Not possible to import modules correctly while running Python within a Pig script

Products

• Services Suite

Issue/Introduction

This article discusses what to do when it is not possible to import modules correctly while running Python within a Pig script. 

When running a Python within a Pig script, the following error was seen:

• The wrong version of Python may be reported, for example, Python version 2.7.10 installed but when "sys.version" is run in Python, a different version is displayed, such as "2.5.3".

• Some modules may not import correctly:

ImportError: No module named json

Jython is being used with version 2.5.3 and does not contain the same number of modules as standard Python distributions.

Environment

Product Version: 3.0

Resolution

Review the Pig script and confirm that Jython is being used. For example, this line runs the Python script utils.py via Jython:

REGISTER './utils.py' using jython as utils; 

Review Jython documentation to add the required module into Jython.

Note: Upgrading to Jython 2.7 will likely help as extra modules are included, such as the JSON module from the example above.