Merge pull request #2110 from hexlet-codebattle/populate-clans-helper

add helper for loading clans from csv

Author: kjubybot

services/app/apps/codebattle/lib/codebattle/utils/populate_clans.ex

@@ -0,0 +1,35 @@
+defmodule Codebattle.Utils.PopulateClans do
+  @moduledoc false
+
+  @doc """
+  Populates clans table from csv file. The file is expected to
+  have two fields in following order: long name, short name.
+  """
+  def from_csv!(file) do
+    utc_now = NaiveDateTime.truncate(NaiveDateTime.utc_now(), :second)
+
+    file
+    |> File.stream!()
+    |> NimbleCSV.RFC4180.parse_stream()
+    |> Stream.chunk_every(500)
+    |> Enum.each(&process_batch(&1, utc_now))
+  end
+
+  defp process_batch(clans, now) do
+    clans = Enum.map(clans, &row_to_clan(&1, now))
+
+    Codebattle.Repo.insert_all(Codebattle.Clan, clans,
+      on_conflict: {:replace, [:long_name]},
+      conflict_target: [:name]
+    )
+  end
+
+  defp row_to_clan([long_name, name], now) do
+    %{
+      name: name,
+      long_name: long_name,
+      inserted_at: now,
+      updated_at: now
+    }
+  end
+end

services/app/apps/codebattle/test/codebattle/utils/populate_clans_test.exs

@@ -0,0 +1,18 @@
+defmodule Codebattle.Utils.PopulateClansTest do
+  use Codebattle.DataCase, async: true
+
+  test "from_csv" do
+    csv = """
+    long,short
+    "the first clan",first_clan
+    secondclan,clan2
+    """
+
+    {fd, path} = Temp.open!()
+    IO.write(fd, csv)
+    File.close(fd)
+
+    assert :ok = Codebattle.Utils.PopulateClans.from_csv!(path)
+    assert %{long_name: "the first clan"} = Codebattle.Clan.get_by_name!("first_clan")
+  end
+end