5 unstable releases

0.11.0 Dec 15, 2021
0.10.2 Nov 3, 2021
0.10.1 Oct 5, 2021
0.10.0 Oct 3, 2021
0.9.0 Jul 22, 2021

#279 in Procedural macros

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866 downloads per month
Used in 14 crates (via doku)

MIT license

846 lines

Doku   crates-badge docs-badge

Doku is a framework for building textual, aesthetic documentation directly from the code; it allows to generate docs for configuration files, HTTP endpoints, and so on.

Say goodbye to stale, hand-written documentation - with Doku, code is the documentation!


doku = "0.11"
use doku::Document;
use serde::Deserialize;

#[derive(Deserialize, Document)]
struct Config {
    /// Database's engine
    db_engine: DbEngine,

    /// Database's host
    #[doku(example = "localhost")]
    db_host: String,

    /// Database's port
    #[doku(example = "5432")]
    db_port: usize,

#[derive(Deserialize, Document)]
enum DbEngine {
    #[serde(rename = "pgsql")]

    #[serde(rename = "mysql")]

fn main() {
    println!("{}", doku::to_json::<Config>());
  // Database's engine
  "db_engine": "pgsql" | "mysql",
  // Database's host
  "db_host": "localhost",
  // Database's port
  "db_port": 5432

You'll find more examples in ./doku/examples; there's also a documentation at https://docs.rs/doku/.


Found a bug, have an idea? Please let us know on GitHub - patches are welcome, too!

If you want to try hacking on Doku, the entry points are:

As for the end-to-end tests, you'll find them inside ./doku/tests.

The way those tests work is that each test-directory contains an input file called input.rs and a set of output files called output.<something>.json.

The input.rs contains a Rust code defining a type called Ty - which can be an enum, a struct, whatever is required for the test - and a top-level comment that specifies which testing-function you want to execute on that type - e.g.:

// run: to_json()

pub struct Ty {
    foo: Vec<String>,

Our procedural macro then finds all of those input.rs-s, reads their // run:, and generates tests resembling:

fn test() {
    mod source {
    to_json::<source::Ty>(/* ... */);

That to_json(), and rest of the testing-functions, generate a documentation for Ty and compare the actual input (as generated from the code) to the expected one (as present inside output.<something>.json) - when there's a mismatch, the test fails:

thread '...' panicked at '
Found differences between `...` and `...`:

When a test fails, you'll see that next to the output.<something>.json file, there appears a new one, called output.<something>.json.new; this *.new file will contain the test's actual result, and it's up to you to decide if this actual result is the correct one.

If the *.new file looks fine, you can either:

  • manually delete output.<something>.json and then rename output.<something>.json.new to output.<something>.json,

  • or, if you have make and fd installed, you can execute make bless - this will automatically fix all of the tests.

Happy hacking!


Licensed under the MIT license.


~23K SLoC