Add error messages for creating/editing pipeline stages

lib/frenzy_web/controllers/pipeline_controller.ex

@@ -49,45 +49,70 @@ defmodule FrenzyWeb.PipelineController do
     stage = conn.assigns[:stage]
     {:ok, options_json} = Jason.encode(stage.options, pretty: true)
 
+    changeset =
+      PipelineStage.changeset(stage, %{
+        options: options_json
+      })
+
     render(conn, "edit.html", %{
       feed: feed,
       stage: stage,
-      options: options_json
+      changeset: changeset
     })
   end
 
-  def update(conn, %{"options" => options_json}) do
+  def update(conn, %{"pipeline_stage" => %{"options" => options_json}}) do
     feed = conn.assigns[:feed]
     stage = conn.assigns[:stage]
-    {:ok, options} = Jason.decode(options_json)
+
+    with {:ok, options} <- Jason.decode(options_json) do
       changeset = PipelineStage.changeset(stage, %{options: options})
       {:ok, _stage} = Repo.update(changeset)
 
       conn
       |> put_flash(:info, "Pipeline Stage updated")
       |> redirect(to: Routes.feed_path(Endpoint, :edit, feed.id))
+    else
+      result ->
+        error_changeset = PipelineStage.changeset(stage, %{options: options_json})
+
+        conn
+        |> put_flash(:error, "Unable to update pipeline stage: #{inspect(result)}")
+        |> render("edit.html", %{
+          feed: feed,
+          stage: stage,
+          changeset: error_changeset
+        })
+    end
   end
 
   def new(conn, _params) do
-    changeset = PipelineStage.changeset(%PipelineStage{}, %{})
+    feed = conn.assigns[:feed]
+
+    changeset =
+      PipelineStage.changeset(%PipelineStage{}, %{
+        index: feed.pipeline_stages |> Enum.count(),
+        options: "{}"
+      })
 
     render(conn, "new.html", %{
-      feed: conn.assigns[:feed],
+      feed: feed,
       changeset: changeset
     })
   end
 
   def create(conn, %{
-        "pipeline_stage" => %{
+        "pipeline_stage" =>
+          %{
             "index" => index,
             "module_name" => module_name,
             "options" => options_json
-        }
+          } = params
       }) do
     feed = conn.assigns[:feed]
-    {index, _} = Integer.parse(index)
-    {:ok, options} = Jason.decode(options_json)
 
+    with {index, _} <- Integer.parse(index),
+         {:ok, options} <- Jason.decode(options_json) do
       changeset =
         Ecto.build_assoc(feed, :pipeline_stages, %{
           index: index,
@@ -100,6 +125,17 @@ defmodule FrenzyWeb.PipelineController do
       conn
       |> put_flash(:info, "Pipeline Stage created")
       |> redirect(to: Routes.feed_path(Endpoint, :edit, feed.id))
+    else
+      result ->
+        error_changeset = PipelineStage.changeset(%PipelineStage{}, params)
+
+        conn
+        |> put_flash(:error, "Unable to create pipeline stage: #{inspect(result)}")
+        |> render("new.html", %{
+          feed: feed,
+          changeset: error_changeset
+        })
+    end
   end
 
   def delete(conn, _params) do

lib/frenzy_web/router.ex

@@ -53,7 +53,7 @@ defmodule FrenzyWeb.Router do
     # resources "/pipelines", PipelineController, only: [:edit, :update, :new, :create]
 
     get "/feeds/:feed_id/pipelines/:stage_id/edit", PipelineController, :edit
-    post "/feeds/:feed_id/pipelines/:stage_id/update", PipelineController, :update
+    put "/feeds/:feed_id/pipelines/:stage_id/update", PipelineController, :update
     delete "/feeds/:feed_id/pipelines/:stage_id/delete", PipelineController, :delete
     get "/feeds/:feed_id/pipelines/new", PipelineController, :new
     post "/feeds/:feed_id/pipelines/create", PipelineController, :create

lib/frenzy_web/templates/pipeline/edit.html.eex

@@ -2,8 +2,8 @@
 <h3>Feed: <%= @feed.title %></h3>
 <h3>Module: <code><%= @stage.module_name %></code></h3>
 
-<%= form_for @conn, Routes.pipeline_path(@conn, :update, @feed.id, @stage.id), fn f -> %>
-  <%= textarea f, :options, value: @options, class: "form-control", rows: 15, style: "font-family: monospace;" %>
+<%= form_for @changeset, Routes.pipeline_path(@conn, :update, @feed.id, @stage.id), fn f -> %>
+  <%= textarea f, :options, class: "form-control", rows: 15, style: "font-family: monospace;" %>
   <%= submit "Update", class: "btn btn-primary mt-2" %>
 <% end %>
 

lib/frenzy_web/templates/pipeline/new.html.eex

@@ -10,13 +10,13 @@
   <div class="form-group row">
     <label class="col-sm-2 col-form-label" for="index">Index</label>
     <div class="col-sm-10">
-      <%= number_input f, :index, value: "#{@feed.pipeline_stages |> Enum.count()}", class: "form-control" %>
+      <%= number_input f, :index, class: "form-control" %>
     </div>
   </div>
   <div class="form-group row">
     <label class="col-sm-2 col-form-label" for="options">Options</label>
     <div class="col-sm-10">
-      <%= textarea f, :options, value: "{}", class: "form-control", rows: 15, style: "font-family: monospace;" %>
+      <%= textarea f, :options, class: "form-control", rows: 15, style: "font-family: monospace;" %>
     </div>
   </div>
   <div class="form-group row">