config: set names automatically on schema upgrade

It's impossible to set names on Tarantool below 3.0.0, as all DDL
is forbidden before schema upgrade.

Let's make names NoOp on schema below Tarantool 3.0.0 and set names
automatically only when schema upgrade is done.

Follow-up tarantool#8978

NO_DOC=tarantool/doc#3661

changelogs/unreleased/gh-8978-config-set-names-automatically.md

@@ -0,0 +1,4 @@
+## feature/config
+
+* If Tarantool is configured via a YAML file or etcd, then instance and replica
+  set names are automatically set when possible (gh-8978).

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

@@ -3,6 +3,7 @@ local log = require('internal.config.utils.log')
 local instance_config = require('internal.config.instance_config')
 local snapshot = require('internal.config.utils.snapshot')
 local schedule_task = fiber._internal.schedule_task
+local mkversion = require('internal.mkversion')
 
 local function peer_uri(configdata, peer_name)
     local iconfig = configdata._peers[peer_name].iconfig_def
@@ -183,6 +184,25 @@ local function names_rw_watcher()
     end)
 end
 
+local function names_schema_upgrade_on_replace(old, new)
+    if old == nil or new == nil then
+        return
+    end
+
+    local version_3 = mkversion(3, 0, 0)
+    local old_version = mkversion.from_tuple(old)
+    local new_version = mkversion.from_tuple(new)
+    if old_version < version_3 and new_version >= version_3 then
+        -- We cannot do it inside on_replace trigger, as the version
+        -- is not considered set yet and we may try to set names, when
+        -- schema is not yet updated, which will fail as DDL is
+        -- prohibited before schema upgrade.
+        box.on_commit(function()
+            names_state.rw_watcher = names_rw_watcher()
+        end)
+    end
+end
+
 local function names_cluster_on_replace(old, new)
     -- Ignore insert of a new replica. Every new replica will have
     -- name set, as it may join to a replicaset only by bootstrap, which
@@ -238,7 +258,7 @@ names_check_and_clean = function()
     end
 end
 
-local function names_apply(config, missing_names)
+local function names_apply(config, missing_names, schema_version)
     -- names_state.config should be updated, as all triggers rely on configdata,
     -- saved in it. configdata may be different from the one, we already have.
     names_state.config = config
@@ -254,11 +274,26 @@ local function names_apply(config, missing_names)
     box.space._schema:on_replace(names_schema_on_replace)
     box.space._cluster:on_replace(names_cluster_on_replace)
 
-    -- Wait for rw state.
-    names_state.rw_watcher = names_rw_watcher()
+    -- Wait for rw state. If schema version is nil, bootstrap is
+    -- going to be done.
+    if schema_version and schema_version < mkversion(3, 0, 0) then
+        box.space._schema:on_replace(names_schema_upgrade_on_replace)
+    else
+        names_state.rw_watcher = names_rw_watcher()
+    end
+
     names_state.is_configured = true
 end
 
+local function get_schema_version_before_cfg(config)
+    local snap_path = snapshot.get_path(config._configdata._iconfig_def)
+    if snap_path ~= nil then
+        return mkversion.from_tuple(snapshot.get_schema_version(snap_path))
+    end
+    -- Bootstrap, config not found
+    return nil
+end
+
 -- Returns nothing or {needs_retry = true}.
 local function apply(config)
     local configdata = config._configdata
@@ -490,17 +525,19 @@ local function apply(config)
     if not missing_names_is_empty(missing_names, names.replicaset_name) then
         if is_startup then
             local on_schema_init
+            -- schema version may be nil, if bootstrap is done.
+            local version = get_schema_version_before_cfg(config)
             -- on_schema init trigger isn't deleted, as it's executed only once.
             on_schema_init = box.ctl.on_schema_init(function()
                 -- missing_names cannot be gathered inside on_schema_init
                 -- trigger, as box.cfg is already considered configured but
                 -- box.info is still not properly initialized.
-                names_apply(config, missing_names)
+                names_apply(config, missing_names, version)
                 box.ctl.on_schema_init(nil, on_schema_init)
             end)
         else
             -- Note, that we try to find new missing names on every reload.
-            names_apply(config, missing_names)
+            names_apply(config, missing_names, mkversion.get())
         end
     end
 

src/box/lua/config/utils/snapshot.lua

@@ -108,7 +108,30 @@ local function get_snapshot_names(snap_path)
     }
 end
 
+local function get_snapshot_schema_version(snap_path)
+    for _, row in xlog.pairs(snap_path) do
+        local body = row.BODY
+        if not body.space_id then
+            goto continue
+        end
+
+        if body.space_id > box.schema.SCHEMA_ID then
+            break
+        end
+
+        if body.space_id == box.schema.SCHEMA_ID then
+            if body.tuple[1] == 'version' then
+                return body.tuple
+            end
+        end
+        ::continue::
+    end
+
+    assert(false)
+end
+
 return {
     get_path = get_snapshot_path,
     get_names = get_snapshot_names,
+    get_schema_version = get_snapshot_schema_version,
 }

