[openstack-dev] [openstack-sdk-php] Use of final and private keywords to limit extending

Matthew Farina matt at mattfarina.com
Tue Jun 24 00:53:39 UTC 2014


This is the follow-up after our conversation last week.

We should have goals to 1) enable a wide array of developers using PHP
to be successful and 2) to keep things as simple as possible.

In the meeting Jamie suggested the Symfony developers and supporting
community around that might be a representative sample of PHP
developers. I don't believe this is the case. There are a few reasons.

1. There are far more Wordpress developers than Symfony by far. I'm
not suggesting we follow the style of Wordpress but a Wordpress
developer shouldn't need to know the style of Symfony to use the SDK.
2. There are far more Drupal developers than Symfony ones. Drupal 7,
which is the current stable version, is far different in style. Drupal
8 is using Symfony but isn't borrowing all the Symfony coding styles.
For example, you're not going to find it using private or final.
3. I've worked in multiple proprietary PHP codebases over the years.
The styles there have been far reaching.

In PHP there isn't one style to rule them all. We need to enable
developers in all these camps to be successful.

There is an assumption we should make as well. We're not going to know
all the ways developers are going to want to use or extend the code.
There may even be organization reasons to stop people from telling us
everything.

If we assume we aren't going to know all the ways people will want to
use and extend the codebase and the wide array or developers using the
project keeping it simple might make it easier for all the camps to
use.

I like to think of this from the outside looking in rather than
someone building the SDK. The two uses that come to mind are:

1. A developer using the library in the SDK to manage services.
2. A developer in any of these camps extending the SDK.

After these two come the developer who is building the SDK.

Since this conversation centers on private and final usage I'm looking
at the #2 case here for developers in the long tail of PHP camps. I've
had the *opportunity* to work in some of these over the years.

I'm thinking in terms of extension use cases like (from my earlier email):

> 1. Someone needs to add functionality to a class but can't add it back
> upstream. That could be because they are in a hurry to get their app
> out and aren't concerned with contributing it or because the
> organization they work for won't let them release it in a timely
> manner or ever.
>
> 2. A vendor needs to extend a class to add functionality. For example,
> extending objet storage to add CDN support.

Given that, using final would block using inheritance which many
developers would want to use for both of these use cases. For example:

class ACMEObject extends Object {

  // Add support for custom extension or fix bug that can't go
upstream right now.

}

This is a way many will pursue and many would argue is legitimate.
Given that, I'd rather sidestep that conversation all together and try
to enable everyone to be successful. We can't dictate how they should
write code. There isn't agreement on "the right" way to do it.

The other space is with private methods. If we have private methods
and someone extends the code they don't have access to the private
methods. That means code duplication is going to happen around that.
We alleviate their pain by not having anything private.

Note, I'm positioning the user who wants to extend the code ahead of
those who develop the code. It's a matter of priority with end users
being higher than developers.

With that in mind, I've worked on software projects where we could use
semantic versioning, protected items (for the first type of user who
calls to objects as an API), simple design, and no use of private or
final without a problem.

If we were creating something designed to be used by Drupal developers
I would do things one way. If it were designed to be used by Wordpress
devs I would do things a different way. If it were designed to be used
by those who do things the Symfony way I would target it to fit there.
Since we want to cover all of these audiences and more let's make it
accessible to all of them.

At it's simplest we can have interfaces that define things and then
check against the interfaces. Then we have objects which provide a
default implementation and building blocks. Users use those building
blocks at their own risk.

For example, we have the class Object.

$o = new Object('http://endpoint');
$o->setContainer('foo');
$o->setPath('bar/baz');
$o->load();

Now we have a loaded object. If someone wants to extend this to create
ACMEObject they can. As long as interfaces are followed behavior will
work.

Now, there is the case for internal methods in our implementation we
might want to change. We avoid making changes. If we must we use
semantic versioning. This is to prioritize our users.

The library in an SDK isn't exciting work. It's not a framework or
some fantastic application. It helps a wide variety of others do that
while consuming our services.

