feat(dbless): improve validation errors from /config

kong/api/routes/config.lua

@@ -24,6 +24,16 @@ local function reports_timer(premature)
 end
 
 
+local function truthy(val)
+  return val == true
+      or val == 1
+      or val == "true"
+      or val == "1"
+      or val == "on"
+      or val == "yes"
+end
+
+
 return {
   ["/config"] = {
     GET = function(self, db)
@@ -57,6 +67,19 @@ return {
         })
       end
 
+      local opts
+      local flatten_errors = truthy(self.params.flatten_errors)
+      self.params.flatten_errors = nil
+      local processed_input
+      if flatten_errors then
+        opts = {
+          handle_error = function(input, err_t)
+            processed_input = input
+            return nil, err_t
+          end,
+        }
+      end
+
       local check_hash, old_hash
       if tostring(self.params.check_hash) == "1" then
         check_hash = true
@@ -68,7 +91,7 @@ return {
 
       local entities, _, err_t, meta, new_hash
       if self.params._format_version then
-        entities, _, err_t, meta, new_hash = dc:parse_table(self.params)
+        entities, _, err_t, meta, new_hash = dc:parse_table(self.params, nil, opts)
       else
         local config = self.params.config
         if not config then
@@ -82,14 +105,22 @@ return {
           end
         end
         entities, _, err_t, meta, new_hash =
-          dc:parse_string(config, nil, old_hash)
+          dc:parse_string(config, nil, old_hash, opts)
       end
 
       if not entities then
         if check_hash and err_t and err_t.error == "configuration is identical" then
           return kong.response.exit(304)
         end
-        return kong.response.exit(400, errors:declarative_config(err_t))
+
+        local res
+        if flatten_errors then
+          res = errors:declarative_config_flattened(err_t, processed_input)
+        else
+          res = errors:declarative_config(err_t)
+        end
+
+        return kong.response.exit(400, res)
       end
 
       local ok, err, ttl = declarative.load_into_cache_with_events(entities, meta, new_hash)

kong/db/declarative/init.lua

@@ -74,6 +74,8 @@ local function pretty_print_error(err_t, item, indent)
 end
 
 
+
+-- @tparam table|nil opts options to pass to the parser
 -- @treturn table|nil a table with the following format:
 --   {
 --     services: {
@@ -89,7 +91,7 @@ end
 --     _format_version: "2.1",
 --     _transform: true,
 --   }
-function _M:parse_file(filename, old_hash)
+function _M:parse_file(filename, old_hash, opts)
   if type(filename) ~= "string" then
     error("filename must be a string", 2)
   end
@@ -99,7 +101,7 @@ function _M:parse_file(filename, old_hash)
     return nil, err
   end
 
-  return self:parse_string(contents, filename, old_hash)
+  return self:parse_string(contents, filename, old_hash, opts)
 end
 
 
@@ -114,14 +116,15 @@ end
 -- @tparam string contents the json/yml/lua being parsed
 -- @tparam string|nil filename. If nil, json will be tried first, then yaml
 -- @tparam string|nil old_hash used to avoid loading the same content more than once, if present
+-- @tparam table|nil opts options to pass to the parser
 -- @treturn nil|string error message, only if error happened
 -- @treturn nil|table err_t, only if error happened
 -- @treturn table|nil a table with the following format:
 --   {
 --     _format_version: "2.1",
 --     _transform: true,
 --   }
-function _M:parse_string(contents, filename, old_hash)
+function _M:parse_string(contents, filename, old_hash, opts)
   -- we don't care about the strength of the hash
   -- because declarative config is only loaded by Kong administrators,
   -- not outside actors that could exploit it for collisions
@@ -171,7 +174,7 @@ function _M:parse_string(contents, filename, old_hash)
     return nil, err, { error = err }
   end
 
-  return self:parse_table(dc_table, new_hash)
+  return self:parse_table(dc_table, new_hash, opts)
 end
 
 
@@ -185,6 +188,7 @@ end
 --     },
 --   }
 --   This table is not flattened: entities can exist inside other entities
+-- @tparam table|nil opts options to pass to the parser
 -- @treturn table|nil A table with the following format:
 --   {
 --     services: {
@@ -202,12 +206,12 @@ end
 --   }
 -- @treturn string|nil given hash if everything went well,
 --                     new hash if everything went well and no given hash,
-function _M:parse_table(dc_table, hash)
+function _M:parse_table(dc_table, hash, opts)
   if type(dc_table) ~= "table" then
     error("expected a table as input", 2)
   end
 
-  local entities, err_t, meta = self.schema:flatten(dc_table)
+  local entities, err_t, meta = self.schema:flatten(dc_table, opts)
   if err_t then
     return nil, pretty_print_error(err_t), err_t
   end