Further refactor Preloader to allow for error recovery

Previous system would crash the calling processes with a `MatchError`
instead of returning an error. The end result after this commit is
still the same - the auto_sync channel will attempt a resync
every 5 seconds. The log messages/user experience should just
be better now.

farmbot_ext/lib/farmbot_ext/amqp/auto_sync_channel.ex

@@ -57,7 +57,7 @@ defmodule FarmbotExt.AMQP.AutoSyncChannel do
     else
       {:error, reason} ->
         BotState.set_sync_status("sync_error")
-        Logger.error("Error preloading. #{reason}")
+        FarmbotCore.Logger.error(1, "Error preloading. #{inspect(reason)}")
         Process.send_after(self(), :preload, 5000)
         {:noreply, state}
     end

farmbot_ext/lib/farmbot_ext/api.ex

@@ -147,22 +147,35 @@ defmodule FarmbotExt.API do
 
   @doc "helper for `GET`ing a path."
   def get_body!(path) do
-    case API.get!(API.client(), path) do
-      %{body: body, status: 200} ->
+    case API.get(API.client(), path) do
+      {:ok, %{body: body, status: 200}} ->
         {:ok, body}
 
-      %{body: error, status: status} ->
-        msg = """
-        HTTP Error getting: #{path}
-        Status Code = #{status}
+      {:ok, %{body: error, status: status}} when is_binary(error) ->
+        get_body_error(path, status, error)
 
-        #{error}
-        """
+      {:ok, %{body: %{"error" => error}, status: status}} when is_binary(error) ->
+        get_body_error(path, status, error)
 
-        {:error, msg}
+      {:ok, %{body: error, status: status}} when is_binary(error) ->
+        get_body_error(path, status, inspect(error))
+
+      {:error, reason} ->
+        {:error, reason}
     end
   end
 
+  defp get_body_error(path, status, error) when is_binary(error) do
+    msg = """
+    HTTP Error getting: #{path}
+    Status Code = #{status}
+
+    #{error}
+    """
+
+    {:error, msg}
+  end
+
   @callback get_changeset(module) :: {:ok, %Ecto.Changeset{}} | {:error, term()}
   @callback get_changeset(data :: module | map(), Path.t()) ::
               {:ok, %Ecto.Changeset{}} | {:error, term()}

farmbot_ext/lib/farmbot_ext/api/eager_loader.ex

@@ -10,7 +10,11 @@ defmodule FarmbotExt.API.EagerLoader do
   require Logger
   use GenServer
 
-  @doc "Does a ton of HTTP requests to preload the cache"
+  @doc """
+  Does a ton of HTTP requests to preload the cache
+  Failure in this function is less than ideal and should probably return an
+  error
+  """
   def preload(%Sync{} = sync) do
     SyncGroup.all_groups()
     |> Enum.map(fn asset_module ->
@@ -24,14 +28,23 @@ defmodule FarmbotExt.API.EagerLoader do
     end)
     |> List.flatten()
     |> Enum.map(&Task.await(&1, :infinity))
+    |> Enum.reduce([], fn
+      {:ok, changeset}, errors ->
+        :ok = cache(changeset)
+        errors
 
-    :ok
+      error, errors ->
+        [error | errors]
+    end)
+    |> case do
+      [] -> :ok
+      errors -> {:error, errors}
+    end
   end
 
   def preload(asset_module, %{id: id}) when is_atom(asset_module) do
     local = Repo.one(from(m in asset_module, where: m.id == ^id)) || asset_module
-    {:ok, changeset} = API.get_changeset(local, id)
-    :ok = cache(changeset)
+    API.get_changeset(local, id)
   end
 
   @doc "Get a Changeset by module and id. May return nil"

farmbot_ext/lib/farmbot_ext/api/preloader.ex

@@ -34,7 +34,7 @@ defmodule FarmbotExt.API.Preloader do
 
       FarmbotCore.Logger.success(3, "Successfully synced bootup resources.")
 
-      :ok = maybe_auto_sync(sync_changeset, auto_sync_change || Query.auto_sync?())
+      maybe_auto_sync(sync_changeset, auto_sync_change || Query.auto_sync?())
     end
   end
 
@@ -52,19 +52,27 @@ defmodule FarmbotExt.API.Preloader do
       |> Repo.transaction()
 
       FarmbotCore.Logger.success(3, "bootup auto sync complete")
+      :ok
     else
-      error -> FarmbotCore.Logger.error(3, "bootup auto sync failed #{inspect(error)}")
+      error ->
+        FarmbotCore.Logger.error(3, "bootup auto sync failed #{inspect(error)}")
+        error
     end
-
-    :ok
   end
 
   # When auto_sync is disabled preload the sync.
   defp maybe_auto_sync(sync_changeset, false) do
     FarmbotCore.Logger.busy(3, "preloading sync")
     sync = Changeset.apply_changes(sync_changeset)
-    EagerLoader.preload(sync)
-    FarmbotCore.Logger.success(3, "preloaded sync ok")
-    :ok
+
+    case EagerLoader.preload(sync) do
+      :ok ->
+        FarmbotCore.Logger.success(3, "preloaded sync ok")
+        :ok
+
+      error ->
+        FarmbotCore.Logger.error(3, "Failed ot preload sync")
+        error
+    end
   end
 end