PYTHON-3636 MongoClient should perform SRV resolution lazily

pymongo/uri_parser.py

@@ -484,6 +484,30 @@ def parse_uri(
     .. versionchanged:: 3.1
         ``warn`` added so invalid options can be ignored.
     """
+    result = _validate_uri(uri, default_port, validate, warn, normalize, srv_max_hosts)
+    result.update(
+        _parse_srv(
+            uri,
+            default_port,
+            validate,
+            warn,
+            normalize,
+            connect_timeout,
+            srv_service_name,
+            srv_max_hosts,
+        )
+    )
+    return result
+
+
+def _validate_uri(
+    uri: str,
+    default_port: Optional[int] = DEFAULT_PORT,
+    validate: bool = True,
+    warn: bool = False,
+    normalize: bool = True,
+    srv_max_hosts: Optional[int] = None,
+) -> dict[str, Any]:
     if uri.startswith(SCHEME):
         is_srv = False
         scheme_free = uri[SCHEME_LEN:]
@@ -527,8 +551,6 @@ def parse_uri(
 
     if opts:
         options.update(split_options(opts, validate, warn, normalize))
-    if srv_service_name is None:
-        srv_service_name = options.get("srvServiceName", SRV_SERVICE_NAME)
     if "@" in host_part:
         userinfo, _, hosts = host_part.rpartition("@")
         user, passwd = parse_userinfo(userinfo)
@@ -550,6 +572,69 @@ def parse_uri(
         fqdn, port = nodes[0]
         if port is not None:
             raise InvalidURI(f"{SRV_SCHEME} URIs must not include a port number")
+    elif not is_srv and options.get("srvServiceName") is not None:
+        raise ConfigurationError(
+            "The srvServiceName option is only allowed with 'mongodb+srv://' URIs"
+        )
+    elif not is_srv and srv_max_hosts:
+        raise ConfigurationError(
+            "The srvMaxHosts option is only allowed with 'mongodb+srv://' URIs"
+        )
+    else:
+        nodes = split_hosts(hosts, default_port=default_port)
+
+    _check_options(nodes, options)
+
+    return {
+        "nodelist": nodes,
+        "username": user,
+        "password": passwd,
+        "database": dbase,
+        "collection": collection,
+        "options": options,
+        "fqdn": fqdn,
+    }
+
+
+def _parse_srv(
+    uri: str,
+    default_port: Optional[int] = DEFAULT_PORT,
+    validate: bool = True,
+    warn: bool = False,
+    normalize: bool = True,
+    connect_timeout: Optional[float] = None,
+    srv_service_name: Optional[str] = None,
+    srv_max_hosts: Optional[int] = None,
+) -> dict[str, Any]:
+    if uri.startswith(SCHEME):
+        is_srv = False
+        scheme_free = uri[SCHEME_LEN:]
+    else:
+        is_srv = True
+        scheme_free = uri[SRV_SCHEME_LEN:]
+
+    options = _CaseInsensitiveDictionary()
+
+    host_plus_db_part, _, opts = scheme_free.partition("?")
+    if "/" in host_plus_db_part:
+        host_part, _, _ = host_plus_db_part.partition("/")
+    else:
+        host_part = host_plus_db_part
+
+    if opts:
+        options.update(split_options(opts, validate, warn, normalize))
+    if srv_service_name is None:
+        srv_service_name = options.get("srvServiceName", SRV_SERVICE_NAME)
+    if "@" in host_part:
+        _, _, hosts = host_part.rpartition("@")
+    else:
+        hosts = host_part
+
+    hosts = unquote_plus(hosts)
+    srv_max_hosts = srv_max_hosts or options.get("srvMaxHosts")
+    if is_srv:
+        nodes = split_hosts(hosts, default_port=None)
+        fqdn, port = nodes[0]
 
