Merge pull request #51 from paulo-ferraz-oliveira/feature/error-acc

Allow accumulating errors instead of displaying them as they happen

README.md

@@ -93,6 +93,18 @@ Different credential providers may have other settings which you can use to
 change their behaviors.  See the documentation for each provider for more
 details.
 
+Error Logging
+-------------
+
+If you prefer to not log errors as they happen (the default behavior), but accumulate
+them for later, you can set erlang environment variable `log_errors_immediately` to
+`false` as in this example:
+
+```erlang
+  {aws_credentials, [{log_errors_immediately, false}]
+  },
+```
+
 License and copyright
 ---------------------
 This project is licensed under the terms of the Apache 2 license. It is a

src/aws_credentials.erl

@@ -35,6 +35,7 @@
         , make_map/3
         , make_map/4
         , make_map/5
+        , log_error/3
         ]).
 
 -record(state, { credentials = undefined :: map()
@@ -167,6 +168,13 @@ format_status(_, [_PDict, State]) ->
 %% Internal functions
 %%====================================================================
 
+-spec log_error(String :: unicode:chardata(), Args :: [term()], logger:metadata()) -> ok.
+log_error(String, Args, Metadata) ->
+    case application:get_env(aws_credentials, log_errors_immediately, true) of
+        true -> ?LOG_ERROR(String, Args, Metadata);
+        false -> ?LOG_INFO(String, Args, Metadata)
+    end.
+
 -spec fetch_credentials(aws_credentials_provider:options()) ->
         {ok, credentials() | 'undefined', reference() | 'undefined'}.
 fetch_credentials(Options) ->
@@ -179,6 +187,12 @@ fetch_credentials(Options) ->
             ?LOG_INFO("No credentials available~n",
                       [],
                       #{domain => [aws_credentials]}),
+            {ok, undefined, setup_callback(?RETRY_DELAY)};
+          {error, ErrorLog} when is_list(ErrorLog) andalso ShouldCatch ->
+            ?LOG_INFO("No credentials available~n",
+                      [],
+                      #{domain => [aws_credentials]}),
+            [?LOG_ERROR(String, Args, Metadata) || {String, Args, Metadata} <- ErrorLog],
             {ok, undefined, setup_callback(?RETRY_DELAY)}
     catch E:R:ST when ShouldCatch ->
             ?LOG_INFO("aws_credentials ignoring exception ~p:~p (~p)~n",

src/aws_credentials_httpc.erl

@@ -74,10 +74,10 @@ request(Method, URL, RequestHeaders, Tries, Remaining, Errs) ->
 
       Error ->
         NewRemaining = Remaining - 1,
-        ?LOG_ERROR("Error fetching URL (attempts left: "
-                   "~p of ~p) ~p: ~p.",
-                   [NewRemaining, Tries, URL, Error],
-                   #{domain => [aws_credentials]}),
+        String = "Error fetching URL (attempts left: ~p of ~p) ~p: ~p.",
+        Args = [NewRemaining, Tries, URL, Error],
+        Metadata = #{domain => [aws_credentials]},
+        aws_credentials:log_error(String, Args, Metadata),
         timer:sleep((Tries - NewRemaining) * ?DELAY),
         request(Method, URL, RequestHeaders, Tries, NewRemaining, [ Error | Errs ])
     end.

src/aws_credentials_provider.erl

@@ -35,6 +35,8 @@
                   | aws_credentials_file
                   | aws_credentials_ecs
                   | aws_credentials_ec2.
+-type error_log_elem() :: {String :: unicode:chardata(), Args :: [term()], logger:metadata()}.
+-type error_log() :: [error_log_elem()].
 -export_type([ options/0, expiration/0 ]).
 
 -callback fetch(options()) ->
@@ -49,28 +51,35 @@
 
 -spec fetch() ->
         {ok, aws_credentials:credentials(), expiration()} |
-        {'error', 'no_credentials'}.
+        {'error', 'no_credentials'} |
+        {'error', error_log()}.
 fetch() ->
     fetch(#{}).
 
 -spec fetch(options()) ->
         {ok, aws_credentials:credentials(), expiration()} |
-        {'error', 'no_credentials'}.
+        {'error', 'no_credentials'} |
+        {'error', error_log()}.
 fetch(Options) ->
     Providers = get_env(credential_providers, ?DEFAULT_PROVIDERS),
-    evaluate_providers(Providers, Options).
+    evaluate_providers(Providers, Options, []).
 
--spec evaluate_providers([provider() | {provider(), options()}], options()) ->
+-spec evaluate_providers([provider() | {provider(), options()}], options(), error_log()) ->
         {ok, aws_credentials:credentials(), expiration()} |
-        {'error', no_credentials}.
-evaluate_providers([], _Options) -> {error, no_credentials};
-evaluate_providers([ Provider | Providers ], Options) ->
+        {'error', no_credentials} |
+        {'error', error_log()}.
+evaluate_providers([], _Options, []) ->
+    {error, no_credentials};
+evaluate_providers([], _Options, Errors) when is_list(Errors) ->
+    {error, lists:reverse(Errors)};
+evaluate_providers([ Provider | Providers ], Options, Errors) ->
     case Provider:fetch(Options) of
         {error, _} = Error ->
-            ?LOG_ERROR("Provider ~p reports ~p",
-                       [Provider, Error],
-                       #{domain => [aws_credentials]}),
-            evaluate_providers(Providers, Options);
+            String = "Provider ~p reports ~p",
+            Args = [Provider, Error],
+            Metadata = #{domain => [aws_credentials]},
+            aws_credentials:log_error(String, Args, Metadata),
+            evaluate_providers(Providers, Options, [{String, Args, Metadata} | Errors]);
         {ok, Credentials, Expiration} ->
             {ok, Credentials, Expiration}
     end.