polars.read_parquet_metadata#

polars.read_parquet_metadata(
source: str | Path | IO[bytes] | bytes,
storage_options: dict[str, Any] | None = None,
credential_provider: CredentialProviderFunction | Literal['auto'] | None = 'auto',
retries: int = 2,
) → dict[str, str][source]#

Get file-level custom metadata of a Parquet file without reading data.

Warning

This functionality is considered experimental. It may be removed or changed at any point without it being considered a breaking change.

Parameters:
source

Path to a file or a file-like object (by “file-like object” we refer to objects that have a read() method, such as a file handler like the builtin open function, or a BytesIO instance). For file-like objects, the stream position may not be updated accordingly after reading.

storage_options

Options that indicate how to connect to a cloud provider.

The cloud providers currently supported are AWS, GCP, and Azure. See supported keys here:

  • aws

  • gcp

  • azure

  • Hugging Face (hf://): Accepts an API key under the token parameter: {'token': '...'}, or by setting the HF_TOKEN environment variable.

If storage_options is not provided, Polars will try to infer the information from environment variables.

credential_provider

Provide a function that can be called to provide cloud storage credentials. The function is expected to return a dictionary of credential keys along with an optional credential expiry time.

Warning

This functionality is considered unstable. It may be changed at any point without it being considered a breaking change.

retries

Number of retries if accessing a cloud instance fails.

Returns:
dict

Dictionary with the metadata. Empty if no custom metadata is available.