         # Use the connection timeout. connectTimeoutMS passed as a keyword
         # argument overrides the same option passed in the connection string.
@@ -572,27 +657,14 @@ def parse_uri(
             raise InvalidURI("You cannot specify replicaSet with srvMaxHosts")
         if "tls" not in options and "ssl" not in options:
             options["tls"] = True if validate else "true"
-    elif not is_srv and options.get("srvServiceName") is not None:
-        raise ConfigurationError(
-            "The srvServiceName option is only allowed with 'mongodb+srv://' URIs"
-        )
-    elif not is_srv and srv_max_hosts:
-        raise ConfigurationError(
-            "The srvMaxHosts option is only allowed with 'mongodb+srv://' URIs"
-        )
     else:
         nodes = split_hosts(hosts, default_port=default_port)
 
     _check_options(nodes, options)
 
     return {
         "nodelist": nodes,
-        "username": user,
-        "password": passwd,
-        "database": dbase,
-        "collection": collection,
         "options": options,
-        "fqdn": fqdn,
     }
 
 

test/asynchronous/test_client.py

@@ -1911,28 +1911,37 @@ async def test_service_name_from_kwargs(self):
             srvServiceName="customname",
             connect=False,
         )
+        await client.aconnect()
         self.assertEqual(client._topology_settings.srv_service_name, "customname")
+        await client.close()
         client = AsyncMongoClient(
             "mongodb+srv://user:[email protected]"
             "/?srvServiceName=shouldbeoverriden",
             srvServiceName="customname",
             connect=False,
         )
+        await client.aconnect()
         self.assertEqual(client._topology_settings.srv_service_name, "customname")
+        await client.close()
         client = AsyncMongoClient(
             "mongodb+srv://user:[email protected]/?srvServiceName=customname",
             connect=False,
         )
+        await client.aconnect()
         self.assertEqual(client._topology_settings.srv_service_name, "customname")
+        await client.close()
 
     async def test_srv_max_hosts_kwarg(self):
         client = self.simple_client("mongodb+srv://test1.test.build.10gen.cc/")
+        await client.aconnect()
         self.assertGreater(len(client.topology_description.server_descriptions()), 1)
         client = self.simple_client("mongodb+srv://test1.test.build.10gen.cc/", srvmaxhosts=1)
+        await client.aconnect()
         self.assertEqual(len(client.topology_description.server_descriptions()), 1)
         client = self.simple_client(
             "mongodb+srv://test1.test.build.10gen.cc/?srvMaxHosts=1", srvmaxhosts=2
         )
+        await client.aconnect()
         self.assertEqual(len(client.topology_description.server_descriptions()), 2)
 
     @unittest.skipIf(

test/asynchronous/test_dns.py

@@ -185,35 +185,24 @@ def create_tests(cls):
 
 class TestParsingErrors(AsyncPyMongoTestCase):
     async def test_invalid_host(self):
-        self.assertRaisesRegex(
-            ConfigurationError,
-            "Invalid URI host: mongodb is not",
-            self.simple_client,
-            "mongodb+srv://mongodb",
-        )
-        self.assertRaisesRegex(
-            ConfigurationError,
-            "Invalid URI host: mongodb.com is not",
-            self.simple_client,
-            "mongodb+srv://mongodb.com",
-        )
-        self.assertRaisesRegex(
-            ConfigurationError,
-            "Invalid URI host: an IP address is not",
-            self.simple_client,
-            "mongodb+srv://127.0.0.1",
-        )
-        self.assertRaisesRegex(
-            ConfigurationError,
-            "Invalid URI host: an IP address is not",
-            self.simple_client,
-            "mongodb+srv://[::1]",
-        )
+        with self.assertRaisesRegex(ConfigurationError, "Invalid URI host: mongodb is not"):
+            client = self.simple_client("mongodb+srv://mongodb")
+            await client.aconnect()
+        with self.assertRaisesRegex(ConfigurationError, "Invalid URI host: mongodb.com is not"):
+            client = self.simple_client("mongodb+srv://mongodb.com")
+            await client.aconnect()
+        with self.assertRaisesRegex(ConfigurationError, "Invalid URI host: an IP address is not"):
+            client = self.simple_client("mongodb+srv://127.0.0.1")
+            await client.aconnect()
+        with self.assertRaisesRegex(ConfigurationError, "Invalid URI host: an IP address is not"):
+            client = self.simple_client("mongodb+srv://[::1]")
+            await client.aconnect()
 
 
 class IsolatedAsyncioTestCaseInsensitive(AsyncIntegrationTest):
     async def test_connect_case_insensitive(self):
         client = self.simple_client("mongodb+srv://TEST1.TEST.BUILD.10GEN.cc/")
+        await client.aconnect()
         self.assertGreater(len(client.topology_description.server_descriptions()), 1)
 
