Defer initialization and allow for deferred retries

lib/openid_connect/worker.ex

@@ -16,15 +16,30 @@ defmodule OpenIDConnect.Worker do
   def init(:ignore) do
     :ignore
   end
-
   def init(provider_configs) do
-    state =
-      Enum.into(provider_configs, %{}, fn {provider, config} ->
-        documents = update_documents(provider, config)
-        {provider, %{config: config, documents: documents}}
-      end)
-
-    {:ok, state}
+    # We do not actually fetch the documents at this point, since failing at
+    # init time can prevent an entire Elixir application from starting, and
+    # for applications that e.g. want to load configuration from a database,
+    # it is better to defer initialization until after startup time, as
+    # we may be part of a supervision tree that is also initializing database
+    # connections.
+    #
+    # However, the first messages this process receives will cause it to try
+    # to retrieve the configs, and the worker can fail at that point, to be
+    # handled by its supervisor however it chooses (e.g. try restarting within
+    # X seconds, or just treat it as a temporary worker - up to the application).
+    #
+    # To make it easy to retry startup up to X times in a supervisor, we
+    # allow an initialization delay to be configured by the application.
+    delay_ms = Application.get_env(:openid_connect, :initialization_delay_ms, 0)
+    case delay_ms do
+      # If delay is 0, we in fact want to send immediately (not semantically
+      # the same as sending after 0ms which could give other processes the
+      # opportunity to put stuff on our message queue).
+      0 -> Process.send(self(), {:init, provider_configs}, [])
+      _ -> Process.send_after(self(), {:init, provider_configs}, delay_ms)
+    end
+    {:ok, %{}}
   end
 
   def handle_call({:discovery_document, provider}, _from, state) do
@@ -42,6 +57,21 @@ defmodule OpenIDConnect.Worker do
     {:reply, config, state}
   end
 
+  def handle_info({:init, provider_configs}, _state) do
+    provider_configs = case provider_configs do
+      {:callback, get_config_fn} ->
+        get_config_fn.()
+      _ ->
+        provider_configs
+    end
+
+    state =
+      Enum.into(provider_configs, %{}, fn {provider, config} ->
+        {provider, %{config: config, documents: update_documents(provider, config)}}
+      end)
+    {:noreply, state}
+  end
+
   def handle_info({:update_documents, provider}, state) do
     config = get_in(state, [provider, :config])
     documents = update_documents(provider, config)

mix.exs

@@ -57,7 +57,7 @@ defmodule OpenIDConnect.Mixfile do
 
   defp deps do
     [
-      {:httpoison, "~> 1.2"},
+      {:httpoison, ">= 1.2.0"},
       {:jason, ">= 1.0.0"},
       {:jose, "~> 1.8"},
       {:earmark, "~> 1.2", only: :dev},

