Settings View Source Existence.Plug (Existence v0.1.1)

Plug responding with a health-check state.

Plug sends a text/plain response depending on the Existence overall health-check state returned by an Existence.get_state/1 function.

Configuration

Plug is configured with a keyword list.

Plug response http status code and body are configurable with the following keys:

• ok_status - response status code for the healthy state. Default: 200.
• ok_body - response body for the healthy state. Default: "OK".
• error_status - response status code for the unhealthy state. Default: 503.
• error_body - response body for the unhealthy state. Default: "Service Unavailable".

Additionally Existence instance can be selected with a :name key. If :name key is not set, Plug will use a default instance: name: Existence. Setting instance name is described in the Existence module documentation.

Usage

Example module use with a Plug.Router.get/3 inside / route scope with a custom unhealthy state response:

defmodule MyAppWeb.Router do
use MyAppWeb, :router

  #...
  scope "/", MyAppWeb do
    pipe_through(:browser)

    get(
      "/healthcheck",
      Existence.Plug,
      [error_status: 500, error_body: "Internal Server Error"],
      alias: false
    )
  end
end

Notice alias: false use to disable scoping on an external Existence.Plug in get/3 function.

Code example above will produce following http responses:

• healthy state:

  $> curl -i http://127.0.0.1:4000/healthcheck
  HTTP/1.1 200 OK
  ...
  OK

• unhealthy state:

  $> curl -i http://127.0.0.1:4000/healthcheck
  HTTP/1.1 500 Internal Server Error
  ...
  Internal Server Error