Bill Fellows shows how to write out your intermediate Biml for debugging purposes:
Using tooling is always a trade-off between time/frustration and monetary cost. BIDS Helper/BimlExpress are free so you’re prioritizing cost over all others. And that’s ok, there’s no judgement here. I know what it’s like to be in places where you can’t buy the tools you really need. One of the hard parts about debugging the expanded Biml from BimlScript is you can’t see the intermediate or flat Biml. You’ve got your Metadata, Biml and BimlScript and a lot of imagination to think through how the code is being generated and where it might be going wrong. That’s tough. Even at this point where I’ve been working with it for four years, I can still spend hours trying to track down just where the heck things went wrong. SPOILER ALERT It’s the metadata, it’s always the metadata (except when it’s not). I end up with NULLs where I don’t expect it or some goofball put the wrong values in a field. But how can you get to a place where you can see the result? That’s what this post is about.
It’s a trivial bit of code but it’s important. You need to add a single Biml file to your project and whenever you want to see the expanded Biml, prior to it being translated into SSIS packages, right click on the file and you’ll get all that Biml dumped to a file. This recipe calls for N steps.
This is a good tip and has helped me a few times in the past.