Release systemdkit 0.1.4

Author: dannote

CHANGELOG.md

@@ -1,5 +1,9 @@
 # Changelog
 
+## v0.1.4
+
+- Added `Systemd.Calendar` helpers for typed daily, weekly, and monthly timer calendar expressions.
+
 ## v0.1.3
 
 - Added `Systemd.UnitFile.equivalent?/2` for semantic unit file comparison after normalization.

lib/systemd/calendar.ex

@@ -0,0 +1,83 @@
+defmodule Systemd.Calendar do
+  @moduledoc "Helpers for building systemd calendar expressions."
+
+  @weekdays %{
+    monday: "Mon",
+    mon: "Mon",
+    tuesday: "Tue",
+    tue: "Tue",
+    wednesday: "Wed",
+    wed: "Wed",
+    thursday: "Thu",
+    thu: "Thu",
+    friday: "Fri",
+    fri: "Fri",
+    saturday: "Sat",
+    sat: "Sat",
+    sunday: "Sun",
+    sun: "Sun"
+  }
+
+  @doc "Builds a daily calendar expression at a time of day."
+  @spec daily_at(String.t() | Time.t()) :: String.t()
+  def daily_at(time), do: "*-*-* #{time!(time)}"
+
+  @doc "Builds a weekly calendar expression for a weekday and time of day."
+  @spec weekly_at(atom() | String.t(), String.t() | Time.t()) :: String.t()
+  def weekly_at(day, time), do: "#{weekday!(day)} *-*-* #{time!(time)}"
+
+  @doc "Builds a monthly calendar expression for a day of month and time of day."
+  @spec monthly_at(pos_integer(), String.t() | Time.t()) :: String.t()
+  def monthly_at(day, time) when is_integer(day) and day in 1..31 do
+    "*-*-#{String.pad_leading(to_string(day), 2, "0")} #{time!(time)}"
+  end
+
+  def monthly_at(day, _time) do
+    raise ArgumentError, "monthly timer day must be an integer from 1 to 31, got: #{inspect(day)}"
+  end
+
+  defp time!(%Time{} = time) do
+    time
+    |> Time.truncate(:second)
+    |> Time.to_iso8601()
+  end
+
+  defp time!(value) when is_binary(value) do
+    value
+    |> normalize_time_string()
+    |> Time.from_iso8601()
+    |> case do
+      {:ok, time} ->
+        time!(time)
+
+      {:error, _reason} ->
+        raise ArgumentError,
+              "expected timer time as HH:MM or HH:MM:SS, got: #{inspect(value)}"
+    end
+  end
+
+  defp time!(value) do
+    raise ArgumentError, "expected timer time as HH:MM, HH:MM:SS, or Time, got: #{inspect(value)}"
+  end
+
+  defp normalize_time_string(<<_h1, _h2, ?:, _m1, _m2>> = time), do: time <> ":00"
+  defp normalize_time_string(time), do: time
+
+  defp weekday!(day) when is_atom(day) do
+    case Map.fetch(@weekdays, day) do
+      {:ok, weekday} -> weekday
+      :error -> raise ArgumentError, "unknown weekday #{inspect(day)}"
+    end
+  end
+
+  defp weekday!(day) when is_binary(day) do
+    weekday = String.downcase(day)
+
+    @weekdays
+    |> Enum.find_value(fn {key, value} -> if Atom.to_string(key) == weekday, do: value end)
+    |> case do
+      nil -> raise ArgumentError, "unknown weekday #{inspect(day)}"
+      value -> value
+    end
+  end
+end

mix.exs

@@ -1,7 +1,7 @@
 defmodule Systemd.MixProject do
   use Mix.Project
 
-  @version "0.1.3"
+  @version "0.1.4"
   @source_url "https://github.com/elixir-vibe/systemdkit"
 
   def project do
@@ -76,6 +76,7 @@ defmodule Systemd.MixProject do
           Systemd.Properties
         ],
         "Unit files": [
+          Systemd.Calendar,
           Systemd.UnitName,
           Systemd.UnitFile,
           Systemd.UnitFile.Blank,

test/systemd/calendar_test.exs

@@ -0,0 +1,27 @@
+defmodule Systemd.CalendarTest do
+  use ExUnit.Case, async: true
+
+  alias Systemd.Calendar
+
+  test "builds daily calendar expressions" do
+    assert Calendar.daily_at("02:30") == "*-*-* 02:30:00"
+    assert Calendar.daily_at("02:30:15") == "*-*-* 02:30:15"
+    assert Calendar.daily_at(~T[02:30:00]) == "*-*-* 02:30:00"
+  end
+
+  test "builds weekly calendar expressions" do
+    assert Calendar.weekly_at(:monday, "02:30") == "Mon *-*-* 02:30:00"
+    assert Calendar.weekly_at("sun", ~T[03:15:00]) == "Sun *-*-* 03:15:00"
+  end
+
+  test "builds monthly calendar expressions" do
+    assert Calendar.monthly_at(1, "02:30") == "*-*-01 02:30:00"
+    assert Calendar.monthly_at(31, ~T[23:59:59]) == "*-*-31 23:59:59"
+  end
+
+  test "rejects invalid values" do
+    assert_raise ArgumentError, ~r/expected timer time/, fn -> Calendar.daily_at("2:30") end
+    assert_raise ArgumentError, ~r/unknown weekday/, fn -> Calendar.weekly_at(:noday, "02:30") end
+    assert_raise ArgumentError, ~r/monthly timer day/, fn -> Calendar.monthly_at(0, "02:30") end
+  end
+end