How do you deal with empty or missing input files in Apache Pig?

Question

Our workflow uses an AWS elastic map reduce cluster to run series of Pig jobs to manipulate a large amount of data into aggregated reports. Unfortunately, the input data is

Answer 1

The approach I've been using is to run pig scripts from a shell. I have one job that gets data from six different input directories. So I've written a fragment for each input file.

The shell checks for the existence of the input file and assembles a final pig script from the fragments.

It then executes the final pig script. I know it's a bit of a Rube Goldberg approach, but so far so good. :-)