storage: allow calling info when disabled

A storage may be marked as disabled, which previously made it difficult
to obtain status information from the component.

This patch allows calling vshard.storage.info even when the component
is disabled. The function now also returns a new boolean field is_enabled
indicating whether the component is currently enabled.

Closes #565

@TarantoolBot document
Title: vshard: storage.info behavior change

vshard.storage.info()

This function can now be called even when the storage is disabled.

It now also returns a new boolean field is_enabled indicating whether
the component is currently enabled.

Author: kamenkremen

test/storage-luatest/storage_1_test.lua

@@ -633,3 +633,44 @@ test_group.test_alerts_for_named_replica = function(g)
 
     test_alerts_for_non_vshard_config_template(g, non_config_replica)
 end
+
+test_group.test_info_disable_consistency = function(g)
+    -- Make storage unconfigured.
+    g.replica_1_a:restart()
+    g.replica_1_a:exec(function(cfg)
+        ivtest.clear_test_cfg_options(cfg)
+        -- Imitate unconfigured box.
+        local old_box_cfg = box.cfg
+        box.cfg = function(...) return old_box_cfg(...) end
+        local _, err = pcall(ivshard.storage.info)
+        ilt.assert_not_equals(err, nil)
+        ilt.assert_str_contains(err.message, 'box seems not to be configured')
+        box.cfg = old_box_cfg
+
+        local old_box_info = box.info
+        box.info = {status = 'loading'}
+        _, err = pcall(ivshard.storage.info)
+        ilt.assert_not_equals(err, nil)
+        ilt.assert_str_contains(err.message, 'instance status is "loading"')
+        box.info = old_box_info
+
+        _, err = pcall(ivshard.storage.info)
+        ilt.assert_not_equals(err, nil)
+        ilt.assert_str_contains(err.message, 'storage is not configured')
+
+        ivshard.storage.cfg(cfg, _G.get_uuid())
+        local res = ivshard.storage.info()
+        ilt.assert_not_equals(res, nil)
+        ilt.assert(res.is_enabled)
+
+        ivshard.storage.disable()
+        res = ivshard.storage.info()
+        ilt.assert_not_equals(res, nil)
+        ilt.assert_not(res.is_enabled)
+
+        ivshard.storage.enable()
+        res = ivshard.storage.info()
+        ilt.assert_not_equals(res, nil)
+        ilt.assert(res.is_enabled)
+    end, {global_cfg})
+end

test/storage/storage.result

@@ -153,6 +153,7 @@ vshard.storage.info()
   uri: [email protected]:3301
   identification_mode: uuid_as_key
   status: 2
+  is_enabled: true
   replication:
     status: slave
   alerts:
@@ -276,6 +277,7 @@ vshard.storage.info()
   uri: [email protected]:3304
   identification_mode: uuid_as_key
   status: 0
+  is_enabled: true
   replication:
     status: follow
     lag: <lag>
@@ -338,6 +340,7 @@ info
   uri: [email protected]:3303
   identification_mode: uuid_as_key
   status: 0
+  is_enabled: true
   replication:
     status: master
   alerts: []
@@ -370,6 +373,7 @@ vshard.storage.info()
   uri: [email protected]:3303
   identification_mode: uuid_as_key
   status: 3
+  is_enabled: true
   replication:
     status: master
   alerts:
@@ -403,6 +407,7 @@ vshard.storage.info()
   uri: [email protected]:3304
   identification_mode: uuid_as_key
   status: 0
+  is_enabled: true
   replication:
     status: follow
     lag: <lag>
@@ -436,6 +441,7 @@ vshard.storage.info()
   uri: [email protected]:3303
   identification_mode: uuid_as_key
   status: 0
+  is_enabled: true
   replication:
     status: master
   alerts: []

vshard/storage/init.lua

@@ -4009,6 +4009,7 @@ local function storage_info(opts)
                 M.instance_watch_service:info(),
         }
     end
+    state.is_enabled = M.is_enabled
     return state
 end
 
@@ -4020,15 +4021,15 @@ end
 -- Arguments are listed explicitly instead of '...' because the latter does not
 -- jit.
 --
-local function storage_api_call_safe(func, ...)
+local function storage_api_call_safe(func, _opts, ...)
     return func(...)
 end
 
 --
 -- Unsafe proxy is loaded with protections. But it is used rarely and only in
 -- the beginning of instance's lifetime.
 --
-local function storage_api_call_unsafe(func, ...)
+local function storage_api_call_unsafe(func, opts, ...)
     -- box.info is quite expensive. Avoid calling it again when the instance
     -- is finally loaded.
     if not M.is_loaded then
@@ -4049,17 +4050,18 @@ local function storage_api_call_unsafe(func, ...)
         local msg = 'storage is not configured'
         return error(lerror.vshard(lerror.code.STORAGE_IS_DISABLED, msg))
     end
-    if not M.is_enabled then
+    local is_disabled_skip = opts and opts.is_disabled_skip
+    if not M.is_enabled and not is_disabled_skip then
         local msg = 'storage is disabled explicitly'
         return error(lerror.vshard(lerror.code.STORAGE_IS_DISABLED, msg))
     end
     M.api_call_cache = storage_api_call_safe
     return func(...)
 end
 
-local function storage_make_api(func)
+local function storage_make_api(func, opts)
     return function(...)
-        return M.api_call_cache(func, ...)
+        return M.api_call_cache(func, opts, ...)
     end
 end
 
@@ -4241,7 +4243,7 @@ return {
     -- Instance info.
     --
     is_locked = storage_make_api(is_this_replicaset_locked),
-    info = storage_make_api(storage_info),
+    info = storage_make_api(storage_info, {is_disabled_skip = true}),
     sharded_spaces = storage_make_api(storage_sharded_spaces),
     _sharded_spaces = storage_sharded_spaces,
     module_version = function() return M.module_version end,