[tarantool-patches] [PATCH 1/3] Update only vshard part of a cfg on reload

[AKhatskevich <avkhatskevich@tarantool.org>]

Box cfg could have been changed by a user and then overridden by
an old vshard config on reload.

Since that commit, box part of a config is applied only when
it is explicitly passed to a `cfg` method.

This change is important for the multiple routers feature.
---
 vshard/cfg.lua          | 54 +++++++++++++++++++++++++------------------------
 vshard/router/init.lua  | 18 ++++++++---------
 vshard/storage/init.lua | 53 ++++++++++++++++++++++++++++--------------------
 3 files changed, 67 insertions(+), 58 deletions(-)

diff --git a/vshard/cfg.lua b/vshard/cfg.lua
index bba12cc..8282086 100644
--- a/vshard/cfg.lua
+++ b/vshard/cfg.lua
@@ -230,48 +230,50 @@ local non_dynamic_options = {
     'bucket_count', 'shard_index'
 }
 
+--
+-- Deepcopy a config and split it into vshard_cfg and box_cfg.
+--
+local function split_cfg(cfg)
+    local vshard_field_map = {}
+    for _, field in ipairs(cfg_template) do
+        vshard_field_map[field[1]] = true
+    end
+    local vshard_cfg = {}
+    local box_cfg = {}
+    for k, v in pairs(cfg) do
+        if vshard_field_map[k] then
+            vshard_cfg[k] = table.deepcopy(v)
+        else
+            box_cfg[k] = table.deepcopy(v)
+        end
+    end
+    return vshard_cfg, box_cfg
+end
+
 --
 -- Check sharding config on correctness. Check types, name and uri
 -- uniqueness, master count (in each replicaset must be <= 1).
 --
-local function cfg_check(shard_cfg, old_cfg)
-    if type(shard_cfg) ~= 'table' then
+local function cfg_check(cfg, old_vshard_cfg)
+    if type(cfg) ~= 'table' then
         error('Сonfig must be map of options')
     end
-    shard_cfg = table.deepcopy(shard_cfg)
-    validate_config(shard_cfg, cfg_template)
-    if not old_cfg then
-        return shard_cfg
+    local vshard_cfg, box_cfg = split_cfg(cfg)
+    validate_config(vshard_cfg, cfg_template)
+    if not old_vshard_cfg then
+        return vshard_cfg, box_cfg
     end
     -- Check non-dynamic after default values are added.
     for _, f_name in pairs(non_dynamic_options) do
         -- New option may be added in new vshard version.
-        if shard_cfg[f_name] ~= old_cfg[f_name] then
+        if vshard_cfg[f_name] ~= old_vshard_cfg[f_name] then
            error(string.format('Non-dynamic option %s ' ..
                                'cannot be reconfigured', f_name))
         end
     end
-    return shard_cfg
-end
-
---
--- Nullify non-box options.
---
-local function remove_non_box_options(cfg)
-    cfg.sharding = nil
-    cfg.weights = nil
-    cfg.zone = nil
-    cfg.bucket_count = nil
-    cfg.rebalancer_disbalance_threshold = nil
-    cfg.rebalancer_max_receiving = nil
-    cfg.shard_index = nil
-    cfg.collect_bucket_garbage_interval = nil
-    cfg.collect_lua_garbage = nil
-    cfg.sync_timeout = nil
-    cfg.connection_outdate_delay = nil
+    return vshard_cfg, box_cfg
 end
 
 return {
     check = cfg_check,
-    remove_non_box_options = remove_non_box_options,
 }
diff --git a/vshard/router/init.lua b/vshard/router/init.lua
index 4cb19fd..e2b2b22 100644
--- a/vshard/router/init.lua
+++ b/vshard/router/init.lua
@@ -496,18 +496,15 @@ end
 --------------------------------------------------------------------------------
 
 local function router_cfg(cfg)
-    cfg = lcfg.check(cfg, M.current_cfg)
-    local new_cfg = table.copy(cfg)
+    local vshard_cfg, box_cfg = lcfg.check(cfg, M.current_cfg)
     if not M.replicasets then
         log.info('Starting router configuration')
     else
         log.info('Starting router reconfiguration')
     end
-    local new_replicasets = lreplicaset.buildall(cfg)
-    local total_bucket_count = cfg.bucket_count
-    local collect_lua_garbage = cfg.collect_lua_garbage
-    local box_cfg = table.copy(cfg)
-    lcfg.remove_non_box_options(box_cfg)
+    local new_replicasets = lreplicaset.buildall(vshard_cfg)
+    local total_bucket_count = vshard_cfg.bucket_count
+    local collect_lua_garbage = vshard_cfg.collect_lua_garbage
     log.info("Calling box.cfg()...")
     for k, v in pairs(box_cfg) do
         log.info({[k] = v})
@@ -530,11 +527,12 @@ local function router_cfg(cfg)
         replicaset:connect_all()
     end
     lreplicaset.wait_masters_connect(new_replicasets)
-    lreplicaset.outdate_replicasets(M.replicasets, cfg.connection_outdate_delay)
-    M.connection_outdate_delay = cfg.connection_outdate_delay
+    lreplicaset.outdate_replicasets(M.replicasets,
+                                    vshard_cfg.connection_outdate_delay)
+    M.connection_outdate_delay = vshard_cfg.connection_outdate_delay
     M.total_bucket_count = total_bucket_count
     M.collect_lua_garbage = collect_lua_garbage
-    M.current_cfg = cfg
+    M.current_cfg = vshard_cfg
     M.replicasets = new_replicasets
     -- Update existing route map in-place.
     local old_route_map = M.route_map
diff --git a/vshard/storage/init.lua b/vshard/storage/init.lua
index 102b942..75f5df9 100644
--- a/vshard/storage/init.lua
+++ b/vshard/storage/init.lua
@@ -1500,13 +1500,17 @@ end
 --------------------------------------------------------------------------------
 -- Configuration
 --------------------------------------------------------------------------------
+-- Private (not accessible by a user) reload indicator.
+local is_reload = false
 local function storage_cfg(cfg, this_replica_uuid)
+    -- Reset is_reload indicator in case of errors.
+    local xis_reload = is_reload
+    is_reload = false
     if this_replica_uuid == nil then
         error('Usage: cfg(configuration, this_replica_uuid)')
     end
-    cfg = lcfg.check(cfg, M.current_cfg)
-    local new_cfg = table.copy(cfg)
-    if cfg.weights or cfg.zone then
+    local vshard_cfg, box_cfg = lcfg.check(cfg, M.current_cfg)
+    if vshard_cfg.weights or vshard_cfg.zone then
         error('Weights and zone are not allowed for storage configuration')
     end
     if M.replicasets then
@@ -1520,7 +1524,7 @@ local function storage_cfg(cfg, this_replica_uuid)
 
