Add HttpWaitStrategy (#237)

* Add `HttpWaitStrategy`

* a test case

* with retry

* Update lib/wait_strategy/http_wait_strategy.ex

Co-authored-by: Jarl André Hübenthal <jarlah@protonmail.com>

---------

Co-authored-by: Jarl André Hübenthal <jarlah@protonmail.com>

Author: gossi

lib/wait_strategy/http_wait_strategy.ex

@@ -0,0 +1,148 @@
+defmodule Testcontainers.HttpWaitStrategy do
+  @moduledoc """
+  Considers the container as ready when a http request is successful.
+  """
+
+  @timeout 5000
+  @max_retries 3
+
+  @typedoc """
+  The HttpWaitStrategy struct
+
+  ## Options
+
+  - `:endpoint` - The endpoint to request
+
+  - `:port` - The exposed port of your container
+
+  Verification Options:
+
+  - `:status_code` - Check if the request responds with the given status code
+
+  - `:match` - Run your custom matcher on the given response. A 1-arity function
+    taking a response as first parameter and must return a boolean
+
+  Request Options:
+
+  - `:protocol` - which protocol to use, defaults to `http`
+
+  - `:method` - the request method, one of [`:head`, `:get`, `:delete`, `:trace`, `:options`, `:post`, `:put`, `:patch`]
+
+  - `:timeout` - The timeout of the request (in milliseconds), defaults to `5000`
+
+  - `:headers` - Apply any headers to your request
+  """
+  @type t() :: %__MODULE__{
+          endpoint: String.t(),
+          port: integer(),
+          protocol: String.t(),
+          method: :get | :post | :patch | :put | :delete | :head | :options | :trace,
+          timeout: integer(),
+          headers: [{binary(), binary()}],
+          status_code: integer(),
+          match: (map() -> boolean())
+        }
+
+  defstruct [
+    :endpoint,
+    :port,
+    # request options
+    protocol: "http",
+    method: :get,
+    headers: [],
+    timeout: @timeout,
+    max_retries: @max_retries,
+    # verification options
+    status_code: nil,
+    match: nil
+  ]
+
+  # Public interface
+
+  @doc """
+  Creates a new HttpWaitStrategy to wait until a http requests succeeds.
+  """
+  def new(endpoint, port, options \\ []) do
+    struct(%__MODULE__{endpoint: endpoint, port: port}, options)
+  end
+
+  # Private functions and implementations
+
+  defimpl Testcontainers.WaitStrategy do
+    alias Testcontainers.HttpWaitStrategy
+    alias Testcontainers.Container
+
+    @impl true
+    def wait_until_container_is_ready(wait_strategy, container, _conn) do
+      client = build_request(wait_strategy, container)
+
+      raw_response =
+        Tesla.request(client,
+          url: wait_strategy.endpoint,
+          method: wait_strategy.method,
+          headers: wait_strategy.headers
+        )
+
+      with response <- validate_response(raw_response),
+           :ok <- verify_status_code(wait_strategy, response),
+           :ok <- verify_match(wait_strategy, response) do
+        :ok
+      else
+        {:error, reason} ->
+          {:error, reason, wait_strategy}
+      end
+    end
+
+    # Response evaluation
+
+    defp validate_response({:ok, response}), do: response
+    defp validate_response({:error, reason}), do: {:error, reason}
+
+    defp verify_status_code(wait_strategy, %{status: status_code})
+         when not is_nil(wait_strategy.status_code) and
+                status_code == wait_strategy.status_code,
+         do: :ok
+
+    defp verify_status_code(wait_strategy, response) when not is_nil(wait_strategy.status_code),
+      do:
+        {:error,
+         "Status Code does not match. Expected: #{wait_strategy.status_code} Received: #{response.status}"}
+
+    defp verify_status_code(wait_strategy, _) when is_nil(wait_strategy.status_code), do: :ok
+
+    defp verify_match(wait_strategy, response)
+         when not is_nil(wait_strategy.match) and is_function(wait_strategy.match) do
+      case wait_strategy.match.(response) do
+        true -> :ok
+        false -> {:error, "Matcher function failed"}
+      end
+    end
+
+    defp verify_match(_, _), do: :ok
+
+    # Request composition
+
+    defp build_request(wait_strategy, container) do
+      base_url = get_base_url(wait_strategy, container)
+      request_timeout = round(wait_strategy.timeout / wait_strategy.max_retries)
+
+      Tesla.client([
+        {Tesla.Middleware.BaseUrl, base_url: base_url},
+        {Tesla.Middleware.Timeout, timeout: request_timeout},
+        {Tesla.Middleware.Retry,
+         delay: 1,
+         max_retries: wait_strategy.max_retries,
+         max_delay: 10,
+         should_retry: fn
+           _, _env, _context -> true
+         end}
+      ])
+    end
+
+    defp get_base_url(%HttpWaitStrategy{} = wait_strategy, %Container{} = container) do
+      port = Container.mapped_port(container, wait_strategy.port)
+
+      "#{wait_strategy.protocol}://#{Testcontainers.get_host()}:#{port}/"
+    end
+  end
+end

test/wait_strategy/http_wait_strategy_test.exs

@@ -0,0 +1,16 @@
+defmodule Testcontainers.HttpWaitStrategyTest do
+  alias Testcontainers.HttpWaitStrategy
+  use ExUnit.Case, async: true
+
+  test "can wait a http request" do
+    port = 80
+
+    config =
+      %Testcontainers.Container{image: "nginx:alpine"}
+      |> Testcontainers.Container.with_exposed_port(port)
+      |> Testcontainers.Container.with_waiting_strategy(HttpWaitStrategy.new("/", port))
+
+    assert {:ok, container} = Testcontainers.start_container(config)
+    assert :ok = Testcontainers.stop_container(container.container_id)
+  end
+end