I can imagine there will be disagreement to this. If someone has a
different view please frame it in terms of the end users, use cases,
and other context. This is about solving problems and enabling users
to be successful over a particular sub-style in the PHP community.

Cheers,
Matt




On Mon, Jun 16, 2014 at 5:16 PM, Matthew Farina <matt at mattfarina.com> wrote:
> Before I dig into the meat of my response, something occurred to me
> that's contextually significant.
>
> PHP is a flexible language. There are numerous ways to do the same
> thing and the language is open enough that those who have differing
> opinions on style and patterns can implement projects their way. When
> we often talk about software we talk about libraries to bring a
> feature. For example, if two or more people want to write a UUID
> library using different styles they can.
>
> The OpenStack PHP SDK isn't about the library itself but rather a pass
> through to the services. Ideally, where there are multiple UUID
> libraries with different patterns we wouldn't have that for the
> OpenStack SDK. It should be flexible enough to fit into multiple
> schemes rather than opinionated to one or two of the different
> philosophies.
>
> Entirely unrelated, there is an interesting post on structure that
> just came out at
> http://technosophos.com/2014/06/13/don-t-shrink-wrap-bananas.html
> (it's about software with shrink wrapping bananas as an illustration).
>
> We need to keep in mind that many of the uses of the SDK will not be
> open source projects. It might be something like a web app that takes
> advantage of OpenStack APIs but itself is not open source. The license
> allows for this. With that in mind and the two use cases I previously
> shared... I reached out to a number of different people in different
> software camps...
>
> No one suggested we use private or final. Even those who sometimes use
> it in their own code. If someone in their app wants to extend one of
> our classes that's fine and on them. Some folks do alterations that
> way so why not let them at their own risk.
>
> Larry Garfield had an interesting suggestion last week that someone
> else suggested to me today as well... have public methods for the
> public APIs to a class. For internal methods that are not public, mark
> them with the @internal annotation. Symfony and Drupal are doing this.
> It's an informal notation. I'm told that toolchains like .NET formally
> support this so you don't see the use of things like final and private
> so much anymore.
>
> If we wanted to protect internal methods/properties from outside
> calling make then protected.
>
> If they change something that's internal they do so at their own risk.
>
> If we define interfaces with clear ins and outs where everything holds
> to them this shouldn't be that much of a big deal either.
>
> If we keep things fairly simple, defined with interfaces, and reusable
> this shouldn't be a problem.
>
> When I asked a wide array of people about this topic without giving an
> opinion I was surprised how many had similar ideas.
>
> Thoughts?
>
> - Matt
>
>
> On Thu, Jun 12, 2014 at 4:12 PM, Matthew Farina <matt at mattfarina.com> wrote:
>> I'm looking over this and reaching out to some folks (e.g., I just chatted
>> with Larry Garfield). Want to let you know that I'm reading the articles,
>> talking with others, and digging into this. I'll respond more after doing
>> some more legwork.
>>
>>
>> On Thu, Jun 12, 2014 at 4:37 AM, Jamie Hannaford
>> <jamie.hannaford at rackspace.com> wrote:
>>>
>>> To make some of my points less abstract, here’s the difference I’m talking
>>> about:
>>>
>>> https://gist.github.com/jamiehannaford/207c011a3cc45ff70e24
>>>
>>> One uses inheritance, the other takes advantage of composition and
>>> interface polymorphism. The second is way more flexible because: the App
>>> class only uses what it needs to (as opposed to being lumbered with dozens
>>> of parent methods it doesn’t want), and secondly it can accept any
>>> implementor of the interface - so it’s not tightly coupled to a specific
>>> implementation.
>>>
>>> An example of how inheritance can go wrong is in our current codebase: the
