Reply by email](reply_by_email.md): Allow users to comment on issues and merge requests by replying to notification emails.
-  - [Postfix for Reply by email](reply_by_email_postfix_setup.md): Set up a basic Postfix mail
+- [Incoming email](incoming_email.md): Configure incoming emails to allow
+  users to [reply by email], create [issues by email] and
+  [merge requests by email], and to enable [Service Desk].
+  - [Postfix for incoming email](reply_by_email_postfix_setup.md): Set up a
+  basic Postfix mail server with IMAP authentication on Ubuntu for incoming
+  emails.
 server with IMAP authentication on Ubuntu, to be used with Reply by email.
 - [User Cohorts](../user/admin_area/user_cohorts.md): Display the monthly cohorts of new users and their activities over time.
 
+[reply by email]: reply_by_email.md
+[issues by email]: ../user/project/issues/create_new_issue.md#new-issue-via-email
+[merge requests by email]: ../user/project/merge_requests/index.md#create-new-merge-requests-by-email
+[Service Desk]: ../user/project/service_desk.md
+
 ## Project settings
 
 - [Container Registry](container_registry.md): Configure Container Registry with GitLab.

doc/administration/reply_by_email_postfix_setup.md

-# Set up Postfix for Reply by email
+# Set up Postfix for incoming email
 
 This document will take you through the steps of setting up a basic Postfix mail
-server with IMAP authentication on Ubuntu, to be used with [Reply by email].
+server with IMAP authentication on Ubuntu, to be used with [incoming email].
 
 The instructions make the assumption that you will be using the email address `incoming@gitlab.example.com`, that is, username `incoming` on host `gitlab.example.com`. Don't forget to change it to your actual host when executing the example code snippets.
 
@@ -329,10 +329,10 @@ Courier, which we will install later to add IMAP authentication, requires mailbo
 
 ## Done!
 
-If all the tests were successful, Postfix is all set up and ready to receive email! Continue with the [Reply by email](./reply_by_email.md) guide to configure GitLab.
+If all the tests were successful, Postfix is all set up and ready to receive email! Continue with the [incoming email] guide to configure GitLab.
 
 ---
 
 _This document was adapted from https://help.ubuntu.com/community/PostfixBasicSetupHowto, by contributors to the Ubuntu documentation wiki._
 
-[reply by email]: reply_by_email.md
+[incoming email]: incoming_email.md

doc/development/emails.md

@@ -18,6 +18,68 @@ See the [Rails guides] for more info.
 [previews]: https://gitlab.com/gitlab-org/gitlab-ce/tree/master/spec/mailers/previews
 [Rails guides]: http://guides.rubyonrails.org/action_mailer_basics.html#previewing-emails
 
+## 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.
+      # The placeholder can be omitted but if present, it must appear in the "user" part of the address (before the `@`).
+      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
+    ```
+
+    As mentioned, the part after `+` is ignored, and this will end up in the mailbox for `gitlab-incoming@gmail.com`.
+
+1. Uncomment the `mail_room` line in your `Procfile`:
+
+    ```yaml
+    mail_room: bundle exec mail_room -q -c config/mail_room.yml
+    ```
+
+1. Restart GitLab:
+
+    ```sh
+    bundle exec foreman start
+    ```
+
+1. Verify that everything is configured correctly:
+
+    ```sh
+    bundle exec rake gitlab:incoming_email:check RAILS_ENV=development
+    ```
+
+1. Reply by email should now be working.
+
 ---
 
 [Return to Development documentation](README.md)

doc/user/project/issues/create_new_issue.md

@@ -37,6 +37,28 @@ It opens a new issue for that project labeled after its respective list.
 
 ![From the issue board](img/new_issue_from_issue_board.png)
 
+## New issue via email
+
+*This feature needs [incoming email](../../../administration/incoming_email.md)
+to be configured by a GitLab administrator to be available for CE/EE users, and
+it's available on GitLab.com.*
+
+At the bottom of a project's issue page, click
+**Email a new issue to this project**, and you will find an email address
+which belongs to you. You could add this address to your contact.
+
+This is a private email address, generated just for you.
+**Keep it to yourself** as anyone who gets ahold of it can create issues or
+merge requests as if they were you. You can add this address to your contact
+list for easy access.
+
+Sending an email to this address will create a new issue on your behalf for
+this project, where the email subject becomes the issue title, and the email
+body becomes the issue description. [Markdown] and [quick actions] are
+supported.
+
+![Bottom of a project issues page](img/new_issue_from_email.png)
+
 ## New issue via Service Desk
 
 Enable [Service Desk](../service_desk.md) to your project and offer email support.
@@ -60,5 +82,5 @@ create issues for the same project.
 
 ![Create issue from group-level issue tracker](img/create_issue_from_group_level_issue_tracker.png)
 
-
-
+[Markdown]: ../../markdown.md
+[quick actions]: ../quick_actions.md

doc/user/project/merge_requests/index.md

@@ -142,6 +142,10 @@ those conflicts in the GitLab UI.
 
 ## Create new merge requests by email
 
+*This feature needs [incoming email](../../../administration/incoming_email.md)
+to be configured by a GitLab administrator to be available for CE/EE users, and
+it's available on GitLab.com.*
+
 You can create a new merge request by sending an email to a user-specific email
 address. The address can be obtained on the merge requests page by clicking on
 a **Email a new merge request to this project** button.  The subject will be

doc/user/project/service_desk.md

@@ -53,7 +53,7 @@ Service Desk is enabled on GitLab.com. If you're a
 [Silver subscriber](https://about.gitlab.com/gitlab-com/),
 you can skip the step 1 below; you only need to enable it per project.
 
-1.   [Set up reply by email][reply-by-email] for the GitLab instance. This must
+1.   [Set up incoming email][incoming-email] for the GitLab instance. This must
      support [email sub-addressing][email-sub-addressing].
 2.   Navigate to your project's **Settings** and scroll down to the **Service Desk**
      section.
@@ -119,7 +119,7 @@ does not count toward the license limit count.
 [ee-149]: https://gitlab.com/gitlab-org/gitlab-ee/issues/149 "Service Desk with email"
 [ee]: https://about.gitlab.com/products/ "GitLab Enterprise Edition landing page"
 [eep-9.1]: https://about.gitlab.com/2017/04/22/gitlab-9-1-released/#service-desk-eep
-[reply-by-email]: ../../administration/reply_by_email.md#set-it-up
+[incoming-email]: ../../administration/incoming_email.md#set-it-up
 [email-sub-addressing]: ../../administration/reply_by_email.md#email-sub-addressing
 [confidential]: ./issues/confidential_issues.md "Confidential issues"
 [akismet]: ../../integration/akismet.md