ddl: fix fetching invalid configuration

Before this patch, in case there is a sharding key record
in _ddl_sharding_key for a non-existing space (for example, if ddl space
wasn't properly dropped) and sharding info needs to be updated, any crud
request will fail with "attempt to index a nil value" error. This patch
fixes the behavior and adds a log warning if ddl configuration is
invalid.

Closes #308

CHANGELOG.md

@@ -12,6 +12,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Changed
 
 ### Fixed
+* Fetching invalid ddl confuguration (sharding key for non-existing space)
+  is no longer breaks CRUD requests (#308, PR #309).
 
 ## [0.12.0] - 28-06-22
 

crud/common/sharding/sharding_metadata.lua

@@ -58,12 +58,20 @@ function sharding_metadata_module.fetch_on_storage()
         for _, tuple in sharding_key_space:pairs() do
             local space_name = tuple[sharding_utils.SPACE_NAME_FIELDNO]
             local sharding_key_def = tuple[sharding_utils.SPACE_SHARDING_KEY_FIELDNO]
-            local space_format = box.space[space_name]:format()
-            metadata_map[space_name] = {
-                sharding_key_def = sharding_key_def,
-                sharding_key_hash = storage_cache.get_sharding_key_hash(space_name),
-                space_format = space_format,
-            }
+            local space = box.space[space_name]
+
+            if space ~= nil then
+                local space_format = space:format()
+                metadata_map[space_name] = {
+                    sharding_key_def = sharding_key_def,
+                    sharding_key_hash = storage_cache.get_sharding_key_hash(space_name),
+                    space_format = space_format,
+                }
+            else
+                log.warn('Found sharding info for %q, but space not exists. ' ..
+                         'Ensure that you did a proper cleanup after DDL space drop.',
+                         space_name)
+            end
         end
     end
 

deps.sh

@@ -28,5 +28,6 @@ rmdir "${TMPDIR}"
 
 tarantoolctl rocks install cartridge 2.7.4
 tarantoolctl rocks install ddl 1.6.0
+tarantoolctl rocks install migrations 0.4.2
 
 tarantoolctl rocks make

test/entrypoint/srv_migration.lua

@@ -0,0 +1,46 @@
+#!/usr/bin/env tarantool
+
+require('strict').on()
+_G.is_initialized = function() return false end
+
+local log = require('log')
+local errors = require('errors')
+local cartridge = require('cartridge')
+
+package.preload['customers-storage'] = function()
+    return {
+        role_name = 'customers-storage',
+        init = function(opts)
+            if opts.is_master then
+                box.schema.space.create('customers')
+
+                box.space['customers']:format{
+                    {name = 'id',           is_nullable = false, type = 'unsigned'},
+                    {name = 'bucket_id',    is_nullable = false, type = 'unsigned'},
+                    {name = 'sharding_key', is_nullable = false, type = 'unsigned'},
+                }
+
+                box.space['customers']:create_index('pk',        {parts = { 'id' }})
+                box.space['customers']:create_index('bucket_id', {parts = { 'bucket_id' }})
+            end
+        end,
+    }
+end
+
+local ok, err = errors.pcall('CartridgeCfgError', cartridge.cfg, {
+    advertise_uri = 'localhost:3301',
+    http_port = 8081,
+    bucket_count = 3000,
+    roles = {
+        'customers-storage',
+        'cartridge.roles.crud-router',
+        'cartridge.roles.crud-storage',
+    }}
+)
+
+if not ok then
+    log.error('%s', err)
+    os.exit(1)
+end
+
+_G.is_initialized = cartridge.is_healthy

test/integration/migration_test.lua

@@ -0,0 +1,65 @@
+local fio = require('fio')
+
+local t = require('luatest')
+
+local helpers = require('test.helper')
+
+local pgroup = t.group('migration', {
+    {engine = 'memtx'},
+    {engine = 'vinyl'},
+})
+
+pgroup.before_all(function(g)
+    g.cluster = helpers.Cluster:new({
+        datadir = fio.tempdir(),
+        server_command = helpers.entrypoint('srv_migration'),
+        use_vshard = true,
+        replicasets = helpers.get_test_replicasets(),
+        env = {
+            ['ENGINE'] = g.params.engine,
+        },
+    })
+    g.cluster:start()
+end)
+
+pgroup.after_all(function(g) helpers.stop_cluster(g.cluster) end)
+
+pgroup.test_gh_308_select_after_improper_ddl_space_drop = function(g)
+    -- Create a space sharded by key with ddl tools.
+    helpers.call_on_storages(g.cluster, function(server)
+        server.net_box:eval([[
+            local migrator_utils = require('migrator.utils')
+
+            if not box.info.ro then
+                box.schema.space.create('customers_v2')
+
+                box.space['customers_v2']:format{
+                    {name = 'id_v2',        is_nullable = false, type = 'unsigned'},
+                    {name = 'bucket_id',    is_nullable = false, type = 'unsigned'},
+                    {name = 'sharding_key', is_nullable = false, type = 'unsigned'},
+                }
+
+                box.space['customers_v2']:create_index('pk',        {parts = { 'id_v2' }})
+                box.space['customers_v2']:create_index('bucket_id', {parts = { 'bucket_id' }})
+
+                migrator_utils.register_sharding_key('customers_v2', {'sharding_key'})
+            end
+        ]])
+    end)
+
+    -- Do not do any requests to refresh sharding metadata.
+
+    -- Drop space, but do not clean up ddl sharding data.
+    helpers.call_on_storages(g.cluster, function(server)
+        server.net_box:eval([[
+            if not box.info.ro then
+                box.space['customers_v2']:drop()
+            end
+        ]])
+    end)
+
+    -- Ensure that crud request for existing space is ok.
+    local _, err = g.cluster.main_server.net_box:call('crud.select',
+                                                      {'customers', nil, { first = 1 }})
+    t.assert_equals(err, nil)
+end