config-easy

config-easy is a small Rust crate for displaying and editing key/value settings stored in a SQLite table.

It is intended for command-line applications that want a simple interactive configuration menu, usually shown when the application is run with a --config option.

Applications remain responsible for schema creation, default values, typed configuration structs, CLI parsing, and app-specific behavior.

Install

[dependencies]
config-easy = "0.1"
rusqlite = "0.32"

Default Schema

CREATE TABLE IF NOT EXISTS settings (
    key TEXT PRIMARY KEY,
    value TEXT NOT NULL
);

Basic Usage

let connection = rusqlite::Connection::open("app.db")?;

config_easy::run(&connection)?;

This uses:

table: settings
key column: key
value column: value
order by: key

Builder Usage

config_easy::builder(&connection)
    .table("settings")
    .key_column("key")
    .value_column("value")
    .order_by("key")
    .run()?;

Table and column names are validated as simple SQL identifiers before being interpolated into SQL. Values are always bound as SQL parameters.

Valid identifiers are non-empty, start with an ASCII letter or _, and contain only ASCII letters, numbers, and _.

Secret Values

config_easy::builder(&connection)
    .secret_keys(["my_api_key"])
    .run()?;

Non-empty secret values are displayed as ********. Empty secret values are displayed as empty. The underlying value is not changed unless the user selects that setting and enters a new value.

Validation

config_easy::builder(&connection)
    .validator(|key, value| {
        if key == "log_level" && !["debug", "info", "warn", "error"].contains(&value) {
            return Err(std::io::Error::new(
                std::io::ErrorKind::InvalidInput,
                "expected one of debug, info, warn, error",
            )
            .into());
        }

        Ok(())
    })
    .run()?;

Validation runs before a setting is updated.

Input values are trimmed before validation and saving.

Custom Actions

config_easy::builder(&connection)
    .action("r", "reset delta link", |conn| {
        conn.execute("DELETE FROM sync_state WHERE key = 'delta_link'", [])?;
        println!("Delta link reset.");
        Ok(())
    })
    .run()?;

Custom actions are displayed in the prompt and run when their key is selected. Action keys cannot be empty, numeric, duplicated, q, or quit.

Deliberately Not Included

Creating the settings table
Seeding default settings
Parsing values into app-specific types
CLI argument parsing
Encryption or secure secret storage
App-specific maintenance logic

config-easy 0.1.0