Thanks Nuno, sorry we were a bit overrun when you emailed.
I had some questions in today's meeting, mostly around the relationship
with global workspace. Andrea was able to clarify the user story, and that
makes sense to me.
Is there any reason to make this a separate setting? Would "turning off"
global be enough to enable this functionality?
I am not too sure about CatalogCapabilities, I understand that the it is a
common design we use to allow implementations to negotiate what
functionality they support. It always makes me uncomfortable, breaking
encapsulation and forcing the use of conditional code. Is there a
possibility of better defining a method to avoid introducing this new class?
--
Jody Garnett
On 31 October 2017 at 02:29, Nuno Oliveira <[email protected]>
wrote:
> Hi all,
>
> A few months ago I started a thread [1] about allowing the definition of
> several workspaces with the same namespace in GeoServer.
> The main (root) use case for this is to allow the publishing of the same
> complex feature type in GeoServer multiple times in different
> workspaces. I finally had time to restart this work and can now give a
> more concrete answers to some of the comments.
>
> The workspace and namespaces relationship boils down to how things are
> grouped together and stored in GeoServer catalog and the
> ability to retrieve them. Let's say that we have an arbitrary resource in
> GeoServer (layer, style, feature type, etc ...), that resource
> can be retrieved like this:
>
> 1. getResourceByName("layer1", ResourceType.class)
> 2. getResourceByName("workspace:layer1", ResourceType.class)
> 3. getResourceByName("{http:\\www.workspace.com}:layer1",
> ResourceType.class)
>
> The three ways above (there is more ways of doing this) are all valid ways
> of referencing the same resource. The workspace name
> and the workspace namespace are used interchangeably, this works fine
> because there is a one to one relationship between them.
> Some business code tend to use the workspace name, and other code like WFS
> tend to use the namespace to reference a catalog
> resource.
>
> The concept of isolated workspaces (or namespaces) allow us to define
> multiple workspaces with the same namespaces. The
> resources of an isolated workspace can only be accessed in the context of
> the virtual service of that workspace. Consider that
> we have two workspaces with the same namespace:
>
> 1. Prefix: ws1, URI: *http://www.gs.com <http://www.gs.com>*,
> Isolated: false
> 2. Prefix: ws2, URI: *http://www.gs.com <http://www.gs.com>*,
> Isolated: true
>
> And consider also that both workspaces have a feature type name
> *complex_feature*. In the catalog point of view all this invocations
> will return the feature_type belonging to first workspace:
>
> - getResourceByName("complex_feature", FeatureType.class)
> - getResourceByName("*ws1*:complex_feature", FeatureType.class)
> - getResourceByName("{*http://www.gs.com
> <http://www.gs.com>*}:complex_feature",
> FeatureType.class)
>
> Only this invocation will retrieve the feature type belonging to the
> isolated workspace (second one):
>
> - getResourceByName("*ws2*:complex_feature", FeatureType.class)
>
> If a resource is identified by its namespace URI the catalog will never be
> able to find that resource if it belongs to an isolated
> workspace, since the same namespace may be used by another workspace.
> That's why we can only retrieve the content of an
> isolated workspace from is virtual service, because if we are in the
> context of a certain virtual service we can automatically
> convert the namespace URI in a specific workspace name \ prefix.
>
> The catalog machinery is quite complex [1] with several wrappers and
> different catalog facades. To support workspaces isolation
> we had to bring the concept of workspace isolation to the catalog facade
> implementations and implement the necessary handling
> in the local catalog wrapper.
>
> The changes in the facade are really simple, *only one line of code* was
> changed in DefaultCatalogFacadeImpl, we just need to make
> sure that when we search a NameSpaceInfo by its URI namespaces that are
> tied to an isolated workspace are ignored. The issue is that
> if a particular catalog facade implementation doesn't do this change
> isolated workspaces are not correctly supported.
>
> To avoid backward compatibility issues I introduced the concept of
> CatalogCapabilities (similar to Query capabilities in GeoTools), unless
> a catalog facade or catalog implementation says explicitly that isolated
> workspaces are supported this functionality will be disabled. This
> can be reused to support the introduction of new catalog features and
> avoiding breaking existing implementations.
>
> The changes to support isolated workspaces are isolated int he catalog
> machinery and transparent to all the other business code. This
> is backward compatible and will not break existing implementations, of
> curse if someone is using its own catalog facade implementation
> isolated workspace will be disabled unless they implement the required
> business code.
>
> I have made some preliminary tests with WMS and WFS operations and
> everything seems to be working as expected.
>
> I hope this clarifies some of the doubts \ questions that were asked
> before.
>
> Cheers,
>
> [1] http://osgeo-org.1560.x6.nabble.com/Allowing-multiple-
> workspaces-to-use-the-same-name-space-URI-td5307302.html
> [2] https://docs.google.com/drawings/d/1AvCBi4yyJQ60cCKcxSJkThom0tT9E
> pna8-mL31zS7Mo/edit?usp=sharing
>
> --
> Regards,
> Nuno Oliveira
> ==
> GeoServer Professional Services from the experts! Visit http://goo.gl/it488V
> for more information.
> ==
>
> Nuno Miguel Carvalho Oliveira
> @nmcoliveira
> Software Engineer
>
> GeoSolutions S.A.S.
> Via di Montramito 3/A
> 55054 Massarosa (LU)
> Italy
> phone: +39 0584 962313 <+39%200584%20962313>
> fax: +39 0584 1660272 <+39%200584%20166%200272>
> http://www.geo-solutions.ithttp://twitter.com/geosolutions_it
>
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