api: fix address already in use error

There was a bug when user wants to change server's `listen` address and
reload config on the fly - error `address already in use` occures.

This patch reworks server's address handling by applying roles' config.

Closes #34

Author: themilchenko

CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- `Address already in use` error on change role's config on the fly (#34).
+
 ### Changed
 
 ## 0.3.0 - 2024-12-27

roles/metrics-export.lua

@@ -339,7 +339,7 @@ local function apply_http(conf)
                     error("failed to parse URI: " .. err, 2)
                 end
                 target = {
-                    value = node.listen,
+                    value = 'listen_' .. host .. ':' .. tostring(port),
                     is_httpd_role = false,
                 }
             else
@@ -350,12 +350,22 @@ local function apply_http(conf)
             end
 
             http_servers = http_servers or {}
+
             -- Since the 'listen' and 'server' names of other servers in the config may be
-            -- the same, we create a unique string concatenating the key name and information
-            -- about whether it is an httpd key or not.
-            enabled[tostring(target.value) .. tostring(target.is_httpd_role)] = true
+            -- the same, we create a unique string concatenating the host and port of a server.
+            enabled[target.value] = true
+
+            if http_servers[target.value] == nil then
+                if not target.is_httpd_role then
+                    for k in pairs(http_servers) do
+                        -- We stop running server before creating a new one if port matches and hosts different.
+                        if k ~= target.value and string.find(k, ':' .. tostring(port)) ~= nil then
+                            http_servers[k].httpd:stop()
+                            enabled[k] = false
+                        end
+                    end
+                end
 
-            if http_servers[tostring(target.value) .. tostring(target.is_httpd_role)] == nil then
                 local httpd
                 if node.listen ~= nil then
                     httpd = http_server.new(host, port, {
@@ -371,14 +381,14 @@ local function apply_http(conf)
                     httpd = httpd_role.get_server(target.value)
                 end
 
-                http_servers[tostring(target.value) .. tostring(target.is_httpd_role)] = {
+                http_servers[target.value] = {
                     httpd = httpd,
                     routes = {},
                     is_httpd_role = target.is_httpd_role,
                 }
             end
 
-            local server = http_servers[tostring(target.value) .. tostring(target.is_httpd_role)]
+            local server = http_servers[target.value]
             local httpd = server.httpd
             local old_routes = server.routes
 
@@ -418,14 +428,16 @@ local function apply_http(conf)
         end
     end
 
-    for target, server in pairs(http_servers) do
+    for target, server in pairs(http_servers or {}) do
         if not enabled[target] then
             if server.is_httpd_role then
                 for path, _ in pairs(server.routes) do
                     server.httpd:delete(path)
                 end
             else
-                server.httpd:stop()
+                if server.httpd.is_run == true then
+                    server.httpd:stop()
+                end
             end
             http_servers[target] = nil
         end

test/integration/reload_config_test.lua

@@ -0,0 +1,74 @@
+local fio = require('fio')
+local yaml = require('yaml')
+local socket = require('socket')
+local helpers = require('test.helpers')
+local server = require('test.helpers.server')
+
+local t = require('luatest')
+local g = t.group()
+
+g.before_all(function()
+    helpers.skip_if_unsupported()
+end)
+
+g.before_each(function(cg)
+    cg.workdir = fio.tempdir()
+    fio.mktree(cg.workdir)
+
+    fio.copytree(".rocks", fio.pathjoin(cg.workdir, ".rocks"))
+    fio.copytree("roles", fio.pathjoin(cg.workdir, "roles"))
+    fio.copytree(fio.pathjoin("test", "ssl_data"), fio.pathjoin(cg.workdir, "ssl_data"))
+    fio.copyfile(fio.pathjoin('test', 'entrypoint', 'config.yaml'), cg.workdir)
+end)
+
+g.after_each(function(cg)
+    cg.server:stop()
+    fio.rmtree(cg.workdir)
+end)
+
+local function is_tcp_connect(host, port)
+    local tcp = socket.tcp()
+    tcp:settimeout(0.3)
+    local ok, _ = tcp:connect(host, port)
+    tcp:close()
+
+    return ok
+end
+
+g.test_reload_config = function(cg)
+    cg.server = server:new({
+        config_file = fio.pathjoin(cg.workdir, 'config.yaml'),
+        chdir = cg.workdir,
+        alias = 'master',
+        workdir = cg.workdir,
+    })
+
+    cg.server:start({wait_until_ready = true})
+
+    local file = fio.open(fio.pathjoin(cg.workdir, 'config.yaml'), {'O_RDONLY'})
+    t.assert(file ~= nil)
+
+    local cfg = file:read()
+    file:close()
+
+    cfg = yaml.decode(cfg)
+    local export_instances = cfg.groups['group-001'].replicasets['replicaset-001'].
+                             instances.master.roles_cfg['roles.metrics-export'].http
+
+    for i, v in pairs(export_instances) do
+        if v.listen ~= nil and v.listen == '127.0.0.1:8082' then
+            export_instances[i].listen = '127.0.0.2:8082'
+        end
+    end
+
+    file = fio.open(fio.pathjoin(cg.workdir, 'config.yaml'), {'O_CREAT', 'O_WRONLY', 'O_TRUNC'}, tonumber('644', 8))
+    file:write(yaml.encode(cfg))
+    file:close()
+
+    t.assert(is_tcp_connect('127.0.0.1', 8082))
+
+    cg.server:eval("require('config'):reload()")
+
+    t.assert_not(is_tcp_connect('127.0.0.1', 8082))
+    t.assert(is_tcp_connect('127.0.0.2', 8082))
+end