[ubuntu-cloud] Fwd: #part-handler
smoser at ubuntu.com
Wed Feb 13 00:16:13 UTC 2013
On Mon, 11 Feb 2013, Bo Shi wrote:
> Hi Folks,
> Is there a way to ensure that a particular custom part-handler is run
> as the very last component to execute?
In multipart input, part-handlers
* the method 'handle_part' with signature (data,ctype,filename,payload)
is the handler
* execute the handler initialization (cdata=__begin__) in the order they
* replace any existing handlers for the types they claim
* will immediately start handling any subsequent parts of the
type they're registered for.
* have handle_part called with cdata='__end__' called in undefined order
after all user-data content has been handled.
> We use EC2 UserData (augmented via Ubuntu's CloudInit) to install
> dependencies and have a relatively generic script to invoke
> ec2-bundle-vol. Due to us not being terribly sophisticated in
> controlling the part execution order of our multi-part UserData, we're
> somewhat constrained on the CloudInit features we can use. It would
> be straightforward to convert it to a part-handler plugin but, of
> course, this particular handler would have to execute last.
So, I'm kind of confused as to what "execute last" means here.
Where you wanting defined execution order of the handle_part with
To control order in which user-data is processed you should just need to
control the order in which it is created.
Does that make sense?
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