From 1d2fb373425a81e38afd5cd21e1776ff100d9a79 Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Tue, 26 Nov 2019 09:12:29 -0800
Subject: [PATCH 01/14] WIP

---
 lib/k8s/client/runner/base.ex            | 40 +++++++++++++++++-------
 lib/k8s/middleware.ex                    | 25 +++++++++++++++
 lib/k8s/middleware/registry.ex           |  9 ++++++
 lib/k8s/middleware/request.ex            | 18 +++++++++++
 lib/k8s/middleware/request/base_url.ex   | 18 +++++++++++
 lib/k8s/middleware/request/initialize.ex | 25 +++++++++++++++
 test/k8s/middleware_test.exs             | 13 ++++++++
 7 files changed, 137 insertions(+), 11 deletions(-)
 create mode 100644 lib/k8s/middleware.ex
 create mode 100644 lib/k8s/middleware/registry.ex
 create mode 100644 lib/k8s/middleware/request.ex
 create mode 100644 lib/k8s/middleware/request/base_url.ex
 create mode 100644 lib/k8s/middleware/request/initialize.ex
 create mode 100644 test/k8s/middleware_test.exs

diff --git a/lib/k8s/client/runner/base.ex b/lib/k8s/client/runner/base.ex
index ffc100a9..1cf945e1 100644
--- a/lib/k8s/client/runner/base.ex
+++ b/lib/k8s/client/runner/base.ex
@@ -80,21 +80,42 @@ defmodule K8s.Client.Runner.Base do
     run(operation, cluster_name, operation.data, opts)
   end
 
+  def apply_middlewares(_cluster_name, headers, body) do
+    middlewares = [
+      fn headers, body ->
+        IO.puts("Inspecting some body: #{inspect(body)}")
+        [headers, body]
+      end
+    ]
+
+    state_args = [headers, body]
+
+    Enum.reduce(middlewares, state_args, fn middleware, args ->
+      apply(middleware, args)
+    end)
+  end
+
   @doc """
   Run an operation with an alternative HTTP Body (map) and pass `opts` to HTTPoison.
   See `run/2`
   """
   @spec run(Operation.t(), atom, map(), keyword()) :: result_t
-  def run(%Operation{} = operation, cluster_name, body, opts \\ []) do
-    with {:ok, url} <- Cluster.url_for(operation, cluster_name),
-         {:ok, conn} <- Cluster.conn(cluster_name),
-         {:ok, request_options} <- RequestOptions.generate(conn),
-         {:ok, http_body} <- encode(body, operation.method) do
-      http_headers = K8s.http_provider().headers(operation.method, request_options)
+  def run(%Operation{} = operation, cluster, body, opts \\ []) do
+    with {:ok, url} <- Cluster.url_for(operation, cluster),
+         req <- %K8s.Middleware.Request{cluster: cluster, method: operation.method},
+         {:ok, req} <- K8s.Middleware.Request.Initialize.call(req) do
+      
+      # ^ replace above with apply_middleware(cluster)
+
+      # Operation.data and body are deconstructed above @ L79...
+      [http_headers, raw_body] = apply_middlewares(cluster, req.headers, body)
+
+      {:ok, http_body} = encode(raw_body, operation.method)
 
       http_opts_params = build_http_params(opts[:params], operation.label_selector)
       opts_with_selector_params = Keyword.put(opts, :params, http_opts_params)
-      http_opts = Keyword.merge([ssl: request_options.ssl_options], opts_with_selector_params)
+
+      http_opts = Keyword.merge(req.opts, opts_with_selector_params)
 
       K8s.http_provider().request(
         operation.method,
@@ -107,10 +128,7 @@ defmodule K8s.Client.Runner.Base do
   end
 
   @spec encode(any(), atom()) :: {:ok, binary} | {:error, any}
-  def encode(body, http_method) when http_method in [:put, :patch, :post] do
-    Jason.encode(body)
-  end
-
+  def encode(body, http_method) when http_method in [:put, :patch, :post], do: Jason.encode(body)
   def encode(_, _), do: {:ok, ""}
 
   @spec build_http_params(nil | keyword | map, nil | K8s.Selector.t()) :: map()
diff --git a/lib/k8s/middleware.ex b/lib/k8s/middleware.ex
new file mode 100644
index 00000000..c52fc3b0
--- /dev/null
+++ b/lib/k8s/middleware.ex
@@ -0,0 +1,25 @@
+# defmodule K8s.Middleware do
+#   use Agent
+
+#   @doc """
+
+#   """
+#   @spec start_link(map) :: :ok
+#   def start_link(%{} = middlwares) do
+#     Agent.start_link(fn -> middlwares end, name: __MODULE__)
+#   end
+
+#   def list(cluster_name) do
+#     Agent.get(__MODULE__, fn state -> Map.get(state, cluster_name, []) end)
+#   end
+
+#   def register(cluster_name, )
+
+#   def value do
+#     Agent.get(__MODULE__, & &1)
+#   end
+
+#   def increment do
+#     Agent.update(__MODULE__, &(&1 + 1))
+#   end  
+# end
diff --git a/lib/k8s/middleware/registry.ex b/lib/k8s/middleware/registry.ex
new file mode 100644
index 00000000..8e2b18f3
--- /dev/null
+++ b/lib/k8s/middleware/registry.ex
@@ -0,0 +1,9 @@
+# Registry should be the agent... MIddleware should be the API
+# K8s.Middleware.request(cluster_name, ...?)
+# Adds a piece of middleware to the stack
+# K8s.Middleware.Registry.add(cluster_name, :request, func_or_module)
+#
+# K8s.Middleware.Registry.defaults(:request)
+#
+# Replaces the existing stack, including defaults
+# K8s.Middleware.Registry.set(cluster_name, :request, list(func_or_module))
diff --git a/lib/k8s/middleware/request.ex b/lib/k8s/middleware/request.ex
new file mode 100644
index 00000000..dca949a0
--- /dev/null
+++ b/lib/k8s/middleware/request.ex
@@ -0,0 +1,18 @@
+defmodule K8s.Middleware.Request do
+  @moduledoc "HTTP Request middleware"
+
+  @typedoc "MIddleware Request type"
+  @type t :: %__MODULE__{
+          cluster: atom(),
+          method: atom(),
+          url: String.t(),
+          body: String.t() | map() | list(map()) | nil,
+          headers: Keyword.t() | nil,
+          opts: Keyword.t() | nil
+        }
+
+  defstruct cluster: nil, method: nil, url: nil, body: nil, headers: [], opts: []
+
+  @doc "Request middleware callback"
+  @callback call(t()) :: {:ok, t()} | :error
+end
diff --git a/lib/k8s/middleware/request/base_url.ex b/lib/k8s/middleware/request/base_url.ex
new file mode 100644
index 00000000..5f2673d1
--- /dev/null
+++ b/lib/k8s/middleware/request/base_url.ex
@@ -0,0 +1,18 @@
+# defmodule K8s.Middleware.Request.BaseURL do
+#   @behaviour K8s.Middleware.Request
+
+#   @doc """
+
+#   ## Examples
+#       iex> conn = K8s.Conn.from_file("./test/support/kube-config.yaml")
+#       ...> K8s.Cluster.Registry.add(:test_cluster, conn)
+#       ...> request = %K8s.Middleware.Request{cluster: :test_cluster}
+#       ...> K8s.Middleware.Request.BaseURL.call(request)      
+#       {:ok, %K8s.Middleware.Request{cluster: :test_cluster, url: "https://localhost:6443"}}
+#   """
+#   @impl true
+#   def call(%K8s.Middleware.Request{} = req) do
+#     {:ok, url} <- Cluster.url_for(operation, cluster_name)
+#     {:ok, req}
+#   end
+# end
diff --git a/lib/k8s/middleware/request/initialize.ex b/lib/k8s/middleware/request/initialize.ex
new file mode 100644
index 00000000..9fd7ccb0
--- /dev/null
+++ b/lib/k8s/middleware/request/initialize.ex
@@ -0,0 +1,25 @@
+defmodule K8s.Middleware.Request.Initialize do
+  @behaviour K8s.Middleware.Request
+  @doc """
+
+  ## Examples
+      iex> conn = K8s.Conn.from_file("./test/support/kube-config.yaml")
+      ...> K8s.Cluster.Registry.add(:test_cluster, conn)
+      ...> request = %K8s.Middleware.Request{cluster: :test_cluster}
+      ...> K8s.Middleware.Request.Initialize.call(request)      
+      {:ok, %K8s.Middleware.Request{cluster: :test_cluster, headers: [{"Accept", "application/json"}, {"Content-Type", "application/json"}], opts: [ssl: [cert: ""]]}}
+  """
+  @impl true
+  def call(%K8s.Middleware.Request{cluster: cluster, method: method, headers: headers, opts: opts} = req) do
+    with {:ok, conn} <- K8s.Cluster.conn(cluster),
+         {:ok, request_options} <- K8s.Conn.RequestOptions.generate(conn) do
+      new_headers = K8s.http_provider().headers(method, request_options)
+      updated_headers = Keyword.merge(headers, new_headers)
+      updated_opts = Keyword.merge([ssl: request_options.ssl_options], opts)
+
+      updated_request = %K8s.Middleware.Request{req| headers: updated_headers, opts: updated_opts}
+
+      {:ok, updated_request}
+    end
+  end
+end
diff --git a/test/k8s/middleware_test.exs b/test/k8s/middleware_test.exs
new file mode 100644
index 00000000..56ed6b12
--- /dev/null
+++ b/test/k8s/middleware_test.exs
@@ -0,0 +1,13 @@
+defmodule K8s.MiddlewareTest do
+  use ExUnit.Case, async: true
+  doctest K8s.Middleware.Request.Initialize
+
+  # TODO:
+  # # K8s.Middleware.Request.EncodeBody
+  # # K8s.Middleware.Request.DefaultParams
+  # # K8s.Middleware.Request.DefaultHTTPOpts
+  # # K8s.Middleware.Request.BaseURL (DiscoveryCluster?) 
+  #     <- Actually this step is Cluster.url_for ... includes path...
+  #     <- May need to visit after JIT Registry
+  # Decide on K8s.Middleware behavior callback error types... {:error, t()} | {:error, String.t(), t()}
+end

From bfb4d52aa196575108fafdfb239f75e897aad4e5 Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Wed, 27 Nov 2019 12:07:22 -0800
Subject: [PATCH 02/14] Base.run/5 abstracted to middleware

Refactored Base to use a middleware-based approach to handling requests.

