3 ms·

Fully seconded, I just want to add for those of you in the asyncio world, aiohttp and FastAPI provide nearly identical APIs to requests and Flask (respectively)

Fully seconded, I just want to add for those of you in the asyncio world, aiohttp and FastAPI provide nearly identical APIs to requests and Flask (respectively), and for those of you familiar with these tools, they're a great way to be productive with asyncio almost immediately.

clintonc 4y ago
What's the advantage over using Flask's built-in support for async described here? https://flask.palletsprojects.com/en/2.1.x/async-await/ https://flask.palletsprojects.com/en/2.1.x/async-await/ This is an honest question; I don't know much about python async yet.
- heavyset_go 4y ago
  Flask still uses WSGI while other options use ASGI or other async interfaces.
- etimberg 4y ago
  Another advantage of FastAPI is the pydantic integration for data validation. That being said, I think FastAPI needs to find a community governance model because there are a lot of long-standing issues that the community has tried to fix only to find those fixes languishing with no official response.
  - whitey0101 4y ago
    Fastapi and sqlmodel both suffer from this (same author).
  - heavyset_go 4y ago
    What are some of the long-standing issues with FastAPI?
- maxbond 4y ago
  I wasn't aware of this support! That would certainly be a more natural choice if you were already familiar with Flask. To me the biggest advantage of FastAPI is the excellent integration with type hinting. It permeates the entire framework and makes things really productive. When I saw how you could use Pydantic models to define the schema of your request and response body, and then have that autogenerated into documentation - there was no going back. https://fastapi.tiangolo.com/tutorial/body/ https://fastapi.tiangolo.com/tutorial/body/ But I would like to stress that, though it has displaced Flask in my workflow, I think of FastAPI as a spiritual successor to Flask, and would never say an ill word about Flask.
  - maxbond 4y ago
    I looked at Flask's docs again for the first time in a few years. And I do miss having such industrial grade documentation for my framework. I miss it real bad.
  - aastronaut 4y ago
    except for the autogenerated docs, you can also make use of Pydantic in Flask easily to validate your models with Flask-Pydantic[0] [0]: https://github.com/bauerji/flask-pydantic https://github.com/bauerji/flask-pydantic
    - ramraj07 4y ago
      I’d still choose FastAPI for its dependency framework which is so much better than the god awful ‘g’.
- aenis 4y ago
  Flask async still uses individual workers for their "async views". So, suppose your db has a bad moment and freezes for 20 seconds. All your flask worker threads become frozen on this IO - say, you have 50 of them. Your backend will time out on the 50 requests and won't even accept the 51st. Depending on how you are hosted, you may begin to autoscale aggresively because your (limited) worker threads on every node are locked. If you get lots of request you will soon find yourself running with hundreds of nodes, all of them waiting for the DB to get unstuck - and costing you money. With a proper async framework, you will keep accepting all the requests as they come -- a single node can take thousands of those requests and time out on them gracefully, as they are just lightweight entries in the event loop, and you can have lots of those compared to # of worker threads. Of course, fully async framework requires all your code to be fully async, which in practice means minimizing the # of dependencies since its hard to trust them. And problems with SDKs, like for instance on GCP where Google keeps lacking async support (!) for most of their things. So with the "hybrid" async you get from Flask you can still choose to use sync code for some things and async for others.
dbcurtis 4y ago
Interesting. I have used Quart in the past for “Flask with asyncio support” and it was a great experience. Everything even played well with an asyncio MODBUS library that was part of the same project.
GOATS- 4y ago
Try httpx if you want an async web client has a more identical API to requests. https://www.python-httpx.org/ https://www.python-httpx.org/
- mmcnl 4y ago
  I learned about this thanks to you. Looks great.

clintonc 4y ago

What's the advantage over using Flask's built-in support for async described here? https://flask.palletsprojects.com/en/2.1.x/async-await/ https://flask.palletsprojects.com/en/2.1.x/async-await/ This is an honest question; I don't know much about python async yet.

heavyset_go 4y ago
Flask still uses WSGI while other options use ASGI or other async interfaces.
etimberg 4y ago
Another advantage of FastAPI is the pydantic integration for data validation. That being said, I think FastAPI needs to find a community governance model because there are a lot of long-standing issues that the community has tried to fix only to find those fixes languishing with no official response.
- whitey0101 4y ago
  Fastapi and sqlmodel both suffer from this (same author).
- heavyset_go 4y ago
  What are some of the long-standing issues with FastAPI?
maxbond 4y ago
I wasn't aware of this support! That would certainly be a more natural choice if you were already familiar with Flask. To me the biggest advantage of FastAPI is the excellent integration with type hinting. It permeates the entire framework and makes things really productive. When I saw how you could use Pydantic models to define the schema of your request and response body, and then have that autogenerated into documentation - there was no going back. https://fastapi.tiangolo.com/tutorial/body/ https://fastapi.tiangolo.com/tutorial/body/ But I would like to stress that, though it has displaced Flask in my workflow, I think of FastAPI as a spiritual successor to Flask, and would never say an ill word about Flask.
- maxbond 4y ago
  I looked at Flask's docs again for the first time in a few years. And I do miss having such industrial grade documentation for my framework. I miss it real bad.
- aastronaut 4y ago
  except for the autogenerated docs, you can also make use of Pydantic in Flask easily to validate your models with Flask-Pydantic[0] [0]: https://github.com/bauerji/flask-pydantic https://github.com/bauerji/flask-pydantic
  - ramraj07 4y ago
    I’d still choose FastAPI for its dependency framework which is so much better than the god awful ‘g’.
aenis 4y ago
Flask async still uses individual workers for their "async views". So, suppose your db has a bad moment and freezes for 20 seconds. All your flask worker threads become frozen on this IO - say, you have 50 of them. Your backend will time out on the 50 requests and won't even accept the 51st. Depending on how you are hosted, you may begin to autoscale aggresively because your (limited) worker threads on every node are locked. If you get lots of request you will soon find yourself running with hundreds of nodes, all of them waiting for the DB to get unstuck - and costing you money. With a proper async framework, you will keep accepting all the requests as they come -- a single node can take thousands of those requests and time out on them gracefully, as they are just lightweight entries in the event loop, and you can have lots of those compared to # of worker threads. Of course, fully async framework requires all your code to be fully async, which in practice means minimizing the # of dependencies since its hard to trust them. And problems with SDKs, like for instance on GCP where Google keeps lacking async support (!) for most of their things. So with the "hybrid" async you get from Flask you can still choose to use sync code for some things and async for others.

dbcurtis 4y ago

Interesting. I have used Quart in the past for “Flask with asyncio support” and it was a great experience. Everything even played well with an asyncio MODBUS library that was part of the same project.

GOATS- 4y ago

Try httpx if you want an async web client has a more identical API to requests. https://www.python-httpx.org/ https://www.python-httpx.org/

mmcnl 4y ago
I learned about this thanks to you. Looks great.