Monday, 4 February 2013

NOTE: Unable to Write to Template Store!

Sometimes you get into a habit that is so deep-seated that you don't realise you're doing it. I was just reminded of a little trick that I regularly use when editing ODS graphics templates.

A colleague of mine was using PROC TEMPLATE and getting the following (apparently) benign error in his log:

15 proc template;
16   edit styles.default as styles.defsize2;
17     style container / font_size=2;
18   end;
ERROR: Template 'Styles.Defsize2' was unable to write to template store!
19 run;

I say "benign" because the code that subsequently used styles.defsize2 worked fine. But we have a coding guideline that says that no errors are allowed in our team's code (not even benign ones!). He was struggling to make the error go away and was promoting the argument that benign errors should be permitted by our coding guidelines.

We discussed the message and what it meant. Templates, by default, are stored in an ITEMSTOR named SASUSER.TEMPLAT. My programmer's code was reading SASUSER.TEMPLAT.STYLES.DEFAULT and attempting to create a new style named SASUSER.TEMPLAT.STYLES.DEFSIZE2. The error message was saying he couldn't do that because DEFSIZE2 already existed. Why did it already exist? Because his code had worked without an error message the very first time he ran it - but he'd forgotten this fact.

So, it wasn't necessary to run the code every time because the DEFSIZE2 style already existed. Of course, each new programmer that ran the code had to run the PROC TEMPLATE once in order to create DEFSIZE2 in their own SASUSER library.

I proposed a slightly different approach: let's create the template in the work library each time the code was run. With this change, the code would run consistently for everybody, everytime.

Making this change is simple, we just need to change the default location for templates to be read from and written to. And the easiest way to do that is to add the WORK library to the ODS search path (adding it to the front of the search path). Specifically, we want to add an ITEMSTOR that's in the WORK library to the ODS search path. The ITEMSTOR need not exist before we write something to it - it'll be created automatically. We can use ODS PATH SHOW to demonstrate the effect:

15 ods path show;
Current ODS PATH list is:

16 ods path(prepend) work.templat(update);

17 ods path show;
Current ODS PATH list is:

The first call to ODS PATH SHOW shows us the two default ITEMSTORs, and then we see that we've added WORK.TEMPLAT to the head of the search path.

We don't need to change any other part of our code because all elements of ODS respect this search path.

So, we updated the code, got rid of the (not so) benign error message, and didn't make any changes to our coding guidelines. An interesting and informative exercise, demonstrating not just the ODS PATH for templates but also the wisdom of not allowing any error messages in SAS logs. The programmers in Cary put those messages in for a reason!

Oh, one more thing. You can use PROC DATASETS to see ITEMSTORs in your libraries, and you can view a list of templates with PROC TEMPLATE's LIST statement (see below), but I haven't figured-out a means of inspecting the content of an ITEMSTOR. Does anybody know how? I appreciate that the SAS Registry is an ITEMSTOR, and you can view that in PC SAS; but how do you view these things if they're on a server and you're using Enterprise Guide?

proc datasets lib=sasuser;

proc template;
  list ;

Answers on a postcard please...