Standardize import style

[c24t]

The google python style guide recommends against importing classes. This makes it clear which namespace defines each class, but is cumbersome and leads to ugly workarounds for common namespace names (e.g. ... import view as view_module).

Most modules have a consistent internal import style, but there's no consistent style across the library. We should decide whether to follow the style guide everywhere or break from it everywhere.

[reyang]

We might need to change the import path due to the refactoring work in #445 (potential breaking changes).

[kshithijiyer]

I feel standardizing imports as per pep8 standards would be better.
https://www.python.org/dev/peps/pep-0008/

[reyang]

@kshithijiyer would you explain why you would prefer pep8?

@c24t @lzchen @songy23 how do you think?

[kshithijiyer]

Pep8 standard in general improves code readability. Apart from that, it has now become the standard for python code. I would say that the standard mentioned in the previous comments is good but creates an issue when we actually import everything into the namespace. For example, if you wish to use randint function from random module following the previous standard says you can do an import random by doing so you actually import a lot of unnecessary functions which will never be used inside the namespace as well. Whereas pep8 says never to use from <module> import * which is the same as import <module>. Hence looking at this I personally feel it's better to use pep8 instead of going with any other standard.

[c24t]

We already follow PEP 8, this ticket is about consistently importing either classes or modules.

you actually import a lot of unnecessary functions which will never be used inside the namespace as well

Whether you import the module or individual functions/classes the import machinery creates the module object and executes the code, there's no reason to prefer importing individual functions/classes except personal style.

pep8 says never to use from <module> import * which is the same as import <module>

import * binds all names defined in the imported module, import foo binds the module object itself.

[dineshkrishnareddy]

hey @c24t @kshithijiyer @reyang can I work on this?

[reyang]

@dineshkrishnareddy definitely!
We kind of solved this issue in OpenTelemetry Python. It'll be great if you could help on OpenCensus.

FYI:

• https://github.com/open-telemetry/opentelemetry-python/blob/master/.isort.cfg
• https://github.com/open-telemetry/opentelemetry-python/blob/1968eedacdceec9856b75f60979391e38a8cb0e6/tox.ini#L58