This is still a WIP.

* [ ] Cluster middleware registry
* [ ] Middleware error handling
---
 Makefile                                      |  5 +-
 lib/k8s/client/runner/base.ex                 | 78 +++++++++----------
 lib/k8s/middleware.ex                         | 17 +++-
 lib/k8s/middleware/request.ex                 |  3 +-
 lib/k8s/middleware/request/encode_body.ex     | 25 ++++++
 lib/k8s/middleware/request/initialize.ex      | 22 ++----
 test/k8s/client/runner/base_test.exs          | 11 ++-
 .../middleware/request/encode_body_test.exs   | 28 +++++++
 .../middleware/request/initialize_test.exs    | 23 ++++++
 test/k8s/middleware_test.exs                  | 13 ----
 10 files changed, 150 insertions(+), 75 deletions(-)
 create mode 100644 lib/k8s/middleware/request/encode_body.ex
 create mode 100644 test/k8s/middleware/request/encode_body_test.exs
 create mode 100644 test/k8s/middleware/request/initialize_test.exs
 delete mode 100644 test/k8s/middleware_test.exs

diff --git a/Makefile b/Makefile
index daa30558..cd998f7c 100644
--- a/Makefile
+++ b/Makefile
@@ -5,6 +5,9 @@ help: ## Show this help
 help:
 	@grep -E '^[\/a-zA-Z0-9._%-]+:.*?## .*$$' Makefile | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
 
+quality: ## Run code quality and test targets
+quality: lint test analyze
+
 clean: ## Remove build/doc dirs
 	rm -rf _build
 	rm -rf cover
@@ -33,7 +36,7 @@ test/master: ## Run test suite against master
 	K8S_SPEC=${MASTER_SWAGGER_PATH} mix test
 
 test/all: ## Run full test suite against 1.10+
-test/all: test/1.10 test/1.11 test/1.12 test/1.13 test/1.14 test/1.15	
+test/all: test/1.10 test/1.11 test/1.12 test/1.13 test/1.14 test/1.15
 
 test/%: ## Run full test suite against a specific k8s version
 	K8S_SPEC=test/support/swagger/$*.json mix test
diff --git a/lib/k8s/client/runner/base.ex b/lib/k8s/client/runner/base.ex
index 1cf945e1..ab71d96a 100644
--- a/lib/k8s/client/runner/base.ex
+++ b/lib/k8s/client/runner/base.ex
@@ -6,8 +6,8 @@ defmodule K8s.Client.Runner.Base do
   @type result_t :: {:ok, map() | reference()} | {:error, atom} | {:error, binary()}
 
   alias K8s.Cluster
-  alias K8s.Conn.RequestOptions
   alias K8s.Operation
+  alias K8s.Middleware.Request
 
   @doc """
   Runs a `K8s.Operation`.
@@ -72,64 +72,62 @@ defmodule K8s.Client.Runner.Base do
 
   @doc """
   Run an operation and pass `opts` to HTTPoison.
+  Destructures `Operation` data and passes as the HTTP body.
 
   See `run/2`
   """
-  @spec run(Operation.t(), binary | atom, keyword()) :: result_t
+  @spec run(Operation.t(), atom, keyword()) :: result_t
   def run(%Operation{} = operation, cluster_name, opts) when is_list(opts) do
     run(operation, cluster_name, operation.data, opts)
   end
 
-  def apply_middlewares(_cluster_name, headers, body) do
-    middlewares = [
-      fn headers, body ->
-        IO.puts("Inspecting some body: #{inspect(body)}")
-        [headers, body]
-      end
-    ]
-
-    state_args = [headers, body]
-
-    Enum.reduce(middlewares, state_args, fn middleware, args ->
-      apply(middleware, args)
-    end)
-  end
-
   @doc """
-  Run an operation with an alternative HTTP Body (map) and pass `opts` to HTTPoison.
+  Run an operation with an HTTP Body (map) and pass `opts` to HTTPoison.
   See `run/2`
   """
   @spec run(Operation.t(), atom, map(), keyword()) :: result_t
   def run(%Operation{} = operation, cluster, body, opts \\ []) do
-    with {:ok, url} <- Cluster.url_for(operation, cluster),
-         req <- %K8s.Middleware.Request{cluster: cluster, method: operation.method},
-         {:ok, req} <- K8s.Middleware.Request.Initialize.call(req) do
-      
-      # ^ replace above with apply_middleware(cluster)
+    with req <- new_request(cluster, operation, body, opts),
+         {:ok, url} <- Cluster.url_for(operation, cluster),
+         # TODO: handle error return here type
+         {:ok, req} <- apply_middleware(req) do
+      K8s.http_provider().request(req.method, url, req.body, req.headers, req.opts)
+    end
+  end
 
-      # Operation.data and body are deconstructed above @ L79...
-      [http_headers, raw_body] = apply_middlewares(cluster, req.headers, body)
+  # TODO: handle error return here type
+  @spec apply_middleware(Request.t()) :: {:ok, Request.t()}
+  defp apply_middleware(req) do
+    middlewares = K8s.Middleware.list(:request, req.cluster)
 
-      {:ok, http_body} = encode(raw_body, operation.method)
+    # TODO: handle error return here type
+    # case( K8s.Middleware.Request | K8s.Middleware.Error(mw, req, actual_error))
 
-      http_opts_params = build_http_params(opts[:params], operation.label_selector)
-      opts_with_selector_params = Keyword.put(opts, :params, http_opts_params)
+    updated_request =
+      Enum.reduce_while(middlewares, req, fn middleware, req ->
+        case apply(middleware, :call, [req]) do
+          {:ok, updated_request} ->
+            {:cont, updated_request}
 
-      http_opts = Keyword.merge(req.opts, opts_with_selector_params)
+          # TODO: handle error return here type
+          _error ->
+            {:halt, :handler_error_return_type_here}
+        end
+      end)
 
-      K8s.http_provider().request(
-        operation.method,
-        url,
-        http_body,
-        http_headers,
-        http_opts
-      )
-    end
+    {:ok, updated_request}
   end
 
-  @spec encode(any(), atom()) :: {:ok, binary} | {:error, any}
-  def encode(body, http_method) when http_method in [:put, :patch, :post], do: Jason.encode(body)
-  def encode(_, _), do: {:ok, ""}
+  @spec new_request(atom(), K8s.Operation.t(), list(map()) | map() | binary() | nil, Keyword.t()) ::
+          Request.t()
+  defp new_request(cluster, %Operation{} = operation, body, opts) do
+    req = %Request{cluster: cluster, method: operation.method, body: body}
+    http_opts_params = build_http_params(opts[:params], operation.label_selector)
+    opts_with_selector_params = Keyword.put(opts, :params, http_opts_params)
+
+    http_opts = Keyword.merge(req.opts, opts_with_selector_params)
+    %Request{req | opts: http_opts}
+  end
 
   @spec build_http_params(nil | keyword | map, nil | K8s.Selector.t()) :: map()
   defp build_http_params(nil, nil), do: %{}
diff --git a/lib/k8s/middleware.ex b/lib/k8s/middleware.ex
index c52fc3b0..25e171dd 100644
--- a/lib/k8s/middleware.ex
+++ b/lib/k8s/middleware.ex
@@ -1,4 +1,17 @@
-# defmodule K8s.Middleware do
+defmodule K8s.Middleware do
+  @moduledoc "Interface for interacting with cluster middleware"
+
+  @doc "Retrieve a list of middleware registered to a cluster"
+  @spec list(:request | :response, atom()) :: list(module())
+  def list(:request, _cluster) do
+    [
+      K8s.Middleware.Request.Initialize,
+      K8s.Middleware.Request.EncodeBody
+    ]
+  end
+end
+
+# Agent should be in Middleware.Registry
 #   use Agent
 
 #   @doc """
@@ -21,5 +34,5 @@
 
 #   def increment do
 #     Agent.update(__MODULE__, &(&1 + 1))
-#   end  
+#   end
 # end
diff --git a/lib/k8s/middleware/request.ex b/lib/k8s/middleware/request.ex
index dca949a0..b30a085c 100644
--- a/lib/k8s/middleware/request.ex
+++ b/lib/k8s/middleware/request.ex
@@ -1,7 +1,7 @@
 defmodule K8s.Middleware.Request do
   @moduledoc "HTTP Request middleware"
 
-  @typedoc "MIddleware Request type"
+  @typedoc "Middleware Request type"
   @type t :: %__MODULE__{
           cluster: atom(),
           method: atom(),
@@ -14,5 +14,6 @@ defmodule K8s.Middleware.Request do
   defstruct cluster: nil, method: nil, url: nil, body: nil, headers: [], opts: []
 
