From e304a8d61d1df6385ff591bd9cac492c931dd24f Mon Sep 17 00:00:00 2001
From: Igor Zolotarev <yngvar.antonsson@gmail.com>
Date: Mon, 12 Sep 2022 20:22:09 +0300
Subject: [PATCH] Reset callbacks on hotreload

---
 CHANGELOG.md                                  |  1 +
 metrics/init.lua                              |  2 ++
 test/integration/cartridge_hotreload_test.lua | 20 +++++++++++++++++++
 test/metrics_test.lua                         | 18 +++++++++++++++++
 4 files changed, 41 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2bc073d6..63b76d07 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 
 - `tnt_synchro_queue_len` metric type
+- Reset callbacks on hotreload
 
 ## [0.15.0] - 2022-08-09
 ### Fixed
diff --git a/metrics/init.lua b/metrics/init.lua
index eba0a685..a23a7a58 100644
--- a/metrics/init.lua
+++ b/metrics/init.lua
@@ -16,6 +16,8 @@ local registry = rawget(_G, '__metrics_registry')
 if not registry then
     registry = Registry.new()
 end
+registry.callbacks = {}
+
 rawset(_G, '__metrics_registry', registry)
 
 local hotreload = package.loaded['cartridge.hotreload']
diff --git a/test/integration/cartridge_hotreload_test.lua b/test/integration/cartridge_hotreload_test.lua
index 756f2453..cdabdd92 100644
--- a/test/integration/cartridge_hotreload_test.lua
+++ b/test/integration/cartridge_hotreload_test.lua
@@ -230,3 +230,23 @@ g.test_cartridge_hotreload_not_reset_collectors = function()
         value = 1,
     })
 end
+
+g.test_cartridge_hotreload_reset_callbacks = function()
+    local main_server = g.cluster:server('main')
+    upload_config()
+
+    local len_before_hotreload = main_server:exec(function()
+        local test_utils = require('test.utils')
+        local Registry = rawget(_G, '__metrics_registry')
+        return test_utils.len(Registry.callbacks)
+    end)
+
+    reload_roles()
+
+    local len_after_hotreload = main_server:exec(function()
+        local test_utils = require('test.utils')
+        local Registry = rawget(_G, '__metrics_registry')
+        return test_utils.len(Registry.callbacks)
+    end)
+    t.assert_equals(len_before_hotreload, len_after_hotreload)
+end
diff --git a/test/metrics_test.lua b/test/metrics_test.lua
index 4a984ac2..e8f1969d 100755
--- a/test/metrics_test.lua
+++ b/test/metrics_test.lua
@@ -138,3 +138,21 @@ g.test_default_metrics_clear = function()
     metrics.invoke_callbacks()
     t.assert(#metrics.collect() > 0)
 end
+
+g.test_hotreload_remove_callbacks = function()
+    metrics.enable_default_metrics()
+
+    local Registry = rawget(_G, '__metrics_registry')
+    local len_before_hotreload = utils.len(Registry.callbacks)
+    t.assert_gt(len_before_hotreload, 0)
+
+    package.loaded['metrics'] = nil
+
+    metrics = require('metrics')
+    metrics.enable_default_metrics()
+
+    Registry = rawget(_G, '__metrics_registry')
+    local len_after_hotreload = utils.len(Registry.callbacks)
+
+    t.assert_equals(len_before_hotreload, len_after_hotreload)
+end