Graphite plugin kills previous workers on init

CHANGELOG.md

@@ -9,6 +9,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - metrics.clear() disables default metrics
 - cartridge role is permanent
 - cartridge role configuration without clusterwide config
+- graphite plugin kills previous workers on init
 
 ### Added
 - Luajit platform metrics

metrics/plugins/graphite/init.lua

@@ -3,6 +3,7 @@ local fiber = require('fiber')
 local metrics = require('metrics')
 local checks = require('checks')
 local log = require('log')
+local fun = require('fun')
 
 local graphite = {}
 
@@ -70,6 +71,10 @@ function graphite.init(opts)
     local port = opts.port or DEFAULT_PORT
     local send_interval = opts.send_interval or DEFAULT_SEND_INTERVAL
 
+    fun.iter(fiber.info()):
+        filter(function(_, x) return x.name == 'metrics_graphite_worker' end):
+        each(function(x) fiber.kill(x) end)
+
     fiber.create(graphite_worker, {
         prefix = prefix,
         sock = sock,

test/plugins/graphite_test.lua

@@ -0,0 +1,65 @@
+#!/usr/bin/env tarantool
+
+require('strict').on()
+
+local t = require('luatest')
+local g = t.group()
+
+local metrics = require('metrics')
+local fiber = require('fiber')
+local fun = require('fun')
+local graphite = require('metrics.plugins.graphite')
+
+g.before_all(function()
+    box.cfg{}
+    box.schema.user.grant(
+        'guest', 'read,write,execute', 'universe', nil, {if_not_exists = true}
+    )
+    local s = box.schema.space.create(
+        'random_space_for_graphite',
+        {if_not_exists = true})
+    s:create_index('pk', {if_not_exists = true})
+
+    local s_vinyl = box.schema.space.create(
+        'random_vinyl_space_for_graphite',
+        {if_not_exists = true, engine = 'vinyl'})
+    s_vinyl:create_index('pk', {if_not_exists = true})
+
+    -- Delete all previous collectors and global labels
+    metrics.clear()
+
+    -- Enable default metrics collections
+    metrics.enable_default_metrics();
+end)
+
+g.after_each(function()
+    -- Delete all collectors and global labels
+    metrics.clear()
+end)
+
+local function mock_graphite_worker()
+    fiber.create(function()
+        fiber.name('metrics_graphite_worker')
+        while true do fiber.sleep(0.01) end
+    end)
+end
+
+local function count_workers()
+    return fun.iter(fiber.info()):
+        filter(function(_, x) return x.name == 'metrics_graphite_worker' end):
+        length()
+end
+
+g.test_graphite_kills_previous_fibers_on_init = function()
+    mock_graphite_worker()
+    mock_graphite_worker()
+    local workers_cnt = count_workers()
+    t.assert_equals(workers_cnt, 2)
+
+    graphite.init({})
+
+    fiber.sleep(0.5)
+    workers_cnt = count_workers()
+    t.assert_equals(workers_cnt, 1)
+end
+