Why use the legacy version of Python?

[cclauss]

Python 3 is more than 3,000 days old and more than 50% of the top 5,000 most used Python packages are Python 3 compatible, and Python 3.6 has great support of asyncio which is key to the Open Whisk approach.

100% of the packages in the Python execution environment have been ported to Python 3 with the exception of enum34 and ipaddress which are built into the Python 3 standard library.

[rabbah]

Bandwidth. We're happy to accept a pull request to add python 3 support.

[rabbah]

Duplicate of https://github.com/openwhisk/openwhisk/issues/1184.

[rabbah]

Closing as duplicate of above referenced issue.

[cclauss]

Reopened because of https://github.com/openwhisk/openwhisk/pull/2094

[csantanapr]

@cclauss both python 2 and 3 are enable, any errors or pain using python 3?

What's the actionable item here?

[rabbah]

@csantanapr it might be worth explaining and documenting why the python:default mode is python:2 not python:3 (as a result of @2094) - I suspect that's @cclauss' concern.

[csantanapr]

oh, yes If initial python support was done with python 3 instead of python 2, then having now default 3 would be fine.

But now we have users that written python 2 actions and have them in the system and using kind default, switching to python 3 as the default will cause them pain as there is high chance their code braking running on python 3 if they re-create/teardown-redeploy those actions.

So for now leaving python:2 as default and making clear in docs and other means to tell folks that now python 3 is available, that is recommended by the python community that python 3 is a better choice and that we are evaluating the option of making python 3 the default, so best practice and to protect your code be explicit which python you want when you create or update your action use python:2 and python:3 not default.

[rabbah]

for posterity, let me add:

--kind python continues to mean python:2. we added explicit kind options for python:2 and python:3 (via #1903). note that we did not have python:default until last week in master, so i don't think this is an issue (namely changing default to mean 2 vs 3).

instead, the real wrinkle is/was with respect to what kind does the CLI assume when creating python actions and no explicit kind is specified. in #1903, this was changed from python (meaning python:2) to python: default.

I favored the more focused change of making that python:2 and leaving python:default to mean python:3. but this would have been inconsistent with stripping all kinds from the CLI and using only family:default instead.

[rabbah]

It will be useful to document the plan to change/bump the default from 2 to 3, and get it rolling.

[cclauss]

Agreed. When Python 3 was released, the current version of Java was 6.0 and Swift and Node were not even released. Somehow OW defaults to Java 8 (~3 years old), Swift 3 (~6 months old), and Nodejs 6 (~6 months old) but does not default to a nine year old version of Python.

[rabbah]

@csantanapr i'll re-open with the action item being: let's make python:default mean python:3. will you drive this? if not, can you enumerate the steps you'd like to see done so someone can drive it?

[csantanapr]

@rabbah I would like someone more verse in python than me to drive this.

• [ ] Blog post "OW loves python 3 you should also" (tell folks about python 3, and about pinning)
• [ ] Discuss in dev list, get feedback from users on slack, when should the date be to allow folks using python 2 to migrate their code to python 3 or pinned to python:2. 1 month?, 2 months?, 3 months?
• [ ] Update Docs with section under python "Pinned to python:2 or python:3, python:default will switch from 2 to 3 on date x"

What you think @rabbah can you drive this, anything else to add to the list?

[rabbah]

@cclauss since you contributed the python 3 pr do you want to blog about it? If so we can mirror it on the openwhisk channel on medium.com.

As for python:default meaning 2 vs 3 I think this is a change we should just make. A brief discussion and quick vote on dev list should suffice. Because default for python didn't exist until a week ago.

I think we can then announce a date to change the inferred type from 2 to 3 - 1 month seems enough to me.

[cclauss]

Yes. I will take that action.