mix.lock

@@ -1,22 +1,22 @@
 %{
-  "base64url": {:hex, :base64url, "0.0.1", "36a90125f5948e3afd7be97662a1504b934dd5dac78451ca6e9abf85a10286be", [:rebar], [], "hexpm"},
-  "certifi": {:hex, :certifi, "2.4.2", "75424ff0f3baaccfd34b1214184b6ef616d89e420b258bb0a5ea7d7bc628f7f0", [:rebar3], [{:parse_trans, "~>3.3", [hex: :parse_trans, repo: "hexpm", optional: false]}], "hexpm"},
+  "base64url": {:hex, :base64url, "0.0.1", "36a90125f5948e3afd7be97662a1504b934dd5dac78451ca6e9abf85a10286be", [:rebar], [], "hexpm", "fab09b20e3f5db886725544cbcf875b8e73ec93363954eb8a1a9ed834aa8c1f9"},
+  "certifi": {:hex, :certifi, "2.9.0", "6f2a475689dd47f19fb74334859d460a2dc4e3252a3324bd2111b8f0429e7e21", [:rebar3], [], "hexpm", "266da46bdb06d6c6d35fde799bcb28d36d985d424ad7c08b5bb48f5b5cdd4641"},
   "cutkey": {:git, "https://github.com/potatosalad/cutkey.git", "47640d04fb4db4a0b79168d7fca0df87aaa42751", []},
-  "earmark": {:hex, :earmark, "1.2.6", "b6da42b3831458d3ecc57314dff3051b080b9b2be88c2e5aa41cd642a5b044ed", [:mix], [], "hexpm"},
-  "ex_doc": {:hex, :ex_doc, "0.19.1", "519bb9c19526ca51d326c060cb1778d4a9056b190086a8c6c115828eaccea6cf", [:mix], [{:earmark, "~> 1.1", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.7", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm"},
-  "hackney": {:hex, :hackney, "1.14.3", "b5f6f5dcc4f1fba340762738759209e21914516df6be440d85772542d4a5e412", [:rebar3], [{:certifi, "2.4.2", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "6.0.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "1.0.1", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "1.0.2", [hex: :mimerl, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "1.1.4", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}], "hexpm"},
-  "httpoison": {:hex, :httpoison, "1.4.0", "e0b3c2ad6fa573134e42194d13e925acfa8f89d138bc621ffb7b1989e6d22e73", [:mix], [{:hackney, "~> 1.8", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm"},
-  "idna": {:hex, :idna, "6.0.0", "689c46cbcdf3524c44d5f3dde8001f364cd7608a99556d8fbd8239a5798d4c10", [:rebar3], [{:unicode_util_compat, "0.4.1", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm"},
-  "jason": {:hex, :jason, "1.1.2", "b03dedea67a99223a2eaf9f1264ce37154564de899fd3d8b9a21b1a6fd64afe7", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm"},
-  "jose": {:hex, :jose, "1.8.4", "7946d1e5c03a76ac9ef42a6e6a20001d35987afd68c2107bcd8f01a84e75aa73", [:mix, :rebar3], [{:base64url, "~> 0.0.1", [hex: :base64url, repo: "hexpm", optional: false]}], "hexpm"},
-  "makeup": {:hex, :makeup, "0.5.5", "9e08dfc45280c5684d771ad58159f718a7b5788596099bdfb0284597d368a882", [:mix], [{:nimble_parsec, "~> 0.4", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm"},
-  "makeup_elixir": {:hex, :makeup_elixir, "0.10.0", "0f09c2ddf352887a956d84f8f7e702111122ca32fbbc84c2f0569b8b65cbf7fa", [:mix], [{:makeup, "~> 0.5.5", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm"},
-  "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm"},
-  "mimerl": {:hex, :mimerl, "1.0.2", "993f9b0e084083405ed8252b99460c4f0563e41729ab42d9074fd5e52439be88", [:rebar3], [], "hexpm"},
-  "mox": {:hex, :mox, "0.4.0", "7f120840f7d626184a3d65de36189ca6f37d432e5d63acd80045198e4c5f7e6e", [:mix], [], "hexpm"},
-  "nimble_parsec": {:hex, :nimble_parsec, "0.4.0", "ee261bb53214943679422be70f1658fff573c5d0b0a1ecd0f18738944f818efe", [:mix], [], "hexpm"},
-  "parse_trans": {:hex, :parse_trans, "3.3.0", "09765507a3c7590a784615cfd421d101aec25098d50b89d7aa1d66646bc571c1", [:rebar3], [], "hexpm"},
+  "earmark": {:hex, :earmark, "1.2.6", "b6da42b3831458d3ecc57314dff3051b080b9b2be88c2e5aa41cd642a5b044ed", [:mix], [], "hexpm", "b42a23e9bd92d65d16db2f75553982e58519054095356a418bb8320bbacb58b1"},
+  "ex_doc": {:hex, :ex_doc, "0.19.1", "519bb9c19526ca51d326c060cb1778d4a9056b190086a8c6c115828eaccea6cf", [:mix], [{:earmark, "~> 1.1", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.7", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm", "dc87f778d8260da0189a622f62790f6202af72f2f3dee6e78d91a18dd2fcd137"},