   @doc "Request middleware callback"
+  # TODO: handle error return here type
   @callback call(t()) :: {:ok, t()} | :error
 end
diff --git a/lib/k8s/middleware/request/encode_body.ex b/lib/k8s/middleware/request/encode_body.ex
new file mode 100644
index 00000000..16b2173a
--- /dev/null
+++ b/lib/k8s/middleware/request/encode_body.ex
@@ -0,0 +1,25 @@
+defmodule K8s.Middleware.Request.EncodeBody do
+  @moduledoc """
+  Naive JSON body encoder.
+
+  Encodes JSON payloads when given an modifiying HTTP verb, otherwise returns an empty string.
+  """
+  @behaviour K8s.Middleware.Request
+  alias K8s.Middleware.Request
+
+  @impl true
+  def call(%Request{method: method, body: body} = req) do
+    case encode(body, method) do
+      {:ok, encoded_body} ->
+        req = %Request{req | body: encoded_body}
+        {:ok, req}
+
+      error ->
+        error
+    end
+  end
+
+  @spec encode(any(), atom()) :: {:ok, binary} | {:error, any}
+  defp encode(body, http_method) when http_method in [:put, :patch, :post], do: Jason.encode(body)
+  defp encode(_, _), do: {:ok, ""}
+end
diff --git a/lib/k8s/middleware/request/initialize.ex b/lib/k8s/middleware/request/initialize.ex
index 9fd7ccb0..d58095f4 100644
--- a/lib/k8s/middleware/request/initialize.ex
+++ b/lib/k8s/middleware/request/initialize.ex
@@ -1,24 +1,18 @@
 defmodule K8s.Middleware.Request.Initialize do
+  @moduledoc """
+  Initializes a request with connection details (header and HTTPoison opts) from `K8s.Conn.RequestOptions`
+  """
   @behaviour K8s.Middleware.Request
-  @doc """
+  alias K8s.Middleware.Request
 
-  ## Examples
-      iex> conn = K8s.Conn.from_file("./test/support/kube-config.yaml")
-      ...> K8s.Cluster.Registry.add(:test_cluster, conn)
-      ...> request = %K8s.Middleware.Request{cluster: :test_cluster}
-      ...> K8s.Middleware.Request.Initialize.call(request)      
-      {:ok, %K8s.Middleware.Request{cluster: :test_cluster, headers: [{"Accept", "application/json"}, {"Content-Type", "application/json"}], opts: [ssl: [cert: ""]]}}
-  """
   @impl true
-  def call(%K8s.Middleware.Request{cluster: cluster, method: method, headers: headers, opts: opts} = req) do
+  def call(%Request{cluster: cluster, method: method, headers: headers, opts: opts} = req) do
     with {:ok, conn} <- K8s.Cluster.conn(cluster),
          {:ok, request_options} <- K8s.Conn.RequestOptions.generate(conn) do
-      new_headers = K8s.http_provider().headers(method, request_options)
-      updated_headers = Keyword.merge(headers, new_headers)
+      request_option_headers = K8s.http_provider().headers(method, request_options)
+      updated_headers = Keyword.merge(headers, request_option_headers)
       updated_opts = Keyword.merge([ssl: request_options.ssl_options], opts)
-
-      updated_request = %K8s.Middleware.Request{req| headers: updated_headers, opts: updated_opts}
-
+      updated_request = %Request{req | headers: updated_headers, opts: updated_opts}
       {:ok, updated_request}
     end
   end
diff --git a/test/k8s/client/runner/base_test.exs b/test/k8s/client/runner/base_test.exs
index 608d58ae..f5d9f43b 100644
--- a/test/k8s/client/runner/base_test.exs
+++ b/test/k8s/client/runner/base_test.exs
@@ -15,7 +15,7 @@ defmodule K8s.Client.Runner.BaseTest do
 
     def request(:get, @namespaced_url, _, _, _), do: render(nil)
 
-    def request(:post, @namespaced_url, _, _, _), do: render(nil)
+    def request(:post, @namespaced_url, body, _, _), do: render(body)
 
     def request(:get, @namespaced_url <> "/test", _body, _headers, _opts) do
       render(nil)
@@ -45,11 +45,11 @@ defmodule K8s.Client.Runner.BaseTest do
     def request(
           :post,
           @base_url <> "/api/v1/namespaces/default/pods/nginx/eviction",
-          _body,
+          body,
           _headers,
           _opts
         ) do
-      render(nil)
+      render(body)
     end
   end
 
@@ -98,7 +98,10 @@ defmodule K8s.Client.Runner.BaseTest do
       labels = %{"env" => "test"}
       body = put_in(make_namespace("test"), ["metadata", "labels"], labels)
 
-      assert {:ok, _} = Base.run(operation, cluster, body)
+      assert {:ok, body} = Base.run(operation, cluster, body)
+
+      assert body ==
+               ~s({"apiVersion":"v1","kind":"Namespace","metadata":{"labels":{"env":"test"},"name":"test"}})
     end
 
     test "running an operation with a custom HTTP body and options", %{
diff --git a/test/k8s/middleware/request/encode_body_test.exs b/test/k8s/middleware/request/encode_body_test.exs
new file mode 100644
index 00000000..af7904d9
--- /dev/null
+++ b/test/k8s/middleware/request/encode_body_test.exs
@@ -0,0 +1,28 @@
+defmodule K8s.Middleware.Request.EncodeBodyTest do
+  use ExUnit.Case, async: true
+
+  test "encode JSON payloads when given a modifying HTTP verb" do
+    data = %{"hello" => "world"}
+    request = %K8s.Middleware.Request{body: data, method: :put}
+    {:ok, %{body: body}} = K8s.Middleware.Request.EncodeBody.call(request)
+
+    assert body == ~s({"hello":"world"})
+  end
+
+  test "returns an empty string if not a modifying verb" do
+    data = %{"hello" => "world"}
+    request = %K8s.Middleware.Request{body: data, method: :get}
+    {:ok, %{body: body}} = K8s.Middleware.Request.EncodeBody.call(request)
+
+    assert body == ""
+  end
+
+  # TODO: handle error return here type
+  # test "failure" do
+  #   data = [should: :fail]
+  #   request = %K8s.Middleware.Request{body: data, method: :post}
+  #   {:ok, %{body: body}} = K8s.Middleware.Request.EncodeBody.call(request)
+
+  #   assert body == ""
+  # end
+end
diff --git a/test/k8s/middleware/request/initialize_test.exs b/test/k8s/middleware/request/initialize_test.exs
new file mode 100644
index 00000000..b570c4a3
--- /dev/null
+++ b/test/k8s/middleware/request/initialize_test.exs
@@ -0,0 +1,23 @@
+defmodule K8s.Middleware.Request.InitializeTest do
+  use ExUnit.Case, async: true
+
+  test "initializes a request headers from K8s.Conn.RequestOptions" do
+    conn = K8s.Conn.from_file("./test/support/kube-config.yaml")
+    K8s.Cluster.Registry.add(:test_cluster, conn)
+
+    request = %K8s.Middleware.Request{cluster: :test_cluster}
+    {:ok, %{headers: headers}} = K8s.Middleware.Request.Initialize.call(request)
+
+    assert headers == [{"Accept", "application/json"}, {"Content-Type", "application/json"}]
+  end
+
+  test "initializes a HTTPoison options from K8s.Conn.RequestOptions" do
+    conn = K8s.Conn.from_file("./test/support/kube-config.yaml")
+    K8s.Cluster.Registry.add(:test_cluster, conn)
+
+    request = %K8s.Middleware.Request{cluster: :test_cluster}
+    {:ok, %{opts: opts}} = K8s.Middleware.Request.Initialize.call(request)
+
+    assert Keyword.has_key?(opts, :ssl)
+  end
+end
diff --git a/test/k8s/middleware_test.exs b/test/k8s/middleware_test.exs
deleted file mode 100644
index 56ed6b12..00000000
--- a/test/k8s/middleware_test.exs
+++ /dev/null
@@ -1,13 +0,0 @@
-defmodule K8s.MiddlewareTest do
-  use ExUnit.Case, async: true
-  doctest K8s.Middleware.Request.Initialize
-
-  # TODO:
-  # # K8s.Middleware.Request.EncodeBody
-  # # K8s.Middleware.Request.DefaultParams
-  # # K8s.Middleware.Request.DefaultHTTPOpts
-  # # K8s.Middleware.Request.BaseURL (DiscoveryCluster?) 
-  #     <- Actually this step is Cluster.url_for ... includes path...
-  #     <- May need to visit after JIT Registry
-  # Decide on K8s.Middleware behavior callback error types... {:error, t()} | {:error, String.t(), t()}
-end

From e13381c6fd81861185eb9ce5ea0cd3ddb63a1336 Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Wed, 27 Nov 2019 12:43:14 -0800
Subject: [PATCH 03/14] middleware error handling

---
 CHANGELOG.md                                  |  3 ++
 lib/k8s/client/runner/base.ex                 | 29 ++------------
 lib/k8s/middleware.ex                         | 39 ++++++++++++++++++-
 lib/k8s/middleware/error.ex                   | 17 ++++++++
 lib/k8s/middleware/request.ex                 |  3 +-
 .../middleware/request/encode_body_test.exs   | 19 +++++----
 6 files changed, 73 insertions(+), 37 deletions(-)
 create mode 100644 lib/k8s/middleware/error.ex

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 12a77658..3e3966bb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Added
+- Request middleware support
+
 ## [0.4.0] - 2019-08-29
 
 ### Changed
diff --git a/lib/k8s/client/runner/base.ex b/lib/k8s/client/runner/base.ex
index ab71d96a..c8bc2a31 100644
--- a/lib/k8s/client/runner/base.ex
+++ b/lib/k8s/client/runner/base.ex
@@ -3,7 +3,8 @@ defmodule K8s.Client.Runner.Base do
   Base HTTP processor for `K8s.Client`
   """
 
