Re: [sca-assembly] issue 243: is default channel configurable? Proposals

From
Eric Johnson <>
Date
2011-11-08T09:39:29+00:00
ID
Thread
Re: [sca-assembly] issue 243: is default channel configurable? Proposals
Hi Anish,

    

    On 11/8/11 8:52 AM, Anish Karmarkar wrote:
    I
      took an AI to provide two competing proposals for resolving issue
      243.
      

      

      Proposal 1: allow the default channel to be configurable.
      

      

      In section 5.9 of WD06, add the following --
      

      The default domain channel, like any domain channel, can be
      configured. Configuring the default domain channel requires one to
      deploy a domain composite containing a channel with the 'name'
      attribute value set to "/". Note that since the default domain
      channel always exists, configuring the default domain channel in a
      running system is equivalent to reconfiguring an existing channel
      and will be subject to restrictions and conditions imposed by a
      runtime on reconfiguration of domain channels.
      

    
    

    I was wondering whether you'd fall into the trap/pitfall you hit. I
    meant to send you an email reminder about that, but I forgot.

    

    This proposal doesn't work, because channel names are declared as "xs:NCName",
    and you can't name a channel "/". We had an issue
    about "/" in the names of channels.

    

    Perhaps something like this?

    The default domain channel, like any domain channel, can be
    configured. Note that how it is configured is determined by the
    implementation, because it cannot be deployed like other channels
    ("/" is not a valid channel name). Also note that since the default
    domain channel always exists, configuring the default domain channel
    in a running system is equivalent to reconfiguring an existing
    channel and will be subject to restrictions and conditions imposed
    by a runtime on reconfiguration of domain channels.

    

    Or, more simply:

    "This specification does not define any way to configure the default
    domain channel."

    

    [In any spec, what the spec explicitly or implicitly chooses not to
    define is, by implication, left to an implementation. I'm not sure
    we need to bludgeon readers with more words, or that they add value
    here.]

    

    I think, instead, if we wish for the default channel to have some
    spec'd way to be configured, then we have to come up with some
    spec'd way to name it, perhaps (borrowing from C) such as
    "__DEFAULT__".

    
      

      

      Proposal 2: do not allow the default channel to be configured.
      

      

      In section 5.9 of WD06, add the following --
      

      Since the default channel always exists, one is not allowed to
      deploy and configure the default channel using a domain composite.
      This does not prohibit runtimes from defining
      implementation-specific ways of statically or dynamically
      specifying configuration of the default channel.
      

    
    

    Given the fact that you cannot, as currently spec'd, name the
    default channel in order to deploy and configure, this new proposal
    just seems like a variation, "configuring the default channel is
    outside the SCA Assembly spec."

    

    
      

      

      Comments?
      

    
    Nope, none.

    

     ;-) 

    

    -Eric.

    
      

      -Anish
      

      --
      

      

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