Merge pull request #62 from configcat/fix/fetch-genserver-timeout

fix: prevent genserver calls from timing out during config fetch

Author: randycoulman

lib/config_cat/cache_policy/auto.ex

@@ -3,9 +3,10 @@ defmodule ConfigCat.CachePolicy.Auto do
 
   use GenServer
 
-  alias ConfigCat.CachePolicy
+  alias ConfigCat.{CachePolicy, Constants}
   alias ConfigCat.CachePolicy.{Behaviour, Helpers}
 
+  require Constants
   require Logger
 
   defstruct mode: "a", on_changed: nil, poll_interval_seconds: 60
@@ -38,22 +39,32 @@ defmodule ConfigCat.CachePolicy.Auto do
 
   @impl GenServer
   def handle_continue(:initial_fetch, state) do
-    polled_refresh(state)
+    refresh(state)
+    schedule_next_refresh(state)
+
+    {:noreply, state}
   end
 
   @impl GenServer
   def handle_info(:polled_refresh, state) do
-    polled_refresh(state)
+    pid = self()
+
+    Task.start_link(fn ->
+      refresh(state)
+      schedule_next_refresh(state, pid)
+    end)
+
+    {:noreply, state}
   end
 
   @impl Behaviour
   def get(policy_id) do
-    GenServer.call(policy_id, :get)
+    GenServer.call(policy_id, :get, Constants.fetch_timeout())
   end
 
   @impl Behaviour
   def force_refresh(policy_id) do
-    GenServer.call(policy_id, :force_refresh)
+    GenServer.call(policy_id, :force_refresh, Constants.fetch_timeout())
   end
 
   @impl GenServer
@@ -72,11 +83,8 @@ defmodule ConfigCat.CachePolicy.Auto do
     end
   end
 
-  defp polled_refresh(%{poll_interval_seconds: seconds} = state) do
-    refresh(state)
-    Process.send_after(self(), :polled_refresh, seconds * 1000)
-
-    {:noreply, state}
+  defp schedule_next_refresh(%{poll_interval_seconds: seconds}, pid \\ self()) do
+    Process.send_after(pid, :polled_refresh, seconds * 1000)
   end
 
   defp refresh(state) do

lib/config_cat/cache_policy/lazy.ex

@@ -3,9 +3,11 @@ defmodule ConfigCat.CachePolicy.Lazy do
 
   use GenServer
 
-  alias ConfigCat.CachePolicy
+  alias ConfigCat.{CachePolicy, Constants}
   alias ConfigCat.CachePolicy.{Behaviour, Helpers}
 
+  require Constants
+
   @enforce_keys [:cache_expiry_seconds]
   defstruct [:cache_expiry_seconds, mode: "l"]
 
@@ -34,12 +36,12 @@ defmodule ConfigCat.CachePolicy.Lazy do
 
   @impl Behaviour
   def get(policy_id) do
-    GenServer.call(policy_id, :get)
+    GenServer.call(policy_id, :get, Constants.fetch_timeout())
   end
 
   @impl Behaviour
   def force_refresh(policy_id) do
-    GenServer.call(policy_id, :force_refresh)
+    GenServer.call(policy_id, :force_refresh, Constants.fetch_timeout())
   end
 
   @impl GenServer

lib/config_cat/cache_policy/manual.ex

@@ -3,9 +3,11 @@ defmodule ConfigCat.CachePolicy.Manual do
 
   use GenServer
 
-  alias ConfigCat.CachePolicy
+  alias ConfigCat.{CachePolicy, Constants}
   alias ConfigCat.CachePolicy.{Behaviour, Helpers}
 
+  require Constants
+
   defstruct mode: "m"
 
   @type t :: %__MODULE__{mode: String.t()}
@@ -34,7 +36,7 @@ defmodule ConfigCat.CachePolicy.Manual do
 
   @impl Behaviour
   def force_refresh(policy_id) do
-    GenServer.call(policy_id, :force_refresh)
+    GenServer.call(policy_id, :force_refresh, Constants.fetch_timeout())
   end
 
   @impl GenServer

lib/config_cat/client.ex

@@ -23,33 +23,37 @@ defmodule ConfigCat.Client do
 
   @spec get_all_keys(client()) :: [Config.key()]
   def get_all_keys(client) do
-    GenServer.call(client, :get_all_keys)
+    GenServer.call(client, :get_all_keys, Constants.fetch_timeout())
   end
 
   @spec get_value(client(), Config.key(), Config.value(), User.t() | nil) :: Config.value()
   def get_value(client, key, default_value, user \\ nil) do
-    GenServer.call(client, {:get_value, key, default_value, user})
+    GenServer.call(client, {:get_value, key, default_value, user}, Constants.fetch_timeout())
   end
 
   @spec get_variation_id(client(), Config.key(), Config.variation_id(), User.t() | nil) ::
           Config.variation_id()
   def get_variation_id(client, key, default_variation_id, user \\ nil) do
-    GenServer.call(client, {:get_variation_id, key, default_variation_id, user})
+    GenServer.call(
+      client,
+      {:get_variation_id, key, default_variation_id, user},
+      Constants.fetch_timeout()
+    )
   end
 
   @spec get_all_variation_ids(client(), User.t() | nil) :: [Config.variation_id()]
   def get_all_variation_ids(client, user \\ nil) do
-    GenServer.call(client, {:get_all_variation_ids, user})
+    GenServer.call(client, {:get_all_variation_ids, user}, Constants.fetch_timeout())
   end
 
   @spec get_key_and_value(client(), Config.variation_id()) :: {Config.key(), Config.value()} | nil
   def get_key_and_value(client, variation_id) do
-    GenServer.call(client, {:get_key_and_value, variation_id})
+    GenServer.call(client, {:get_key_and_value, variation_id}, Constants.fetch_timeout())
   end
 
   @spec force_refresh(client()) :: refresh_result()
   def force_refresh(client) do
-    GenServer.call(client, :force_refresh)
+    GenServer.call(client, :force_refresh, Constants.fetch_timeout())
   end
 
   @impl GenServer

lib/config_cat/config_fetcher.ex

@@ -28,8 +28,8 @@ defmodule ConfigCat.CacheControlConfigFetcher do
   alias ConfigFetcher.RedirectMode
   alias HTTPoison.Response
 
-  require ConfigCat.Constants
-  require ConfigFetcher.RedirectMode
+  require Constants
+  require RedirectMode
   require Logger
 
   @type option ::
@@ -76,7 +76,7 @@ defmodule ConfigCat.CacheControlConfigFetcher do
 
   @impl ConfigFetcher
   def fetch(fetcher) do
-    GenServer.call(fetcher, :fetch)
+    GenServer.call(fetcher, :fetch, Constants.fetch_timeout())
   end
 
   @impl GenServer

lib/config_cat/constants.ex

@@ -19,4 +19,5 @@ defmodule ConfigCat.Constants do
   defmacro percentage, do: "p"
   defmacro value, do: "v"
   defmacro variation_id, do: "i"
+  defmacro fetch_timeout, do: 10_000
 end