SNOW-1526475: str typing for private_key is misleading and causes errors if used

[sfc-gh-turbaszek]

Python version

3.10

Operating system and processor architecture

macOS-14.5-arm64-arm-64bit

Installed packages

annotated-types==0.6.0
anyio==4.3.0
asn1crypto==1.5.1
atpublic==4.1.0
beautifulsoup4==4.12.3
certifi==2024.2.2
cffi==1.16.0
cfgv==3.4.0
charset-normalizer==3.3.2
click==8.1.7
cloudpickle==2.2.1
coverage==7.5.4
cryptography==42.0.5
DatastreamPy==2.0.21
distlib==0.3.8
execnet==2.1.1
filelock==3.13.1
gitdb==4.0.11
GitPython==3.1.43
h11==0.14.0
hatch==1.10.0
hatchling==1.24.2
httpcore==1.0.5
httpx==0.27.0
hyperlink==21.0.0
identify==2.5.35
idna==3.6
importlib-metadata==7.0.1
iniconfig==2.0.0
jaraco.classes==3.3.1
Jinja2==3.1.4
keyring==24.3.1
markdown-it-py==3.0.0
MarkupSafe==2.1.5
mdurl==0.1.2
more-itertools==10.2.0
nodeenv==1.8.0
numpy==1.26.4
packaging==23.2
pandas==2.2.1
pathspec==0.12.1
pexpect==4.9.0
pkginfo==1.10.0
platformdirs==3.11.0
pluggy==1.5.0
pre-commit==3.6.2
ptyprocess==0.7.0
pycparser==2.21
pydantic==2.7.4
pydantic_core==2.18.4
Pygments==2.17.2
PyJWT==2.8.0
pyOpenSSL==24.0.0
pytest==8.2.2
pytest-randomly==3.15.0
python-dateutil==2.8.2
pytz==2024.1
PyYAML==6.0.1
requests==2.32.3
requirements-parser==0.9.0
rich==13.7.1
shellingham==1.5.4
six==1.16.0
smmap==5.0.1
sniffio==1.3.1
snowflake-connector-python==3.11.0
snowflake-snowpark-python==1.15.0
snowflake.core==0.8.0
sortedcontainers==2.4.0
soupsieve==2.5
strictyaml==1.7.3
sybil==6.0.2
syrupy==4.6.1
tomli_w==1.0.0
tomlkit==0.12.5
trove-classifiers==2024.3.3
typer==0.12.3
types-setuptools==69.1.0.20240229
typing_extensions==4.10.0
tzdata==2024.1
urllib3==2.2.1
userpath==1.9.2
uv==0.1.42
virtualenv==20.26.1
zipp==3.17.0
zstandard==0.22.0

What did you do?

The connector has the following code
https://github.com/snowflakedb/snowflake-connector-python/blob/b3e816be80545e34d28d60bcec18460b8ff81e67/src/snowflake/connector/connection.py#L1040-L1053
where

"private_key": (None, (type(None), str, RSAPrivateKey)),

unfortunately passing private_key as str will cause an error because `AuthByKeyPair` which we use expects
```py
 private_key: bytes | RSAPrivateKey

and raises

            raise TypeError(
                f"Expected bytes or RSAPrivateKey, got {type(self._private_key)}"
            )

### What did you expect to see?

It would make sens to handle string on connector side allowing users to pass the key as env variable.

### Can you set logging to DEBUG and collect the logs?

_No response_

[sfc-gh-sghosh]

Hello @sfc-gh-turbaszek ,

When using key-pair authentication, you need to pass PrivateKey object and not String. For the Snowflake Python driver, authentication using a private key involves using PrivateKey object.

String is not the expected type, read the private key from the PEM file, Convert the PEM formatted string to a PrivateKey object.

Regards,
Sujan