data-prep

Data Preparation Examples

This directory contains examples demonstrating how to separate data preparation from script evaluation in go-polyscript.

Overview

The data preparation pattern separates static configuration data from dynamic runtime data, making code more modular and flexible. This pattern uses a composite data provider combining static and dynamic data sources, with a clear separation between configuration, preparation, and evaluation phases.

When to Use This Pattern

This pattern is valuable for:

• Distributed Architecture: Prepare data on one system (e.g., web server) and evaluate on another (e.g., worker)
• Separation of Concerns: Clearly separate data processing from script execution
• Layered Data Access: Combine static configuration with dynamic runtime data
• Performance Optimization: Prepare data asynchronously while other operations are happening

Implementation Pattern

These examples follow a consistent three-phase pattern:

1. Create evaluator with static data: Set up an evaluator with configuration data that remains constant across executions
2. Prepare runtime data: Add dynamic data to the context using the AddDataToContext method
3. Evaluate script: Execute the script with the enriched context

Running the Examples

Each example follows the same pattern but demonstrates it with a different script engine:

go run examples/data-prep/<engine>/main.go

Note: The Extism example requires a WASM file. If not found automatically, you may need to compile it using the Makefile in /engines/extism/testdata/.

Related Patterns

• Simple Examples: Basic one-time execution pattern
• Multiple Instantiation Examples: Compile-once-run-many pattern