Add an option idle_timeout

Option idle_timeout allows to set a maximum amount of time an idle
(keep-alive) connection will remain idle before closing. When the idle
timeout is exceeded, HTTP server closes the keepalive connection.

Fixes #137

Reviewed-by: Alexander Turenko <alexander.turenko@tarantool.org>

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 ### Added
 
 - Add option to control keepalive connection state (#137).
+- Add option to control idle connections (#137).
 
 ## [1.2.0] - 2021-11-10
 

README.md

@@ -146,6 +146,9 @@ httpd = require('http.server').new(host, port[, { options } ])
   })
   ```
 
+* `idle_timeout` - maximum amount of time an idle (keep-alive) connection will
+  remain idle before closing. When the idle timeout is exceeded, HTTP server
+  closes the keepalive connection. Default value: 0 seconds (disabled).
 
 ## Using routes
 

http/server.lua

@@ -758,9 +758,9 @@ local function process_client(self, s, peer)
 
         local is_eof = false
         while true do
-            local chunk = s:read{
-                delimiter = { "\n\n", "\r\n\r\n" }
-            }
+            local chunk = s:read({
+                delimiter = { "\n\n", "\r\n\r\n" },
+            }, self.idle_timeout)
 
             if chunk == '' then
                 is_eof = true
@@ -1306,6 +1306,10 @@ local exports = {
         if type(disable_keepalive) ~= 'table' then
             error('Option disable_keepalive must be a table.')
         end
+        if options.idle_timeout ~= nil and
+           type(options.idle_timeout) ~= 'number' then
+            error('Option idle_timeout must be a number.')
+        end
 
         local default = {
             max_header_size     = 4096,
@@ -1320,6 +1324,7 @@ local exports = {
             log_errors          = true,
             display_errors      = false,
             disable_keepalive   = {},
+            idle_timeout        = 0, -- no timeout, option is disabled
         }
 
         local self = {
@@ -1355,6 +1360,7 @@ local exports = {
             },
 
             disable_keepalive   = tomap(disable_keepalive),
+            idle_timeout        = options.idle_timeout,
 
             internal = {
                 preprocess_client_handler = function() end,

test/integration/http_server_options_test.lua

@@ -87,3 +87,81 @@ g.test_disable_keepalive_default = function(g)
     local httpd = g.httpd
     t.assert_equals(table.getn(httpd.options.disable_keepalive), 0)
 end
+
+g.before_test('test_idle_timeout_default', function()
+    g.httpd = helpers.cfgserv()
+    g.httpd:start()
+end)
+
+g.test_idle_timeout_default = function(g)
+    local httpd = g.httpd
+    t.assert_equals(httpd.options.idle_timeout, 0)
+end
+
+g.before_test('test_idle_timeout_is_set', function()
+    g.idle_timeout = 0.5
+    g.httpd = helpers.cfgserv({
+        idle_timeout = g.idle_timeout,
+    })
+    g.httpd:start()
+end)
+
+g.test_idle_timeout_is_set = function(g)
+    local conn_is_opened = false
+    local conn_is_closed = false
+    local httpd = g.httpd
+    g.httpd.internal.preprocess_client_handler = function() conn_is_opened = true end
+    g.httpd.internal.postprocess_client_handler = function() conn_is_closed = true end
+
+    t.assert_equals(httpd.options.idle_timeout, g.idle_timeout)
+
+    -- Set HTTP keepalive headers: Connection:Keep-Alive and
+    -- Keep-Alive:timeout=<keepalive_idle>. Otherwise HTTP client will send
+    -- "Connection:close".
+    local opts = {
+        keepalive_idle = 3600,
+        keepalive_interval = 3600,
+    }
+    local r = http_client.new():request('GET', helpers.base_uri .. '/test', nil, opts)
+    t.assert_equals(r.status, 200)
+    t.assert_equals(r.headers.connection, 'keep-alive')
+    t.assert_equals(conn_is_opened, true)
+
+    helpers.retrying({
+        timeout = g.idle_timeout * 2,
+    }, function()
+        assert(conn_is_closed, 'connection is closed')
+    end)
+    t.assert_equals(conn_is_closed, true) -- Connection is closed.
+end
+
+g.before_test('test_idle_timeout_is_unset', function()
+    g.httpd = helpers.cfgserv({})
+    g.httpd:start()
+end)
+
+g.test_idle_timeout_is_unset = function(g)
+    local conn_is_opened = false
+    local conn_is_closed = false
+    g.httpd.internal.preprocess_client_handler = function() conn_is_opened = true end
+    g.httpd.internal.postprocess_client_handler = function() conn_is_closed = true end
+
+    -- Set HTTP keepalive headers: Connection:Keep-Alive and
+    -- Keep-Alive:timeout=<keepalive_idle>. Otherwise HTTP client will send
+    -- "Connection:close".
+    local opts = {
+        keepalive_idle = 3600,
+        keepalive_interval = 3600,
+    }
+    local r = http_client.new():request('GET', helpers.base_uri .. '/test', nil, opts)
+
+    -- The server should not close the connection during the keepalive_idle
+    -- seconds. We could check that server will close connection after
+    -- keepalive_idle seconds, but HTTP server under test does not support
+    -- "Keep-Alive: timeout=NUM" header.
+
+    t.assert_equals(r.status, 200)
+    t.assert_equals(r.headers.connection, 'keep-alive')
+    t.assert_equals(conn_is_opened, true)
+    t.assert_equals(conn_is_closed, false) -- Connection is alive.
+end