fix(schema registry): handle large names during lookup

Fixes https://emqx.atlassian.net/browse/EMQX-12692

apps/emqx_schema_registry/src/emqx_schema_registry.erl

@@ -44,6 +44,12 @@
     get_serde/1
 ]).
 
+%%-------------------------------------------------------------------------------------------------
+%% Type definitions
+%%-------------------------------------------------------------------------------------------------
+
+-define(BAD_SCHEMA_NAME, <<"bad_schema_name">>).
+
 -type schema() :: #{
     type := serde_type(),
     source := binary(),
@@ -87,6 +93,8 @@ get_schema(SchemaName) ->
         Config ->
             {ok, Config}
     catch
+        throw:#{reason := ?BAD_SCHEMA_NAME} ->
+            {error, not_found};
         throw:not_found ->
             {error, not_found}
     end.
@@ -343,16 +351,20 @@ to_bin(A) when is_atom(A) -> atom_to_binary(A);
 to_bin(B) when is_binary(B) -> B.
 
 schema_name_bin_to_atom(Bin) when size(Bin) > 255 ->
-    throw(
-        iolist_to_binary(
+    Msg = iolist_to_binary(
         io_lib:format(
             "Name is is too long."
             " Please provide a shorter name (<= 255 bytes)."
             " The name that is too long: \"~s\"",
             [Bin]
         )
-        )
-    );
+    ),
+    Reason = #{
+        kind => validation_error,
+        reason => ?BAD_SCHEMA_NAME,
+        hint => Msg
+    },
+    throw(Reason);
 schema_name_bin_to_atom(Bin) ->
     try
         binary_to_existing_atom(Bin, utf8)

apps/emqx_schema_registry/test/emqx_schema_registry_http_api_SUITE.erl

@@ -347,7 +347,8 @@ t_crud(Config) ->
 
     ok.
 
-%% Tests that we can't create names that are too long and get a decent error message.
+%% Tests that we can't create or lookup names that are too long and get a decent error
+%% message.
 t_name_too_long(Config) ->
     SerdeType = ?config(serde_type, Config),
     SourceBin = ?config(schema_source, Config),
@@ -368,4 +369,11 @@ t_name_too_long(Config) ->
         }},
         request({post, Params})
     ),
+    ?assertMatch(
+        {ok, 404, #{
+            <<"code">> := <<"NOT_FOUND">>,
+            <<"message">> := <<"Schema not found">>
+        }},
+        request({get, SchemaName})
+    ),
     ok.