conn: create from socket fd

This patch adds the ability to create Tarantool connection
using an existing socket fd.

Closes #304

Author: askalt

CHANGELOG.md

@@ -4,6 +4,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## Unreleased
+
+### Added
+- The ability to connect to the Tarantool using an existing socket fd (#304).
+
 ## 1.1.2 - 2023-09-20
 
 ### Fixed

tarantool/connection.py

@@ -623,7 +623,7 @@ def __init__(self, host, port,
             Unix sockets.
         :type host: :obj:`str` or :obj:`None`
 
-        :param port: Server port or Unix socket path.
+        :param port: Server port, socket fd or Unix socket path.
         :type port: :obj:`int` or :obj:`str`
 
         :param user: User name for authentication on the Tarantool
@@ -941,9 +941,13 @@ def connect_unix(self):
             self.connected = True
             if self._socket:
                 self._socket.close()
-            self._socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+            if isinstance(self.port, int):
+                # Use an existing fd to create a socket, take ownership.
+                self._socket = socket.socket(fileno=self.port)
+            else:
+                self._socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+                self._socket.connect(self.port)
             self._socket.settimeout(self.connection_timeout)
-            self._socket.connect(self.port)
             self._socket.settimeout(self.socket_timeout)
         except socket.error as exc:
             self.connected = False

tarantool/mesh_connection.py

@@ -139,23 +139,23 @@ def format_error(address, err):
             result[key] = val
 
     if isinstance(result['port'], int):
-        # Looks like an inet address.
+        # Looks like an inet address or socket fd.
 
         # Validate host.
-        if 'host' not in result or result['host'] is None:
-            return format_error(result,
-                                'host is mandatory for an inet result')
-        if not isinstance(result['host'], str):
-            return format_error(result,
-                                'host must be a string for an inet result')
+        if ('host' in result and result['host'] is not None
+                and not isinstance(result['host'], str)):
+            return format_error(result, 'host must be a string for an inet result, '
+                                        'or None for a socket fd result')
 
         # Validate port.
         if not isinstance(result['port'], int):
             return format_error(result,
-                                'port must be an int for an inet result')
-        if result['port'] < 1 or result['port'] > 65535:
-            return format_error(result, 'port must be in range [1, 65535] '
-                                        'for an inet result')
+                                'port must be an int for an inet/socket fd result')
+        if 'host' in result and isinstance(result['host'], str):
+            # Check that the port is correct.
+            if result['port'] < 1 or result['port'] > 65535:
+                return format_error(result, 'port must be in range [1, 65535] '
+                                            'for an inet result')
 
         # Looks okay.
         return result, None
@@ -447,7 +447,8 @@ def __init__(self, host=None, port=None,
             # Don't change user provided arguments.
             addrs = addrs[:]
 
-        if host and port:
+        if port:
+            # host can be None in the case of socket fd or Unix socket.
             addrs.insert(0, {'host': host,
                              'port': port,
                              'transport': transport,

test/suites/test_dml.py

@@ -1,6 +1,7 @@
 """
 This module tests basic data operations.
 """
+import socket
 # pylint: disable=missing-class-docstring,missing-function-docstring,protected-access,fixme,too-many-public-methods,duplicate-code
 
 import sys
@@ -430,6 +431,20 @@ def test_16_extra_error_info_fields(self):
         else:
             self.fail('Expected error')
 
+    @unittest.skipIf(sys.platform.startswith("win"),
+                     "Skip UNIX socket tests on Windows since it uses remote server")
+    def test_17_socket_fd(self):
+        # pylint: disable=E1101
+        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        sock.connect(self.sock_srv.args['primary'])
+
+        sock_con = tarantool.connect(self.sock_srv.host, sock.fileno())
+        sock.detach()
+        try:
+            self.assertEqual(sock_con.ping(notime=True), "Success")
+        finally:
+            sock_con.close()
+
     @classmethod
     def tearDownClass(cls):
         cls.con.close()

test/suites/test_mesh.py

@@ -2,6 +2,7 @@
 This module tests work with a cluster of Tarantool servers through
 MeshConnection.
 """
+import socket
 # pylint: disable=missing-class-docstring,missing-function-docstring
 
