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HBase, mail # dev - Declaring HBase Public API in 0.94


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Aleksandr Shulman 2013-04-08, 18:07
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Elliott Clark 2013-04-08, 20:49
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Ted Yu 2013-04-08, 21:24
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Todd Lipcon 2013-04-08, 21:50
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Enis Söztutar 2013-04-08, 22:07
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lars hofhansl 2013-04-08, 22:08
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Re: Declaring HBase Public API in 0.94
Todd Lipcon 2013-04-08, 22:55
The advantage of the annotations is that Tom White already did the work for
jdiff to ignore non-public classes over in Hadoop land. We could leverage
that work, whether we re-use the o.a.h.classification annotations or add
our own copies in org.apache.hbase.*.

-Todd

On Mon, Apr 8, 2013 at 3:08 PM, lars hofhansl <[EMAIL PROTECTED]> wrote:

> It seems we could just generally document that:
> - no RPC incompatibilities
> - no API breaking changes to any user facing classes (now we'll pay better
> attention to this)
> - best effort to keep coprocessor API changes backward compatible
>
> If - on the other hand - we wanted to automate API checks then we'd need
> tagging (either in form of an annotation or Javadoc)
>
> +1 on the javadoc tagging if you're willing to take than on. As other have
> said -1 on pulling Interface Audience in.
> Your set of classes looks good.
>
> -- Lars
>
>
>
> ________________________________
>  From: Elliott Clark <[EMAIL PROTECTED]>
> To: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> Sent: Monday, April 8, 2013 1:49 PM
> Subject: Re: Declaring HBase Public API in 0.94
>
> Please don't pull in @InterfaceAudience.  Keeping 0.2x compatibility was
> something that was hard won in 0.94, it would be a real shame to loose that
> now.
>
>
> On Mon, Apr 8, 2013 at 11:07 AM, Aleksandr Shulman <[EMAIL PROTECTED]
> >wrote:
>
> > Hi everyone,
> >
> > In light of all the conversation on compatibility, I wanted to float the
> > idea of documenting which Java packages, classes, and methods we want to
> > declare as being API compatible in 0.94.x. I'd like your input on:
> > 1. JavaDoc vs. using AudienceInterface
> > 2. What the javadoc notation should look like
> > 3. Which pieces of code should be tagged
> >
> > What do I mean by documenting API compatibility? That means that we
> suggest
> > the anyone building applications use specific methods because they would
> > continue to be both binary and RPC-compatible going forward. Any
> > application written, either running on a node of a cluster or on a remote
> > machine, would continue to work properly without recompile for all
> versions
> > of 0.94.x running on the cluster.
> >
> > *Benefits:*
> > It would prevent developers from using calls that are subject to change.
> > This would give developers more confidence in using the platform, which
> > will encourage more development on our platform.
> > 0.94 will still be with us for some time and I think the
> > better-late-than-never approach will save us pain down the road. Finally,
> > it would allow us to more easily verify that we are in fact API
> compatible.
> >
> > *Can we use AudienceInterface?*
> > HBase 0.94 can be compiled against both hadoop 0.2x, 1.x, and 2.0.x. In
> the
> > case of 0.2x, the AudienceInterface classes were not bundled. Therefore,
> we
> > cannot expect HBase 0.94 to support it. For that reason, I think JavaDoc
> > might be better.
> > On the other hand, perhaps we might just want to bundle AudienceInterface
> > with 0.94 going forward? Then we can have consistent annotations in 0.94,
> > 0.95, and 0.96 without worrying about the hadoop version.
> >
> > Please correct me if I'm wrong about any of the above.
> >
> > *Clarification of RPC compatibility:*
> > We care about RPC compatibility when we create clients that bundle their
> > dependency jars with them. These jars are used to form a request that is
> > executed on a remote machine (i.e. the cluster). If the cluster is
> upgraded
> > and no longer recognizes the command, then this will break RPC
> > compatibility.
> >
> > *Clarification of Binary compatibility:*
> > We care about binary compatibility when a client is created and compiled,
> > and the jars on which is depends change. It should still be able to form
> > requests using those jars. If the cluster is upgraded and the compiled
> > client code cannot find a method it was depending on to be there, we
> break
> > binary compatibility. A recent example is in 0.94.2, where the return

Todd Lipcon
Software Engineer, Cloudera
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Aleksandr Shulman 2013-04-09, 17:47
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Aleksandr Shulman 2013-04-16, 20:56
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Nick Dimiduk 2013-04-16, 21:14
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Aleksandr Shulman 2013-04-17, 18:01