-  @type result_t :: {:ok, map() | reference()} | {:error, atom} | {:error, binary()}
+  @type result_t ::
+          {:ok, map() | reference()} | {:error, atom | binary() | K8s.Middleware.Error.t()}
 
   alias K8s.Cluster
   alias K8s.Operation
@@ -89,35 +90,11 @@ defmodule K8s.Client.Runner.Base do
   def run(%Operation{} = operation, cluster, body, opts \\ []) do
     with req <- new_request(cluster, operation, body, opts),
          {:ok, url} <- Cluster.url_for(operation, cluster),
-         # TODO: handle error return here type
-         {:ok, req} <- apply_middleware(req) do
+         {:ok, req} <- K8s.Middleware.run(req) do
       K8s.http_provider().request(req.method, url, req.body, req.headers, req.opts)
     end
   end
 
-  # TODO: handle error return here type
-  @spec apply_middleware(Request.t()) :: {:ok, Request.t()}
-  defp apply_middleware(req) do
-    middlewares = K8s.Middleware.list(:request, req.cluster)
-
-    # TODO: handle error return here type
-    # case( K8s.Middleware.Request | K8s.Middleware.Error(mw, req, actual_error))
-
-    updated_request =
-      Enum.reduce_while(middlewares, req, fn middleware, req ->
-        case apply(middleware, :call, [req]) do
-          {:ok, updated_request} ->
-            {:cont, updated_request}
-
-          # TODO: handle error return here type
-          _error ->
-            {:halt, :handler_error_return_type_here}
-        end
-      end)
-
-    {:ok, updated_request}
-  end
-
   @spec new_request(atom(), K8s.Operation.t(), list(map()) | map() | binary() | nil, Keyword.t()) ::
           Request.t()
   defp new_request(cluster, %Operation{} = operation, body, opts) do
diff --git a/lib/k8s/middleware.ex b/lib/k8s/middleware.ex
index 25e171dd..8a87f371 100644
--- a/lib/k8s/middleware.ex
+++ b/lib/k8s/middleware.ex
@@ -1,14 +1,49 @@
 defmodule K8s.Middleware do
   @moduledoc "Interface for interacting with cluster middleware"
 
+  alias K8s.Middleware.{Error, Request}
+
   @doc "Retrieve a list of middleware registered to a cluster"
   @spec list(:request | :response, atom()) :: list(module())
   def list(:request, _cluster) do
     [
-      K8s.Middleware.Request.Initialize,
-      K8s.Middleware.Request.EncodeBody
+      Request.Initialize,
+      Request.EncodeBody
     ]
   end
+
+  @doc """
+  Applies middlewares registered to a `K8s.Cluster` to a `K8s.Middleware.Request`
+  """
+  @spec run(Request.t()) :: {:ok, Request.t()} | {:error, Error.t()}
+  def run(req) do
+    middlewares = list(:request, req.cluster)
+
+    result =
+      Enum.reduce_while(middlewares, req, fn middleware, req ->
+        case apply(middleware, :call, [req]) do
+          {:ok, updated_request} ->
+            {:cont, updated_request}
+
+          {:error, error} ->
+            {:halt, error(middleware, req, error)}
+        end
+      end)
+
+    case result do
+      %Request{} -> {:ok, result}
+      %Error{} -> {:error, result}
+    end
+  end
+
+  @spec error(module(), Request.t(), any()) :: Error.t()
+  defp error(middleware, req, error) do
+    %K8s.Middleware.Error{
+      middleware: middleware,
+      error: error,
+      request: req
+    }
+  end
 end
 
 # Agent should be in Middleware.Registry
diff --git a/lib/k8s/middleware/error.ex b/lib/k8s/middleware/error.ex
new file mode 100644
index 00000000..dc00439e
--- /dev/null
+++ b/lib/k8s/middleware/error.ex
@@ -0,0 +1,17 @@
+defmodule K8s.Middleware.Error do
+  @moduledoc "Encapsulates middleware process errors"
+
+  @typedoc """
+  Middleware processing error
+
+  * `middleware` middleware module that caused the error
+  * `request` `K8s.Middleware.Request`
+  * `error` actual error, can be `any()` type
+  """
+  @type t :: %__MODULE__{
+          request: K8s.Middleware.Request.t() | nil,
+          middleware: module(),
+          error: any()
+        }
+  defstruct [:request, :middleware, :error]
+end
diff --git a/lib/k8s/middleware/request.ex b/lib/k8s/middleware/request.ex
index b30a085c..b0114654 100644
--- a/lib/k8s/middleware/request.ex
+++ b/lib/k8s/middleware/request.ex
@@ -14,6 +14,5 @@ defmodule K8s.Middleware.Request do
   defstruct cluster: nil, method: nil, url: nil, body: nil, headers: [], opts: []
 
   @doc "Request middleware callback"
-  # TODO: handle error return here type
-  @callback call(t()) :: {:ok, t()} | :error
+  @callback call(t()) :: {:ok, t()} | {:error, any()}
 end
diff --git a/test/k8s/middleware/request/encode_body_test.exs b/test/k8s/middleware/request/encode_body_test.exs
index af7904d9..cf362fb2 100644
--- a/test/k8s/middleware/request/encode_body_test.exs
+++ b/test/k8s/middleware/request/encode_body_test.exs
@@ -17,12 +17,17 @@ defmodule K8s.Middleware.Request.EncodeBodyTest do
     assert body == ""
   end
 
-  # TODO: handle error return here type
-  # test "failure" do
-  #   data = [should: :fail]
-  #   request = %K8s.Middleware.Request{body: data, method: :post}
-  #   {:ok, %{body: body}} = K8s.Middleware.Request.EncodeBody.call(request)
+  test "returns an error when the body cannot be encoded" do
+    data = [should: :fail]
+    request = %K8s.Middleware.Request{body: data, method: :post}
+    result = K8s.Middleware.Request.EncodeBody.call(request)
 
-  #   assert body == ""
-  # end
+    assert result ==
+             {:error,
+              %Protocol.UndefinedError{
+                description: "Jason.Encoder protocol must always be explicitly implemented",
+                protocol: Jason.Encoder,
+                value: {:should, :fail}
+              }}
+  end
 end

From 653bd353bc3a32e39f96e0f56ad1c5bf34366883 Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Wed, 27 Nov 2019 12:56:00 -0800
Subject: [PATCH 04/14] wip - registry

---
 Makefile                              |  2 +-
 coveralls.json                        |  3 ++-
 lib/k8s/middleware.ex                 | 37 ++++++---------------------
 lib/k8s/middleware/registry.ex        | 30 +++++++++++++++-------
 test/k8s/middleware/registry_test.exs |  3 +++
 test/k8s/middleware_test.exs          |  3 +++
 6 files changed, 38 insertions(+), 40 deletions(-)
 create mode 100644 test/k8s/middleware/registry_test.exs
 create mode 100644 test/k8s/middleware_test.exs

diff --git a/Makefile b/Makefile
index cd998f7c..e921f9f6 100644
--- a/Makefile
+++ b/Makefile
@@ -6,7 +6,7 @@ help:
 	@grep -E '^[\/a-zA-Z0-9._%-]+:.*?## .*$$' Makefile | sort | awk 'BEGIN {FS = ":.*?## "}; {printf "\033[36m%-30s\033[0m %s\n", $$1, $$2}'
 
 quality: ## Run code quality and test targets
-quality: lint test analyze
+quality: cov lint analyze
 
 clean: ## Remove build/doc dirs
 	rm -rf _build
diff --git a/coveralls.json b/coveralls.json
index 6dba97d0..c656300f 100644
--- a/coveralls.json
+++ b/coveralls.json
@@ -13,6 +13,7 @@
     "def.+(.+\/\/.+).+do"
   ],
   "coverage_options": {
-    "treat_no_relevant_lines_as_covered": true
+    "treat_no_relevant_lines_as_covered": true,
+    "minimum_coverage": 85
   }
 }
diff --git a/lib/k8s/middleware.ex b/lib/k8s/middleware.ex
index 8a87f371..fddb7de1 100644
--- a/lib/k8s/middleware.ex
+++ b/lib/k8s/middleware.ex
@@ -3,15 +3,20 @@ defmodule K8s.Middleware do
 
   alias K8s.Middleware.{Error, Request}
 
-  @doc "Retrieve a list of middleware registered to a cluster"
-  @spec list(:request | :response, atom()) :: list(module())
-  def list(:request, _cluster) do
+  def defaults(:request) do
     [
       Request.Initialize,
       Request.EncodeBody
     ]
   end
 
