Don't reset collectors when Cartridge roles hot reloads (#341)

Author: yngvar-antonsson

CHANGELOG.md

@@ -6,6 +6,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+- Don't reset collectors when Cartridge roles hot reload
+
 ### Deprecated
 
 - Metrics:

metrics/init.lua

@@ -17,6 +17,11 @@ if not registry then
 end
 rawset(_G, '__metrics_registry', registry)
 
+local hotreload = package.loaded['cartridge.hotreload']
+if hotreload ~= nil then
+    hotreload.whitelist_globals({'__metrics_registry'})
+end
+
 local function collectors()
     return registry.collectors
 end

test/helper.lua

@@ -24,7 +24,7 @@ function helpers.entrypoint(name)
     return path
 end
 
-function helpers.init_cluster()
+function helpers.init_cluster(env)
     local cluster = helpers.Cluster:new({
         datadir = fio.tempdir(),
         server_command = helpers.entrypoint('srv_basic'),
@@ -38,6 +38,7 @@ function helpers.init_cluster()
                 },
             },
         },
+        env = env,
     })
     cluster:start()
     return cluster

test/integration/cartridge_hotreload_test.lua

@@ -3,11 +3,12 @@ local t = require('luatest')
 local g = t.group()
 
 local helpers = require('test.helper')
+local utils = require('test.utils')
 
 g.before_all(function()
     t.skip_if(type(helpers) ~= 'table', 'Skip cartridge test')
     helpers.skip_cartridge_version_less('2.3.0')
-    g.cluster = helpers.init_cluster()
+    g.cluster = helpers.init_cluster({TARANTOOL_ROLES_RELOAD_ALLOWED = 'true'})
 end)
 
 g.after_all(function()
@@ -57,9 +58,9 @@ end
 
 local function reload_roles()
     local main_server = g.cluster:server('main')
-    main_server.net_box:eval([[
-        require('cartridge.roles').reload()
-    ]])
+    t.assert(main_server.net_box:eval([[
+        return require('cartridge.roles').reload()
+    ]]))
 end
 
 g.test_cartridge_hotreload_set_export = function()
@@ -198,3 +199,34 @@ g.test_cartridge_hotreload_labels_from_config_and_set_labels = function()
         t.assert_equals(obs.label_pairs.alias, 'main')
     end
 end
+
+g.test_cartridge_hotreload_not_reset_collectors = function()
+    local main_server = g.cluster:server('main')
+    upload_config()
+
+    main_server:exec(function()
+        local metrics = require('cartridge').service_get('metrics')
+        metrics.gauge('hotreload_checker'):set(1)
+    end)
+
+    local resp = main_server:http_request('get', '/new-metrics', {raise = false})
+    t.assert_equals(resp.status, 200)
+
+    local obs = utils.find_metric('hotreload_checker', resp.json)
+    t.assert_covers(obs[1], {
+        metric_name = 'hotreload_checker',
+        value = 1,
+    })
+
+    reload_roles()
+
+    main_server = g.cluster:server('main')
+    resp = main_server:http_request('get', '/new-metrics', {raise = false})
+    t.assert_equals(resp.status, 200)
+
+    obs = utils.find_metric('hotreload_checker', resp.json)
+    t.assert_covers(obs[1], {
+        metric_name = 'hotreload_checker',
+        value = 1,
+    })
+end