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Steve and Mark M then opened the discussion with the issue of python 2.  Mark asked if we were to remove python 2 from the containers, would it break anything in JEDI.  Steve V responded that it would break a few of his converter scripts in the ioda-converters repository but he and Mark O agreed that this would be easily remedied.  Travis commented that they have achieved identical results between their python 2 and 3 scripts for SOCA and commented that these could be used as templates for others to convert their applications in a way that doesn't change results. Mark O added that python installations typically include tools to convert python 2 scripts to python 3.

Yannick then asked the group if there is anyone that requires python 2.  There were no responses.  Mark then asked for the perspective of some visitors to our meeting that were joining us from NOAA/EMC/EIB.  Kate Friedman responded and said that they are in the process of converting their python 2 scripts to python 3 but they really just started with this.  She said they don't use much python so it is not a high priority.   Rahul added that ecflow uses python but this should be easy to update to python 3.  Stylianos confirmed that python3 is already available on WCOSS.  However, Cory said that the Cray still has python 2.  In an email, Arun Chawla (EIB) informed Mark M that "We are moving everything to Python 3.6. It will take some time but we are transitioning to that. It took a year but all the operational HPC platforms now have Python 3.6 and that was the delay in transitioning over. "


virtualenv works by having the user/developer specify a list of dependencies in a text file.   Rahul mentioned that, when running at operational centers, it may be necessary to get this pre-approved.  Steve H and Yannick asked how to know what packages are acceptable - is there is list somewhere?  Nobody was aware of one but it was mentioned that we should ask the EIB lead (Arun). Sarah K volunteered to check if the Navy also has restrictions on python packages.

There was general agreement that this strategy of using virtualenv to manage python dependencies is the best option.