Faultex

Faultex is a simple Elixir fault injection library.

USAGE

Faultex can be use with the Plug and HTTPoison

Faultex.Plug

Add the :faultex to your project’s mix.exs:

defp deps do
  [
    {:plug, "~> 1.0"},
    {:faultex, "~> 0.1"}
  ]
end

  defmodule MyRouter do
    use Faultex.Plug, injectors: [
     %Faultex.Injector.SlowInjector{
      path: "/test/*/bar",
      headers: [{"X-Fault-Inject", "auth-failed"}],
      percentage: 100,
      resp_delay: 1000
     }
    ]
     
    get "test/:foo/bar" do
      ...
    end
  end

Faultex.HTTPoison

Add the :faultex to your project’s mix.exs:

defp deps do
  [
    {:httpoison, "~> 1.0"},
    {:faultex, "~> 0.1"}
  ]
end

defmodule MyApp.HTTPoison do
  use Faultex.HTTPoison, injectors: [
     %Faultex.Injector.FaultInjector{
      path: "/test/*/bar",
      method: "GET",
      headers: [{"X-Fault-Inject", "auth-failed"}],
      percentage: 100,
      resp_status: 401,
      resp_body: Jason.encode!(%{message: "Autharization failed"}),
      resp_headers: [],
      resp_delay: 1000
      }
    ]
end

alias MyApp.HTTPoison as HTTPoison

# receive 401
res = HTTPoison.request!(:get, "test/foo/bar", body, headers)

> res%{
}

Use config.exs

 config :faultex, 
   injectors: [{:register_fail, Faultex.Injector.FaultInjector}]
     
 config :faultex, :register_fail 
   # Request matcher parameters
   host: "example.com"
   path: "/auth/*/*/register",
   method: "POST",
   exact: true,
   header: {"X-Fault-Inject", "auth-failed"},
   percentage: 100,

   # Response parameters
   resp_status: 401,
   resp_handler: MyApp.FailureHandler,
   resp_body: Jason.encode!(%{message: "Autharization failed"}),
   resp_headers: [],
   resp_delay: 1000

use Faultex.HTTPoison, Application.compile_env!(faultex, :injectors)

Global Parameters

disable: if true, disable all injectors
injectors: list of injectors

Fault Injector Configuration

In some request match parameters, you can set "*". which means matches all incoming parameters.

disable: optional. if true, disable this injectors. if omit this parameter, set default to false
host: optioanl. matches request host. if omit this parameters, set default to "*"
path: optional. matches pattern for request path. You can use Plug.Router style path parameters like :id and wildcard pattern like /*path default is *
methd: optional. metches request method. atom or string. default is "*"
header: optional. matches request headers. default is []
percentage: optional. default is 100.
resp_status: optional.
resp_body: optional.
resp_headers: optional.
resp_handler: optioanl.
resp_delay: optioanl.

TODO

[x] Allow :resp_headers key.
[x] Allow :resp_delay key.
[x] Allow :percentage key.
[x] :headers are should parse list (cowboy style headers) [{key, value}].
[x] Allow response handlers
[x] Disaced config.exs
[x] Faultex.Plug and Faultex.HTTPoison are should have using macro and compile routes dinamicaly
[x] Allow :disable key.
[] Allow :exact key.
[] - pass the path parameters to resp_handler
[x] match/5 check request path pattern
[x] match/4, match/5 returns {:ok, true, %Faultex} | {:ok, false, nil}
[] debug log
[x] example project
[x] Injecror to Behaviour
[x] FaultInjector
[x] SlowInjector
[] RejectInjector