+  @doc "Retrieve a list of middleware registered to a cluster"
+  @spec list(:request | :response, atom()) :: list(module())
+  def list(:request, _cluster) do
+    # TODO interact w/ registry
+    defaults(:request)
+  end
+
   @doc """
   Applies middlewares registered to a `K8s.Cluster` to a `K8s.Middleware.Request`
   """
@@ -45,29 +50,3 @@ defmodule K8s.Middleware do
     }
   end
 end
-
-# Agent should be in Middleware.Registry
-#   use Agent
-
-#   @doc """
-
-#   """
-#   @spec start_link(map) :: :ok
-#   def start_link(%{} = middlwares) do
-#     Agent.start_link(fn -> middlwares end, name: __MODULE__)
-#   end
-
-#   def list(cluster_name) do
-#     Agent.get(__MODULE__, fn state -> Map.get(state, cluster_name, []) end)
-#   end
-
-#   def register(cluster_name, )
-
-#   def value do
-#     Agent.get(__MODULE__, & &1)
-#   end
-
-#   def increment do
-#     Agent.update(__MODULE__, &(&1 + 1))
-#   end
-# end
diff --git a/lib/k8s/middleware/registry.ex b/lib/k8s/middleware/registry.ex
index 8e2b18f3..11cf4655 100644
--- a/lib/k8s/middleware/registry.ex
+++ b/lib/k8s/middleware/registry.ex
@@ -1,9 +1,21 @@
-# Registry should be the agent... MIddleware should be the API
-# K8s.Middleware.request(cluster_name, ...?)
-# Adds a piece of middleware to the stack
-# K8s.Middleware.Registry.add(cluster_name, :request, func_or_module)
-#
-# K8s.Middleware.Registry.defaults(:request)
-#
-# Replaces the existing stack, including defaults
-# K8s.Middleware.Registry.set(cluster_name, :request, list(func_or_module))
+defmodule K8s.Middleware.Registry do
+  @moduledoc """
+  Cluster middleware registry
+  """
+  use Agent
+
+  @spec start_link(map()) :: :ok
+  def start_link(registry = %{}) do
+    Agent.start_link(fn -> registry end, name: __MODULE__)
+  end
+
+  @doc "Adds a middleware to the end of the middleware stack"
+  @spec add(atom, :request | :response, module()) :: :ok
+  def add(cluster, type, middleware) do
+  end
+
+  @doc "Sets/replaces the middleware stack"
+  @spec set(atom, :request | :response, list(module())) :: :ok
+  def set(cluster, type, middlewares) do
+  end
+end
diff --git a/test/k8s/middleware/registry_test.exs b/test/k8s/middleware/registry_test.exs
new file mode 100644
index 00000000..9394a25a
--- /dev/null
+++ b/test/k8s/middleware/registry_test.exs
@@ -0,0 +1,3 @@
+defmodule K8s.Middleware.RegistryTest do
+  use ExUnit.Case, async: true
+end
diff --git a/test/k8s/middleware_test.exs b/test/k8s/middleware_test.exs
new file mode 100644
index 00000000..4ee97df6
--- /dev/null
+++ b/test/k8s/middleware_test.exs
@@ -0,0 +1,3 @@
+defmodule K8s.MiddlewareTest do
+  use ExUnit.Case, async: true
+end

From 15820c5533be3f3327befe474ce9c2cee43e5a5f Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Wed, 27 Nov 2019 13:27:33 -0800
Subject: [PATCH 05/14] registry state impl

---
 lib/k8s/application.ex                |  6 ++-
 lib/k8s/middleware/registry.ex        | 32 ++++++++++++---
 test/k8s/middleware/registry_test.exs | 56 ++++++++++++++++++++++++++-
 3 files changed, 86 insertions(+), 8 deletions(-)

diff --git a/lib/k8s/application.ex b/lib/k8s/application.ex
index 4e42b73b..b83dd4ce 100644
--- a/lib/k8s/application.ex
+++ b/lib/k8s/application.ex
@@ -8,7 +8,11 @@ defmodule K8s.Application do
     :ets.new(K8s.Conn, [:set, :public, :named_table])
     :ets.new(K8s.Cluster.Group, [:set, :public, :named_table])
 
-    children = [{K8s.Cluster.Registry, []}]
+    # TODO: register defaults for each cluster
+    children = [
+      {K8s.Middleware.Registry, []},
+      {K8s.Cluster.Registry, []}
+    ]
 
     opts = [strategy: :one_for_one, name: K8s.Supervisor]
     Supervisor.start_link(children, opts)
diff --git a/lib/k8s/middleware/registry.ex b/lib/k8s/middleware/registry.ex
index 11cf4655..396b1e42 100644
--- a/lib/k8s/middleware/registry.ex
+++ b/lib/k8s/middleware/registry.ex
@@ -1,21 +1,41 @@
 defmodule K8s.Middleware.Registry do
-  @moduledoc """
-  Cluster middleware registry
-  """
+  @moduledoc "Cluster middleware registry"
   use Agent
 
-  @spec start_link(map()) :: :ok
-  def start_link(registry = %{}) do
-    Agent.start_link(fn -> registry end, name: __MODULE__)
+  @spec start_link(Keyword.t()) :: Agent.on_start()
+  def start_link(_opts) do
+    Agent.start_link(fn -> %{} end, name: __MODULE__)
   end
 
   @doc "Adds a middleware to the end of the middleware stack"
   @spec add(atom, :request | :response, module()) :: :ok
   def add(cluster, type, middleware) do
+    Agent.update(__MODULE__, fn registry ->
+      cluster_middlewares = Map.get(registry, cluster, %{})
+      middleware_list = Map.get(cluster_middlewares, type, [])
+
+      updated_middleware_list = middleware_list ++ [middleware]
+      updated_cluster_middlewares = Map.put(cluster_middlewares, type, updated_middleware_list)
+
+      put_in(registry, [cluster], updated_cluster_middlewares)
+    end)
   end
 
   @doc "Sets/replaces the middleware stack"
   @spec set(atom, :request | :response, list(module())) :: :ok
   def set(cluster, type, middlewares) do
+    Agent.update(__MODULE__, fn registry ->
+      cluster_middlewares = Map.get(registry, cluster, %{})
+      updated_cluster_middlewares = Map.put(cluster_middlewares, type, middlewares)
+
+      put_in(registry, [cluster], updated_cluster_middlewares)
+    end)
+  end
+
+  @doc "Returns middleware stack for a cluster and (request or response)"
+  @spec list(atom, :request | :response) :: :ok
+  def list(cluster, type) do
+    registry = Agent.get(__MODULE__, & &1[cluster]) || %{}
+    Map.get(registry, type, [])
   end
 end
diff --git a/test/k8s/middleware/registry_test.exs b/test/k8s/middleware/registry_test.exs
index 9394a25a..5a4dda76 100644
--- a/test/k8s/middleware/registry_test.exs
+++ b/test/k8s/middleware/registry_test.exs
@@ -1,3 +1,57 @@
 defmodule K8s.Middleware.RegistryTest do
-  use ExUnit.Case, async: true
+  use ExUnit.Case, async: false
+  alias K8s.Middleware.Registry
+
+  defmodule BarMiddleware do
+    @behaviour K8s.Middleware.Request
+    def call(req), do: {:ok, req}
+  end
+
+  defmodule FooMiddleware do
+    @behaviour K8s.Middleware.Request
+    def call(req), do: {:ok, req}
+  end
+
+  describe "list/2" do
+    test "returns an empty list when none are registered", %{test: id} do
+      assert [] == Registry.list(id, :request)
+    end
+
+    test "returns registered middlewares modules", %{test: id} do
+      mw = K8s.Middleware.RegistryTest.FooMiddleware
+      :ok = Registry.add(id, :request, mw)
+      middlewares = Registry.list(id, :request)
+
+      assert middlewares == [K8s.Middleware.RegistryTest.FooMiddleware]
+    end
+  end
+
+  test "adding a middleware", %{test: id} do
+    mw = K8s.Middleware.RegistryTest.FooMiddleware
+    :ok = Registry.add(id, :request, mw)
+
+    middlewares = Agent.get(Registry, & &1[id])
+    assert middlewares == %{request: [K8s.Middleware.RegistryTest.FooMiddleware]}
+  end
+
+  test "setting the middleware stack", %{test: id} do
+    mw = K8s.Middleware.RegistryTest.FooMiddleware
+    :ok = Registry.add(id, :request, mw)
+
+    stack = [
+      K8s.Middleware.RegistryTest.BarMiddleware,
+      K8s.Middleware.RegistryTest.FooMiddleware
+    ]
+
+    :ok = Registry.set(id, :request, stack)
+
+    middlewares = Agent.get(Registry, & &1[id])
+
+    assert middlewares == %{
+             request: [
+               K8s.Middleware.RegistryTest.BarMiddleware,
+               K8s.Middleware.RegistryTest.FooMiddleware
+             ]
+           }
+  end
 end

From 99fb305023bfec1c013a60e04191010e7a139c2a Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Wed, 27 Nov 2019 13:28:51 -0800
Subject: [PATCH 06/14] dialyzer

---
 coveralls.json                        | 2 +-
 test/k8s/middleware/registry_test.exs | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/coveralls.json b/coveralls.json
index c656300f..94cff1ad 100644
--- a/coveralls.json
+++ b/coveralls.json
@@ -14,6 +14,6 @@
   ],
   "coverage_options": {
     "treat_no_relevant_lines_as_covered": true,
-    "minimum_coverage": 85
+    "minimum_coverage": 88
   }
 }
diff --git a/test/k8s/middleware/registry_test.exs b/test/k8s/middleware/registry_test.exs
index 5a4dda76..41dbdee0 100644
--- a/test/k8s/middleware/registry_test.exs
+++ b/test/k8s/middleware/registry_test.exs
@@ -4,11 +4,13 @@ defmodule K8s.Middleware.RegistryTest do
 
   defmodule BarMiddleware do
     @behaviour K8s.Middleware.Request
+    @impl true
     def call(req), do: {:ok, req}
   end
 
   defmodule FooMiddleware do
     @behaviour K8s.Middleware.Request
+    @impl true
     def call(req), do: {:ok, req}
   end
 

From da8ed397e714490d923853bc8a81156bc8bf1a03 Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Wed, 27 Nov 2019 13:36:32 -0800
Subject: [PATCH 07/14] typespecs