 import sys
@@ -19,8 +20,8 @@
 from .utils import assert_admin_success
 
 
-def create_server(_id):
-    srv = TarantoolServer()
+def create_server(_id, create_unix_socket=False):
+    srv = TarantoolServer(create_unix_socket=create_unix_socket)
     srv.script = 'test/suites/box.lua'
     srv.start()
     resp = srv.admin(f"""
@@ -85,6 +86,11 @@ def setUp(self):
         self.define_cluster_function(self.get_all_nodes_func_name,
                                      self.servers)
 
+        if not sys.platform.startswith("win"):
+            self.sock_srv = create_server(3, create_unix_socket=True)
+        else:
+            self.sock_srv = None
+
     def test_00_basic(self):
         def assert_srv_id(con, srv_id):
             with warnings.catch_warnings():
@@ -315,9 +321,31 @@ def test_07_discovery_exclude_address(self):
         finally:
             con.close()
 
+    @unittest.skipIf(sys.platform.startswith("win"),
+                     "Skip UNIX socket tests on Windows since it uses remote server")
+    def test_08_socket_fd(self):
+        path = self.sock_srv.args['primary']
+        # pylint: disable=E1101
+        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        sock.connect(path)
+
+        sock_con = tarantool.MeshConnection(
+            self.sock_srv.host, sock.fileno(), user='test', password='test'
+        )
+        sock.detach()
+
+        try:
+            self.assertEqual(sock_con.ping(notime=True), "Success")
+        finally:
+            sock_con.close()
+
     def tearDown(self):
         self.srv.stop()
         self.srv.clean()
 
         self.srv2.stop()
         self.srv2.clean()
+
+        if self.sock_srv is not None:
+            self.sock_srv.stop()
+            self.sock_srv.clean()

test/suites/test_pool.py

@@ -2,6 +2,7 @@
 This module tests work with a cluster of Tarantool servers through
 ConnectionPool.
 """
+import socket
 # pylint: disable=missing-class-docstring,missing-function-docstring,too-many-public-methods,too-many-locals,duplicate-code,bad-option-value,no-self-use
 
 import sys
@@ -23,8 +24,8 @@
 from .utils import assert_admin_success
 
 
-def create_server(_id):
-    srv = TarantoolServer()
+def create_server(_id, create_unix_socket=False):
+    srv = TarantoolServer(create_unix_socket=create_unix_socket)
     srv.script = 'test/suites/box.lua'
     srv.start()
     resp = srv.admin(f"""
@@ -107,6 +108,11 @@ def setUp(self):
             self.servers.append(srv)
             self.addrs.append({'host': srv.host, 'port': srv.args['primary']})
 
+        if not sys.platform.startswith("win"):
+            self.sock_srv = create_server(self.servers_count, create_unix_socket=True)
+        else:
+            self.sock_srv = None
+
     def test_00_basic(self):
         self.set_cluster_ro([False, False, True, False, True])
 
@@ -581,10 +587,31 @@ def test_16_is_closed(self):
 
         self.assertEqual(self.pool.is_closed(), True)
 
+    @unittest.skipIf(sys.platform.startswith("win"),
+                     "Skip UNIX socket tests on Windows since it uses remote server")
+    def test_17_socket_fd(self):
+        # pylint: disable=E1101
+        sock = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
+        sock.connect(self.sock_srv.args['primary'])
+
+        self.pool = tarantool.ConnectionPool(
+            addrs=[{'host': None, 'port': sock.fileno()}],
+            user='test',
+            password='test'
+        )
+        sock.detach()
+        try:
+            self.assertEqual(self.pool.ping(notime=True, mode=tarantool.Mode.ANY), "Success")
+        finally:
+            self.pool.close()
+
     def tearDown(self):
         if self.pool:
             self.pool.close()
 
         for srv in self.servers:
             srv.stop()
             srv.clean()
+        if self.sock_srv is not None:
+            self.sock_srv.stop()
+            self.sock_srv.clean()