refactor: Make config optional

Co-authored-by: Brandyn Bennett <brandynbennett@users.noreply.github.com>

Author: rai200890

.formatter.exs

@@ -1,4 +1,4 @@
 # Used by "mix format"
 [
-  inputs: ["lib/tzdata/period_builder.ex", "test/tz_period_builder_test.exs"]
+  inputs: ["lib/tzdata/period_builder.ex", "test/data_loader_test.exs", "test/tz_period_builder_test.exs"]
 ]

.tool-versions

@@ -0,0 +1,3 @@
+erlang 24.3.4.10
+elixir 1.14.2-otp-24
+

README.md

@@ -88,6 +88,17 @@ in the release_ets sub-dir of the "data_dir" (see the "Data directory and releas
 When IANA releases new versions of the time zone data, this Tzdata library can be used to generate
 a new .ets file containing the new data.
 
+## Set IANA database updates origin
+
+It is also possible to override IANA database url in case you want to pin a specific database version.
+
+Available versions can be found at: https://data.iana.org/time-zones/releases
+
+```elixir
+config :tzdata, :download_url, "https://data.iana.org/time-zones/tzdata2024a.tar.gz"
+```
+
+
 ## Changes from 0.1.x to 0.5.x
 
 The 0.5.1+ versions uses ETS tables and automatically polls the IANA

lib/tzdata/data_loader.ex

@@ -4,8 +4,11 @@ defmodule Tzdata.DataLoader do
   require Logger
   # Can poll for newest version of tz data and can download
   # and extract it.
+
+  @default_download_url "https://data.iana.org/time-zones/tzdata-latest.tar.gz"
+
   def download_url do
-    Application.fetch_env!(:tzdata, :download_url)
+    Application.get_env(:tzdata, :download_url, @default_download_url)
   end
 
   def download_new do

lib/tzdata/release_updater.ex

@@ -45,14 +45,18 @@ defmodule Tzdata.ReleaseUpdater do
         :do_nothing
 
       {:ok, false} ->
+        try do
         case Tzdata.DataBuilder.load_and_save_table() do
           {:ok, _, _} ->
             Tzdata.EtsHolder.new_release_has_been_downloaded()
 
           {:error, error} ->
             {:error, error}
         end
-
+      rescue
+        error -> Logger.error("Unable to retrieve latest tz database due to unexpected error #{error}")
+        {:error, error}
+      end
       _ ->
         :do_nothing
     end

mix.exs

@@ -34,7 +34,7 @@ defmodule Tzdata.Mixfile do
   defp docs do
     [
       main: "readme",
-      extras: ["README.md", "VERSION"],
+      extras: ["README.md"],
       source_ref: "v#{version()}"
     ]
   end
@@ -58,7 +58,7 @@ defmodule Tzdata.Mixfile do
       licenses: ["MIT"],
       maintainers: ["Lau Taarnskov"],
       links: %{"GitHub" => "https://github.com/lau/tzdata"},
-      files: ~w(lib priv mix.exs README* LICENSE*
+      files: ~w(lib priv mix.exs README* LICENSE* VERSION
                  CHANGELOG*)
     }
   end

test/data_loader_test.exs

@@ -6,27 +6,45 @@ defmodule Tzdata.DataLoaderTest do
 
   setup :verify_on_exit!
 
+  @default_download_url "https://data.iana.org/time-zones/tzdata-latest.tar.gz"
+
+  @config_download_url "https://data.iana.org/time-zones/tzdata2024a.tar.gz"
+
+  @custom_download_url "https://data.iana.org/time-zones/tzdata2024b.tar.gz"
+
   setup do
     client = Application.get_env(:tzdata, :http_client)
-    Application.put_env(:tzdata, :http_client, Tzdata.HTTPClient.Mock)
 
-    Application.put_env(
-      :tzdata,
-      :download_url,
-      "https://data.iana.org/time-zones/tzdata-latest.tar.gz"
-    )
+    :ok = Application.put_env(:tzdata, :http_client, Tzdata.HTTPClient.Mock)
 
     on_exit(fn ->
       Application.put_env(:tzdata, :http_client, client)
       :ok
     end)
   end
 
-  describe "download_new/1" do
-    test "when url not given, should download content from default url" do
-      expect(Mock, :get, fn "https://data.iana.org/time-zones/tzdata-latest.tar.gz",
-                            _,
-                            [follow_redirect: true] ->
+  describe "download_new/0" do
+    test "when download_url config not set, should download content from default url" do
+      expect(Mock, :get, fn @default_download_url, _, [follow_redirect: true] ->
+        {:ok,
+         {200, [{"Last-Modified", "Wed, 21 Oct 2015 07:28:00 GMT"}],
+          File.read!("test/tzdata_fixtures/tzdata2024a.tar.gz")}}
+      end)
+
+      assert {:ok, 451_270, "2024a", _new_dir_name, "Wed, 21 Oct 2015 07:28:00 GMT"} =
+               Tzdata.DataLoader.download_new()
+    end
+
+    test "when download_url config set, should download content from given url" do
+      download_url = Application.get_env(:tzdata, :download_url)
+      :ok = Application.put_env(:tzdata, :download_url, @config_download_url)
+
+      on_exit(fn ->
+        Application.put_env(:tzdata, :download_url, download_url)
+        :ok
+      end)
+
+      expect(Mock, :get, fn @config_download_url, _, [follow_redirect: true] ->
         {:ok,
          {200, [{"Last-Modified", "Wed, 21 Oct 2015 07:28:00 GMT"}],
           File.read!("test/tzdata_fixtures/tzdata2024a.tar.gz")}}
@@ -35,18 +53,18 @@ defmodule Tzdata.DataLoaderTest do
       assert {:ok, 451_270, "2024a", _new_dir_name, "Wed, 21 Oct 2015 07:28:00 GMT"} =
                Tzdata.DataLoader.download_new()
     end
+  end
 
-    test "when url given, should download content from given url" do
-      expect(Mock, :get, fn "https://data.iana.org/time-zones/tzdata2024a.tar.gz", _, _ ->
+  describe "download_new/1" do
+    test "should download content from given url" do
+      expect(Mock, :get, fn @custom_download_url, _, _ ->
         {:ok,
          {200, [{"Last-Modified", "Wed, 21 Oct 2015 07:28:00 GMT"}],
           File.read!("test/tzdata_fixtures/tzdata2024a.tar.gz")}}
       end)
 
       assert {:ok, 451_270, "2024a", _new_dir_name, "Wed, 21 Oct 2015 07:28:00 GMT"} =
-               Tzdata.DataLoader.download_new(
-                 "https://data.iana.org/time-zones/tzdata2024a.tar.gz"
-               )
+               Tzdata.DataLoader.download_new(@custom_download_url)
     end
   end
 end