---
 lib/k8s/middleware.ex          | 9 ++++++++-
 lib/k8s/middleware/registry.ex | 6 +++---
 2 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/lib/k8s/middleware.ex b/lib/k8s/middleware.ex
index fddb7de1..f1f83924 100644
--- a/lib/k8s/middleware.ex
+++ b/lib/k8s/middleware.ex
@@ -3,6 +3,13 @@ defmodule K8s.Middleware do
 
   alias K8s.Middleware.{Error, Request}
 
+  @typedoc "Middleware type"
+  @type type_t :: :request | :response
+
+  @typedoc "List of middlewares"
+  @type stack_t :: list(module())
+
+  @spec defaults(K8s.Middleware.type_t()) :: stack_t
   def defaults(:request) do
     [
       Request.Initialize,
@@ -11,7 +18,7 @@ defmodule K8s.Middleware do
   end
 
   @doc "Retrieve a list of middleware registered to a cluster"
-  @spec list(:request | :response, atom()) :: list(module())
+  @spec list(type_t, atom()) :: stack_t
   def list(:request, _cluster) do
     # TODO interact w/ registry
     defaults(:request)
diff --git a/lib/k8s/middleware/registry.ex b/lib/k8s/middleware/registry.ex
index 396b1e42..1e315b77 100644
--- a/lib/k8s/middleware/registry.ex
+++ b/lib/k8s/middleware/registry.ex
@@ -8,7 +8,7 @@ defmodule K8s.Middleware.Registry do
   end
 
   @doc "Adds a middleware to the end of the middleware stack"
-  @spec add(atom, :request | :response, module()) :: :ok
+  @spec add(atom, K8s.Middleware.type_t(), module()) :: :ok
   def add(cluster, type, middleware) do
     Agent.update(__MODULE__, fn registry ->
       cluster_middlewares = Map.get(registry, cluster, %{})
@@ -22,7 +22,7 @@ defmodule K8s.Middleware.Registry do
   end
 
   @doc "Sets/replaces the middleware stack"
-  @spec set(atom, :request | :response, list(module())) :: :ok
+  @spec set(atom, K8s.Middleware.type_t(), list(module())) :: :ok
   def set(cluster, type, middlewares) do
     Agent.update(__MODULE__, fn registry ->
       cluster_middlewares = Map.get(registry, cluster, %{})
@@ -33,7 +33,7 @@ defmodule K8s.Middleware.Registry do
   end
 
   @doc "Returns middleware stack for a cluster and (request or response)"
-  @spec list(atom, :request | :response) :: :ok
+  @spec list(atom, K8s.Middleware.type_t()) :: K8s.Middleware.stack_t()
   def list(cluster, type) do
     registry = Agent.get(__MODULE__, & &1[cluster]) || %{}
     Map.get(registry, type, [])

From 344e818d9bf0711c2cf292e2f59a456cc886a72a Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Wed, 27 Nov 2019 13:44:38 -0800
Subject: [PATCH 08/14] auto reg mw defaults at boot

---
 lib/k8s/cluster/registry.ex |  1 +
 lib/k8s/middleware.ex       | 22 +++++++++-------------
 2 files changed, 10 insertions(+), 13 deletions(-)

diff --git a/lib/k8s/cluster/registry.ex b/lib/k8s/cluster/registry.ex
index 9eeb2623..fb74534b 100644
--- a/lib/k8s/cluster/registry.ex
+++ b/lib/k8s/cluster/registry.ex
@@ -33,6 +33,7 @@ defmodule K8s.Cluster.Registry do
   @spec add(atom(), K8s.Conn.t()) :: {:ok, atom()} | {:error, atom()}
   def add(cluster, conn) do
     with true <- :ets.insert(K8s.Conn, {cluster, conn}),
+         :ok <- K8s.Middleware.initialize(cluster),
          {:ok, resources_by_group} <- Discovery.resources_by_group(cluster) do
       K8s.Cluster.Group.insert_all(cluster, resources_by_group)
       K8s.Sys.Event.cluster_registered(%{}, %{cluster: cluster})
diff --git a/lib/k8s/middleware.ex b/lib/k8s/middleware.ex
index f1f83924..d9564eb9 100644
--- a/lib/k8s/middleware.ex
+++ b/lib/k8s/middleware.ex
@@ -10,18 +10,14 @@ defmodule K8s.Middleware do
   @type stack_t :: list(module())
 
   @spec defaults(K8s.Middleware.type_t()) :: stack_t
-  def defaults(:request) do
-    [
-      Request.Initialize,
-      Request.EncodeBody
-    ]
-  end
-
-  @doc "Retrieve a list of middleware registered to a cluster"
-  @spec list(type_t, atom()) :: stack_t
-  def list(:request, _cluster) do
-    # TODO interact w/ registry
-    defaults(:request)
+  def defaults(:request), do: [Request.Initialize, Request.EncodeBody]
+  def defaults(:response), do: []
+
+  @doc "Initialize a clusters middleware stacks"
+  @spec initialize(atom) :: :ok
+  def initialize(cluster) do
+    K8s.Middleware.Registry.set(cluster, :request, defaults(:request))
+    K8s.Middleware.Registry.set(cluster, :response, defaults(:response))
   end
 
   @doc """
@@ -29,7 +25,7 @@ defmodule K8s.Middleware do
   """
   @spec run(Request.t()) :: {:ok, Request.t()} | {:error, Error.t()}
   def run(req) do
-    middlewares = list(:request, req.cluster)
+    middlewares = K8s.Middleware.Registry.list(req.cluster, :request)
 
     result =
       Enum.reduce_while(middlewares, req, fn middleware, req ->

From 40b1446d9b6f097fe46ffd0cddbfcdda4c657a9d Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Wed, 27 Nov 2019 14:03:05 -0800
Subject: [PATCH 09/14] httpoison update for hackney honor ciphor issue

---
 README.md |  1 +
 mix.lock  | 34 +++++++++++++++++-----------------
 2 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/README.md b/README.md
index f080c02c..7c7d87aa 100644
--- a/README.md
+++ b/README.md
@@ -26,6 +26,7 @@
 * Kube config file parsing
 * Certificate and service account based auth
 * Pluggable auth providers
+* HTTP Request middleware
 * Macro free; fast compile & fast startup
 
