Wednesday, March 28, 2012

Finding Containers and Variables from Script task?

Hi,
* Here's my use case:
I have 20 odd event handlers in various containers that all do the exact same thing. Even though they're simple (a Script and an Execute SQL Task), its a right pain to copy them & keep them synced. I could probably create a custom task for the content of each handler, but I would still need to copy & configure it across 20 event handlers.
My (maybe impossible) idea to handle this was to:
Create a single event handler at the global scope. When invoked, use System::SourceID or System::SourceName to either
- GetContainer(SourceID).Variables("myVar") (had there been such a function call)
- Traverse the package object model to find the container, i.e:
Package.Executables(SourceName).Variables("myVar")
Is it true that there is no practical way of doing this?

* "Variables on the container ... are visible to the event handler that handles the event on that container"
As I understand it, this is only true when attaching an event handler to the specific container generating the event. If a container has no event handler, the event will propagate up through the hierarchy all the way to the package scope if needed. As soon as the event has propagated even once, the invoked event handler no longer has access to the local variables of the source container. Is this a reasonably correct description?
Event handlers and propagation would be _strikingly_ more useful if the handler had access to the source container environment that created the event, or am I missing something obvious?

* As a second possibility, can I create a _custom task_ (as opposed to a script) that _can_ traverse the object model of a package created in the designer (i.e. I'm not creating the whole package in my own code)?

If you lasted this long, thanks!-)
KI think I answered this on the NG, but the variables on the parent of the eventhandler that raised the event are visible to the event handler.
You can also create a package that handle the events and uses parent package configurations to pass in the values for the events. Then use an execute package task in all your event handlers that references that shared package.
Tasks cannot traverse the object model. They are prohibited and variables will refuse to hold a reference to IS object model objects with an error.|||Although I did implement using those 20 event handlers, I've now ditched that in favour of parsing the needed info out of sysdtslog90, which does away with the need for all those event handlers. Always a good feeling when stripping out half the 'code' but none of the functionalityBig Smile
Very useful to understand how & when to use the event handlers though, thanks!
K

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