Use new function `Repo.with_adapter/1' (#56)

This change adds `Repo.with_adapter/1` as suggested in
#51 (comment)

Author: odarriba

lib/error_tracker/migration.ex

@@ -109,10 +109,10 @@ defmodule ErrorTracker.Migration do
   end
 
   defp migrator do
-    case ErrorTracker.Repo.__adapter__() do
-      Ecto.Adapters.Postgres -> ErrorTracker.Migration.Postgres
-      Ecto.Adapters.SQLite3 -> ErrorTracker.Migration.SQLite
+    ErrorTracker.Repo.with_adapter(fn
+      :postgres -> ErrorTracker.Migration.Postgres
+      :sqlite -> ErrorTracker.Migration.SQLite
       adapter -> raise "ErrorTracker does not support #{adapter}"
-    end
+    end)
   end
 end

lib/error_tracker/migration/sql_migrator.ex

@@ -63,8 +63,8 @@ defmodule ErrorTracker.Migration.SQLMigrator do
   defp record_version(opts, version) do
     timestamp = DateTime.utc_now() |> DateTime.to_unix()
 
-    case repo().__adapter__() do
-      Ecto.Adapters.Postgres ->
+    ErrorTracker.Repo.with_adapter(fn
+      :postgres ->
         prefix = opts[:prefix]
 
         execute """
@@ -79,12 +79,12 @@ defmodule ErrorTracker.Migration.SQLMigrator do
         VALUES ('migration_version', '#{version}'), ('migration_timestamp', '#{timestamp}')
         ON CONFLICT (key) DO UPDATE SET value = EXCLUDED.value
         """
-    end
+    end)
   end
 
   defp meta_table_exists?(repo, opts) do
-    case repo.__adapter__() do
-      Ecto.Adapters.Postgres ->
+    ErrorTracker.Repo.with_adapter(fn
+      :postgres ->
         Ecto.Adapters.SQL.query!(
           repo,
           "SELECT TRUE FROM information_schema.tables WHERE table_name = 'error_tracker_meta' AND table_schema = $1",
@@ -96,6 +96,6 @@ defmodule ErrorTracker.Migration.SQLMigrator do
 
       _other ->
         Ecto.Adapters.SQL.table_exists?(repo, "error_tracker_meta", log: false)
-    end
+    end)
   end
 end

lib/error_tracker/repo.ex

@@ -29,19 +29,24 @@ defmodule ErrorTracker.Repo do
     dispatch(:aggregate, [queryable, aggregate], opts)
   end
 
-  def __adapter__, do: repo().__adapter__()
+  def with_adapter(fun) do
+    adapter =
+      case repo().__adapter__() do
+        Ecto.Adapters.Postgres -> :postgres
+        Ecto.Adapters.SQLite3 -> :sqlite
+      end
+
+    fun.(adapter)
+  end
 
   defp dispatch(action, args, opts) do
     repo = repo()
 
     defaults =
-      case repo.__adapter__() do
-        Ecto.Adapters.Postgres ->
-          [prefix: Application.get_env(:error_tracker, :prefix, "public")]
-
-        _ ->
-          []
-      end
+      with_adapter(fn
+        :postgres -> [prefix: Application.get_env(:error_tracker, :prefix, "public")]
+        _ -> []
+      end)
 
     opts_w_defaults = Keyword.merge(defaults, opts)