Extract all HAProxy stats, return pretty HTML on web

lib/ha_handler.ex

@@ -1,7 +1,20 @@
 defmodule HAHandler do
-  @moduledoc false
+  @moduledoc """
+  This top-level module only contains generic configuration helpers.
+  """
 
-  def http_port, do: Application.get_env(:ha_handler, :http_port)
+  # Mix is not available in releases, and these things are static
-  def haproxy_socket, do: Application.get_env(:ha_handler, :haproxy_socket)
+  # anyway (@variables are evaluated at compile time).
-  def acme_challenge_path, do: Application.get_env(:ha_handler, :acme_challenge_path)
+  @otp_app Mix.Project.config()[:app]
+  @version Mix.Project.config[:version]
+  @env Mix.env
+
+  def http_port, do: Application.get_env(@otp_app, :http_port)
+  def haproxy_socket, do: Application.get_env(@otp_app, :haproxy_socket)
+  def acme_challenge_path, do: Application.get_env(@otp_app, :acme_challenge_path)
+  def static_path(), do: Application.app_dir(@otp_app, "priv/static/")
+
+  def otp_app(), do: @otp_app
+  def version(), do: @version
+  def env(), do: @env
 end

lib/ha_handler/ha_proxy.ex

@@ -34,28 +34,52 @@ defmodule HAHandler.HAProxy do
     end
   end
 
+  defp extract_stats(data) do
+    extracted = for entry <- data do
+      for mapping <- entry do
+        case mapping do
+          %{
+            "id" => id,
+            "objType" => type,
+            "field" => %{"name" => name},
+            "value" => %{"value" => value},
+          } ->
+            %{:id => id, :type => type, :field => name, :value => value}
+          _ ->
+            nil
+        end
+      end
+    end
+
+    extracted
+    |> List.flatten()
+    |> Enum.group_by(
+      fn mapping -> {mapping.type, mapping.id} end,
+      fn mapping -> %{mapping.field => mapping.value} end
+    )
+    |> Enum.map(
+      fn {{type, id}, grouped_mappings} ->
+        grouped_mappings
+        |> Enum.reduce(fn l, r -> Map.merge(l,r) end)
+        |> Map.put("type", type)
+        |> Map.put("id", id)
+      end
+    )
+    |> Enum.group_by(
+      fn entry -> Map.get(entry, "type") end
+    )
+  end
+
   @doc """
   Executes and parse the output of the `show stats` HAProxy command, returning
   a list of Maps.
-
-  TODO: extract more informations from stats output.
   """
   def get_stats() do
     case execute("show stat json") do
       {:ok, raw} ->
         case Poison.decode(raw) do
           {:ok, data} ->
-            for entry <- data do
+            extract_stats(data)
-              attrs =
-                entry
-                |> Enum.filter(fn m -> get_in(m, ["field", "name"]) == "pxname" end)
-                |> Enum.at(0)
-
-              %{
-                type: attrs |> Map.get("objType"),
-                name: get_in(attrs, ["value", "value"])
-              }
-            end
 
           {:error, err} ->
             {:error, err}

lib/ha_handler/web/controller.ex

@@ -3,16 +3,30 @@ defmodule HAHandler.Web.Controller do
 
 	alias HAHandler.HAProxy
 
-	def index(conn) do
+	@templates_dir "lib/ha_handler/web/templates"
-		{:ok, hostname} = :inet.gethostname()
 
-		stats = HAProxy.get_stats()
+	defp render(conn, template, assigns) do
-		reply = "OK #{hostname}"
+		template_path = Path.join(@templates_dir, template)
-					<> "\nPROXY: "
+		quoted = EEx.compile_file(template_path)
-					<> inspect(stats)
+		{body, _binding} = Code.eval_quoted(quoted, assigns)
 
 		conn
-		|> put_resp_content_type("text/plain")
+		|> put_resp_content_type("text/html")
-		|> send_resp(200, reply)
+		|> send_resp(200, body)
+	end
+
+	def index(conn) do
+		{:ok, hostname} = :net_adm.dns_hostname(:net_adm.localhost)
+
+		stats = HAProxy.get_stats()
+
+		assigns = [
+			haproxy_stats: stats,
+			hostname: hostname,
+			otp_app: HAHandler.otp_app(),
+			version: HAHandler.version(),
+			env: HAHandler.env()
+		]
+		render(conn, "index.html.eex", assigns)
 	end
 end

lib/ha_handler/web/router.ex

@@ -8,7 +8,7 @@ defmodule HAHandler.Web.Router do
 
 	use Plug.Router
 
-	import HAHandler, only: [acme_challenge_path: 0]
+	import HAHandler, only: [acme_challenge_path: 0, static_path: 0]
 
 	alias HAHandler.Web.Controller
 
@@ -24,6 +24,10 @@ defmodule HAHandler.Web.Router do
 		at: "/.well-known/acme-challenge/",
 		from: acme_challenge_path()
 