>>> RemoteObject and Object classes. One of them inherits the other and has to
>>> override lots of methods just to get things to work. The result is confusion
>>> and incoherence because you have no freedom and flexibility when inheriting
>>> classes with dozens of methods that do a very specific thing.
>>>
>>> I’m guessing that the vast majority of developers will want to access SDK
>>> behavior, not augment it. For those that do want the latter, all they need
>>> to do is access the behavior and modify it outside of the class using
>>> composition - picking the methods they want and modifying behavior
>>> externally. IMO, inheritance is not a requirement for this.
>>>
>>> Jamie
>>>
>>> On June 12, 2014 at 2:49:55 AM, Matthew Farina (matt at mattfarina.com)
>>> wrote:
>>>
>>> We've been talking a bit theoretically here. Let me try to jump in
>>> with two use cases.
>>>
>>> 1. Someone needs to add functionality to a class but can't add it back
>>> upstream. That could be because they are in a hurry to get their app
>>> out and aren't concerned with contributing it or because the
>>> organization they work for won't let them release it in a timely
>>> manner or ever.
>>>
>>> 2. A vendor needs to extend a class to add functionality. For example,
>>> extending objet storage to add CDN support.
>>>
>>> I've personally run into cases in codebases to do both of these. While
>>> I was sitting here I came up with multiple examples of both that I've
>>> experienced and seen.
>>>
>>> When I look at this SDK I look at the library in it as a collection of
>>> building blocks that can be swapped out and used together with some
>>> helper code to make it easily work together. One can have access to
>>> all the low level parts and use them or use a high level API and
>>> brings it together.
>>>
>>> PHP is a popular language. According to w3techs.com "PHP is used by
>>> 82.1% of all the websites whose server-side programming language we
>>> know". The style of extension you're talking about is used by a subset
>>> of PHP developers. Should we enable folks to extend this codebase the
>>> way they generally extend code or push them into extending this in a
>>> different manner from the other code they work with?
>>>
>>> You can allow for extension along multiple avenues and still have good
>>> design. A number of popular languages don't have the ability to use
>>> final or private. They have well designed apps and libraries without a
>>> problem.
>>>
>>> If we want to have something well designed we should have interfaces.
>>> Anything that implements those interfaces should be fine to use with
>>> anything that accepts them. We provide classes that handle the
>>> interactions with the services. They can be extended, replaced, or
>>> what not. As long as the class implements the interface with the other
>>> things that work with that interface it's fine.
>>>
>>> One thing did catch my attention. "we need to understand how and why
>>> users want to interact with, or augment, the functionality of our
>>> SDK". I don't think we'll ever be able to know all the ways people may
>>> want to extend things in the ways they are comfortable extending
>>> things. There is a wide array of things that this can happen. Trying
>>> to know all these things and control them will be difficult for them
>>> to use and us to support.
>>>
>>> - Matt
>>>
>>> On Tue, Jun 10, 2014 at 4:10 AM, Choi, Sam <sam.choi at hp.com> wrote:
>>> > To be clear, I don’t question his credentials as the blog post was quite
>>> > thorough and informative. I’m just pointing out that he may be writing
>>> > the
>>> > post primarily from the viewpoint of an enterprise developer.
>>> >
>>> >
>>> >
>>> > About the “nobody else is using it” argument, I guess I should have
>>> > clarified so my apologies. Linking back to my previous statement, I’m
>>> > saying
>>> > that there are occasionally different design philosophies and opinions
>>> > based
>>> > on the type of project. It has simply been my observation that the
>>> > enterprise applications I’ve dealt with did use ‘final’ for a number of
>>> > classes. As I mentioned, this makes sense since this is in the scope of
>>> > a