+  "hackney": {:hex, :hackney, "1.18.1", "f48bf88f521f2a229fc7bae88cf4f85adc9cd9bcf23b5dc8eb6a1788c662c4f6", [:rebar3], [{:certifi, "~> 2.9.0", [hex: :certifi, repo: "hexpm", optional: false]}, {:idna, "~> 6.1.0", [hex: :idna, repo: "hexpm", optional: false]}, {:metrics, "~> 1.0.0", [hex: :metrics, repo: "hexpm", optional: false]}, {:mimerl, "~> 1.1", [hex: :mimerl, repo: "hexpm", optional: false]}, {:parse_trans, "3.3.1", [hex: :parse_trans, repo: "hexpm", optional: false]}, {:ssl_verify_fun, "~> 1.1.0", [hex: :ssl_verify_fun, repo: "hexpm", optional: false]}, {:unicode_util_compat, "~> 0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "a4ecdaff44297e9b5894ae499e9a070ea1888c84afdd1fd9b7b2bc384950128e"},
+  "httpoison": {:hex, :httpoison, "2.1.0", "655fd9a7b0b95ee3e9a3b535cf7ac8e08ef5229bab187fa86ac4208b122d934b", [:mix], [{:hackney, "~> 1.17", [hex: :hackney, repo: "hexpm", optional: false]}], "hexpm", "fc455cb4306b43827def4f57299b2d5ac8ac331cb23f517e734a4b78210a160c"},
+  "idna": {:hex, :idna, "6.1.1", "8a63070e9f7d0c62eb9d9fcb360a7de382448200fbbd1b106cc96d3d8099df8d", [:rebar3], [{:unicode_util_compat, "~> 0.7.0", [hex: :unicode_util_compat, repo: "hexpm", optional: false]}], "hexpm", "92376eb7894412ed19ac475e4a86f7b413c1b9fbb5bd16dccd57934157944cea"},
+  "jason": {:hex, :jason, "1.1.2", "b03dedea67a99223a2eaf9f1264ce37154564de899fd3d8b9a21b1a6fd64afe7", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "fdf843bca858203ae1de16da2ee206f53416bbda5dc8c9e78f43243de4bc3afe"},
+  "jose": {:hex, :jose, "1.8.4", "7946d1e5c03a76ac9ef42a6e6a20001d35987afd68c2107bcd8f01a84e75aa73", [:mix, :rebar3], [{:base64url, "~> 0.0.1", [hex: :base64url, repo: "hexpm", optional: false]}], "hexpm", "d28c8e54f06d7a668e98ca9e5b9b2b56764bdd95b69e9185e8209a3e880f10a0"},
+  "makeup": {:hex, :makeup, "0.5.5", "9e08dfc45280c5684d771ad58159f718a7b5788596099bdfb0284597d368a882", [:mix], [{:nimble_parsec, "~> 0.4", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "d7152ff93f2eac07905f510dfa03397134345ba4673a00fbf7119bab98632940"},
+  "makeup_elixir": {:hex, :makeup_elixir, "0.10.0", "0f09c2ddf352887a956d84f8f7e702111122ca32fbbc84c2f0569b8b65cbf7fa", [:mix], [{:makeup, "~> 0.5.5", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "4a36dd2d0d5c5f98d95b3f410d7071cd661d5af310472229dd0e92161f168a44"},
+  "metrics": {:hex, :metrics, "1.0.1", "25f094dea2cda98213cecc3aeff09e940299d950904393b2a29d191c346a8486", [:rebar3], [], "hexpm", "69b09adddc4f74a40716ae54d140f93beb0fb8978d8636eaded0c31b6f099f16"},
+  "mimerl": {:hex, :mimerl, "1.2.0", "67e2d3f571088d5cfd3e550c383094b47159f3eee8ffa08e64106cdf5e981be3", [:rebar3], [], "hexpm", "f278585650aa581986264638ebf698f8bb19df297f66ad91b18910dfc6e19323"},
+  "mox": {:hex, :mox, "0.4.0", "7f120840f7d626184a3d65de36189ca6f37d432e5d63acd80045198e4c5f7e6e", [:mix], [], "hexpm", "64fca8aca4699cc1acf7db19237ce781cfa46683082a440e9f4e1ac29e290d89"},
+  "nimble_parsec": {:hex, :nimble_parsec, "0.4.0", "ee261bb53214943679422be70f1658fff573c5d0b0a1ecd0f18738944f818efe", [:mix], [], "hexpm", "ebb595e19456a72786db6dcd370d320350cb624f0b6203fcc7e23161d49b0ffb"},
+  "parse_trans": {:hex, :parse_trans, "3.3.1", "16328ab840cc09919bd10dab29e431da3af9e9e7e7e6f0089dd5a2d2820011d8", [:rebar3], [], "hexpm", "07cd9577885f56362d414e8c4c4e6bdf10d43a8767abb92d24cbe8b24c54888b"},
   "poison": {:hex, :poison, "3.1.0", "d9eb636610e096f86f25d9a46f35a9facac35609a7591b3be3326e99a0484665", [:mix], [], "hexpm"},
-  "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.4", "f0eafff810d2041e93f915ef59899c923f4568f4585904d010387ed74988e77b", [:make, :mix, :rebar3], [], "hexpm"},
-  "unicode_util_compat": {:hex, :unicode_util_compat, "0.4.1", "d869e4c68901dd9531385bb0c8c40444ebf624e60b6962d95952775cac5e90cd", [:rebar3], [], "hexpm"},
+  "ssl_verify_fun": {:hex, :ssl_verify_fun, "1.1.6", "cf344f5692c82d2cd7554f5ec8fd961548d4fd09e7d22f5b62482e5aeaebd4b0", [:make, :mix, :rebar3], [], "hexpm", "bdb0d2471f453c88ff3908e7686f86f9be327d065cc1ec16fa4540197ea04680"},
+  "unicode_util_compat": {:hex, :unicode_util_compat, "0.7.0", "bc84380c9ab48177092f43ac89e4dfa2c6d62b40b8bd132b1059ecc7232f9a78", [:rebar3], [], "hexpm", "25eee6d67df61960cf6a794239566599b09e17e668d3700247bc498638152521"},
 }