 ## Installation
diff --git a/mix.lock b/mix.lock
index fd1e309b..c80cc5fd 100644
--- a/mix.lock
+++ b/mix.lock
@@ -2,36 +2,36 @@
   "assertions": {:hex, :assertions, "0.14.1", "352391bbcecbfce7d4594df1267ee4ca7a8b79981859a4befdf62dd798769c42", [:mix], [], "hexpm"},
   "bunt": {:hex, :bunt, "0.2.0", "951c6e801e8b1d2cbe58ebbd3e616a869061ddadcc4863d0a2182541acae9a38", [:mix], [], "hexpm"},
   "bypass": {:hex, :bypass, "1.0.0", "b78b3dcb832a71aca5259c1a704b2e14b55fd4e1327ff942598b4e7d1a7ad83d", [:mix], [{:plug, "~> 1.7", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 1.0 or ~> 2.0", [hex: :plug_cowboy, repo: "hexpm", optional: false]}], "hexpm"},
-  "certifi": {:hex, :certifi, "2.4.2", "75424ff0f3baaccfd34b1214184b6ef616d89e420b258bb0a5ea7d7bc628f7f0", [:rebar3], [{:parse_trans, "~>3.3", [hex: :parse_trans, repo: "hexpm", optional: false]}], "hexpm"},
+  "certifi": {:hex, :certifi, "2.5.1", "867ce347f7c7d78563450a18a6a28a8090331e77fa02380b4a21962a65d36ee5", [:rebar3], [{:parse_trans, "~>3.3", [hex: :parse_trans, repo: "hexpm", optional: false]}], "hexpm"},
   "cowboy": {:hex, :cowboy, "2.6.1", "f2e06f757c337b3b311f9437e6e072b678fcd71545a7b2865bdaa154d078593f", [:rebar3], [{:cowlib, "~> 2.7.0", [hex: :cowlib, repo: "hexpm", optional: false]}, {:ranch, "~> 1.7.1", [hex: :ranch, repo: "hexpm", optional: false]}], "hexpm"},
   "cowlib": {:hex, :cowlib, "2.7.0", "3ef16e77562f9855a2605900cedb15c1462d76fb1be6a32fc3ae91973ee543d2", [:rebar3], [], "hexpm"},
-  "credo": {:hex, :credo, "1.0.0", "aaa40fdd0543a0cf8080e8c5949d8c25f0a24e4fc8c1d83d06c388f5e5e0ea42", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
-  "dialyxir": {:hex, :dialyxir, "1.0.0-rc.6", "78e97d9c0ff1b5521dd68041193891aebebce52fc3b93463c0a6806874557d7d", [:mix], [{:erlex, "~> 0.2.1", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm"},
-  "earmark": {:hex, :earmark, "1.3.2", "b840562ea3d67795ffbb5bd88940b1bed0ed9fa32834915125ea7d02e35888a5", [:mix], [], "hexpm"},
-  "erlex": {:hex, :erlex, "0.2.1", "cee02918660807cbba9a7229cae9b42d1c6143b768c781fa6cee1eaf03ad860b", [:mix], [], "hexpm"},
-  "ex_doc": {:hex, :ex_doc, "0.20.2", "1bd0dfb0304bade58beb77f20f21ee3558cc3c753743ae0ddbb0fd7ba2912331", [:mix], [{:earmark, "~> 1.3", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.10", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
-  "excoveralls": {:hex, :excoveralls, "0.10.4", "b86230f0978bbc630c139af5066af7cd74fd16536f71bc047d1037091f9f63a9", [:mix], [{:hackney, "~> 1.13", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
-  "file_system": {:hex, :file_system, "0.2.6", "fd4dc3af89b9ab1dc8ccbcc214a0e60c41f34be251d9307920748a14bf41f1d3", [:mix], [], "hexpm"},
-  "hackney": {:hex, :hackney, "1.15.0", "287a5d2304d516f63e56c469511c42b016423bcb167e61b611f6bad47e3ca60e", [:rebar3], [{:certifi, "2.4.2", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "6.0.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "1.0.2", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.4", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
-  "httpoison": {:hex, :httpoison, "1.5.0", "71ae9f304bdf7f00e9cd1823f275c955bdfc68282bc5eb5c85c3a9ade865d68e", [:mix], [{:hackney, "~> 1.8", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm"},
+  "credo": {:hex, :credo, "1.0.5", "fdea745579f8845315fe6a3b43e2f9f8866839cfbc8562bb72778e9fdaa94214", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
+  "dialyxir": {:hex, :dialyxir, "1.0.0-rc.7", "6287f8f2cb45df8584317a4be1075b8c9b8a69de8eeb82b4d9e6c761cf2664cd", [:mix], [{:erlex, ">= 0.2.5", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm"},
+  "earmark": {:hex, :earmark, "1.4.3", "364ca2e9710f6bff494117dbbd53880d84bebb692dafc3a78eb50aa3183f2bfd", [:mix], [], "hexpm"},
+  "erlex": {:hex, :erlex, "0.2.5", "e51132f2f472e13d606d808f0574508eeea2030d487fc002b46ad97e738b0510", [:mix], [], "hexpm"},
+  "ex_doc": {:hex, :ex_doc, "0.21.2", "caca5bc28ed7b3bdc0b662f8afe2bee1eedb5c3cf7b322feeeb7c6ebbde089d6", [:mix], [{:earmark, "~> 1.3.3 or ~> 1.4", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
+  "excoveralls": {:hex, :excoveralls, "0.12.1", "a553c59f6850d0aff3770e4729515762ba7c8e41eedde03208182a8dc9d0ce07", [:mix], [{:hackney, "~> 1.0", [hex: :hackney, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm"},
+  "file_system": {:hex, :file_system, "0.2.7", "e6f7f155970975789f26e77b8b8d8ab084c59844d8ecfaf58cbda31c494d14aa", [:mix], [], "hexpm"},
+  "hackney": {:hex, :hackney, "1.15.2", "07e33c794f8f8964ee86cebec1a8ed88db5070e52e904b8f12209773c1036085", [:rebar3], [{:certifi, "2.5.1", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "6.0.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~>1.1", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.5", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
+  "httpoison": {:hex, :httpoison, "1.6.2", "ace7c8d3a361cebccbed19c283c349b3d26991eff73a1eaaa8abae2e3c8089b6", [:mix], [{:hackney, "~> 1.15 and >= 1.15.2", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm"},
   "idna": {:hex, :idna, "6.0.0", "689c46cbcdf3524c44d5f3dde8001f364cd7608a99556d8fbd8239a5798d4c10", [:rebar3], [{:unicode_util_compat, "0.4.1", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm"},
   "jason": {:hex, :jason, "1.1.2", "b03dedea67a99223a2eaf9f1264ce37154564de899fd3d8b9a21b1a6fd64afe7", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm"},
-  "makeup": {:hex, :makeup, "0.8.0", "9cf32aea71c7fe0a4b2e9246c2c4978f9070257e5c9ce6d4a28ec450a839b55f", [:mix], [{:nimble_parsec, "~> 0.5.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm"},
-  "makeup_elixir": {:hex, :makeup_elixir, "0.13.0", "be7a477997dcac2e48a9d695ec730b2d22418292675c75aa2d34ba0909dcdeda", [:mix], [{:makeup, "~> 0.8", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm"},
+  "makeup": {:hex, :makeup, "1.0.0", "671df94cf5a594b739ce03b0d0316aa64312cee2574b6a44becb83cd90fb05dc", [:mix], [{:nimble_parsec, "~> 0.5.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm"},
+  "makeup_elixir": {:hex, :makeup_elixir, "0.14.0", "cf8b7c66ad1cff4c14679698d532f0b5d45a3968ffbcbfd590339cb57742f1ae", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm"},
   "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm"},
   "mime": {:hex, :mime, "1.3.1", "30ce04ab3175b6ad0bdce0035cba77bba68b813d523d1aac73d9781b4d193cf8", [:mix], [], "hexpm"},
-  "mimerl": {:hex, :mimerl, "1.0.2", "993f9b0e084083405ed8252b99460c4f0563e41729ab42d9074fd5e52439be88", [:rebar3], [], "hexpm"},
+  "mimerl": {:hex, :mimerl, "1.2.0", "67e2d3f571088d5cfd3e550c383094b47159f3eee8ffa08e64106cdf5e981be3", [:rebar3], [], "hexpm"},
   "mix_test_watch": {:hex, :mix_test_watch, "0.9.0", "c72132a6071261893518fa08e121e911c9358713f62794a90c95db59042af375", [:mix], [{:file_system, "~> 0.2.1 or ~> 0.3", [hex: :file_system, repo: "hexpm", optional: false]}], "hexpm"},
-  "nimble_parsec": {:hex, :nimble_parsec, "0.5.0", "90e2eca3d0266e5c53f8fbe0079694740b9c91b6747f2b7e3c5d21966bba8300", [:mix], [], "hexpm"},
+  "nimble_parsec": {:hex, :nimble_parsec, "0.5.2", "1d71150d5293d703a9c38d4329da57d3935faed2031d64bc19e77b654ef2d177", [:mix], [], "hexpm"},
   "notion": {:hex, :notion, "0.2.0", "0facad61b5a071dc27fff3afb8630868178f3b6369d047b5eba1c3cc86d44e37", [:mix], [{:telemetry, "~> 0.4.0", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm"},
   "parse_trans": {:hex, :parse_trans, "3.3.0", "09765507a3c7590a784615cfd421d101aec25098d50b89d7aa1d66646bc571c1", [:rebar3], [], "hexpm"},
   "plug": {:hex, :plug, "1.7.1", "8516d565fb84a6a8b2ca722e74e2cd25ca0fc9d64f364ec9dbec09d33eb78ccd", [:mix], [{:mime, "~> 1.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.0", [hex: :plug_crypto, repo: "hexpm", optional: false]}], "hexpm"},
   "plug_cowboy": {:hex, :plug_cowboy, "2.0.1", "d798f8ee5acc86b7d42dbe4450b8b0dadf665ce588236eb0a751a132417a980e", [:mix], [{:cowboy, "~> 2.5", [hex: :cowboy, repo: "hexpm", optional: false]}, {:plug, "~> 1.7", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm"},
   "plug_crypto": {:hex, :plug_crypto, "1.0.0", "18e49317d3fa343f24620ed22795ec29d4a5e602d52d1513ccea0b07d8ea7d4d", [:mix], [], "hexpm"},
   "ranch": {:hex, :ranch, "1.7.1", "6b1fab51b49196860b733a49c07604465a47bdb78aa10c1c16a3d199f7f8c881", [:rebar3], [], "hexpm"},
-  "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.4", "f0eafff810d2041e93f915ef59899c923f4568f4585904d010387ed74988e77b", [:make, :mix, :rebar3], [], "hexpm"},
-  "stream_data": {:hex, :stream_data, "0.4.2", "fa86b78c88ec4eaa482c0891350fcc23f19a79059a687760ddcf8680aac2799b", [:mix], [], "hexpm"},
-  "telemetry": {:hex, :telemetry, "0.4.0", "8339bee3fa8b91cb84d14c2935f8ecf399ccd87301ad6da6b71c09553834b2ab", [:rebar3], [], "hexpm"},
+  "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.5", "6eaf7ad16cb568bb01753dbbd7a95ff8b91c7979482b95f38443fe2c8852a79b", [:make, :mix, :rebar3], [], "hexpm"},
+  "stream_data": {:hex, :stream_data, "0.4.3", "62aafd870caff0849a5057a7ec270fad0eb86889f4d433b937d996de99e3db25", [:mix], [], "hexpm"},
+  "telemetry": {:hex, :telemetry, "0.4.1", "ae2718484892448a24470e6aa341bc847c3277bfb8d4e9289f7474d752c09c7f", [:rebar3], [], "hexpm"},
   "unicode_util_compat": {:hex, :unicode_util_compat, "0.4.1", "d869e4c68901dd9531385bb0c8c40444ebf624e60b6962d95952775cac5e90cd", [:rebar3], [], "hexpm"},
   "yamerl": {:hex, :yamerl, "0.7.0", "e51dba652dce74c20a88294130b48051ebbbb0be7d76f22de064f0f3ccf0aaf5", [:rebar3], [], "hexpm"},
   "yaml_elixir": {:hex, :yaml_elixir, "2.4.0", "2f444abc3c994c902851fde56b6a9cb82895c291c05a0490a289035c2e62ae71", [:mix], [{:yamerl, "~> 0.7", [hex: :yamerl, repo: "hexpm", optional: false]}], "hexpm"},

From 474e4ebce2f67a978917fd23c6408c4524add082 Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Wed, 27 Nov 2019 17:04:30 -0800
Subject: [PATCH 10/14] appease the dialyzer

---
 .gitignore                     |  4 ++++
 .travis.yml                    |  3 +++
 lib/k8s/client/runner/base.ex  | 21 ++++++++++++++-------
 lib/k8s/client/runner/watch.ex |  4 ++--
 lib/k8s/cluster.ex             |  2 +-
 mix.exs                        |  3 ++-
 6 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/.gitignore b/.gitignore
index ce1fb630..a9fdb933 100644
--- a/.gitignore
+++ b/.gitignore
@@ -28,3 +28,7 @@ k8s-*.tar
 
