config: introduce fiber applier

This patch introduces the fiber applier. This applier is used to set
fiber options.

Part of #8789

NO_DOC=will be added later
NO_CHANGELOG=will be added later

src/box/CMakeLists.txt

@@ -40,6 +40,7 @@ lua_source(lua_sources lua/merger.lua merger_lua)
 lua_source(lua_sources lua/config/applier/box_cfg.lua     config_applier_box_cfg_lua)
 lua_source(lua_sources lua/config/applier/console.lua     config_applier_console_lua)
 lua_source(lua_sources lua/config/applier/credentials.lua config_applier_credentials_lua)
+lua_source(lua_sources lua/config/applier/fiber.lua       config_applier_fiber_lua)
 lua_source(lua_sources lua/config/applier/mkdir.lua       config_applier_mkdir_lua)
 lua_source(lua_sources lua/config/cluster_config.lua      config_cluster_config_lua)
 lua_source(lua_sources lua/config/configdata.lua          config_configdata_lua)

src/box/lua/config/applier/fiber.lua

+local fiber = require('fiber')
+local log = require('internal.config.utils.log')
+
+local function apply(config)
+    local configdata = config._configdata
+    local slice = configdata:get('fiber.slice', {use_default = true})
+    assert(slice ~= nil)
+    log.verbose('fiber.apply: fiber.set_max_slice: %s', slice)
+    fiber.set_max_slice(slice)
+
+    local top = configdata:get('fiber.top', {use_default = true})
+    assert(type(top) == 'table')
+    assert(type(top.enabled) == 'boolean')
+    if top.enabled then
+        log.verbose('fiber.apply: enable fiber top')
+        fiber.top_enable()
+    else
+        log.verbose('fiber.apply: disable fiber top')
+        fiber.top_disable()
+    end
+end
+
+return {
+    name = 'fiber',
+    apply = apply,
+}

src/box/lua/init.c

@@ -138,6 +138,7 @@ extern char session_lua[],
 	config_applier_box_cfg_lua[],
 	config_applier_console_lua[],
 	config_applier_credentials_lua[],
+	config_applier_fiber_lua[],
 	config_applier_mkdir_lua[],
 	config_cluster_config_lua[],
 	config_configdata_lua[],
@@ -332,6 +333,10 @@ static const char *lua_sources[] = {
 	"internal.config.applier.credentials",
 	config_applier_credentials_lua,
 
+	"config/applier/fiber",
+	"internal.config.applier.fiber",
+	config_applier_fiber_lua,
+
 	"config/applier/mkdir",
 	"internal.config.applier.mkdir",
 	config_applier_mkdir_lua,

test/config-luatest/appliers_test.lua

@@ -19,6 +19,11 @@ local appliers_script = [[
         memtx = {
             memory = 100000000,
         },
+        fiber = {
+            top = {
+                enabled = true,
+            },
+        },
         groups = {
             ['group-001'] = {
                 replicasets = {
@@ -45,6 +50,8 @@ local appliers_script = [[
     credentials.apply(config)
     local console = require('internal.config.applier.console')
     console.apply(config)
+    local fiber = require('internal.config.applier.fiber')
+    fiber.apply(config)
     %s
     os.exit(0)
 ]]
@@ -121,3 +128,18 @@ g.test_applier_console = function()
     t.assert_equals(res.exit_code, 0)
     t.assert_equals(res.stdout, 'Tarantool (Lua console)')
 end
+
+g.test_applier_fiber = function()
+    local dir = treegen.prepare_directory(g, {}, {})
+    local injection = [[
+        fiber = require('fiber')
+        print(fiber.top() ~= nil)
+    ]]
+    treegen.write_script(dir, 'main.lua', appliers_script:format(injection))
+
+    local env = {}
+    local opts = {nojson = true, stderr = false}
+    local res = justrun.tarantool(dir, env, {'main.lua'}, opts)
+    t.assert_equals(res.exit_code, 0)
+    t.assert_equals(res.stdout, 'true')
+end