polars.read_parquet_metadata

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

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.

Deprecated since version 1.37.1: Pass {“max_retries”: n} via storage_options instead.

Returns:

dict

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