Added test for check hotreload.

Also, also added some comments and removed duplicate code

Makefile

@@ -1,6 +1,7 @@
 all:
 	@echo "Only tests are available: make test"
 
+.PHONY: test
 test:
 	rm -rf *.xlog* *.snap 51{2,3,4,5,6,7}
 	INDEX_TYPE='TREE' SPACE_TYPE='vinyl' ./test.lua

expirationd.lua

@@ -56,13 +56,15 @@ local constants = {
 -- Task fibers
 -- ------------------------------------------------------------------------- --
 
+-- get all fields in primary key(composite possible) from tuple
 local function construct_key(space_id, tuple)
     return fun.map(
         function(x) return tuple[x.fieldno] end,
         box.space[space_id].index[0].parts
     ):totable()
 end
 
+-- do expiration process on tuple
 local function expiration_process(task, tuple)
     task.checked_tuples_count = task.checked_tuples_count + 1
     if task.is_tuple_expired(task.args, tuple) then
@@ -71,19 +73,22 @@ local function expiration_process(task, tuple)
     end
 end
 
+-- stop for some time
 local function suspend_basic(scan_space, task, len)
     local delay = (task.tuples_per_iteration * task.full_scan_time)
     delay = math.min(delay / len, task.iteration_delay)
     fiber.sleep(delay)
 end
 
 local function suspend(scan_space, task)
+    -- Return the number of tuples in the space
     local space_len = scan_space:len()
     if space_len > 0 then
         suspend_basic(scan_space, task, space_len)
     end
 end
 
+-- delete with some suspend and some tuples limit
 local function tree_index_iter(scan_space, task)
     -- iteration with GT iterator
     local params = {iterator = 'GT', limit = task.tuples_per_iteration}
@@ -96,6 +101,7 @@ local function tree_index_iter(scan_space, task)
         end
         suspend(scan_space, task)
         local key = construct_key(scan_space.id, last_id)
+        -- select all greater then last key
         tuples = scan_space.index[0]:select(key, params)
     end
 
@@ -186,6 +192,7 @@ local function guardian_loop(task)
     fiber.name(string.format("guardian of %q", task.name), { truncate = true })
 
     while true do
+        -- if fiber doesn't exist
         if get_fiber_id(task.worker_fiber) == 0 then
             -- create worker fiber
             task.worker_fiber = fiber.create(worker_loop, task)
@@ -205,7 +212,7 @@ end
 -- * task:start()      -- start task
 -- * task:stop()       -- stop task
 -- * task:restart()    -- restart task
--- * task:kill()       -- delete task and restart
+-- * task:kill()       -- stop task and delete
 -- * task:statistics() -- return table with statistics
 local Task_methods = {
     start = function (self)
@@ -502,10 +509,7 @@ local function expirationd_task_stats(name)
     return retval
 end
 
--- kill task
-local function expirationd_kill_task(name)
-    return get_task(name):kill()
-end
+
 
 -- get task by name
 local function expirationd_get_task(name)

test/entrypoint/srv_basic.lua

@@ -0,0 +1,43 @@
+#!/usr/bin/env tarantool
+
+require('strict').on()
+
+local log = require('log')
+local errors = require('errors')
+local cartridge = require('cartridge')
+errors.set_deprecation_handler(function(err)
+    log.error('%s', err)
+    os.exit(1)
+end)
+
+package.preload['mymodule'] = function()
+
+    return {
+        role_name = 'myrole',
+        validate_config = function()
+            return true
+        end,
+        init = function(opts) end,
+        apply_config = function(_, opts) end,
+        stop = function() end,
+    }
+end
+
+local ok, err = errors.pcall('CartridgeCfgError', cartridge.cfg, {
+    advertise_uri = 'localhost:3301',
+    http_port = 8081,
+    bucket_count = 3000,
+    roles = {
+        'mymodule',
+    },
+    roles_reload_allowed = true,
+    -- Compatibility tests run on cartridge 1.2.0
+    -- which doesn't support it yet.
+    upload_prefix = package.loaded['cartridge.upload'] and '../upload',
+})
+if not ok then
+    log.error('%s', err)
+    os.exit(1)
+end
+
+_G.is_initialized = cartridge.is_healthy

