config: automatically set names on schema upgrade

This commit adds a trigger, which sets names via box.cfg, when
dd_version_id, seen from box.schema event, is changed to the
version >= 3.0.0 from version < 3.0.0.

On master instances we set replicaset_name and instance_name.
On replicas - only instance_name, they'll automatically register
themselves in _cluster space by making IPROTO_REGISTER to master.
This behavior allows live upgrade to Tarantool 3.0.0.

Closes tarantool#8978

NO_DOC=tarantool/doc#3661

changelogs/unreleased/config-automatic-names.md

@@ -0,0 +1,4 @@
+## feature/config
+
+* If Tarantool is congired via yaml file or etcd, then
+  instance/replicaset/cluster names will be automatically set on schema upgrade.

src/box/lua/config/applier/box_cfg.lua

@@ -1,6 +1,8 @@
+local fiber = require('fiber')
 local fio = require('fio')
 local log = require('internal.config.utils.log')
 local instance_config = require('internal.config.instance_config')
+local mkversion = require('internal.mkversion')
 
 local function peer_uri(configdata, peer_name)
     local iconfig = configdata._peers[peer_name].iconfig_def
@@ -117,6 +119,47 @@ local function has_snapshot(configdata)
     return #fio.glob(pattern) > 0
 end
 
+--
+-- If schema version is less than 3.0.0, set box.watch trigger, which
+-- automatically configures names as soon as schema is upgraded to
+-- the version >= 3.0.0
+--
+local function apply_names_on_upgrade(names, is_rw)
+    local version = mkversion.get()
+    local version_3 = mkversion(3, 0, 0)
+    if version >= version_3 then
+        return
+    end
+
+    box.watch('box.schema', function(_, value)
+        local id = value.dd_version_id
+        -- dd_version_id is not updated in most cases.
+        if id == version.id then
+            return
+        end
+
+        if version < version_3 and mkversion.from_id(id) >= version_3 then
+            -- Indefinitely retry setting names, schema was already updated,
+            -- we must set names before restart. Otherwise, it will be
+            -- impossible to start instance again with yaml config.
+            -- Manual intervention will be required: configure without names,
+            -- set names with box.cfg.
+            while true do
+                local ok, err = pcall(box.cfg, {
+                    instance_name = names.instance_name,
+                    replicaset_name = is_rw and names.replicaset_name or nil,
+                })
+                if ok then
+                    break
+                end
+
+                log.info('Failed to set names: %s. Retrying...', err)
+                fiber.sleep(1)
+            end
+        end
+    end)
+end
+
 -- Returns nothing or {needs_retry = true}.
 local function apply(config)
     local configdata = config._configdata
@@ -395,6 +438,7 @@ local function apply(config)
 
         log.debug('box_cfg.apply (startup): %s', box_cfg)
         box.cfg(box_cfg)
+        apply_names_on_upgrade(names, configured_as_rw)
 
         -- NB: needs_retry should be true when force_read_only is
         -- true. It is so by construction.
@@ -404,6 +448,9 @@ local function apply(config)
     -- If it is reload, just apply the new configuration.
     log.debug('box_cfg.apply: %s', box_cfg)
     box.cfg(box_cfg)
+    if is_startup then
+        apply_names_on_upgrade(names, not box_cfg.read_only)
+    end
 end
 
 return {

test/box-luatest/upgrade/2.11.0/replicaset/instance-001/gen.lua

@@ -0,0 +1,16 @@
+box.cfg{
+    replicaset_uuid = 'cbf06940-0790-498b-948d-042b62cf3d29',
+    instance_uuid = '8a274925-a26d-47fc-9e1b-af88ce939412',
+    replication = {3301, 3302},
+    listen = 3301,
+}
+
+box.schema.user.grant('guest', 'super')
+box.schema.create_space('test_space')
+while not box.info.replication[2] or
+      not box.info.replication[2].downstream or
+      box.info.replication[2].downstream.status ~= 'follow' do
+    require('fiber').yield(0.1)
+end
+box.snapshot()
+os.exit(0)

