aoc-star

Library and CLI tool to manage your Advent of Code solutions.

This crate:

• lets you annotate solution functions with a #[star(day = ..., part = ..., year = ...)] attribute
• and provides a small CLI runner that picks the right solution based on command line flags, loads inputs and (optionally) submits answers via aoc-client.

Installation

Add this to your Cargo.toml:

[dependencies]
aoc-star = "0.1"

Enable the optional features as needed:

[dependencies]
aoc-star = { version = "0.1", features = ["aoc-client"] }

They allow you to automatically fetch puzzle inputs and submit answers to Advent of Code provided you configure your session cookie (see below).

Usage

Add the dependency to your Cargo.toml, by running:

cargo add aoc-star

Annotate your solution functions with the #[star(...)] attribute, specifying the day, part, and year:

use aoc_star::star;

#[star(day = 1, part = 1, year = 2024)]
fn day1_part1(input: String) -> String {
    // implement your solution using the full puzzle input in `input`
    input.lines().count().to_string()
}

#[star(day = 1, part = 2, year = 2024)]
fn day1_part2(input: String) -> String {
    // ...
    "42".to_string()
}

fn main() -> Result<(), Box<dyn std::error::Error>> {
    aoc_star::run()
}

Build and run:

cargo run -- --day 1 --part 1 --year 2024 --input-file path/to/input.txt

If you enable the aoc-client feature and configure your session cookie (see below), you can omit --input-file and the input will be fetched from Advent of Code directly. You can also use --publish to submit your answer:

cargo run -- --day 1 --part 1 --year 2024 --publish

Since a single year is used in all functions, you can set it in the config file (see below) and omit --year:

cargo run -- --day 1 --part 1

You can also use a less verbose syntax and use single-dash flags:

cargo run -- -d 1 -p 1

See the CLI flags section for more details and run cargo run -- --help to see all available options.

Example

You can find a complete example project here.

CLI flags

The runner provided by aoc-star::run() accepts:

• -d, --day <DAY>: Advent of Code day (1–25). Required.
• -p, --part <PART>: puzzle part (usually 1 or 2, defaults to 1).
• -y, --year <YEAR>: Advent of Code year. Optional; when omitted, it is resolved from config or the current year.
• --input-file <PATH>: read the puzzle input from PATH. If omitted and aoc-client is enabled, the input will be fetched remotely.
• --publish: when aoc-client is enabled, submit the computed answer to Advent of Code and show the outcome.
• --setup: If the config file does not exist, create it using the value of the AOC_TOKEN environment variable as the session cookie and the current year.

Configuration

aoc-star can read a config file to determine:

• your session cookie (needed for remote input fetching and answer submission),
• a default year.

The config is searched in:

1. the current directory (aoc-star.yml), then
2. the global config directory (typically ~/.config/aoc-star/config.yml).

If none exists, a new config file is created in the global config directory using environment variables and the current year.

Example config

token: "your_aoc_session_cookie_here"
year: 2024

Alternatively, you can set the AOC_TOKEN environment variable; the config loader will use it when creating a new config.

Features

• aoc-client (optional): enable remote input fetching and answer submission with the aoc-client crate.
• test-helpers: export a small testing API:
  • aoc_star::test_helpers::CommandArgument
  • aoc_star::test_helpers::run_with_result

These are useful for integration tests that want to bypass actual CLI parsing.

Session cookie

To fetch puzzle inputs and submit answers, aoc-star needs your Advent of Code session cookie.

You can find it by inspecting the cookies in your browser while logged in to Advent of Code. Look for a cookie named session. Set it in the config file as shown above, or set the AOC_TOKEN environment variable before running your binary. You can see more details in the aoc-cli documentation.

License

This project is licensed under the MIT License and the Apache License (Version 2.0).