 

test/test_client.py

@@ -1868,28 +1868,37 @@ def test_service_name_from_kwargs(self):
             srvServiceName="customname",
             connect=False,
         )
+        client._connect()
         self.assertEqual(client._topology_settings.srv_service_name, "customname")
+        client.close()
         client = MongoClient(
             "mongodb+srv://user:[email protected]"
             "/?srvServiceName=shouldbeoverriden",
             srvServiceName="customname",
             connect=False,
         )
+        client._connect()
         self.assertEqual(client._topology_settings.srv_service_name, "customname")
+        client.close()
         client = MongoClient(
             "mongodb+srv://user:[email protected]/?srvServiceName=customname",
             connect=False,
         )
+        client._connect()
         self.assertEqual(client._topology_settings.srv_service_name, "customname")
+        client.close()
 
     def test_srv_max_hosts_kwarg(self):
         client = self.simple_client("mongodb+srv://test1.test.build.10gen.cc/")
+        client._connect()
         self.assertGreater(len(client.topology_description.server_descriptions()), 1)
         client = self.simple_client("mongodb+srv://test1.test.build.10gen.cc/", srvmaxhosts=1)
+        client._connect()
         self.assertEqual(len(client.topology_description.server_descriptions()), 1)
         client = self.simple_client(
             "mongodb+srv://test1.test.build.10gen.cc/?srvMaxHosts=1", srvmaxhosts=2
         )
+        client._connect()
         self.assertEqual(len(client.topology_description.server_descriptions()), 2)
 
     @unittest.skipIf(

test/test_dns.py

@@ -183,35 +183,24 @@ def create_tests(cls):
 
 class TestParsingErrors(PyMongoTestCase):
     def test_invalid_host(self):
-        self.assertRaisesRegex(
-            ConfigurationError,
-            "Invalid URI host: mongodb is not",
-            self.simple_client,
-            "mongodb+srv://mongodb",
-        )
-        self.assertRaisesRegex(
-            ConfigurationError,
-            "Invalid URI host: mongodb.com is not",
-            self.simple_client,
-            "mongodb+srv://mongodb.com",
-        )
-        self.assertRaisesRegex(
-            ConfigurationError,
-            "Invalid URI host: an IP address is not",
-            self.simple_client,
-            "mongodb+srv://127.0.0.1",
-        )
-        self.assertRaisesRegex(
-            ConfigurationError,
-            "Invalid URI host: an IP address is not",
-            self.simple_client,
-            "mongodb+srv://[::1]",
-        )
+        with self.assertRaisesRegex(ConfigurationError, "Invalid URI host: mongodb is not"):
+            client = self.simple_client("mongodb+srv://mongodb")
+            client._connect()
+        with self.assertRaisesRegex(ConfigurationError, "Invalid URI host: mongodb.com is not"):
+            client = self.simple_client("mongodb+srv://mongodb.com")
+            client._connect()
+        with self.assertRaisesRegex(ConfigurationError, "Invalid URI host: an IP address is not"):
+            client = self.simple_client("mongodb+srv://127.0.0.1")
+            client._connect()
+        with self.assertRaisesRegex(ConfigurationError, "Invalid URI host: an IP address is not"):
+            client = self.simple_client("mongodb+srv://[::1]")
+            client._connect()
 
 
 class TestCaseInsensitive(IntegrationTest):
     def test_connect_case_insensitive(self):
         client = self.simple_client("mongodb+srv://TEST1.TEST.BUILD.10GEN.cc/")
+        client._connect()
         self.assertGreater(len(client.topology_description.server_descriptions()), 1)