Config cleanup (#55)

* Clear the ENV in the setup in appsignal_config_test

* Test default and valid configurations

* Split up the application environment config tests

* Remove Heroku DYNO check, add test for :running_in_container

* Clean up minimum configuration tests

* Add tests to make sure the System env gets set from the application env

* Set APPSIGNAL_FILTER_PARAMETERS from application env

* Set APPSIGNAL_SEND_PARAMS from application env

*  Add tests to make sure the application env gets set from the System env

*  Set :ignore_actions from system env

* Set :ignore_errors from system env

*  Set :log from system env

*  Set :log_path from system env

* Remove duplicate config tests

* Clean up the setup block in the config tests

* Add a test to make sure the system environment overwrites the application environment configuration

* :running_in_container gets set automatically on Heroku

* Clear APPSIGNAL_FILTER_PARAMETERS in filter_test.exs

Since 4fb068, APPSIGNAL_FILTER_PARAMETERS gets set from
Appsignal.write_to_environment/1. This commit clears it in
filter_test.exs, so it doesn't get set into the application config in
the next test.

lib/appsignal/config.ex

@@ -3,13 +3,14 @@ defmodule Appsignal.Config do
 
   @default_config %{
     debug: false,
-    ignore_errors: [],
-    ignore_actions: [],
-    env: :dev,
-    send_params: true,
-    endpoint: "https://push.appsignal.com",
     enable_host_metrics: false,
+    endpoint: "https://push.appsignal.com",
+    env: :dev,
     filter_parameters: nil,
+    ignore_actions: [],
+    ignore_errors: [],
+    running_in_container: false,
+    send_params: true,
     skip_session_data: false
   }
 
@@ -20,10 +21,12 @@ defmodule Appsignal.Config do
   """
   @spec initialize() :: :ok | {:error, :invalid_config}
   def initialize() do
+    system_config = %{running_in_container: System.get_env("DYNO") != nil}
     app_config = Application.get_env(:appsignal, :config, []) |> coerce_map
     env_config = load_from_environment()
 
     config = @default_config
+    |> Map.merge(system_config)
     |> Map.merge(app_config)
     |> Map.merge(env_config)
 
@@ -63,6 +66,7 @@ defmodule Appsignal.Config do
     "APPSIGNAL_FRONTEND_ERROR_CATCHING_PATH" => :frontend_error_catching_path,
     "APPSIGNAL_FILTER_PARAMETERS" => :filter_parameters,
     "APPSIGNAL_DEBUG" => :debug,
+    "APPSIGNAL_LOG" => :log,
     "APPSIGNAL_LOG_PATH" => :log_path,
     "APPSIGNAL_IGNORE_ERRORS" => :ignore_errors,
     "APPSIGNAL_IGNORE_ACTIONS" => :ignore_actions,
@@ -73,10 +77,10 @@ defmodule Appsignal.Config do
     "APPSIGNAL_SKIP_SESSION_DATA" => :skip_session_data
   }
 
-  @string_keys ~w(APPSIGNAL_PUSH_API_KEY APPSIGNAL_PUSH_API_ENDPOINT APPSIGNAL_FRONTEND_ERROR_CATCHING_PATH APPSIGNAL_HTTP_PROXY APPSIGNAL_LOG_PATH APPSIGNAL_WORKING_DIR_PATH APP_REVISION)
+  @string_keys ~w(APPSIGNAL_PUSH_API_KEY APPSIGNAL_PUSH_API_ENDPOINT APPSIGNAL_FRONTEND_ERROR_CATCHING_PATH APPSIGNAL_HTTP_PROXY APPSIGNAL_LOG APPSIGNAL_LOG_PATH APPSIGNAL_WORKING_DIR_PATH APP_REVISION)
   @bool_keys ~w(APPSIGNAL_ACTIVE APPSIGNAL_DEBUG APPSIGNAL_INSTRUMENT_NET_HTTP APPSIGNAL_ENABLE_FRONTEND_ERROR_CATCHING APPSIGNAL_ENABLE_ALLOCATION_TRACKING APPSIGNAL_ENABLE_GC_INSTRUMENTATION APPSIGNAL_RUNNING_IN_CONTAINER APPSIGNAL_ENABLE_HOST_METRICS APPSIGNAL_SKIP_SESSION_DATA)
   @atom_keys ~w(APPSIGNAL_APP_NAME APPSIGNAL_ENVIRONMENT)
-  @string_list_keys ~w(APPSIGNAL_FILTER_PARAMETERS)
+  @string_list_keys ~w(APPSIGNAL_FILTER_PARAMETERS APPSIGNAL_IGNORE_ACTIONS APPSIGNAL_IGNORE_ERRORS)
 
   defp load_environment(config, list, converter) do
     list |> Enum.reduce(
@@ -93,8 +97,6 @@ defmodule Appsignal.Config do
 
   defp load_from_environment() do
     %{}
-    # Heroku is a container based system
-    |> Map.put(:running_in_container, System.get_env("DYNO") != nil)
     |> load_environment(@string_keys, &(&1))
     |> load_environment(@bool_keys, &(true?(&1)))
     |> load_environment(@atom_keys, &(String.to_atom(&1)))
@@ -138,8 +140,12 @@ defmodule Appsignal.Config do
     unless empty?(config[:http_proxy]) do
       System.put_env("APPSIGNAL_HTTP_PROXY", config[:http_proxy])
     end
+    unless empty?(config[:filter_parameters]) do
+      System.put_env("APPSIGNAL_FILTER_PARAMETERS", config[:filter_parameters] |> Enum.join(","))
+    end
     System.put_env("APPSIGNAL_IGNORE_ACTIONS", config[:ignore_actions] |> Enum.join(","))
     System.put_env("APPSIGNAL_IGNORE_ERRORS", config[:ignore_errors] |> Enum.join(","))
+    System.put_env("APPSIGNAL_SEND_PARAMS", Atom.to_string(config[:send_params]))
     System.put_env("APPSIGNAL_RUNNING_IN_CONTAINER", Atom.to_string(config[:running_in_container]))
     unless empty?(config[:working_dir_path]) do
       System.put_env("APPSIGNAL_WORKING_DIR_PATH", config[:working_dir_path])