Ensure poorly formatted chardata is pruned in Logger watcher

Signed-off-by: José Valim <[email protected]>

Author: José Valim

lib/logger/lib/logger/backends/console.ex

@@ -74,11 +74,16 @@ defmodule Logger.Backends.Console do
       enabled: Keyword.get(colors, :enabled, IO.ANSI.enabled?)}
   end
 
-  defp log_event(level, msg, ts, md, %{colors: colors} = state) do
+  defp log_event(level, msg, ts, md, %{colors: colors, device: device} = state) do
     output =
       format_event(level, msg, ts, md, state)
       |> color_event(level, colors)
-    IO.write(state.device, output)
+    try do
+      IO.write(device, output)
+    rescue
+      ArgumentError ->
+        IO.write(device, Logger.Utils.prune(output))
+    end
   end
 
   defp format_event(level, msg, ts, md, %{format: format, metadata: keys}) do

lib/logger/lib/logger/utils.ex

@@ -1,6 +1,25 @@
 defmodule Logger.Utils do
   @moduledoc false
 
+  @replacement "�"
+
+  @doc """
+  Prune non-valid UTF-8 codepoints.
+  """
+  @spec prune(IO.chardata) :: IO.chardata
+  def prune(binary) when is_binary(binary), do: prune_binary(binary, "")
+  def prune([h|t]) when h in 0..1114111, do: [h|prune(t)]
+  def prune([h|t]), do: [prune(h)|prune(t)]
+  def prune([]), do: []
+  def prune(_), do: @replacement
+
+  defp prune_binary(<<h::utf8, t::binary>>, acc),
+    do: prune_binary(t, <<acc::binary, h::utf8>>)
+  defp prune_binary(<<_, t::binary>>, acc),
+    do: prune_binary(t, <<acc::binary, @replacement>>)
+  defp prune_binary(<<>>, acc),
+    do: acc
+
   @doc """
   Truncates a char data into n bytes.
 

lib/logger/lib/logger/watcher.ex

@@ -10,9 +10,9 @@ defmodule Logger.Watcher do
   """
   def start_link(m, f, a) do
     import Supervisor.Spec
-    child = worker(__MODULE__, [],
-      [function: :watcher, restart: :transient])
-    options  = [strategy: :simple_one_for_one, name: @name]
+    child = worker(__MODULE__, [], [function: :watcher, restart: :transient])
+    options  = [strategy: :simple_one_for_one, name: @name,
+                max_restarts: 30, max_seconds: 3]
     case Supervisor.start_link([child], options) do
       {:ok, _} = ok ->
         _ = for {mod, handler, args} <- apply(m, f, a) do

lib/logger/test/logger/utils_test.exs

@@ -6,6 +6,14 @@ defmodule Logger.UtilsTest do
   import Kernel, except: [inspect: 2]
   defp inspect(format, args), do: Logger.Utils.inspect(format, args, 10)
 
+  test "prune/1" do
+    assert prune(1) == "�"
+    assert prune(<<"hí", 233>>) == "hí�"
+    assert prune(["hi"|233]) == ["hi"|"�"]
+    assert prune([233|"hi"]) == [233|"hi"]
+    assert prune([[]|[]]) == [[]]
+  end
+
   test "truncate/2" do
     # ASCII binaries
     assert truncate("foo", 4) == "foo"
@@ -80,16 +88,16 @@ defmodule Logger.UtilsTest do
            {'~ts~ts~ts', ["abcdeabcde", "", ""]}
   end
 
-  test "timestamp" do
+  test "timestamp/1" do
     assert {{_, _, _}, {_, _, _, _}} = timestamp(true)
   end
 
-  test "format_date" do
+  test "format_date/1" do
     date = {2015, 1, 30}
     assert format_date(date) == ["2015", ?-, [?0, "1"], ?-, "30"]
   end
 
-  test "format_time" do
+  test "format_time/1" do
     time = {12, 30, 10, 1}
     assert format_time(time) == ["12", ?:, "30", ?:, "10", ?., [?0, ?0, "1"]]