Remove global variables

[AtomsForPeace]

An attempt to remove the global variables #117.

Any feedback or ideas?

I've been able to remove one pytest.mark.skip with these changes.

[codecov-io]

Codecov Report

Merging #140 into master will increase coverage by 0.07%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #140      +/-   ##
==========================================
+ Coverage   95.15%   95.22%   +0.07%     
==========================================
  Files           4        5       +1     
  Lines         454      461       +7     
  Branches       96       94       -2     
==========================================
+ Hits          432      439       +7     
  Misses          7        7              
  Partials       15       15

Impacted Files	Coverage Δ
sanic_openapi/spec.py	100% <100%> (ø)
sanic_openapi/swagger.py	94.69% <100%> (-0.4%)	⬇️

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[chenjr0719]

Hi @AtomsForPeace

Thanks for your contribution. I think this PR fixes the swagger._spec global variable very well. And, do you have any plans to fix other global variables? Should I approve and merge this PR first or waiting for other global variable fixes?

[AtomsForPeace]

@chenjr0719 Thanks. I think merging this now would be good. I've had a look at the other global variables and they're not as easy. I was thinking maybe doing something along the lines of this: https://flask.palletsprojects.com/en/1.1.x/patterns/appfactories/#factories-extensions

The issue would be backwards compatibility though.

What's your opinion on it?

[chenjr0719]

@AtomsForPeace Sorry for the delay. I agree with using the factory pattern to fix all global variables. And about backward compatibility, I would say maybe we can have a PoC first and this might help us to decide what is the better way to keep the compatibility.