>>> > closed environment and the author is trying to enforce a constraint of
>>> > future developers who may edit legacy code many years later. So in this
>>> > context, sure, ‘final’ classes can prove to be useful.
>>> >
>>> >
>>> >
>>> > For open source APIs, final classes are used much more sparingly since
>>> > the
>>> > end goal should really be to allow other devs to make practical
>>> > applications
>>> > by using the API to suit their needs. Also, ‘better ways’ to allow
>>> > extensions are fairly subjective and based on a dev’s past experience
>>> > and
>>> > current project. As Matt mentioned, we need to help the typical PHP dev,
>>> > who
>>> > may naturally gravitate towards extending based on past experience. On
>>> > the
>>> > other hand, the top devs will find clever workarounds to suit their
>>> > needs.
>>> > So again, why enforce the end users to follow a specific and opinionated
>>> > design philosophy?
>>> >
>>> >
>>> >
>>> >
>>> >
>>> > From: Jamie Hannaford [mailto:jamie.hannaford at rackspace.com]
>>> > Sent: Tuesday, June 10, 2014 12:44 AM
>>> > To: Matthew Farina; Choi, Sam
>>> > Cc: Glen Campbell; OpenStack Development Mailing List (not for usage
>>> > questions); Shaunak Kashyap; Farina, Matt
>>> > Subject: RE: [openstack-sdk-php] Use of final and private keywords to
>>> > limit
>>> > extending
>>> >
>>> >
>>> >
>>> > I met Matthias a few weeks ago at PHP day in Verona and he really knows
>>> > his
>>> > stuff. I don’t think his work experience is relevance - just the clarity
>>> > and
>>> > applicability of his ideas. FWIW, he works closely with the folks at
>>> > Inviqa,
>>> > who are creating some of the best OSS in the PHP community. Like me,
>>> > they
>>> > value his opinion because it’s well-founded and generally applicable to
>>> > any
>>> > kind of software. Same goes with all the attendees who listen to his
>>> > talks.
>>> >
>>> >
>>> >
>>> > I don’t understand the “well nobody else is using it” argument. We
>>> > should
>>> > examine the merits of this proposal based on whether we deem it a good
>>> > design choice, not by looking over our shoulders.
>>> >
>>> >
>>> >
>>> > We are not constricting users here. There are better ways to allow
>>> > extendability that work much better than inheritance
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> > On June 10, 2014 at 9:34:38 AM, Choi, Sam (sam.choi at hp.com) wrote:
>>> >
>>> > Regarding use of the final keyword and limiting extending in general, a
>>> > few
>>> > thoughts below:
>>> >
>>> > - While I found the blog post about final classes to be informative, I'd
>>> > take it with a grain of salt. The author bills himself as a consultant
>>> > who
>>> > works with enterprise web applications. Briefly looking at his
>>> > background,
>>> > practically all his gigs were short consulting jobs. I don't see a track
>>> > record for open source projects so it would appear that his views are
>>> > likely
>>> > more applicable for enterprise developers working within closed systems.
>>> > - The Java community has already beaten this subject to death over the
>>> > past
>>> > decade. During recent years, it seems that the debate has waned. I
>>> > occasionally see enterprise Java devs use final to communicate their
>>> > intent
>>> > so that their system isn't butchered many years down the road when it
>>> > becomes poorly understood legacy code.
>>> > - On the other hand, I hardly ever see final classes in open source
>>> > code/APIs.
>>> > - Regarding future-proofing, I agree that it's easier to switch from
>>> > final
>>> > to not using final than the other way around. However, I've actually had
>>> > cases where I needed to extend a final class in an API and was simply
>>> > annoyed by the author's desire to control how I use the API. I also
>>> > understood that if the author were to change certain things, my
>>> > extension
>>> > may have to be refactored. That's a risk I'm certainly willing to take
>>> > to
>>> > get the job done.
>>> >
>>> > Thanks,
>>> > --
>>> > Sam Choi
>>> > Hewlett-Packard Co.
>>> > HP Cloud Services
>>> > +1 650 316 1652 / Office
>>> >
>>> >
>>> >
>>> > Jamie Hannaford
>>> > Software Developer III - CH
>>> >
>>> > Tel:
>>> >