+	plug Plug.Static,
+		at: "/static",
+		from: static_path()
+
 	plug :match
 	plug :dispatch
 

lib/ha_handler/web/templates/index.html.eex

@@ -0,0 +1,103 @@
+<!DOCTYPE html>
+<html>
+	<head>
+		<title>[HA] <%= hostname %></title>
+		<link rel="stylesheet" href="/static/app.css">
+	</head>
+	<body>
+		<main>
+			<div>
+				<img id="logo" src="/static/logo.svg" />
+			</div>
+
+			<h1>Recycled Cloud HA handler</h1>
+
+			<p>
+				This service supervises the various components of
+				the Recycled Cloud's High Availability
+				infrastruture. Documentation and source code can be
+				found on <a
+				href="https://code.recycled.cloud/RecycledCloud/ha-handler">our
+			software forge</a>.
+			</p>
+
+			<hr />
+
+			<h2>Handler</h2>
+
+			<%= otp_app %> <b>v<%= version %></b> (<%= env %>) running on <b><%= hostname %></b>
+
+			<hr />
+
+			<h2>HAProxy</h2>
+
+			<h3>Frontends</h3>
+			<table>
+				<thead>
+					<tr>
+						<th>Name</th>
+						<th>Status</th>
+						<th>Bytes in</th>
+						<th>Bytes out</th>
+					</tr>
+				</thead>
+				<tbody>
+					<%= for entry <- Map.get(haproxy_stats, "Frontend") do %>
+						<tr>
+							<td><%= entry["pxname"] %></td>
+							<td><%= entry["status"] %></td>
+							<td><%= entry["bin"] %></td>
+							<td><%= entry["bout"] %></td>
+						</tr>
+					<% end %>
+				</tbody>
+			</table>
+
+			<h3>Backends</h3>
+			<table>
+				<thead>
+					<tr>
+						<th>#</th>
+						<th>Name</th>
+						<th>Status</th>
+						<th>algo</th>
+					</tr>
+				</thead>
+				<tbody>
+					<%= for entry <- Map.get(haproxy_stats, "Backend") do %>
+						<tr>
+							<td><%= entry["iid"] %></td>
+							<td><%= entry["pxname"] %></td>
+							<td><%= entry["status"] %></td>
+							<td><%= entry["algo"] %></td>
+						</tr>
+					<% end %>
+				</tbody>
+			</table>
+
+			<h3>Servers</h3>
+			<table>
+				<thead>
+					<tr>
+						<th>#</th>
+						<th>Name</th>
+						<th>Status</th>
+						<th>Mode</th>
+						<th>Address</th>
+					</tr>
+				</thead>
+				<tbody>
+					<%= for entry <- Map.get(haproxy_stats, "Server") do %>
+						<tr>
+							<td><%= entry["iid"] %></td>
+							<td><%= entry["pxname"] %></td>
+							<td><%= entry["status"] %></td>
+							<td><%= entry["mode"] %></td>
+							<td><%= entry["addr"] %></td>
+						</tr>
+					<% end %>
+				</tbody>
+			</table>
+		</main>
+	</body>
+</html>

priv/static/app.css

@@ -0,0 +1,34 @@
+main {
+	width: 500px;
+	margin-top: 50px;
+	margin-left: auto;
+	margin-right: auto;
+	text-align: center;
+}
+
+h2 {
+	margin-top: 0;
+	margin-bottom: 5px;
+	font-size: 20px;
+}
+
+h3 {
+	margin-top: 0;
+	margin-bottom: 5px;
+	font-size: 12px;
+	text-align: left;
+}
+
+table {
+	width: 100%;
+	text-align: left;
+}
+
+table thead {
+  background-color: #D6EED6;
+}
+
+#logo {
+	width: 200px;
+}
+

priv/static/logo.svg

@@ -0,0 +1 @@
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