From ec7e4db437011f9654198a84f28b0df5a901b3a3 Mon Sep 17 00:00:00 2001
From: Johannes Christ <jc@jchri.st>
Date: Mon, 10 Apr 2023 01:59:13 +0200
Subject: [PATCH] Add dirtyconfig capability

---
 config/dev.exs            |  1 -
 config/prod.exs           |  1 -
 lib/crow/worker.ex        | 18 +++++++++++++-----
 test/crow/worker_test.exs | 16 +++++++++++++++-
 4 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/config/dev.exs b/config/dev.exs
index 8b13789..e69de29 100644
--- a/config/dev.exs
+++ b/config/dev.exs
@@ -1 +0,0 @@
-
diff --git a/config/prod.exs b/config/prod.exs
index 8b13789..e69de29 100644
--- a/config/prod.exs
+++ b/config/prod.exs
@@ -1 +0,0 @@
-
diff --git a/lib/crow/worker.ex b/lib/crow/worker.ex
index c146426..8dc90b0 100644
--- a/lib/crow/worker.ex
+++ b/lib/crow/worker.ex
@@ -18,17 +18,22 @@ defmodule Crow.Worker do
     {:ok, hostname} = :inet.gethostname()
     :ok = :gen_tcp.send(conn, '# munin node at #{hostname}\n')
     Logger.debug("accepted connection from #{:inet.ntoa(ip)}:#{port}.")
-    {:noreply, conn}
+    {:noreply, {[], conn}}
   end
 
   @doc false
   @impl true
-  def handle_info({:tcp, sock, "cap" <> _rest}, state) do
-    :ok = :gen_tcp.send(sock, 'cap\n')
-    {:noreply, state}
+  def handle_info({:tcp, sock, "cap" <> requested_caps}, {used_caps, conn}) do
+    if String.contains?(requested_caps, "dirtyconfig") do
+      :ok = :gen_tcp.send(sock, 'cap dirtyconfig\n')
+      {:noreply, {[:dirtyconfig], conn}}
+    else
+      :ok = :gen_tcp.send(sock, 'cap\n')
+      {:noreply, {used_caps, conn}}
+    end
   end
 
-  def handle_info({:tcp, sock, "config " <> rest}, state) do
+  def handle_info({:tcp, sock, "config " <> rest}, {client_caps, _conn} = state) do
     plugin_name =
       rest
       |> String.trim()
@@ -42,8 +47,11 @@ defmodule Crow.Worker do
     if matching_plugin == nil do
       :gen_tcp.send(sock, '# unknown plugin\n')
     else
+      dirty_values = if :dirtyconfig in client_caps, do: matching_plugin.values(), else: []
+
       response =
         matching_plugin.config()
+        |> Kernel.++(dirty_values)
         |> Stream.intersperse('\n')
         |> Enum.to_list()
         |> :lists.concat()
diff --git a/test/crow/worker_test.exs b/test/crow/worker_test.exs
index e1e864f..72a864a 100644
--- a/test/crow/worker_test.exs
+++ b/test/crow/worker_test.exs
@@ -29,10 +29,15 @@ defmodule Crow.WorkerTest do
   end
 
   describe "cap command" do
-    test "displays no capabilities", %{socket: socket} do
+    test "with no capabilities", %{socket: socket} do
       :ok = :gen_tcp.send(socket, 'cap\n')
       assert_receive {:tcp, ^socket, "cap\n"}
     end
+
+    test "with dirtyconfig capability", %{socket: socket} do
+      :ok = :gen_tcp.send(socket, 'cap dirtyconfig\n')
+      assert_receive {:tcp, ^socket, "cap dirtyconfig\n"}
+    end
   end
 
   describe "config command" do
@@ -47,6 +52,15 @@ defmodule Crow.WorkerTest do
     end
   end
 
+  describe "dirtyconfig capability" do
+    test "adds values in config command", %{socket: socket} do
+      :ok = :gen_tcp.send(socket, 'cap dirtyconfig\n')
+      assert_receive {:tcp, ^socket, "cap dirtyconfig\n"}
+      :ok = :gen_tcp.send(socket, 'config custom_name\n')
+      assert_receive {:tcp, ^socket, "graph_title fizz buzz\nfoo.value 3\n.\n"}
+    end
+  end
+
   describe "fetch command" do
     test "displays values for known plugins", %{socket: socket} do
       :ok = :gen_tcp.send(socket, 'fetch custom_name\n')