Resolve space name from id in statistics

`crud.len` supports using space id instead of name. After this patch,
stats wrapper support mapping id to name.

Since using space id is a questionable pattern (see #255), this commit
may be reverted later.

Part of #224

Author: DifferentialOrange

crud/stats/module.lua

@@ -166,6 +166,17 @@ local function wrap_tail(space_name, op, opts, start_time, call_status, ...)
         end
     end
 
+    -- If space id is provided instead of name, resolve name.
+    -- If using space id will be deprecated, remove this code as well,
+    -- see https://github.com/tarantool/crud/issues/255
+    if type(space_name) ~= 'string' then
+        if space == nil then
+            space = utils.get_space(space_name, vshard.router.routeall())
+        end
+
+        space_name = space.name
+    end
+
     if context_stats ~= nil then
         if context_stats.map_reduces ~= nil then
             registry.observe_map_reduces(context_stats.map_reduces, space_name)

test/entrypoint/srv_stats.lua

@@ -23,6 +23,7 @@ package.preload['customers-storage'] = function()
                 },
                 if_not_exists = true,
                 engine = engine,
+                id = 542,
             })
             -- primary index
             customers_space:create_index('id_index', {

test/integration/stats_test.lua

@@ -7,6 +7,7 @@ local stats_registry_common = require('crud.stats.registry_common')
 local g = t.group('stats_integration')
 local helpers = require('test.helper')
 
+local space_id = 542
 local space_name = 'customers'
 local unknown_space_name = 'non_existing_space'
 local new_space_name = 'newspace'
@@ -637,6 +638,15 @@ for name, case in pairs(select_cases) do
 end
 
 
+g.test_resolve_name_from_id = function(g)
+    local op = 'len'
+    g.router:call('crud.len', { space_id })
+
+    local stats = g:get_stats(space_name)
+    t.assert_not_equals(stats[op], nil, "Statistics is filled by name")
+end
+
+
 g.before_test(
     'test_role_reload_do_not_reset_observations',
     generate_stats)

test/unit/stats_test.lua

@@ -9,6 +9,7 @@ local utils = require('crud.common.utils')
 local g = t.group('stats_unit')
 local helpers = require('test.helper')
 
+local space_id = 542
 local space_name = 'customers'
 local unknown_space_name = 'non_existing_space'
 
@@ -528,3 +529,11 @@ g.test_map_reduce_increment = function(g)
     t.assert_equals(stats.spaces[space_name][op].details.map_reduces, inc,
         "Counter of map reduces incremented")
 end
+
+g.test_resolve_name_from_id = function(g)
+    local op = stats_module.op.LEN
+    g.router:eval(call_wrapped, { 'return_true', stats_module.op.LEN, {}, space_id })
+
+    local stats = g:get_stats(space_name)
+    t.assert_not_equals(stats[op], nil, "Statistics is filled by name")
+end