Make SDX Local Controller a WSGI app

[sajith]

Resolves #86.

[coveralls]

Pull Request Test Coverage Report for Build 9556400895

Details

• 0 of 10 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.3%) to 77.103%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
sdx_lc/app.py	0	10	0.0%

Totals
Change from base Build 9519814897:	-0.3%
Covered Lines:	978
Relevant Lines:	1215

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9558410474

Details

• 0 of 11 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.1%) to 77.273%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
sdx_lc/app.py	0	11	0.0%

Totals
Change from base Build 9519814897:	-0.1%
Covered Lines:	978
Relevant Lines:	1212

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9558450035

Details

• 0 of 11 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.1%) to 77.273%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
sdx_lc/app.py	0	11	0.0%

Totals
Change from base Build 9519814897:	-0.1%
Covered Lines:	978
Relevant Lines:	1212

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9568411630

Details

• 0 of 18 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 77.729%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
sdx_lc/app.py	0	18	0.0%

Totals
Change from base Build 9519814897:	0.3%
Covered Lines:	978
Relevant Lines:	1204

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9568543362

Details

• 0 of 19 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 77.671%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
sdx_lc/app.py	0	19	0.0%

Totals
Change from base Build 9519814897:	0.3%
Covered Lines:	978
Relevant Lines:	1205

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9568572969

Details

• 0 of 19 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 77.671%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
sdx_lc/app.py	0	19	0.0%

Totals
Change from base Build 9519814897:	0.3%
Covered Lines:	978
Relevant Lines:	1205

---

💛 - Coveralls

[coveralls]

Pull Request Test Coverage Report for Build 9570971840

Details

• 0 of 19 (0.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.3%) to 77.671%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
sdx_lc/app.py	0	19	0.0%

Totals
Change from base Build 9519814897:	0.3%
Covered Lines:	978
Relevant Lines:	1205

---

💛 - Coveralls

[YufengXin]

ASGI vs WSGI;

Flask vs. uvicorn vs. gunicorn

FastAPI vs. swagger UI

Please write a blog for educational purpose...

[sajith]

ASGI vs WSGI;

Flask vs. uvicorn vs. gunicorn

FastAPI vs. swagger UI

Please write a blog for educational purpose...

@YufengXin Is that a request meant for me?

🙈 🙉 🙊

[YufengXin]

@sajith Yes-:) I assume you're moving to upgrade sdx-controller too?
The justification on the choice would be nice to be included in the annual report.

[sajith]

This is already done on sdx-controller.

For production usage, using Flask's built-in web server directly is not a good idea, since it is single threaded and synchronous. It is good enough during development, but it just not meant to be used in production. It should be used in conjunction with a WSGI server (Gunicorn, uWSGI), since it is more secure, scalable, and can work with reverse proxy web servers (such as nginx or caddy, which we will need for SSL termination).

ASGI is essentially the updated version of WSGI that understands async/await. We are not quite there, but I liked uvicorn, which is an ASGI server, enough to make our app sort-of-ASGI with WsgiToAsgi() adaptor. We can always switch to gunicorn or uWSGI or something else if we need to do so.

[YufengXin]

The first part is clear as we always do.

I don't know much about ASGI. So the key is the wsgi_to_asgi converter. as my naive understanding is that FASTAPI is to ASGI as Flask to WSGI. But somebody on Internet said Flask2.0 supports ASGI....

Nice upgrade. I'll read more into it.

[sajith]

FastAPI is an alternative to connexion and Flask, if I understood correctly. It probably would be nicer too, but it is also very likely to come with its own set of limitations.

Since the choice has already been made, and since we're somewhat familiar with Flask and connexion, and since there is a cost (time and opportunity) to switching, I am of the opinion that we should continue working with the current setup. Unless there is a good reason to switch to something else, of course. :-)

[sajith]

Also the WsgiToAsgi() call is really optional. We can simply remove that line and use gunicorn instead of uvicorn and forget that we ever tried to use an ASGI server.

[YufengXin]

Totally agree. Let's keep it this way, because you made it work well-:)

[sajith]

Thank you. There's more to be done, of course. :-)