Reset indexes when persisted logs are inserted

These logs likely have a much higher index in the metadata and any new
logs will show up "before" these logs even though new logs are newer.
Also reset the default buffer anytime the configuration changes, so we
don't have duplicate logs when we reinsert the existing logs.

lib/ring_logger/server.ex

@@ -139,14 +139,9 @@ defmodule RingLogger.Server do
   def handle_call({:configure, opts}, _from, state) do
     logs = merge_buffers(state)
 
-    state =
-      case Keyword.get(opts, :max_size) do
-        nil ->
-          state
+    max_size = Keyword.get(opts, :max_size, @default_max_size)
 
-        max_size ->
-          %__MODULE__{state | default_buffer: CircularBuffer.new(max_size)}
-      end
+    state = %__MODULE__{state | default_buffer: CircularBuffer.new(max_size)}
 
     state =
       case Keyword.get(opts, :buffers) do
@@ -330,7 +325,10 @@ defmodule RingLogger.Server do
     case Persistence.load(state.persist_path) do
       logs when is_list(logs) ->
         state =
-          Enum.reduce(logs, state, fn log_entry, state ->
+          logs
+          |> Enum.with_index()
+          |> Enum.reduce(state, fn {log_entry, index}, state ->
+            log_entry = %{log_entry | metadata: Keyword.put(log_entry.metadata, :index, index)}
             insert_log(state, log_entry)
           end)
 

test/ring_logger_test.exs

@@ -833,6 +833,50 @@ defmodule RingLoggerTest do
 
       File.rm!("test/persistence.log")
     end
+
+    test "loading the log resets indexes", %{io: io} do
+      Logger.remove_backend(RingLogger)
+
+      logs = [
+        %{
+          level: :debug,
+          module: Logger,
+          message: "Foo",
+          timestamp: {{2023, 2, 8}, {13, 58, 31, 343}},
+          metadata: [index: 5000]
+        },
+        %{
+          level: :debug,
+          module: Logger,
+          message: "Bar",
+          timestamp: {{2023, 2, 8}, {13, 58, 31, 343}},
+          metadata: [index: 6000]
+        }
+      ]
+
+      :ok = Persistence.save("test/persistence.log", logs)
+
+      # Start the backend with _just_ the persist_path and restore old
+      # config to allow other tests to run without loading a log file
+      old_env = Application.get_env(:logger, RingLogger)
+      Application.put_env(:logger, RingLogger, persist_path: "test/persistence.log")
+      Logger.add_backend(RingLogger)
+      Application.put_env(:logger, RingLogger, old_env)
+
+      Logger.add_backend(RingLogger)
+
+      :ok = RingLogger.attach(io: io)
+
+      [foo, bar] = RingLogger.get(0, 0)
+
+      assert foo.message == "Foo"
+      assert foo.metadata[:index] == 0
+
+      assert bar.message == "Bar"
+      assert bar.metadata[:index] == 1
+
+      File.rm!("test/persistence.log")
+    end
   end
 
   defp capture_log(fun) do