Implementation:PrefectHQ Prefect Asset Constructor

Metadata
Source	Repo: Prefect
Domains	Data_Engineering, Orchestration
Last Updated	2026-02-09 00:00 GMT

Overview

Concrete class for defining named data assets with unique keys provided by the Prefect library.

Description

The Asset class from prefect.assets creates named data asset identifiers. Each Asset is initialized with a key parameter using URI format. These Asset instances are then passed to the @materialize decorator to create tracked data products.

Code Reference

• Repository: https://github.com/PrefectHQ/prefect
• File: src/prefect/assets/core.py (L36) for Asset class, examples/atproto_dashboard_with_prefect_assets.py (L63-65) for usage
• Signature:

class Asset:
    def __init__(self, key: str):
        """
        Args:
            key: Unique asset identifier using URI format (e.g., "pipeline://raw_data", "s3://bucket/path")
        """

• Import: from prefect.assets import Asset

I/O Contract

• Inputs: key (str, required -- unique asset URI identifier)
• Outputs: Asset instance used as argument to @materialize

Usage Example

from prefect.assets import Asset, materialize

# Define assets with descriptive keys
raw_data_asset = Asset(key="pipeline://raw_data")
processed_data_asset = Asset(key="pipeline://processed_data")
analytics_asset = Asset(key="pipeline://analytics")

# Use with @materialize
@materialize(raw_data_asset)
def fetch_raw_data() -> dict:
    return {"items": ["item1", "item2"], "count": 2}

Related Pages

Principle:PrefectHQ_Prefect_Asset_Definition