config: simplify sharding.roles validation

Now there is the `validate_scope` function, so we can write less code
for validation of this kind. And we can move the validation to the lower
level (`sharding` -> `sharding.roles`), because the `validate`
annotation is now supported by the `schema.set()` constructor (see the
previous commit).

NO_DOC=no behavior changes except the config validation error message
NO_CHANGELOG=see NO_DOC

Author: Totktonada

src/box/lua/config/instance_config.lua

@@ -1739,11 +1739,12 @@ return schema.new('instance_config', schema.record({
             default = 1,
             validate = validators['sharding.weight'],
         }),
-        -- TODO: Add validate.
         roles = schema.set({
             'router',
             'storage',
             'rebalancer',
+        }, {
+            validate = validators['sharding.roles'],
         }),
         -- Global vshard options.
         shard_index = schema.scalar({
@@ -1811,8 +1812,6 @@ return schema.new('instance_config', schema.record({
             default = 1,
             validate = validators['sharding.sched_move_quota'],
         }),
-    }, {
-        validate = validators['sharding'],
     }),
     audit_log = enterprise_edition(schema.record({
         -- The same as the destination for the logger, audit logger destination

src/box/lua/config/validators.lua

@@ -338,29 +338,6 @@ end
 
 -- {{{ sharding
 
-M['sharding'] = function(data, w)
-    -- Forbid sharding.roles in instance scope.
-    local scope = w.schema.computed.annotations.scope
-    if data.roles ~= nil and scope == 'instance' then
-        w.error('sharding.roles cannot be defined in the instance ' ..
-                'scope')
-    end
-    -- Make sure that if the rebalancer role is present, the storage
-    -- role is also present.
-    if data.roles ~= nil then
-        local has_storage = false
-        local has_rebalancer = false
-        for _, role in pairs(data.roles) do
-            has_storage = has_storage or role == 'storage'
-            has_rebalancer = has_rebalancer or role == 'rebalancer'
-        end
-        if has_rebalancer and not has_storage then
-            w.error('The rebalancer role cannot be present without ' ..
-                    'the storage role')
-        end
-    end
-end
-
 M['sharding.bucket_count'] = function(_data, w)
     validate_scope(w, {'global'})
 end
@@ -397,6 +374,26 @@ M['sharding.rebalancer_mode'] = function(_data, w)
     validate_scope(w, {'global'})
 end
 
+M['sharding.roles'] = function(roles, w)
+    -- Forbid in the instance scope, because it has no
+    -- sense to set the option for a part of a
+    -- replicaset.
+    validate_scope(w, {'global', 'group', 'replicaset'})
+
+    -- Make sure that if the rebalancer role is present, the storage
+    -- role is also present.
+    local has_storage = false
+    local has_rebalancer = false
+    for _, role in pairs(roles) do
+        has_storage = has_storage or role == 'storage'
+        has_rebalancer = has_rebalancer or role == 'rebalancer'
+    end
+    if has_rebalancer and not has_storage then
+        w.error('The rebalancer role cannot be present without ' ..
+                'the storage role')
+    end
+end
+
 M['sharding.sched_move_quota'] = function(_data, w)
     validate_scope(w, {'global'})
 end

test/config-luatest/cluster_config_schema_test.lua

@@ -625,32 +625,6 @@ g.test_name_failure = function()
     end
 end
 
-g.test_sharding = function()
-    local config = {
-        groups = {
-            ['group-001'] = {
-                replicasets = {
-                    ['replicaset-001'] = {
-                        instances = {
-                            ['instance-001'] = {
-                                sharding = {
-                                    roles = {'storage'},
-                                },
-                            },
-                        },
-                    },
-                },
-            },
-        },
-    }
-    local err = '[cluster_config] groups.group-001.replicasets.' ..
-                'replicaset-001.instances.instance-001.sharding: ' ..
-                'sharding.roles cannot be defined in the instance scope'
-    t.assert_error_msg_equals(err, function()
-        cluster_config:validate(config)
-    end)
-end
-
 -- Verify options consistency on the global level.
 --
 -- Expected instance config fields plus the following additional
@@ -778,6 +752,7 @@ end
 -- * sharding.shard_index
 -- * sharding.sync_timeout
 -- * sharding.weight
+-- * sharding.roles
 g.test_scope = function()
     local function exp_err(path, scope)
         return ('[cluster_config] %s: The option must not be present in the ' ..
@@ -1003,6 +978,18 @@ g.test_scope = function()
             replicaset = true,
             instance = false,
         },
+        {
+            name = 'sharding.roles',
+            data = {
+                sharding = {
+                    roles = {'storage'},
+                },
+            },
+            global = true,
+            group = true,
+            replicaset = true,
+            instance = false,
+        },
     }
 
     for _, case in ipairs(cases) do

test/config-luatest/instance_config_schema_test.lua

@@ -1727,8 +1727,8 @@ g.test_sharding = function()
             roles = {'router', 'rebalancer'},
         },
     }
-    local err = '[instance_config] sharding: The rebalancer role cannot be ' ..
-                'present without the storage role'
+    local err = '[instance_config] sharding.roles: The rebalancer role ' ..
+                'cannot be present without the storage role'
     t.assert_error_msg_equals(err, function()
         instance_config:validate(iconfig)
     end)