test/box-luatest/upgrade/2.11.0/replicaset/instance-002/gen.lua

@@ -0,0 +1,10 @@
+box.cfg{
+    replicaset_uuid = 'cbf06940-0790-498b-948d-042b62cf3d29',
+    instance_uuid = '3de2e3e1-9ebe-4d0d-abb1-26d301b84633',
+    replication = {3301, 3302},
+    read_only = true,
+    listen = 3302,
+}
+
+box.snapshot()
+os.exit(0)

test/config-luatest/upgrade_test.lua

@@ -0,0 +1,108 @@
+local t = require('luatest')
+local server = require('test.luatest_helpers.server')
+local treegen = require('test.treegen')
+
+local g = t.group('config_upgrade_test')
+
+g.before_all(function()
+    treegen.init(g)
+    local dir = treegen.prepare_directory(g, {}, {})
+    local config = [[
+    credentials:
+      users:
+        guest:
+          roles: [super]
+    iproto:
+      listen: 'unix/:./{{ instance_name }}.iproto'
+    wal:
+      dir: %s
+    snapshot:
+      dir: %s
+    groups:
+      group-001:
+        replicasets:
+          replicaset-001:
+            database:
+              replicaset_uuid: 'cbf06940-0790-498b-948d-042b62cf3d29'
+            instances:
+              instance-001:
+                database:
+                  mode: rw
+                  instance_uuid: '8a274925-a26d-47fc-9e1b-af88ce939412'
+              instance-002:
+                database:
+                  mode: ro
+                  instance_uuid: '3de2e3e1-9ebe-4d0d-abb1-26d301b84633'
+    ]]
+
+    local datadir_prefix = 'test/box-luatest/upgrade/2.11.0/replicaset/'
+    -- Create dirs to generate config
+    g.server_1 = server:new({
+        -- Requires non-empty config
+        chdir = dir,
+        config_file = '',
+        alias = 'instance-001',
+        datadir = datadir_prefix .. 'instance-001',
+    })
+    g.server_2 = server:new({
+        chdir = dir,
+        config_file = '',
+        alias = 'instance-002',
+        datadir = datadir_prefix .. 'instance-002',
+    })
+
+    local config_1 = string.format(config, g.server_1.workdir,
+                                   g.server_1.workdir, g.server_1.workdir)
+    local config_2 = string.format(config, g.server_2.workdir,
+                                   g.server_2.workdir, g.server_2.workdir)
+
+    local config_file_1 = treegen.write_script(dir, 'config_1.yaml', config_1)
+    local config_file_2 = treegen.write_script(dir, 'config_2.yaml', config_2)
+
+    g.server_1.net_box_uri = 'unix/:' .. dir .. '/instance-001.iproto'
+    g.server_1.config_file = config_file_1
+    g.server_1:initialize()
+
+    g.server_2.net_box_uri = 'unix/:' .. dir .. '/instance-002.iproto'
+    g.server_2.config_file = config_file_2
+    g.server_2:initialize()
+
+    g.server_1:start({wait_until_ready = false})
+    g.server_2:start({wait_until_ready = false})
+    g.server_1:wait_until_ready()
+    g.server_2:wait_until_ready()
+end)
+
+g.after_all(function()
+    g.server_1:stop()
+    g.server_2:stop()
+    treegen.clean(g)
+end)
+
+local function assert_before_upgrade()
+    t.assert_equals(box.space._schema:get{'version'}, {'version', 2, 11, 0})
+    local info = box.info
+    t.assert_equals(info.name, nil)
+    t.assert_equals(info.replicaset.name, nil)
+end
+
+local function assert_after_upgrade(instance_name, replicaset_name)
+    local info = box.info
+    t.helpers.retrying({}, function()
+        t.assert_equals(box.space._schema:get{'version'}, {'version', 3, 0, 0})
+        t.assert_equals(info.name, instance_name)
+        t.assert_equals(info.replicaset.name, replicaset_name)
+    end)
+end
+
+g.test_upgrade = function()
+    g.server_1:exec(assert_before_upgrade)
+    g.server_2:exec(assert_before_upgrade)
+
+    g.server_1:exec(function() box.schema.upgrade() end)
+    g.server_2:wait_for_vclock_of(g.server_1)
+
+    local rs_name = 'replicaset-001'
+    g.server_1:exec(assert_after_upgrade, {g.server_1.alias, rs_name})
+    g.server_2:exec(assert_after_upgrade, {g.server_2.alias, rs_name})
+end