     local this_replicaset
     local this_replica
-    local new_replicasets = lreplicaset.buildall(cfg)
+    local new_replicasets = lreplicaset.buildall(vshard_cfg)
     local min_master
     for rs_uuid, rs in pairs(new_replicasets) do
         for replica_uuid, replica in pairs(rs.replicas) do
@@ -1553,18 +1557,19 @@ local function storage_cfg(cfg, this_replica_uuid)
     --
     -- If a master role of the replica is not changed, then
     -- 'read_only' can be set right here.
-    cfg.listen = cfg.listen or this_replica.uri
-    if cfg.replication == nil and this_replicaset.master and not is_master then
-        cfg.replication = {this_replicaset.master.uri}
+    box_cfg.listen = box_cfg.listen or this_replica.uri
+    if box_cfg.replication == nil and this_replicaset.master
+            and not is_master then
+        box_cfg.replication = {this_replicaset.master.uri}
     else
-        cfg.replication = {}
+        box_cfg.replication = {}
     end
     if was_master == is_master then
-        cfg.read_only = not is_master
+        box_cfg.read_only = not is_master
     end
     if type(box.cfg) == 'function' then
-        cfg.instance_uuid = this_replica.uuid
-        cfg.replicaset_uuid = this_replicaset.uuid
+        box_cfg.instance_uuid = this_replica.uuid
+        box_cfg.replicaset_uuid = this_replicaset.uuid
     else
         local info = box.info
         if this_replica_uuid ~= info.uuid then
@@ -1578,12 +1583,14 @@ local function storage_cfg(cfg, this_replica_uuid)
                                 this_replicaset.uuid))
         end
     end
-    local total_bucket_count = cfg.bucket_count
-    local rebalancer_disbalance_threshold = cfg.rebalancer_disbalance_threshold
-    local rebalancer_max_receiving = cfg.rebalancer_max_receiving
-    local shard_index = cfg.shard_index
-    local collect_bucket_garbage_interval = cfg.collect_bucket_garbage_interval
-    local collect_lua_garbage = cfg.collect_lua_garbage
+    local total_bucket_count = vshard_cfg.bucket_count
+    local rebalancer_disbalance_threshold =
+        vshard_cfg.rebalancer_disbalance_threshold
+    local rebalancer_max_receiving = vshard_cfg.rebalancer_max_receiving
+    local shard_index = vshard_cfg.shard_index
+    local collect_bucket_garbage_interval =
+        vshard_cfg.collect_bucket_garbage_interval
+    local collect_lua_garbage = vshard_cfg.collect_lua_garbage
 
     -- It is considered that all possible errors during cfg
     -- process occur only before this place.
@@ -1598,7 +1605,7 @@ local function storage_cfg(cfg, this_replica_uuid)
     -- a new sync timeout.
     --
     local old_sync_timeout = M.sync_timeout
-    M.sync_timeout = cfg.sync_timeout
+    M.sync_timeout = vshard_cfg.sync_timeout
 
     if was_master and not is_master then
         local_on_master_disable_prepare()
@@ -1607,9 +1614,10 @@ local function storage_cfg(cfg, this_replica_uuid)
         local_on_master_enable_prepare()
     end
 
-    local box_cfg = table.copy(cfg)
-    lcfg.remove_non_box_options(box_cfg)
-    local ok, err = pcall(box.cfg, box_cfg)
+    local ok, err = true, nil
+    if not xis_reload then
+        ok, err = pcall(box.cfg, box_cfg)
+    end
     while M.errinj.ERRINJ_CFG_DELAY do
         lfiber.sleep(0.01)
     end
@@ -1639,7 +1647,7 @@ local function storage_cfg(cfg, this_replica_uuid)
     M.shard_index = shard_index
     M.collect_bucket_garbage_interval = collect_bucket_garbage_interval
     M.collect_lua_garbage = collect_lua_garbage
-    M.current_cfg = new_cfg
+    M.current_cfg = vshard_cfg
 
     if was_master and not is_master then
         local_on_master_disable()
@@ -1874,6 +1882,7 @@ if not rawget(_G, MODULE_INTERNALS) then
     rawset(_G, MODULE_INTERNALS, M)
 else
     reload_evolution.upgrade(M)
+    is_reload = true
     storage_cfg(M.current_cfg, M.this_replica.uuid)
     M.module_version = M.module_version + 1
 end
-- 
2.14.1