Bureaucrat is a library that lets you generate API documentation of your Phoenix app from tests.

First, add Bureaucrat to your mix.exs dependencies:

defp deps do
  [{:bureaucrat, "~> 0.1.4"}]
end

Then, update your dependencies:

$ mix deps.get

Next, in your test/test_helper.exs you should start Bureaucrat and configure ExUnit to use its formatter. You would probably like to keep the default ExUnit.CLIFormatter as well.

Bureaucrat.start
ExUnit.start(formatters: [ExUnit.CLIFormatter, Bureaucrat.Formatter])

And finally, import Bureaucrat helpers in test/support/conn_case.ex:

defmodule Spell.ConnCase do
  using do
    quote do
      import Bureaucrat.Helpers
    end
  end
end

To generate Phoenix channel documentation, import the helpers in test/support/channel_case.ex alike.

Bureaucrat collects data from connection structs used in tests. If you want a connection to be documented, pass it to the doc/1 function:

test "GET /api/v1/products" do
  conn = conn()
      |> get("/api/v1/products")
      |> doc
  assert conn.status == 200
end

Additional options can be passed to the backend formatter:

test "GET /api/v1/products" do
  conn = conn()
      |> get("/api/v1/products")
      |> doc(description: "List all products", operation_id: "list_products")
  assert conn.status == 200
end

Then, to generate the documentation file(s) run DOC=1 mix test. The default output file is web/controllers/README.md.

To add a custom intro section, for each output file, bureaucrat will look for an intro markdown file in the output directory, named like the output file with a _intro or _INTRO suffix (before .md, if present), e.g.

• web/controllers/README -> web/controllers/README_INTRO
• web/controllers/readme.md -> web/controllers/readme_intro.md

Currently only supported by the (default) Bureaucrat.MarkdownWriter.

Bureaucrat can also generate documentation for messages, replies and broadcasts in Phoenix Channels.

Results of assert_push, assert_broadcast and the underlying assert_receive (if used for messages or broadcasts) can be passed to the doc function.

To document usage of Phoenix.ChannelTest helpers push, broadcast_from and broadcast_from!, Bureaucrat includes documenting alternatives, prefixed with doc_:

• doc_push
• doc_broadcast_from
• doc_broadcast_from!

test "message:new broadcasts are pushed to the client", %{socket: socket} do
  doc_broadcast_from! socket, "message:new", %{body: "Hello there!", timestamp: 1483971926566, user: "marla"}
  assert_push("message:new", %{body: "Hello there!", timestamp: 1483971926566, user: "marla"})
  |> doc
end

Channels docs output is currently only supported by the Bureaucrat.MarkdownWriter and only to the default_path (see Configuration below).

Bureaucrat comes with the Bureaucrat.SwaggerSlateMarkdownWriter backend that will merge test examples with a swagger spec to produce markdown files that can be processed with the slate static generator.

To configure swagger integration, first write a swagger file by hand or generate one using phoenix_swagger. In the example below, the swagger file exists in the project at priv/static/swagger.json.

Clone the slate project into a directory in your project:

git clone --shallow https://github.com/lord/slate doc

Configure Bureaucrat writer, default_path and swagger:

Bureaucrat.start(
  env_var: "DOC",
  writer: Bureaucrat.SwaggerSlateMarkdownWriter,
  default_path: "doc/source/index.html.md",
  swagger: "priv/static/swagger.json" |> File.read!() |> Poison.decode!())

Within each test, link the test example to a swagger operation by passing an operation_id to the doc helper:

test "creates and renders resource when data is valid", %{conn: conn} do
  conn =
    conn
    |> post(user_path(conn, :create), user: @valid_attrs)
    |> doc(operation_id: "create_user")

  assert json_response(conn, 201)["data"]["id"]
  assert Repo.get_by(User, @valid_attrs)
end

Now generate documentation with DOC=1 mix test.

Use slate to convert the markdown to HTML:

cd doc
bundle install
bundle exec middleman build

To serve the documentation directly from your application, copy the slate build output to your priv/static directory:

mkdir priv/static/doc
cp -R doc/build/* priv/static/doc

Whitelist the doc directory for static assets in the Plug.Static configuration:

plug Plug.Static,
  at: "/", from: :swagger_demo, gzip: false,
  only: ~w(css doc fonts images js favicon.ico robots.txt)

Run your application with mix phoenix.server and visit http://localhost:4000/doc/index.html to see your documentation.

For a full example see the examples/swagger_demo project.

The configuration options can be passed to Bureaucrat.start:

Bureaucrat.start(
 writer: Bureaucrat.MarkdownWriter,
 default_path: "web/controllers/README.md",
 paths: [],
 titles: [],
 env_var: "DOC"
)

The available options are:

• :writer: The module used to generate docs from the list of captured connections.
• :default_path: The path where the docs are written by default.
• :paths: Allows you to specify different doc paths for some of your modules. For example [{YourApp.Api.V1, "web/controllers/api/v1/README.md"}] will cause the docs for controllers under YourApp.Api.V1 namespace to be written to web/controllers/api/v1/README.md.
• :titles: Allows you to specify explicit titles for some of your modules. For example [{YourApp.Api.V1.UserController, "API /v1/users"}] will change the title (Table of Contents entry and heading) for this controller.
• :env_var: The environment variable used as a flag to trigger doc generation.