Gnoll

gnoll is a simple library that helps you load your configs from files. It currently supports the following file formats.

• json
• yaml

gnoll is no real substitute for a well thoughtout configuration system but will play nicely with application code.

Note: code/issues and all work are hosted at https://gitlab.com/kobolds-io/gnoll

Usage

Using gnoll is pretty simple.

// import the library into your file
const gnoll = @import("gnoll");
const Gnoll = gnoll.Gnoll;
const ConfigInfo = gnoll.ConfigInfo; // if you like types
const GnollOptions = gnoll.GnollOptions; // if you like types

// Define your config type
const TestConfig = struct {
    key_0: u32,
    key_1: []const u8,
    key_2: struct {
        key_0: []f32,
    },
};

fn main(init: std.process.Init) !void {
    const io = init.io;

    // Define some filepaths to check for configuration files
    const gnoll_options = GnollOptions{
        .config_infos = &.{
            // if we can't find this file, fallback to the next one etc...
            ConfigInfo{
                .filepath = "./test_data/config_0.json",
                .format = .json,
            },
            ConfigInfo{
                .filepath = "./test_data/config_1.yaml",
                .format = .yaml,
            },
        },
    };

    // Initialize Gnoll with your config Type
    var gnoll = try Gnoll(TestConfig).init(allocator, io, gnoll_options);
    defer gnoll.deinit(allocator);

    // get values from `gnoll` after initialization
    std.debug.print("key_0 value: {d}\n", .{gnoll.config.key_0});
    std.debug.print("key_2.key_0 value: {any}\n", .{gnoll.config.key_2.key_0});
}

Installation

zig version	stdx version
0.15.x	0.1.0
0.16.0	0.2.x

You can install gnoll just like any other zig dependency by editing your build.zig.zon file or by using the zig fetch command.

zig fetch --save https://gitlab.com/kobolds-io/gnoll/-/archive/v0.2.1/gnoll-v0.2.1.tar.gz

In your build.zig file add the library as a dependency.

// ...boilerplate

const gnoll_dep = b.dependency("gnoll", .{
    .target = target,
    .optimize = optimize,
});
const gnoll_mod = gnoll_dep.module("gnoll");

exe.root_module.addImport("gnoll", gnoll_mod);

Overview

gnoll works by cycling through the passed GnollOptions during the init function call to find a valid configuration. Once a configuration file exists on the file system, gnoll will use the appropriate parser to load into the gnoll.config field. Overall, pretty simple but nice and useful.

Features

Feature	Implemented
json support	yes
yaml support	yes
toml support	no
do not immediately fail on first failed parsed	no