 # Ignore master version as its always pulled w/ make test/all
 test/support/swagger/master.json
+
+# Ignore dialyzer files
+/priv/plts/*.plt
+/priv/plts/*.plt.hash
diff --git a/.travis.yml b/.travis.yml
index e53fa42a..af9eee71 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,8 @@
 language: elixir
 sudo: false
+cache:
+  directories:
+    - priv/plts
 elixir:
   - 1.8
   - 1.7
diff --git a/lib/k8s/client/runner/base.ex b/lib/k8s/client/runner/base.ex
index c8bc2a31..dbdc91fd 100644
--- a/lib/k8s/client/runner/base.ex
+++ b/lib/k8s/client/runner/base.ex
@@ -4,7 +4,14 @@ defmodule K8s.Client.Runner.Base do
   """
 
   @type result_t ::
-          {:ok, map() | reference()} | {:error, atom | binary() | K8s.Middleware.Error.t()}
+          {:ok, map() | reference()}
+          # | {:error, atom | binary() | K8s.Middleware.Error.t()}
+          | {:error, K8s.Middleware.Error.t()}
+          | {:error, :cluster_not_registered | :missing_required_param | :unsupported_api_version}
+          | {:error, binary()}
+
+  @typedoc "Acceptable HTTP body types"
+  @type body_t :: list(map()) | map() | binary() | nil
 
   alias K8s.Cluster
   alias K8s.Operation
@@ -88,22 +95,22 @@ defmodule K8s.Client.Runner.Base do
   """
   @spec run(Operation.t(), atom, map(), keyword()) :: result_t
   def run(%Operation{} = operation, cluster, body, opts \\ []) do
-    with req <- new_request(cluster, operation, body, opts),
-         {:ok, url} <- Cluster.url_for(operation, cluster),
+    with {:ok, url} <- Cluster.url_for(operation, cluster),
+         req <- new_request(cluster, url, operation, body, opts),
          {:ok, req} <- K8s.Middleware.run(req) do
-      K8s.http_provider().request(req.method, url, req.body, req.headers, req.opts)
+      K8s.http_provider().request(req.method, req.url, req.body, req.headers, req.opts)
     end
   end
 
-  @spec new_request(atom(), K8s.Operation.t(), list(map()) | map() | binary() | nil, Keyword.t()) ::
+  @spec new_request(atom(), String.t(), K8s.Operation.t(), body_t, Keyword.t()) ::
           Request.t()
-  defp new_request(cluster, %Operation{} = operation, body, opts) do
+  defp new_request(cluster, url, %Operation{} = operation, body, opts) do
     req = %Request{cluster: cluster, method: operation.method, body: body}
     http_opts_params = build_http_params(opts[:params], operation.label_selector)
     opts_with_selector_params = Keyword.put(opts, :params, http_opts_params)
 
     http_opts = Keyword.merge(req.opts, opts_with_selector_params)
-    %Request{req | opts: http_opts}
+    %Request{req | opts: http_opts, url: url}
   end
 
   @spec build_http_params(nil | keyword | map, nil | K8s.Selector.t()) :: map()
diff --git a/lib/k8s/client/runner/watch.ex b/lib/k8s/client/runner/watch.ex
index b81c11ad..ab3f6cbc 100644
--- a/lib/k8s/client/runner/watch.ex
+++ b/lib/k8s/client/runner/watch.ex
@@ -78,8 +78,8 @@ defmodule K8s.Client.Runner.Watch do
         rv = parse_resource_version(payload)
         {:ok, rv}
 
-      {:error, error} ->
-        {:error, error}
+      error ->
+        error
     end
   end
 
diff --git a/lib/k8s/cluster.ex b/lib/k8s/cluster.ex
index e494a084..fcfbd189 100644
--- a/lib/k8s/cluster.ex
+++ b/lib/k8s/cluster.ex
@@ -18,7 +18,7 @@ defmodule K8s.Cluster do
 
   """
   @spec url_for(Operation.t(), atom) :: {:ok, binary} | {:error, atom(), binary()}
-  def url_for(%Operation{api_version: api_version, name: name, verb: verb} = operation, cluster) do
+  def url_for(%Operation{api_version: api_version, name: name, verb: _verb} = operation, cluster) do
     with {:ok, conn} <- Cluster.conn(cluster),
          {:ok, name} <- Cluster.Group.resource_name_for_kind(cluster, api_version, name),
          operation <- Map.put(operation, :name, name),
diff --git a/mix.exs b/mix.exs
index 57b34aaa..68796f80 100644
--- a/mix.exs
+++ b/mix.exs
@@ -25,7 +25,8 @@ defmodule K8s.MixProject do
       elixirc_paths: elixirc_paths(Mix.env()),
       dialyzer: [
         plt_add_apps: [:mix, :eex],
-        ignore_warnings: ".dialyzer_ignore.exs"
+        ignore_warnings: ".dialyzer_ignore.exs",
+        plt_file: {:no_warn, "priv/plts/k8s.plt"}
       ]
     ]
   end

From 59269b12b973eb2f12cb87fb2cf72765e49c085e Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Wed, 27 Nov 2019 17:16:09 -0800
Subject: [PATCH 11/14] K8s.Middleware.run/2 tests

---
 lib/k8s/middleware.ex        |  4 ++++
 test/k8s/middleware_test.exs | 26 ++++++++++++++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/lib/k8s/middleware.ex b/lib/k8s/middleware.ex
index d9564eb9..ba6a0edb 100644
--- a/lib/k8s/middleware.ex
+++ b/lib/k8s/middleware.ex
@@ -26,7 +26,11 @@ defmodule K8s.Middleware do
   @spec run(Request.t()) :: {:ok, Request.t()} | {:error, Error.t()}
   def run(req) do
     middlewares = K8s.Middleware.Registry.list(req.cluster, :request)
+    run(req, middlewares)
+  end
 
+  @spec run(Request.t(), list(module())) :: {:ok, Request.t()} | {:error, Error.t()}
+  def run(req, middlewares) do
     result =
       Enum.reduce_while(middlewares, req, fn middleware, req ->
         case apply(middleware, :call, [req]) do
diff --git a/test/k8s/middleware_test.exs b/test/k8s/middleware_test.exs
index 4ee97df6..109478d4 100644
--- a/test/k8s/middleware_test.exs
+++ b/test/k8s/middleware_test.exs
@@ -1,3 +1,29 @@
 defmodule K8s.MiddlewareTest do
   use ExUnit.Case, async: true
+
+  defmodule EnvLabeler do
+    @behaviour K8s.Middleware.Request
+
+    @impl true
+    def call(%{body: body} = req) do
+      updated_body = put_in(body, ["metadata", "labels"], %{"env" => "prod"})
+      updated_req = %K8s.Middleware.Request{req | body: updated_body}
+      {:ok, updated_req}
+    end
+  end
+
+  describe "run/2" do
+    test "Applies middleware to a request" do
+      req = %K8s.Middleware.Request{
+        cluster: :foo,
+        url: "http://example.com",
+        method: :post,
+        body: %{"metadata" => %{"name" => "nginx"}}
+      }
+
+      {:ok, %{body: body}} = K8s.Middleware.run(req, [K8s.MiddlewareTest.EnvLabeler])
+
+      assert body == %{"metadata" => %{"name" => "nginx", "labels" => %{"env" => "prod"}}}
+    end
+  end
 end

From 284a4a7719f62fa9c6188afba6f8c8a0ac7873a5 Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Wed, 27 Nov 2019 17:18:29 -0800
Subject: [PATCH 12/14] Bump version to 0.5.0

---
 mix.exs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mix.exs b/mix.exs
index 68796f80..182d3cf8 100644
--- a/mix.exs
+++ b/mix.exs
@@ -5,7 +5,7 @@ defmodule K8s.MixProject do
     [
       app: :k8s,
       description: "Kubernetes API Client for Elixir",
-      version: "0.4.0",
+      version: "0.5.0",
       elixir: "~> 1.6",
       start_permanent: Mix.env() == :prod,
       deps: deps(),

From d1f7162f30bd2d0f0b5faf06c60068630a0ce677 Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Wed, 27 Nov 2019 17:25:50 -0800
Subject: [PATCH 13/14] setting prerelease version

---
 mix.exs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mix.exs b/mix.exs
index 182d3cf8..4af00f67 100644
--- a/mix.exs
+++ b/mix.exs
@@ -5,7 +5,7 @@ defmodule K8s.MixProject do
     [
       app: :k8s,
       description: "Kubernetes API Client for Elixir",
-      version: "0.5.0",
+      version: "0.5.0-alpha.1",
       elixir: "~> 1.6",
       start_permanent: Mix.env() == :prod,
       deps: deps(),

From 2c7a9855b0fa4bc2acbdd968287dee5dd10e58d3 Mon Sep 17 00:00:00 2001
From: Cory O'Daniel <cory@coryodaniel.com>
Date: Wed, 27 Nov 2019 17:27:05 -0800
Subject: [PATCH 14/14] setting prerelease version

---
 mix.exs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mix.exs b/mix.exs
index 4af00f67..2a37f1a7 100644
--- a/mix.exs
+++ b/mix.exs
@@ -5,7 +5,7 @@ defmodule K8s.MixProject do
     [
       app: :k8s,
       description: "Kubernetes API Client for Elixir",
-      version: "0.5.0-alpha.1",
+      version: "0.5.0-rc.1",
       elixir: "~> 1.6",
       start_permanent: Mix.env() == :prod,
       deps: deps(),