windmill-labs/windmill · error · Exception

Could not generate Polars S3 connection settings from the…

Error message

Could not generate Polars S3 connection settings from the provided resource

What it means

get_polars_connection_settings() converts an S3 resource into Polars storage settings via a server endpoint; a non-JSON response (JSONDecodeError) is re-raised with this message. It means the server could not produce valid settings for the given S3 resource.

Solutions

Confirm the resource path and its s3 type in the workspace Resources page.
Inspect the server response/log for the underlying error body.
Try the default resource by passing s3_resource_path=''.
Fix the S3 resource's credentials/configuration in the workspace.

Example fix

// before
settings = client.get_polars_connection_settings(s3_resource_path='s3_res/typo_name')
// after
settings = client.get_polars_connection_settings(s3_resource_path='u/admin/s3_prod')  # verified path

Defensive patterns

Strategy: validation

Validate before calling

def s3_resource_exists(client, path):
    if not path:
        return True
    resources = client.get(f'/w/{client.workspace}/resources/list').json()
    return any(r['path'] == path and r['resource_type'] == 's3' for r in resources)

Try / catch

try:
    settings = client.get_polars_connection_settings(s3_resource_path=path)
except Exception as e:
    if 'Polars S3 connection settings' in str(e):
        raise RuntimeError(f'S3 resource {path!r} invalid or missing; check workspace resources') from e
    raise

Prevention

Validate the resource exists and is s3-typed before the call.
Use the default resource ('') when applicable.
Check server logs when the wrapped exception appears to find the real cause.

When it happens

Trigger: get_polars_connection_settings(s3_resource_path='...') with a nonexistent/mistyped resource path, a non-S3 resource, missing workspace S3 configuration, or a server error returning a non-JSON error body.

Common situations: Wrong workspace context; resource path typo; S3 resource credentials invalid so the settings endpoint fails; calling from a context where the resource isn't accessible.

Related errors

AI-assisted analysis of windmill-labs/windmill@e474e8803c (2026-09-03). Data as JSON: /api/errors/2aeec55e94e91985. Report an issue: GitHub.

Appendix: source

Thrown at python-client/wmill/wmill/client.py:889

    def get_polars_connection_settings(
        self,
        s3_resource_path: str = "",
    ) -> PolarsConnectionSettings:
        """
        Convenient helpers that takes an S3 resource as input and returns the settings necessary to
        initiate an S3 connection from Polars
        """
        s3_resource_path = parse_resource_syntax(s3_resource_path) or s3_resource_path
        try:
            raw_obj = self.post(
                f"/w/{self.workspace}/job_helpers/v2/polars_connection_settings",
                json={}
                if s3_resource_path == ""
                else {"s3_resource_path": s3_resource_path},
            ).json()
            return PolarsConnectionSettings(raw_obj)
        except JSONDecodeError as e:
            raise Exception(
                "Could not generate Polars S3 connection settings from the provided resource"
            ) from e

    def get_boto3_connection_settings(
        self,
        s3_resource_path: str = "",
    ) -> Boto3ConnectionSettings:
        """
        Convenient helpers that takes an S3 resource as input and returns the settings necessary to
        initiate an S3 connection using boto3
        """
        s3_resource_path = parse_resource_syntax(s3_resource_path) or s3_resource_path
        try:
            s3_resource = self.post(
                f"/w/{self.workspace}/job_helpers/v2/s3_resource_info",
                json={}
                if s3_resource_path == ""
                else {"s3_resource_path": s3_resource_path},

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