add a catch-all for handling unexpected messages on the genserver

We're seeing something similar to
benoitc/hackney#464 that is causing the
genserver to crash, because it's not handling a message that seems to be
leaking from hackney / httpoison. This change should prevent that crash
from happening.

lib/statsig_ex.ex

@@ -1,11 +1,24 @@
 defmodule StatsigEx do
   use GenServer
+  require Logger
   alias StatsigEx.Utils
 
   # default intervals
   @flush_interval 60_000
   @reload_interval 60_000
 
+  @moduledoc """
+  `StatsigEx` is the module through which all interaction with flags and configs
+  should flow. At a high level, it works like this:
+
+  * at startup, a `GenServer` is created that stores the most recent flag and config
+    definitions.
+  * (either via `check_gate` or )
+  * every `@reload_interval` milliseconds, the server pulls any recent changes to
+    flag or config definitions and updates its copy.
+  * every `@flush_interval` milliseconds, the server pushes exposure logs to statsig.
+  """
+
   def start_link(opts \\ []) do
     opts =
       opts
@@ -42,6 +55,9 @@ defmodule StatsigEx do
     # end
   end
 
+  @doc """
+  For a user, check a gate.
+  """
   def check_gate(user, gate, server \\ __MODULE__)
   def check_gate(nil, _gate, _server), do: {:error, :no_user}
 
@@ -116,6 +132,12 @@ defmodule StatsigEx do
     {:noreply, Map.put(state, :events, remaining)}
   end
 
+  # might want to log these messages
+  def handle_info(msg, state) do
+    Logger.info("unhandled message: #{inspect(msg)}")
+    {:noreply, state}
+  end
+
   def terminate(_reason, %{api_key: key, events: events}),
     do: flush_events(key, events)
 

lib/statsig_ex/evaluator.ex

@@ -1,6 +1,10 @@
 defmodule StatsigEx.Evaluator do
   @unsupported ["ip_based"]
 
+  @moduledoc """
+  It is rare, but there may be a case where you need to get an evaluation result directly
+  """
+
   defmodule Result do
     defstruct exposures: [],
               secondary_exposures: [],

test/consistency_test.exs

@@ -11,38 +11,9 @@ defmodule StatsigEx.ConsistencyTest do
   |> Map.get("data")
   |> generate_all_tests()
 
-  @tag :skip
-  test "one test" do
-    result =
-      StatsigEx.Evaluator.eval(
-        %{
-          "appVersion" => "1.3",
-          "ip" => "1.0.0.0",
-          "locale" => "en_US",
-          "statsigEnvironment" => %{"tier" => "DEVELOPMENT"},
-          "userAgent" =>
-            "Mozilla/5.0 (iPhone; CPU iPhone OS 10_3_1 like Mac OS X) AppleWebKit/603.1.30 (KHTML, like Gecko) Version/10.0 Mobile/14E304 Safari/602.1",
-          "userID" => "123"
-        },
-        "test_gate_with_targeting_gate",
-        :gate,
-        :test
-      )
-
-    secondary = [
-      %{
-        "gate" => "global_holdout",
-        "gateValue" => "false",
-        "ruleID" => "3QoA4ncNdVGBaMt3N1KYjz:0.50:1"
-      },
-      %{
-        "gate" => "test_targeting_gate_with_no_rules",
-        "gateValue" => "false",
-        "ruleID" => "default"
-      }
-    ]
-
-    [_ | sec] = result.exposures
-    assert Enum.sort(secondary) == Enum.sort(sec)
+  test "random messages are properly handled" do
+    assert :ok = Process.send(:test, {:ssl_closed, {:sslsocket, {:gen_tcp, :etc}}}, [])
+    # give the server time to handle the message
+    Process.sleep(100)
   end
 end