Question

Passing a list parameter to an FME workbench from the command line

  • 31 August 2021
  • 2 replies
  • 42 views
S

Hello,

 

I am passing in a list of values to a user parameter (eg: LGA LGATYPE ABBNAME). The user parameter is assigned to a parameter of ChangeDetector (Selected Attributes).

 

2021-08-31 17_58_42-ChangeDetector Parameters 

If I open the FME workbench and run it, the ChangeDetector recognises the parameter value passed as a list of attributes. It then uses those attributes to check for any differences between 2 datasets. That is as expected.

 

However, if I run the tool from the command line and pass in the attribute list as a parameter, (eg: LGA LGATYPE ABBNAME), ChangeDetector does not recognise it as a list and does not find any attribute based changes.

 

If I reduce the command line parameter down to just one attribute (eg: LGA) then it works.

 

The parameter is a list parameter:

 

2021-08-31 18_09_21-User Parameters for 'Main' 

Any thoughts on what might be going wrong?

2 replies

david_r
Rank
Userlevel 4

Make sure you have double quotation marks around the list of values, e.g.

--MATCHATTRS "LGA LGATYPE ABBNAME"

 

S

Thanks for the reply David.

 

Sorry, I should not have said 'command line'. I am calling this from a Python program and I am using ArcGIS Data Interoperability extension to access FME functionality.

 

The parameter is passed as a string. I am logging the parameter values using MessageLogger and if I use additional quotes then I can see those quotes as part of the parameter value, ie `_MATCHATTRS' has value `"LGA LGATYPE ABBNAME"' and it doesn't fix the ChangeDetector issue.

 

Looking at the parameter logs for both the FME workbench run and the Python run I cannot see any difference if values, which has me confused: `_MATCHATTRS' has value `LGA LGATYPE ABBNAME'. It kind of makes me feel like FME is not interpreting the parameter as a list but rather a single value, when passed through Python.

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