test/openid_connect/worker_test.exs

@@ -53,6 +53,20 @@ defmodule OpenIDConnect.WorkerTest do
     assert get_in(config, [:google]) == google_config
   end
 
+  test "worker started using callback function can respond to a call for the config" do
+    mock_http_requests()
+
+    config = Application.get_env(:openid_connect, :providers)
+
+    {:ok, pid} = start_supervised({OpenIDConnect.Worker, {:callback, fn ->
+      config
+    end}})
+
+    google_config = GenServer.call(pid, {:config, :google})
+
+    assert get_in(config, [:google]) == google_config
+  end
+
   test "worker can respond to a call for a provider's discovery document" do
     mock_http_requests()
 
@@ -91,11 +105,33 @@ defmodule OpenIDConnect.WorkerTest do
     assert expected_jwk == jwk
   end
 
+  test "worker can start without internet connectivity, initialization is deferred" do
+    mock_http_internet_down()
+
+    config = Application.get_env(:openid_connect, :providers)
+    {:error, :update_documents, _} = OpenIDConnect.update_documents(config)
+
+    config = Application.get_env(:openid_connect, :providers)
+
+    {:ok, pid} = start_supervised({OpenIDConnect.Worker, config})
+    catch_exit(GenServer.call(pid, {:jwk, :google}))
+  end
+
   defp mock_http_requests do
     HTTPClientMock
     |> expect(:get, fn "https://accounts.google.com/.well-known/openid-configuration", _headers, _opts ->
       @google_document
     end)
     |> expect(:get, fn "https://www.googleapis.com/oauth2/v3/certs", _headers, _opts -> @google_certs end)
   end
+
+  defp mock_http_internet_down do
+    HTTPClientMock
+    |> expect(:get, fn _, _, _ ->
+      {:error, %HTTPoison.Error{id: nil, reason: :nxdomain}}
+    end)
+    |> expect(:get, fn _, _, _ ->
+      {:error, %HTTPoison.Error{id: nil, reason: :nxdomain}}
+    end)
+  end
 end