BIND 10 #2835: add interface to get properties of datasrc clients from ClientList

[BIND 10 Development]

#2835: add interface to get properties of datasrc clients from ClientList
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            Reporter:  jinmei        |                        Owner:
                Type:  task          |  vorner
            Priority:  medium        |                       Status:
           Component:  data source   |  accepted
            Keywords:                |                    Milestone:
           Sensitive:  0             |  Sprint-20130319
         Sub-Project:  DNS           |                   Resolution:
Estimated Difficulty:  5             |                 CVSS Scoring:
         Total Hours:  0             |              Defect Severity:  N/A
                                     |  Feature Depending on Ticket:
                                     |  shared memory data source
                                     |          Add Hours to Ticket:  0
                                     |                    Internal?:  0
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Old description:

> subtask of #2830.  no dependency.
>
> We'll need some generic way of getting a list of data source clients
> with properties of "cache" in a `ClientList`.  That will be needed
> to decide whether we need to do "map" operation on a specific client,
> etc.
>
> First, we should introduce the name of client.  It would be the same
> as the data source type like "sqlite3", but can be configured.
> The names should be unique in the client list.
>
> Then, through an added method to `ClientList`, we'll get a
> (conceptual) list of following:
> - client name
> - cache is enabled or not
> - if cache is enabled, some cache-specific parameters. (this would
>   probably have to be opaque, maybe in the form of ConstElementPtr)
>
> Define a set of such info and add a method to `ClientList` so the
> caller can go through this conceptual list.

New description:

 subtask of #2830.  depend on #2832.

 See also the total design at http://bind10.isc.org/wiki/SharedMemoryIPC

 We'll need some generic way of getting a list of data source clients
 with properties of "cache" in a `ClientList`.  That will be needed
 to decide whether we need to do "map" operation on a specific client,
 etc.

 This will be a list of entries of `DataSourceStatus` as described in the
 design memo (structure name and member types are tentative; they should
 be reconsidered and fixed in this task).

 As for the data source name, see #2832.

 Define a set of such info and add a method to `ClientList` so the
 caller can go through this conceptual list.

--

Comment (by jinmei):

 (note: I've updated the description to match #2830.  Dependency on #2832
 is
 only for the concept of data source name, so we can probably complete this
 task
 without #2832).

-- 
Ticket URL: <http://bind10.isc.org/ticket/2835#comment:5>
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