improve on reusability

config/config.exs

@@ -7,9 +7,6 @@
 # General application configuration
 import Config
 
-config :tesla, DockerEngineAPI.Connection,
-  adapter: Tesla.Adapter.Hackney
-
 # Import environment specific config. This must remain at the bottom
 # of this file so it overrides the configuration defined above.
 #

config/runtime.exs

@@ -6,7 +6,3 @@ import Config
 # and secrets from environment variables or elsewhere. Do not define
 # any compile-time configuration in here, as it won't be applied.
 # The block below contains prod specific runtime configuration.
-
-if base_url = System.get_env("DOCKER_ENGINE_API_BASE_URI") do
-  config :docker_engine_api, base_url: base_url
-end

lib/docker_engine_api/connection.ex

@@ -48,7 +48,7 @@ defmodule DockerEngineAPI.Connection do
   """
   @spec new() :: Tesla.Env.client()
   def new do
-    Tesla.client(middleware(), adapter())
+    Tesla.client(middleware(), adapter(adapter: Tesla.Adapter.Hackney))
   end
 
   @doc """
@@ -67,7 +67,7 @@ defmodule DockerEngineAPI.Connection do
   def new(options) when is_list(options) do
     options
     |> middleware()
-    |> Tesla.client(adapter())
+    |> Tesla.client(adapter(options))
   end
 
 
@@ -116,8 +116,11 @@ defmodule DockerEngineAPI.Connection do
   @doc """
   Returns the default adapter for this API.
   """
-  def adapter do
-    get_tesla_options()
-    |> Keyword.get(:adapter, nil)
+  def adapter(options \\ []) do
+    Keyword.get(
+      options,
+      :adapter,
+      get_tesla_options() |> Keyword.get(:adapter, nil)
+    )
   end
 end

test/connection_test.exs

@@ -1,11 +1,19 @@
 defmodule DockerEngineAPI.ConnectionTest do
   use ExUnit.Case
 
-  test "can list images" do
+  test "can list images with hackney adapter" do
     {:ok, list} = DockerEngineAPI.Connection.new(
-      base_url: "http+unix://%2Fvar%2Frun%2Fdocker.sock/v1.43"
+      base_url: "http+unix://%2Fvar%2Frun%2Fdocker.sock/v1.43",
+      adapter: Tesla.Adapter.Hackney
     )
     |> DockerEngineAPI.Api.Image.image_list()
     assert is_list(list)
   end
+
+  test "doesnt work without adapter" do
+    {:error, {:bad_scheme, ~c"http+unix"}} = DockerEngineAPI.Connection.new(
+      base_url: "http+unix://%2Fvar%2Frun%2Fdocker.sock/v1.43"
+    )
+    |> DockerEngineAPI.Api.Image.image_list()
+  end
 end