[PYD-141] PostgresDsn doesn't accept valid socket for host host

[mangecoeur]

Checks

• [x ] I added a descriptive title to this issue
• [ x] I have searched (google, github) for similar issues and couldn't find anything
• [ x] I have read and followed the docs and still think this is a bug

Bug

It is valid to give a unix socket file as a host when connecting to Postgres (e.g. via sqlalchemy) but PostgresDsn throws a 'URL host invalid' error.

from pydantic import BaseSettings, PostgresDsn

class PGSettings(BaseSettings):
    dsn: PostgresDsn = 'postgresql://derp@/databasename?host=/var/run/postgresql'

Output of python -c "import pydantic.utils; print(pydantic.utils.version_info())":

pydantic version: 1.9.0
            pydantic compiled: True
                 install path: /opt/conda/envs/geneap-1/lib/python3.9/site-packages/pydantic
               python version: 3.9.9 | packaged by conda-forge | (main, Dec 20 2021, 02:41:03)  [GCC 9.4.0]
                     platform: Linux-5.11.0-36-generic-x86_64-with-glibc2.31
     optional deps. installed: ['dotenv', 'typing-extensions']

_PYD-141

[mangecoeur]

P.S. Valid format of postgres connection string:

postgresql://[user[:password]@][netloc][:port][/dbname][?param1=value1&...]

References

https://stackoverflow.com/questions/27037990/connecting-to-postgres-via-database-url-and-unix-socket-in-rails

https://www.postgresql.org/docs/current/libpq-connect.html

Browsing the code I see that PostgresDsn subclasses AnyUrl, I think it's quite possible to construct a valid Postgres connection string that is not a valid URL.

[Hajbo]

I've encountered the same thing a few days ago.
It seems like this issue has been around for a while, see #960

[wasauce]

Ran into this due to google cloud. Seems like #960 was closed

Do you think the community would be open to a PR to support a new PostgresDsn -- e.g. GoogleCloudPostgresDsn

[danizen]

Yup - just ran into this on https://github.com/danizen/fastapi-bakeoff

[samuelcolvin]

My guess would be that this is fixed in v2 she therefore main, PR welcome to add a unit test to check.

[pgiraud]

My guess would be that this is fixed in v2 she therefore main, PR welcome to add a unit test to check.

I would have been happy to add a unit test but unfortunately such a DNS still isn't considered valid.

>>> PGSettings(dsn="postgresql://derp@/databasename?host=/var/run/postgresql")
dsn
  Input should be a valid URL, empty host [type=url_parsing, input_value='postgresql://derp@/datab...ost=/var/run/postgresql', input_type=str]

However, what's new is that the following is considered valid in v2 (which is not the case in v1):

PGSettings(dsn="postgresql://derp@%2Fvar%2Frun%2Fpostgresql/databasename")

[samuelcolvin]

Thanks for investigating, looks like this needs to be fixed in pydantic-core, I've created pydantic/pydantic-core#378.

PR welcome to fix that.

[sydney-runkle]

We’re no longer actively developing Pydantic V1 (although it will continue to receive security fixes for the next year or so), so we’re closing issues solely related to V1. If you really think this shouldn’t be closed, please comment or create a new issue 🚀.