Unions with multiple inputs when some input can be missing

[Ryan_Myers]

I have a real simple question that i can't seem to find the answer to.  I have several inputs and each input goes through its own transformation to get the data in the same format then the files are Unioned to get one output.  The problem is that sometime some of the inputs are missing and that prevents the workflow from running.  How can i build something that will return a message in the output that says that file was missing (while still returning the results for all the other files.  

I have attached a real simple workflow.  2 of the inputs exists but the third is missing.  In my main workflow there are 20 plus files and the file format is different for each which means there are different transformation steps between the input and the Union.  

[Ryan_Myers]

@mceleavey -It is a File Not found error.  Sometimes these files are completely missing in the folder (not just missing data).  So i need a way for the workflow to continue even if the file is missing. 

[mceleavey]

Can you show me, because now I'm really confused! The only file not found error you can get on a dynamic input is if you're pointing to a non-existent template file, and as I previously mentioned you need to just point that to a copy of the same files you're trying to load, so that can't happen unless you move that file.

The "Input Data Source Template file must exist. That just needs to be one of the older files you've already used. It needs to be the same schema.

Can you please show me the error?

[Ryan_Myers]

@mceleavey 

Ok,  that was the part i didn't really understand.  So your suggestion is to have one folder with all the possible input files and the dynamic input tool points to the files in that Folder.  Then have the Directory Tool point to where the actual real live files would be located.  I tried that in my workflow and now it is working as you described.  Many thanks for hanging with me through this.  

[mceleavey]

Hey, no problem at all, and yes, that's the approach. If you have one file for each input, you can use that as the template, then when are no files there should be no error. This will allow you to run the workflow with no files without it falling over.

M.