Yes the tuple binding approach you suggest is the one we at ApacheDS
have been experimenting with. One that also notifies all runtime Config
Admin instances of changes to the persisted configurations.
thanks for clarifying this issue,
John Conlon
Verticon, Inc.
BJ Hargrave wrote:
The spec was written with a single OSGi runtime in mind. In your case with
multiple OSGi runtime, the binding should be between a Configuration and a
(location, OSGi runtime) tuple. So within a specific OSGi runtime, there
is a 1..1 mapping between a Configuration and a location. But across a set
of OSGi runtimes, a Configuration is bound to a unique location within
each OSGi runtime.
This means your ConfigAdmin impl will need to persist the Configuration
<--> (location, OSGi runtime) mappings and if the Configuration is
modified, make all the necessary calls in each OSGi runtime.
BJ Hargrave
Senior Technical Staff Member, IBM
OSGi Fellow and CTO of the OSGi Alliance
[EMAIL PROTECTED]
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"John E. Conlon" <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED]
01/22/2007 10:46 AM
Please respond to
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Peter Kriens <[EMAIL PROTECTED]>
cc
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Subject
Re: [osgi-dev] Configuration Admin and Bundle Location
Your right when the Configuration object is created it can be bound to a
bundleLocation or not (left null). But when a Configuration Target
(ManagedService or ManagedServiceFactory) registers and the
bundleLocation of its matched configuration is found to be null. (ie
not bound) Then its bundleLocation is bound dynamically to the
configuration.
104.12.3 says: "In this scenario the Configuration Object must become
bound to the first bundle that registers a ManageService (or
ManagedServiceFactory) with the right PID."
If a second bundle in the same or a different OSGi runtime tries to
register a bundle that also utilizes the same configuration data (same
ServicePID) 'an error should be logged and that the registering bundle
should only be given a null'.
104.4.1 : "If a Managed Service is registered with a PID that is already
bound to another location, the normal callback to ManagedService.updated
must not take place."
On the other hand this binding is set to null when the bundle is
unregistered from the runtime, but this still limits the configuration
to a one at a time binding.
So if I have a enterprise directory server that I wish to use to serve
up configurations to OSGi applications throughout the enterprise. I
will not be able to have more than one bundle registering and bound to
each configuration. Effectively limiting the enterprise directory to
service one application instance at a time. If I needed N number of
instances of an application deployed through out an enterprise I would
need a number of configurations on the directory server equal to the
number of expected concurrent configuration targets. In other words
ConfigurationAdmin is constrained to a 1..1 relationship of concurrent
configuration targets to persisted configurations.
Perhaps I am overlooking a workaround somewhere?
cheers,
John
Peter Kriens wrote:
First the location binding is option, if it is set to null, it no
longer plays a role.
I am not sure I can follow your logic. Could you give a concrete use
case that seems impossible to you? I do not think a backend is in any
way constrained.
Kind regards,
Peter Kriens
JEC> Section 104.15.2.8 of the R4 for Configuration Admin, specifies
that
JEC> bundle locations can be be bound at configuration creation time to
JEC> persisted Configuration entities. Does 'bound' mean that this
value
JEC> should be persisted along with the configuration data?
JEC> Section 104.4.1 specifies how Configuration Target bundles should
be
JEC> bound dynamically on registration to Configuration objects.
JEC> These location binding requirements seem to constrain the
Configuration
JEC> Admin to offer only a 1..1 relationship between a persisted
JEC> configuration entity and a single configuration target instance. As
I
JEC> understand it the spec also seem to rule out the use case where an
JEC> organization wishes to use a common Enterprise Store as a central
JEC> configuration repository for persisted entities serving N number of
JEC> configuration targets on multiple osgi runtimes. (1..n
relationship
JEC> between persisted entities and configuration targets.)
JEC> Is this the intention? If so, how could the 1..n use case I
describe be
JEC> accomplished?
JEC> thanks for any clarification,
JEC> John Conlon
JEC> Verticon, Inc.
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