>>> > +41434303908
>>> >
>>> > Mob:
>>> >
>>> > +41791009767
>>> >
>>> >
>>> >
>>> >
>>>
>>>
>>>
>>> Jamie Hannaford
>>> Software Developer III - CH
>>> Tel: +41434303908
>>> Mob: +41791009767
>>>
>>>
>>>
>>> -----Original Message-----
>>> > From: Matthew Farina [mailto:matt at mattfarina.com]
>>> > Sent: Monday, June 09, 2014 7:09 AM
>>> > To: Jamie Hannaford
>>> > Cc: Shaunak Kashyap; Glen Campbell; OpenStack Development Mailing List
>>> > (not
>>> > for usage questions); Choi, Sam; Farina, Matt
>>> > Subject: Re: [openstack-sdk-php] Use of final and private keywords to
>>> > limit
>>> > extending
>>> >
>>> > If you don't mind I'd like to step back for a moment and talk about the
>>> > end
>>> > users of this codebase and the types code it will be used in.
>>> >
>>> > We're looking to make application developers successful in PHP. The top
>>> > 10%
>>> > of PHP application developers aren't an issue. If they have an SDK or
>>> > not
>>> > they will build amazing things. It's the long tail of app devs. Many of
>>> > these developers don't know things we might take for granted, like
>>> > dependency injection. A lot of them may writing spaghetti procedural
>>> > code. I
>>> > use these examples because I've run into them in the past couple months.
>>> > We
>>> > need to make these folks successful in a cost effective and low barrier
>>> > to
>>> > entry manner.
>>> >
>>> > When I've gotten into the world of closed source PHP (or any other
>>> > language
>>> > for that matter) and work that's not in the popular space I've seen many
>>> > things that aren't clean or pretty. But, they work.
>>> >
>>> > That means this SDK needs to be useful in the modern frameworks (which
>>> > vary
>>> > widely on opinions) and in environments we may not like.
>>> >
>>> > The other thing I'd like to talk about is the protected keyword. I use
>>> > this
>>> > a lot. Using protected means an outside caller can't access the method.
>>> > Only
>>> > other methods on the class or classes that extend it.
>>> > This is an easy way to have an API and internals.
>>> >
>>> > Private is different. Private means it's part of the class but not there
>>> > for
>>> > extended classes. It's not just about controlling the public API for
>>> > callers
>>> > but not letting classes that extend this one have access to the
>>> > functionality.
>>> >
>>> > Given the scope of who our users are...
>>> >
>>> > - Any place we use the `final` scoping we need to explain how to extend
>>> > it
>>> > properly. It's a teaching moment for someone who might not come to a
>>> > direction on what to do very quickly. Think about the long tail of
>>> > developers and projects, most of which are not open source.
>>> >
>>> > Note, I said I'm not opposed to using final. It's an intentional
>>> > decision.
>>> > For the kinds of things we're doing I can't see all to many use cases
>>> > for
>>> > using final. We need to enable users to be successful without
>>> > controlling
>>> > how they write applications because this is an add-on to help them not a
>>> > driver for their architecture.
>>> >
>>> > - For scoping private and public APIs, `protected` is a better keyword
>>> > unless we are intending on blocking extension. If we block extension we
>>> > should explain how to handled overriding things that are likely to
>>> > happen in
>>> > real world applications that are not ideally written or architected.
>>> >
>>> > At the end of the day, applications that successfully do what they need
>>> > to
>>> > do while using OpenStack on the backend is what will make OpenStack more
>>> > successful. We need to help make it easy for the developers, no matter
>>> > how
>>> > they choose to code, to be successful. I find it useful to focus on end
>>> > users and their practical cases over the theory of how to design
>>> > something.
>>> >
>>> > Thoughts,
>>> > Matt
>>> >
>>> >
>>> > On Fri, Jun 6, 2014 at 10:01 AM, Jamie Hannaford
>>> > <jamie.hannaford at rackspace.com> wrote:
>>> >> So this is an issue that’s been heavily discussed recently in the PHP
>>> >> community.
>>> >>
>>> >> Based on personal opinion, I heavily favor and use private properties
>>> >> in software I write. I haven’t, however, used the “final” keyword that
