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Configuration Extractor: Struct-to-TOML Conversion Tool

Overview

This MR introduces a configuration extraction tool that converts Go structs into TOML format using a bottom-up tree construction algorithm. The tool leverages the visitor pattern with reflectwalk to traverse complex nested structures and generate example configuration files.

Implementation Details

Core Algorithm

The extractor uses a bottom-up tree construction approach with two synchronized stacks:

Values stack: Builds nested containers (map[string]any{} for structs/maps, []any{} for slices/arrays)
Keys stack: Tracks field names extracted from TOML tags or struct field names

Three-Phase Processing

Phase 1 - Container Creation (Enter):

Creates empty containers when encountering structs, maps, slices, or arrays
Extracts field names from toml tags or uses default field names
Implements extraction level filtering (minimal/complete) based on example tag values

Phase 2 - Leaf Processing (Primitives):

Processes primitive values (strings, numbers, booleans) by popping the current container
Adds the value using appropriate key (for maps) or index (for slices)
Pushes the updated container back to maintain stack integrity

Phase 3 - Container Completion (Exit):

Performs bottom-up assembly when exiting containers
Attaches completed child containers to their parents
Maintains proper nesting hierarchy through controlled stack operations

The extracted map structure is used for TOML generation via github.com/pelletier/go-toml/v2.

Features

Flexible Extraction Levels: Support for minimal and complete extraction modes
TOML Tag Support: Honors toml struct tags for field naming
Complex Type Handling: Supports nested structs, pointers, slices, arrays, and maps
Stack-Based Architecture: Ensures proper hierarchical construction without recursion issues

Related to #6730 (closed)

Edited Jun 17, 2025 by 🤖 GitLab Bot 🤖

tools: Add POC for bottom-up config.toml.example generator