Introduction

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rust-config-tree provides reusable configuration-tree loading and CLI helpers for Rust applications that use layered config files.

The crate is designed around a small division of responsibilities:

• confique owns schema definitions, code defaults, validation, and config template generation.
• figment owns runtime loading and runtime source metadata.
• rust-config-tree owns recursive include traversal, include path resolution, .env loading, template target discovery, and reusable clap commands.

The crate is useful when an application wants a natural config file layout such as this:

include:
  - config/server.yaml
  - config/database.yaml

log:
  level: info

Each included file can use the same schema shape, and relative include paths are resolved from the file that declared them. The final config is still a normal confique schema value.

Main Features

• Recursive include traversal with cycle detection.
• Relative include paths resolved from the declaring file.
• .env loading before environment providers are evaluated.
• Schema-declared environment variables without delimiter splitting.
• Figment metadata for runtime source tracking.
• TRACE-level source tracking events through tracing.
• Draft 7 JSON Schema generation for editor completion and basic schema checks.
• Field value validation in application code through #[config(validate = Self::validate)], executed by load_config or config-validate.
• YAML, TOML, JSON, and JSON5 template generation.
• TOML #:schema, YAML Language Server schema modelines, and JSON/JSON5 $schema fields for generated templates.
• Opt-in YAML template splitting for nested sections marked with x-tree-split.
• Built-in clap subcommands for config templates, JSON Schema, and shell completions.
• A lower-level tree API for callers that do not use confique.

Public Entry Points

Use these APIs for most applications:

• load_config::<S>(path) loads the final schema.
• load_config_with_figment::<S>(path) loads the schema and returns the Figment graph used for source tracking.
• write_config_templates::<S>(config_path, output_path) writes the root template and recursively discovered child templates.
• write_config_schemas::<S>(output_path) writes root and section Draft 7 JSON Schemas.
• handle_config_command::<Cli, S>(command, config_path) handles built-in clap config commands.

Use load_config_tree when you need the traversal primitive without confique.