The spec of Zaqar mail delivery

This work is aimed to enable Zaqar to send email subscription
without the third part tools.

Change-Id: Id775c3dae4ee92198cf1bb9e20f5f83e3ad27e44
implements: blueprint zaqar-email-delivery

specs/stein/email-notification-by-internal-tool.rst

@@ -0,0 +1,136 @@
+..
+     This work is aimed to implement zaqar email delivery
+ through smtp service,and Chinese translation support.
+
+Support zaqar_sendmail
+==================================
+
+https://blueprints.launchpad.net/zaqar/+spec/zaqar-email-delivery
+
+Problem description
+===================
+
+Currently the email subscription in Zaqar relay on the third part tools, such
+as "sendmail". It means that deployer should install it out of Zaqar. If he
+forgets, Zaqar will raise internal error. This work let Zaqar support email
+subscription by itself using the ``smtp`` python library.
+
+Use Cases
+---------
+
+The modification enables users to send email subscriptions without the third
+part tools.
+
+Proposed change
+===============
+
+A new config option ``smtp_mode`` will be added, it has two value choices,
+["third_part", "self_local"]. ``third_part`` means Zaqar will use the tools
+from which ``smtp_command`` config option provides to send email subscription.
+``self_local`` means Zaqar will use the ``smtp`` python library instead.
+
+A email template file will be added as well. Some parameters in the file should
+be configured firstly before using. Those parameters include something like
+smtp service account/passwrod, smtp service address and so on. These value
+should come from config options as well.
+
+The email body in the template file should be configured as well. Currently,
+it can only be managed by operators out of Zaqar. In the future, we can use
+jinja template way to let it be configurable by Zaqar.
+
+Once ``self_local`` is used, Zaqar will fill up the template file first, then
+use ``stmp`` lib to send the email subscription.
+
+Alternatives
+------------
+
+None
+
+
+REST API impact
+---------------
+
+None
+
+Security impact
+---------------
+
+None
+
+Notifications impact
+--------------------
+
+None
+
+
+Other end user impact
+---------------------
+
+None
+
+Performance Impact
+------------------
+
+None
+
+Other deployer impact
+---------------------
+
+A new config option called ``smtp_mode`` is added. To keep backward
+compatibility the default behavior is keeping use third part tools to send
+email subscription. If you don't want to install the third part email tools
+anymore, please change its value to ``self_local``.
+
+Developer impact
+----------------
+
+None
+
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+changyufei<changyufei@unitedstack.com>
+
+Work Items
+----------
+
+1. Add a new config option ``smtp_mode``
+2. Add the email template
+3. Add the logic to use ``smtp`` python lib
+4. The test code should be added.
+5. Document.
+
+Milestones
+----------
+
+R-3
+
+
+Dependencies
+============
+
+None
+
+Testing
+=======
+
+For functional test, here is no good way to test it in Upstream since
+OpenStack CI/CD environment doesn't has a email service. Or we may ask the
+community for help to give Zaqar team a test account within @openstack.org
+email system. Or any other third part company can provide one for us. Otherwise
+we could only test it locally to make sure it works well.
+
+
+Documentation Impact
+====================
+
+A new send email way will be added. It should be documented.
+
+References
+==========
+
+None

specs/stein/index.rst

@@ -5,3 +5,5 @@
 .. toctree::
    :glob:
    :maxdepth: 2
+
+   email-notification-by-internal-tool