Support reset of cache with sharding keys

Part of #166

Author: ligurio

crud/common/sharding_key.lua

@@ -122,6 +122,11 @@ function sharding_key_module.fetch_on_router(space_name)
     return cache.sharding_key_def[space_name]
 end
 
+function sharding_key_module.update_sharding_keys_cache(space_name)
+    cache.drop_caches()
+    return sharding_key_module.fetch_on_router(space_name)
+end
+
 -- Make sure sharding key definition is a part of primary key.
 -- sharding_key_as_index_obj is not used in CRUD, it was added to be able to
 -- use it in unit tests.

test/helper.lua

@@ -230,4 +230,13 @@ function helpers.get_other_storage_bucket_id(cluster, bucket_id)
     ]], {bucket_id})
 end
 
+function helpers.update_sharding_keys_cache(cluster, space_name)
+    return cluster.main_server.net_box:eval([[
+        local sharding_key = require('crud.common.sharding_key')
+
+        local space_name = ...
+        return sharding_key.update_sharding_keys_cache(space_name)
+    ]], {space_name})
+end
+
 return helpers

test/integration/ddl_sharding_key_test.lua

@@ -546,3 +546,22 @@ pgroup.test_delete_secondary_idx = function(g)
         "Sharding key for space \"customers_secondary_idx_name_key\" is missed in primary index, specify bucket_id")
     t.assert_equals(result, nil)
 end
+
+pgroup.test_update_sharding_keys_cache = function(g)
+    local space_name = 'customers_name_key'
+    local sharding_key = helpers.update_sharding_keys_cache(g.cluster, space_name)
+    t.assert_equals(sharding_key, {'name'})
+
+    helpers.call_on_servers(g.cluster, {'s1-master', 's2-master'}, function(server)
+        server.net_box:call('set_sharding_key', {space_name, {'age'}})
+    end)
+    sharding_key = helpers.update_sharding_keys_cache(g.cluster, space_name)
+    t.assert_equals(sharding_key, {'age'})
+
+    -- Recover sharding key.
+    helpers.call_on_servers(g.cluster, {'s1-master', 's2-master'}, function(server)
+        server.net_box:call('set_sharding_key', {space_name, {'name'}})
+    end)
+    sharding_key = helpers.update_sharding_keys_cache(g.cluster, space_name)
+    t.assert_equals(sharding_key, {'name'})
+end