router: disable box.cfg

There is no reason for router to have box configured. It needs neither
storage nor listening on a port. This is breaking change, so user's
code, which relies on vshard.router.cfg to call box.cfg must be changed.

Closes #353
Closes #428

@TarantoolBot document
Title: vshard: disable box.cfg on routers

Since vshard 0.1.25 vshard.router.cfg doesn't call box.cfg and this must
be done manually outside of vshard.

example/router.lua

@@ -17,8 +17,8 @@ cfg = dofile('localcfg.lua')
 if arg[1] == 'discovery_disable' then
     cfg.discovery_mode = 'off'
 end
-cfg.listen = 3300
 
+box.cfg{listen = 3300}
 -- Start the database with sharding
 vshard = require('vshard')
 vshard.router.cfg(cfg)

test/router-luatest/router_test.lua

@@ -462,33 +462,16 @@ g.test_enable_disable = function(g)
         _G.ivshard.router.internal.errinj.ERRINJ_CFG_DELAY = true
     end)
     router:exec(function(cfg)
-        rawset(_G, 'fiber_static', ifiber.new(ivshard.router.cfg, cfg))
-        rawset(_G, 'fiber_new', ifiber.new(ivshard.router.new,
-                                           'new_router', cfg))
+        rawset(_G, 'fiber_static', ifiber.create(ivshard.router.cfg, cfg))
+        rawset(_G, 'fiber_new', ifiber.create(ivshard.router.new,
+                                              'new_router', cfg))
         _G.fiber_static:set_joinable(true)
         _G.fiber_new:set_joinable(true)
-    end, {global_cfg})
-
-    local err1, err2 = router:exec(function()
-        -- emulate unconfigured box
-        local old_box_cfg = box.cfg
-        box.cfg = function(...) return old_box_cfg(...) end
 
-        rawset(_G, 'static_router', ivshard.router.internal.routers._static_router)
-        rawset(_G, 'new_router', ivshard.router.internal.routers.new_router)
-        local _, err_1 = pcall(_G.static_router.info, _G.static_router)
-        local _, err_2 = pcall(_G.new_router.info, _G.new_router)
-
-        box.cfg = old_box_cfg
-        return err_1, err_2
-    end)
-    assert_errors_equals(err1, err2, 'box seems not to be configured')
-
-    -- set box status to loading
-    router:exec(function()
-        rawset(_G, 'old_box_info', box.info)
-        box.info = {status = 'loading'}
-    end)
+        local routers = ivshard.router.internal.routers
+        rawset(_G, 'static_router', routers._static_router)
+        rawset(_G, 'new_router', routers.new_router)
+    end, {global_cfg})
 
     local echo_func = function()
         return router:exec(function(timeout)
@@ -502,15 +485,7 @@ g.test_enable_disable = function(g)
         end, {vtest.wait_timeout})
     end
 
-    err1, err2 = echo_func()
-    assert_errors_equals(err1, err2, 'instance status is "loading"')
-
-    -- restore proper box configuration
-    router:exec(function()
-        box.info = _G.old_box_info
-    end)
-
-    err1, err2 = echo_func()
+    local err1, err2 = echo_func()
     assert_errors_equals(err1, err2, 'router is not configured')
 
     -- unblock router's configuration and wait until it's finished

vshard/router/init.lua

@@ -56,8 +56,6 @@ if not M then
         -- This counter is used to restart background fibers with
         -- new reloaded code.
         module_version = 0,
-        -- Flag whether box.info.status is acceptable.
-        is_loaded = false,
 
         ----------------------- Map-Reduce -----------------------
         -- Storage Ref ID. It must be unique for each ref request
@@ -1258,31 +1256,23 @@ end
 -- Configuration
 --------------------------------------------------------------------------------
 
-local function router_cfg(router, cfg, is_reload)
+local function router_cfg(router, cfg)
     cfg = lcfg.check(cfg, router.current_cfg)
-    local vshard_cfg, box_cfg = lcfg.split(cfg)
+    local vshard_cfg = lcfg.split(cfg)
     if not M.replicasets then
         log.info('Starting router configuration')
     else
         log.info('Starting router reconfiguration')
     end
     local new_replicasets = lreplicaset.buildall(vshard_cfg)
-    log.info("Calling box.cfg()...")
-    for k, v in pairs(box_cfg) do
-        log.info({[k] = v})
-    end
     -- It is considered that all possible errors during cfg
     -- process occur only before this place.
     -- This check should be placed as late as possible.
     if M.errinj.ERRINJ_CFG then
         error('Error injection: cfg')
     end
-    if not is_reload then
-        box.cfg(box_cfg)
-        log.info("Box has been configured")
-        while M.errinj.ERRINJ_CFG_DELAY do
-            lfiber.sleep(0.01)
-        end
+    while M.errinj.ERRINJ_CFG_DELAY do
+        lfiber.sleep(0.01)
     end
     -- Move connections from an old configuration to a new one.
     -- It must be done with no yields to prevent usage both of not
@@ -1323,13 +1313,13 @@ local function router_cfg(router, cfg, is_reload)
     router.is_configured = true
 end
 
-local function router_cfg_fiber_safe(router, cfg, is_reload)
+local function router_cfg_fiber_safe(router, cfg)
     if router.is_cfg_in_progress then
         error(lerror.vshard(lerror.code.ROUTER_CFG_IS_IN_PROGRESS, router.name))
     end
 
     router.is_cfg_in_progress = true
-    local ok, err = pcall(router_cfg, router, cfg, is_reload)
+    local ok, err = pcall(router_cfg, router, cfg)
     router.is_cfg_in_progress = false
     if not ok then
         error(err)
@@ -1683,20 +1673,6 @@ end
 -- the beginning of instance's lifetime.
 --
 local function router_api_call_unsafe(func, router, ...)
-    -- box.info is quite expensive. Avoid calling it again when the instance
-    -- is finally loaded.
-    if not M.is_loaded then
-        if type(box.cfg) == 'function' then
-            local msg = 'box seems not to be configured'
-            return error(lerror.vshard(lerror.code.ROUTER_IS_DISABLED, msg))
-        end
-        local status = box.info.status
-        if status ~= 'running' then
-            local msg = ('instance status is "%s"'):format(status)
-            return error(lerror.vshard(lerror.code.ROUTER_IS_DISABLED, msg))
-        end
-        M.is_loaded = true
-    end
     if not router.is_configured then
         local msg = 'router is not configured'
         return error(lerror.vshard(lerror.code.ROUTER_IS_DISABLED, msg))
@@ -1734,7 +1710,9 @@ end
 
 local router_mt = {
     __index = {
-        cfg = function(router, cfg) return router_cfg_fiber_safe(router, cfg, false) end,
+        cfg = function(router, cfg)
+            return router_cfg_fiber_safe(router, cfg)
+        end,
         info = router_make_api(router_info),
         buckets_info = router_make_api(router_buckets_info),
         call = router_make_api(router_call),
@@ -1832,7 +1810,7 @@ local function legacy_cfg(cfg)
         end
     else
         -- Reconfigure
-        router_cfg_fiber_safe(router, cfg, false)
+        router_cfg_fiber_safe(router, cfg)
     end
 end
 
@@ -1861,7 +1839,7 @@ else
         if router.api_call_cache == nil then
             router.api_call_cache = router_api_call_unsafe
         end
-        router_cfg_fiber_safe(router, router.current_cfg, true)
+        router_cfg_fiber_safe(router, router.current_cfg)
         setmetatable(router, router_mt)
     end
     if M.static_router then