feat(clustering/sync): flatten and report validation error

kong/clustering/services/sync/rpc.lua

@@ -66,6 +66,15 @@ end
 function _M:init_cp(manager)
   local purge_delay = manager.conf.cluster_data_plane_purge_delay
 
+  -- CP
+  -- Method: kong.sync.v2.notify_validation_error
+  -- Params: msg: list of current versions of the database
+  -- example: { version = <lastest version of deltas>, error = <flatten error>, }
+  manager.callbacks:register("kong.sync.v2.notify_validation_error", function(node_id, msg)
+    ngx_log(ngx_DEBUG, "[kong.sync.v2] received validation error")
+    return true
+  end)
+
   -- CP
   -- Method: kong.sync.v2.get_delta
   -- Params: versions: list of current versions of the database
@@ -179,6 +188,22 @@ local function is_rpc_ready()
 end
 
 
+-- tell cp that the deltas validation failed
+local function notify_error(ver, err_t)
+  local msg = {
+    version = ver or "v02_deltas_have_no_latest_version_field",
+    error = err_t,
+  }
+
+  local ok, err = kong.rpc:notify("control_plane",
+                                  "kong.sync.v2.notify_validation_error",
+                                  msg)
+  if not ok then
+    ngx_log(ngx_ERR, "notifying validation errors failed: ", err)
+  end
+end
+
+
 -- tell cp we already updated the version by rpc notification
 local function update_status(ver)
   local msg = { default = { version = ver, }, }
@@ -300,8 +325,9 @@ local function do_sync()
   assert(type(kong.default_workspace) == "string")
 
   -- validate deltas
-  local ok, err = validate_deltas(deltas, wipe)
+  local ok, err, err_t = validate_deltas(deltas, wipe)
   if not ok then
+    notify_error(ns_delta.lastest_version, err_t)
     return nil, err
   end
 

kong/clustering/services/sync/validate.lua

@@ -1,17 +1,38 @@
 local declarative = require("kong.db.declarative")
 local declarative_config = require("kong.db.schema.others.declarative_config")
+local db_errors = require("kong.db.errors")
+local ERRORS = require("kong.constants").CLUSTERING_DATA_PLANE_ERROR
 
 
 local null = ngx.null
+local insert = table.insert
 local pk_string = declarative_config.pk_string
 local validate_references_sync = declarative_config.validate_references_sync
 local pretty_print_error = declarative.pretty_print_error
 
 
+-- It refers to format_error() function in kong/clustering/config_helper.lua.
+local function format_error(err_t)
+  -- Declarative config parse errors will include all the input entities in
+  -- the error table. Strip these out to keep the error payload size small.
+  local errors = err_t.flattened_errors
+  if type(errors) ~= "table" then
+    return
+  end
+
+  for i = 1, #errors do
+    local err = errors[i]
+    if type(err) == "table" then
+      err.entity = nil
+    end
+  end
+end
+
+
 local function validate_deltas(deltas, is_full_sync)
 
   local errs = {}
-  local errs_n = 0
+  local errs_entities = {}
 
   -- generate deltas table mapping primary key string to entity item
   local deltas_map = {}
@@ -46,27 +67,46 @@ local function validate_deltas(deltas, is_full_sync)
 
         local ok, err_t = dao.schema:validate(copy)
         if not ok then
-          errs_n = errs_n + 1
-          errs[errs_n] = { [delta_type] = err_t }
+          if not errs[delta_type] then
+            errs[delta_type] = {}
+          end
+          insert(errs[delta_type], err_t)
+
+          if not errs_entities[delta_type] then
+            errs_entities[delta_type] = {}
+          end
+          insert(errs_entities[delta_type], delta_entity)
         end
       end
     end
   end
 
-  if next(errs) then
-    return nil, pretty_print_error(errs, "deltas")
-  end
-
   -- validate references
-  local ok, err_t = validate_references_sync(deltas, deltas_map, is_full_sync)
-  if not ok then
-    return nil, pretty_print_error(err_t)
+
+  if not next(errs) then
+    local ok
+    ok, errs = validate_references_sync(deltas, deltas_map, is_full_sync)
+    if ok then
+      return true
+    end
   end
 
-  return true
+  -- error handling
+
+  local err = pretty_print_error(errs)
+
+  local err_t = db_errors:sync_deltas_flattened(errs, errs_entities)
+
+  err_t.name = ERRORS.DELTAS_PARSE
+  err_t.source = "kong.clustering.services.sync.validate.validate_deltas"
+
+  format_error(err_t)
+
+  return nil, err, err_t
 end
 
 
 return {
   validate_deltas = validate_deltas,
+  format_error = format_error,
 }

kong/constants.lua

@@ -231,6 +231,7 @@ local constants = {
   CLUSTERING_OCSP_TIMEOUT = 5000, -- 5 seconds
   CLUSTERING_DATA_PLANE_ERROR = {
     CONFIG_PARSE     = "declarative configuration parse failure",
+    DELTAS_PARSE     = "sync deltas parse failure",
     RELOAD           = "configuration reload failed",
     GENERIC          = "generic or unknown error",
   },

kong/db/errors.lua

@@ -500,6 +500,17 @@ function _M:declarative_config(err_t)
 end
 
 
+function _M:sync_deltas(err_t)
+  if type(err_t) ~= "table" then
+    error("err_t must be a table", 2)
+  end
+
+  local message = fmt("sync deltas is invalid: %s", pl_pretty(err_t, ""))
+
+  return new_err_t(self, ERRORS.SYNC_DELTAS, message, err_t)
+end
+
+
 function _M:invalid_workspace(ws_id)
   if type(ws_id) ~= "string" then
     error("ws_id must be a string", 2)
@@ -1171,4 +1182,30 @@ function _M:declarative_config_flattened(err_t, input)
 end
 
 
+-- traverse schema validation errors and correlate them with objects/entities
+-- which does not pass delta validation for sync.v2
+--
+---@param  err_t table
+---@param  err_entities table
+---@return table
+function _M:sync_deltas_flattened(err_t, err_entities)
+  if type(err_t) ~= "table" then
+    error("err_t must be a table", 2)
+  end
+
+  if type(err_entities) ~= "table" then
+    error("err_entities is nil or not a table", 2)
+  end
+
+  local flattened = flatten_errors(err_entities, err_t)
+
+  err_t = self:sync_deltas(err_t)
+
+  err_t.flattened_errors = flattened
+
+  return err_t
+
+end
+
+
 return _M