test/helper.lua

@@ -0,0 +1,30 @@
+require('strict').on()
+
+local fio = require('fio')
+local digest = require('digest')
+local helpers = table.copy(require('cartridge.test-helpers'))
+
+helpers.project_root = fio.dirname(debug.sourcedir())
+
+fio.tempdir = function(base)
+    base = base or os.getenv('TMPDIR') or '/tmp'
+    local random = digest.urandom(9)
+    local suffix = digest.base64_encode(random, {urlsafe = true})
+    local path = fio.pathjoin(base, 'tmp.cartridge.' .. suffix)
+    fio.mktree(path)
+    return path
+end
+
+function helpers.entrypoint(name)
+    local path = fio.pathjoin(
+            helpers.project_root,
+            'test', 'entrypoint',
+            string.format('%s.lua', name)
+    )
+    if not fio.path.exists(path) then
+        error(path .. ': no such entrypoint', 2)
+    end
+    return path
+end
+
+return helpers

test/integration/hotreload_test.lua

@@ -0,0 +1,98 @@
+local fio = require('fio')
+local utils = require('cartridge.utils')
+local t = require('luatest')
+local g = t.group("hot_reload")
+
+local helpers = require('test.helper')
+
+local function reload_myrole(fn)
+    -- For the sake of string.dump() function must have no upvalues.
+    -- https://www.lua.org/manual/5.1/manual.html#pdf-string.dump
+    utils.assert_upvalues(fn, {})
+
+    local ok, err = g.srv.net_box:eval([[
+        package.preload["mymodule"] = loadstring(...)
+        return require("cartridge.roles").reload()
+    ]], {string.dump(fn)})
+
+    t.assert_equals({ok, err}, {true, nil})
+end
+
+g.before_all(function()
+    local tempdir = fio.tempdir()
+    g.cluster = helpers.Cluster:new({
+        datadir = tempdir,
+        server_command = helpers.entrypoint('srv_basic'),
+        cookie = "secret-cluster-cookie",
+        replicasets = {{
+                           alias = 'A',
+                           roles = {'myrole'},
+                           servers = 1,
+                       }},
+    })
+    g.srv = g.cluster:server('A-1')
+    g.cluster:start()
+
+    local ok, err = g.srv.net_box:eval([[
+        local a = box.schema.create_space('origin', {
+            if_not_exists = true
+        })
+        a:create_index('pri')
+        return true, nil
+    ]])
+    t.assert_equals({ok, err}, {true, nil})
+end)
+
+g.after_all(function()
+    g.cluster:stop()
+    fio.rmtree(g.cluster.datadir)
+end)
+
+function g.test_reload_config()
+    reload_myrole(function()
+        return {
+            role_name = 'myrole',
+            init = function()
+                rawset(_G, "expirationd", require('expirationd'))
+                box.space.origin:insert({1})
+                local function is_expired(args, tuple)
+                    return true
+                end
+                expirationd.start("clean_all", box.space.origin.id, is_expired, {force = true})
+                return true, nil
+            end,
+            stop = function()
+                for _, task in pairs(expirationd.tasks()) do
+                    expirationd.kill(task)
+                end
+                box.space.origin:insert({2})
+            end
+        }
+    end)
+    t.assert_equals(
+            g.srv.net_box:eval('return box.space.origin:select()'),
+            {}
+    )
+    reload_myrole(function()
+        return {
+            role_name = 'myrole',
+            init = function()
+                rawset(_G, "expirationd", require('expirationd'))
+                local function is_expired(args, tuple)
+                    return true
+                end
+                expirationd.start("clean_all", box.space.origin.id, is_expired)
+                return true, nil
+            end,
+            stop = function()
+                for _, task in pairs(expirationd.tasks()) do
+                    expirationd.kill(task)
+                end
+            end
+        }
+    end)
+    t.assert_equals(
+            g.srv.net_box:eval('return box.space.origin:select()'),
+            {{ 2 }}
+    )
+end