>>> >> much.
>>> >> But the more I read about and see it being used, the more inclined I
>>> >> am to use it in projects. Here’s a great overview of why it’s useful
>>> >> for public
>>> >> APIs: http://verraes.net/2014/05/final-classes-in-php/
>>> >>
>>> >> Here’s a tl;dr executive summary:
>>> >>
>>> >> - Open/Closed principle. It’s important to understand that “Open for
>>> >> extension”, does not mean “Open for inheritance”. Composition,
>>> >> strategies, callbacks, plugins, event listeners, … are all valid ways
>>> >> to extend without inheritance. And usually, they are much preferred to
>>> >> inheritance – hence the conventional recommendation in OOP to “favour
>>> >> composition over inheritance”.
>>> >> Inheritance creates more coupling, that can be hard to get rid of, and
>>> >> that can make understanding the code quite tough.
>>> >>
>>> >> - Providing an API is a responsibility: by allowing end-users to
>>> >> access features of our SDK, we need to give certain guarantees of
>>> >> stability or low change frequency. The behavior of classes should be
>>> >> deterministic - i.e. we should be able to trust that a class does a
>>> >> certain thing. There’s no trust whatsoever if that behavior can be
>>> >> edited
>>> >> and overridden from external code.
>>> >>
>>> >> - Future-proofing: the fewer behaviours and extension points we
>>> >> expose, the more freedom we have to change system internals. This is
>>> >> the idea behind encapsulation.
>>> >>
>>> >> You said that we should only use private and final keywords if there’s
>>> >> an overwhelming reason to do so. I completely disagree. I actually
>>> >> want to flip the proposition here: I think we should only use public
>>> >> keywords if we’re CERTAIN we want to encourage and allow the
>>> >> inheritance of that class. By making a class inheritable, you are
>>> >> saying to the outside world: this class is meant to be extended. And
>>> >> the
>>> >> majority of times this is not what we want.
>>> >> Sure there are times when inheritance may well be the best option -
>>> >> but you can support extension points in different, often better, ways.
>>> >> Declaring explicitly what the extension points are is part of the
>>> >> contract your code has with the rest of the system. Final classes help
>>> >> to enforce this contract.
>>> >>
>>> >> To summarize, we have nothing to lose by favoring private and final
>>> >> keywords. We gain the above advantages, and if we later decide to open
>>> >> up that class as an extension point we can remove the keywords without
>>> >> any issues. Should a valid reason come up to open it up, it will be
>>> >> easy to do so, because nothing depends on it being closed. On the
>>> >> other hand, if you start by making everything open or inheritable, it
>>> >> will be very hard to close it later.
>>> >>
>>> >> Jamie
>>> >>
>>> >> On June 5, 2014 at 6:24:52 PM, Matthew Farina (matt at mattfarina.com)
>>> >> wrote:
>>> >>
>>> >> Some recent reviews have started to include the use of the private
>>> >> keyword for methods and talk of using final on classes. I don't think
>>> >> we have consistent agreement on how we should do this.
>>> >>
>>> >> My take is that we should not use private or final unless we can
>>> >> articulate the design decision to intentionally do so.
>>> >>
>>> >> To limit public the public API for a class we can use protected.
>>> >> Moving from protected to private or the use of final should have a
>>> >> good reason.
>>> >>
>>> >> In open source software code is extended in ways we often don't think
>>> >> of up front. Using private and final limits how those things can
>>> >> happen. When we use them we are intentionally limiting extending so we
>>> >> should be able to articulate why we want to put that limitation in
>>> >> place.
>>> >>
>>> >> Given the reviews that have been put forth I think there is a
>>> >> different stance. If there is one please share it.
>>> >>
>>> >> - Matt
>>> >>
>>> >>
>>> >>
>>> >> Jamie Hannaford
>>> >> Software Developer III - CH
>>> >> Tel: +41434303908
>>> >> Mob: +41791009767
>>> >>
>>> >>
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>>> > of America