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/names_upgrade_test.lua

@@ -0,0 +1,128 @@
+local t = require('luatest')
+local treegen = require('test.treegen')
+local server = require('test.luatest_helpers.server')
+local yaml = require('yaml')
+local fun = require('fun')
+local fio = require('fio')
+
+local g = t.group('set-names-automatically-on-upgrade')
+
+g.before_all(function(g)
+    treegen.init(g)
+
+    g.uuids = {
+        ['replicaset-001'] = 'cbf06940-0790-498b-948d-042b62cf3d29',
+        ['instance-001'] =   '8a274925-a26d-47fc-9e1b-af88ce939412',
+        ['instance-002'] =   '3de2e3e1-9ebe-4d0d-abb1-26d301b84633'
+    }
+
+    local datadir_prefix = 'test/box-luatest/upgrade/2.11.0/replicaset/'
+    local datadir_1 = fio.abspath(fio.pathjoin(datadir_prefix, 'instance-001'))
+    local datadir_2 = fio.abspath(fio.pathjoin(datadir_prefix, 'instance-002'))
+
+    local dir = treegen.prepare_directory(g, {}, {})
+    local workdir_1 = fio.pathjoin(dir, 'instance-001')
+    local workdir_2 = fio.pathjoin(dir, 'instance-002')
+
+    fio.mktree(workdir_1)
+    fio.mktree(workdir_2)
+
+    fio.copytree(datadir_1, workdir_1)
+    fio.copytree(datadir_2, workdir_2)
+
+    local config = {
+        credentials = {
+            users = {
+                guest = {
+                    roles = {'super'},
+                },
+            },
+        },
+
+        iproto = {
+            listen = 'unix/:./{{ instance_name }}.iproto',
+        },
+
+        groups = {
+            ['group-001'] = {
+                replicasets = {
+                    ['replicaset-001'] = {
+                        database = {
+                            replicaset_uuid = g.uuids['replicaset-001']
+                        },
+                        instances = {
+                            ['instance-001'] = {
+                                snapshot = { dir = workdir_1, },
+                                wal = { dir = workdir_1, },
+                                database = {
+                                    instance_uuid = g.uuids['instance-001'],
+                                    mode = 'rw',
+                                },
+                            },
+                            ['instance-002'] = {
+                                snapshot = { dir = workdir_2, },
+                                wal = { dir = workdir_2, },
+                                database = {
+                                    instance_uuid = g.uuids['instance-002']
+                                },
+                            },
+                        },
+                    },
+                },
+            },
+        },
+    }
+
+    local cfg = yaml.encode(config)
+    local config_file = treegen.write_script(dir, 'cfg.yaml', cfg)
+    local opts = {config_file = config_file, chdir = dir}
+    g.instance_1 = server:new(fun.chain(opts, {alias = 'instance-001'}):tomap())
+    g.instance_2 = server:new(fun.chain(opts, {alias = 'instance-002'}):tomap())
+
+    g.instance_1:start({wait_until_ready = false})
+    g.instance_2:start({wait_until_ready = false})
+    g.instance_1:wait_until_ready()
+    g.instance_2:wait_until_ready()
+end)
+
+g.after_all(function(g)
+    g.instance_1:drop()
+    g.instance_2:drop()
+    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, names)
+    t.helpers.retrying({}, function()
+        local info = box.info
+        t.assert_equals(info.name, instance_name)
+        t.assert_equals(info.replicaset.name, replicaset_name)
+
+        local alerts = require('config')._alerts
+        for name, _ in pairs(names) do
+            t.assert_equals(alerts[name], nil)
+        end
+    end)
+end
+
+g.test_upgrade = function()
+    g.instance_1:exec(assert_before_upgrade)
+    g.instance_2:exec(assert_before_upgrade)
+
+    g.instance_1:exec(function()
+        box.ctl.wait_rw()
+        box.schema.upgrade()
+    end)
+
+    g.instance_2:wait_for_vclock_of(g.instance_1)
+
+    local rs = 'replicaset-001'
+    g.instance_1:exec(assert_after_upgrade, {g.instance_1.alias, rs, g.uuids})
+    g.instance_2:exec(assert_after_upgrade, {g.instance_2.alias, rs, g.uuids})
+end