Flask example gives ImportError

[MattKleinsmith]

Might be the only answer for now?

Approach: Downgrade.

How: Replace the entire contents of graphene-sqlalchemy/examples/flask_sqlalchemy/requirements.txt with:

flask-graphql==2.0.1
graphene==2.1.9
graphene-sqlalchemy==2.3.0

Original post

Hello,

I followed the README instructions for Example Flask+SQLAlchemy Project and I'm getting the following error:

ImportError: cannot import name 'get_default_backend' from 'graphql' (/home/mwk/code/graphene-sqlalchemy/.venv/lib/python3.9/site-packages/graphql/__init__.py)

My intention with this issue is to figure it out, documenting it for others, including a future me. Help is welcomed.

Upon pip install -r requirements.txt, I see this list of packages and versions (removed some probably-irrelevant ones:

"Successfully installed":

• Flask-GraphQL-2.0.0
• SQLAlchemy-1.4.46
• flask-2.2.2
• graphene-3.2.1
• graphene-sqlalchemy-3.0.0b3
• graphql-core-3.2.3
• graphql-relay-3.2.0
• graphql-server-core-1.1.1

Perhaps one of these versions is not the one I should be using.

I'm using Python 3.9.4, on WSL 2, Ubuntu 22.04.1 LTS, VS Code, pipenv shell.

Relevant discussions:

graphql-python/graphene#1086
https://stackoverflow.com/questions/70204957/flask-graphql-import-fails
#348
graphql-python/graphql-server#29
graphql-python/flask-graphql#66

[MattKleinsmith]

Someone suggested upgrading Flask-GraphQL to 2.0.1, here:

https://stackoverflow.com/questions/70204957/flask-graphql-import-fails

I'll try it.

"Successfully installed":

• Flask-GraphQL-2.0.1
• graphql-core-2.3.2
• rx-1.6.3

Now the error is:

ImportError: cannot import name 'GraphQLResolveInfo' from 'graphql' (/home/mwk/code/graphene-sqlalchemy/.venv/lib/python3.9/site-packages/graphql/__init__.py)

I used pip install Flask-GraphQL==2.0.1, but someone in the same Stack Overflow post recommended putting flask-graphql>=2.0.1 in requirements.txt instead. I'll try it.

Result: Pip conflict:

The conflict is caused by:
flask-graphql 2.0.1 depends on graphql-core<3 and >=2.1
graphene 3.2.1 depends on graphql-core<3.3 and >=3.1
[...]
flask-graphql 2.0.1 depends on graphql-core<3 and >=2.1
graphene 3.0b7 depends on graphql-core<4 and >=3.1.2

Interesting note from flask-graphql:

[MattKleinsmith]

Going to try downgrading graphene-sqlalchemy (or Graphene itself?) from v3.0, because the README says:

Version 3.0 is in beta stage. Please read #348 to learn about progress and changes in upcoming beta releases.

Scratch this. Not sure which version I should downgrade to. Going to instead chase the errors by editing the pip packages.

[MattKleinsmith]

Okay, flask-graphql's fix was to pin graphql-core to be under version 3.

However, the latest graphene versions require graphql-core to be over version 3.1.

So, I will try to find the latest graphene version that allows graphql-core to be under version 3.

The target version seems to be: graphene==2.1.9
Given this: https://pypi.org/project/graphene/#history

This leads to a new dependency error:

The user requested graphene==2.1.9
graphene-sqlalchemy 3.0.0b3 depends on graphene>=3.0.0b7

The target version seems to be: graphene-sqlalchemy==2.3.0
Given this: https://pypi.org/project/graphene-sqlalchemy/#history

[MattKleinsmith]

Seems to be working now:

Approach: Downgrade.

How: Replace the entire contents of graphene-sqlalchemy/examples/flask_sqlalchemy/requirements.txt with:

flask-graphql==2.0.1
graphene==2.1.9
graphene-sqlalchemy==2.3.0

[erikwrede]

I'd strongly advise using the 3.0 beta if you're starting off a new project. It works best together with an asyncio-based framework like FastAPI, but flask is also fine.
https://github.com/ciscorn/starlette-graphene3

This should work with flask + graphene 3: https://github.com/graphql-python/graphql-server

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