>>> > Rackspace US, Inc privacy policy can be viewed at
>>> > www.rackspace.com/information/legal/privacystatement
>>> > -
>>> > Rackspace Limited is a company registered in England & Wales (company
>>> > registered number 03897010) whose registered office is at 5 Millington
>>> > Road,
>>> > Hyde Park Hayes, Middlesex UB3 4AZ.
>>> > Rackspace Limited privacy policy can be viewed at
>>> > www.rackspace.co.uk/legal/privacy-policy
>>> > -
>>> > Rackspace Benelux B.V. is a company registered in the Netherlands
>>> > (company
>>> > KvK nummer 34276327) whose registered office is at Teleportboulevard
>>> > 110,
>>> > 1043 EJ Amsterdam.
>>> > Rackspace Benelux B.V privacy policy can be viewed at
>>> > www.rackspace.nl/juridisch/privacy-policy
>>> > -
>>> > Rackspace Asia Limited is a company registered in Hong Kong (Company no:
>>> > 1211294) whose registered office is at 9/F, Cambridge House, Taikoo
>>> > Place,
>>> > 979 King's Road, Quarry Bay, Hong Kong.
>>> > Rackspace Asia Limited privacy policy can be viewed at
>>> > www.rackspace.com.hk/company/legal-privacy-statement.php
>>> > -
>>> > This e-mail message (including any attachments or embedded documents) is
>>> > intended for the exclusive and confidential use of the individual or
>>> > entity
>>> > to which this message is addressed, and unless otherwise expressly
>>> > indicated, is confidential and privileged information of Rackspace. Any
>>> > dissemination, distribution or copying of the enclosed material is
>>> > prohibited. If you receive this transmission in error, please notify us
>>> > immediately by e-mail at abuse at rackspace.com and delete the original
>>> > message. Your cooperation is appreciated.
>>>
>>> Rackspace International GmbH a company registered in the Canton of Zurich,
>>> Switzerland (company identification number CH-020.4.047.077-1) whose
>>> registered office is at Pfingstweidstrasse 60, 8005 Zurich, Switzerland.
>>> Rackspace International GmbH privacy policy can be viewed at
>>> www.rackspace.co.uk/legal/swiss-privacy-policy
>>> -
>>> Rackspace Hosting Australia PTY LTD a company registered in the state of
>>> Victoria, Australia (company registered number ACN 153 275 524) whose
>>> registered office is at Suite 3, Level 7, 210 George Street, Sydney, NSW
>>> 2000, Australia. Rackspace Hosting Australia PTY LTD privacy policy can be
>>> viewed at www.rackspace.com.au/company/legal-privacy-statement.php
>>> -
>>> Rackspace US, Inc, 5000 Walzem Road, San Antonio, Texas 78218, United
>>> States of America
>>> Rackspace US, Inc privacy policy can be viewed at
>>> www.rackspace.com/information/legal/privacystatement
>>> -
>>> Rackspace Limited is a company registered in England & Wales (company
>>> registered number 03897010) whose registered office is at 5 Millington Road,
>>> Hyde Park Hayes, Middlesex UB3 4AZ.
>>> Rackspace Limited privacy policy can be viewed at
>>> www.rackspace.co.uk/legal/privacy-policy
>>> -
>>> Rackspace Benelux B.V. is a company registered in the Netherlands (company
>>> KvK nummer 34276327) whose registered office is at Teleportboulevard 110,
>>> 1043 EJ Amsterdam.
>>> Rackspace Benelux B.V privacy policy can be viewed at
>>> www.rackspace.nl/juridisch/privacy-policy
>>> -
>>> Rackspace Asia Limited is a company registered in Hong Kong (Company no:
>>> 1211294) whose registered office is at 9/F, Cambridge House, Taikoo Place,
>>> 979 King's Road, Quarry Bay, Hong Kong.
>>> Rackspace Asia Limited privacy policy can be viewed at
>>> www.rackspace.com.hk/company/legal-privacy-statement.php
>>> -
>>> This e-mail message (including any attachments or embedded documents) is
>>> intended for the exclusive and confidential use of the individual or entity
>>> to which this message is addressed, and unless otherwise expressly
>>> indicated, is confidential and privileged information of Rackspace. Any
>>> dissemination, distribution or copying of the enclosed material is
>>> prohibited. If you receive this transmission in error, please notify us
>>> immediately by e-mail at abuse at rackspace.com and delete the original
>>> message. Your cooperation is appreciated.
>>
>>



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