<div dir="ltr"><div><div><div><div>hi brandon,<br><br></div>thanks for your answer.<br><br></div><div>my answers inline,<br><br></div><div></div> <br></div></div><div><div><div></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Aug 18, 2015 at 8:53 PM, Brandon Logan <span dir="ltr"><<a href="mailto:brandon.logan@rackspace.com" target="_blank">brandon.logan@rackspace.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr" style="font-size:12pt;color:#000000;background-color:#ffffff;font-family:Calibri,Arial,Helvetica,sans-serif">
<p>So let me make sure I understand this. You want to do a separate service plugin for what would normally be separate drivers under one service plugin. The reasons for this are:<br>
</p>
<p><br>
</p>
<p>1. You dont want users the ability to choose the type, you want it always to be the same one<br>
</p>
<p>2. Some types do want to be the source of truth of the data stored, instead of it being the service plugin database.<br>
</p>
<p><br>
</p>
<p>First, let me address the possibility of a solution using one service plugin and multiple drivers per type:<br>
</p>
<p><br>
</p>
<p>I think that you can overcome #1 in the instantiation of the service plugin to check if there are more than 1 provider active, if so you can just throw an exception saying you can only have 1. I'd have to look at it more to see if there are any caveats
to this, but I think that would work.<br>
</p>
<p><br>
</p>
<p>For #2, assuming #1 works, then the drivers that are defined can have some boolean that they set that will tell the plugin whether they are the source of truth or not, and depending on that you can store the data in the service plugin's db or just pass the
data along, also pass GET requests to the drivers as well.<br>
</p>
<p></p></div></blockquote><div><br></div><div>I agree that those workarounds will surely works but I wonder what is the meaning of a service plugin/type that can only support one service provider? can't the service plugin be the service provider directly? <br><br>The reasons why I'm considering this change are :<br><br>1. I'm not sure we would have some use cases
where we would be able to choose one bgpvpn backend independently from the provider of the core plugin (or a mech driver in the ML2 case)
and/or the router plugin.<br><div>If one use ODL to manage its core resources, he won't be able to use nuage or contrail to manage its bgpvpn connection. <br></div><div>The bgpvpn project is more about having a common API than having the capacity to mix backends. At least for the moment.<br></div><br>2.
I'm also considering that each plugin, which would be backend dependent, could declare what features it
supports through the use of extensions. Each plugin would be a "bgpvpn"
service type, and would implement the bgpvpn extension, but some of them
could extend the bgpvpn_connection resource with other extensions also
hosted in the bgpvpn project. Since some backends only support
attachment of networks to a bgpvpn_connection, others support attachment
of routers, and others both attachments, I'm considering having an extension for
each type of attachment. Then the bgpvpn plugin declares what extensions it
supports and the end user can act accordingly depending on the scan of
neutron extensions.<br></div><div>By moving to one plugin per backend, the load of extensions would be done by the neutron framework, natively. We won't have to scan each service providers to see what extensions it supports, as it is done by the ML2 extension manager.<br></div><div>But I agree that with your workaround, of allowing only one service provider, we can easily scan this driver for its extensions.<br></div><div><br></div><div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr" style="font-size:12pt;color:#000000;background-color:#ffffff;font-family:Calibri,Arial,Helvetica,sans-serif"><p><br>
</p>
<p>As for making a service plugin for each type, I don't see why that wouldn't work. It seems a bit overkill to me though because you'd probably end up having 2 base classes for every service plugin type, one for using the service plugin database and another
for the data source of truth being external. Probably a better way to do this, I'm sure I'm oversimplifying. </p></div></blockquote><div>You're right, and you're not oversimplifying. With this change, the
bgpvpn framework will only manage API extensions and the DB layer if
needed. And we don't want this framework to be complicated, in a first step, we just want to have a consistent API for every backends.<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr" style="font-size:12pt;color:#000000;background-color:#ffffff;font-family:Calibri,Arial,Helvetica,sans-serif"><p>I don't see much technical reasons why you couldn't do this, though. It's just inconsistent and might cause some confusion. I'd need to spend some
time on it to really have an educated opinion.<br>
</p>
</div></blockquote><div>The fact that this change will lead to inconsistency between usage of each service plugins is a valid point and might be enough to not do it and instead limiting the bgpvpn <span id="transmark"></span>service plugin to be able to only load one service driver for the moment. Which is also inconsistent with some other service plugins, but probably less.<br><br></div><div>thanks brandon.<br><br></div><div>Mathieu<br></div><div><br> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr" style="font-size:12pt;color:#000000;background-color:#ffffff;font-family:Calibri,Arial,Helvetica,sans-serif">
<p>Thanks,<br>
Brandon<br>
</p>
<div style="color:rgb(33,33,33)">
<hr style="display:inline-block;width:98%">
<div dir="ltr"><font style="font-size:11pt" color="#000000" face="Calibri, sans-serif"><b>From:</b> Mathieu Rohon <<a href="mailto:mathieu.rohon@gmail.com" target="_blank">mathieu.rohon@gmail.com</a>><br>
<b>Sent:</b> Tuesday, August 18, 2015 7:13 AM<br>
<b>To:</b> OpenStack Development Mailing List<br>
<b>Subject:</b> [openstack-dev] [Neutron][bgpvpn] Service Plugin vs Service driver</font>
<div> </div>
</div><div><div class="h5">
<div>
<div dir="ltr">Adding the related subject :)<span></span><br>
<div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Tue, Aug 18, 2015 at 10:35 AM, Mathieu Rohon <span dir="ltr">
<<a href="mailto:mathieu.rohon@gmail.com" target="_blank">mathieu.rohon@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div dir="ltr">
<div>
<div>
<div>
<div>
<div>Hi all,<br>
<br>
</div>
The current bgpvpn implementation is using the service type framework, with a service plugin and one or more service providers.<br>
</div>
<br>
After registering the bug [1], I wonder if we would rather use a service plugin per implementation type (bagpipe, ODL, OpenContrail, Nuage...) which handles API calls, instead of having one service plugin which forwards API calls to a service driver depending
on the provider chosen by the end user.</div>
<div><br>
</div>
I would like to better understand what would be the main drawbacks of such a move apart from the fact that a deployment would be tightly coupled to a bgpvpn plugin, and multiple implementations of the plugin couldn't coexist.<br>
<br>
</div>
Thanks,<br>
<br>
</div>
Mathieu<br>
<br>
[1]<a href="https://bugs.launchpad.net/bgpvpn/+bug/1485515" target="_blank">https://bugs.launchpad.net/bgpvpn/+bug/1485515</a><br>
<div>
<div>
<div></div>
</div>
</div>
</div>
</blockquote>
</div>
<br>
</div>
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</div>
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