[Python] Add "servers" support in path, operation (#2052)

* add servers to path, operation

* add path/operation server support to python client

* update python samples

* fix index

* fix python code style

modules/openapi-generator/src/main/resources/python/api.mustache

@@ -82,6 +82,14 @@ class {{classname}}(object):
                  returns the request thread.
         """
 
+        {{#servers.0}}
+        local_var_hosts = [{{#servers}}'{{{url}}}'{{^-last}}, {{/-last}}{{/servers}}]  # noqa: E501
+        local_var_host = local_var_hosts[0]
+        if kwargs.get('_host_index'):
+            if int(kwags.get('_host_index')) < 0 or int(kawgs.get('_host_index')) >= len(local_var_hosts):
+                raise ValueError("Invalid host index. Must be 0 <= index < %s" % len(local_var_host))
+            local_var_host = local_var_hosts[int(kwargs.get('_host_index'))]
+        {{/servers.0}}
         local_var_params = locals()
 
         all_params = [{{#allParams}}'{{paramName}}'{{#hasMore}}, {{/hasMore}}{{/allParams}}]  # noqa: E501
@@ -91,7 +99,7 @@ class {{classname}}(object):
         all_params.append('_request_timeout')
 
         for key, val in six.iteritems(local_var_params['kwargs']):
-            if key not in all_params:
+            if key not in all_params{{#servers.0}} and key != "_host_index"{{/servers.0}}:
                 raise TypeError(
                     "Got an unexpected keyword argument '%s'"
                     " to method {{operationId}}" % key
@@ -212,6 +220,9 @@ class {{classname}}(object):
             _return_http_data_only=local_var_params.get('_return_http_data_only'),  # noqa: E501
             _preload_content=local_var_params.get('_preload_content', True),
             _request_timeout=local_var_params.get('_request_timeout'),
+            {{#servers.0}}
+            _host=local_var_host,
+            {{/servers.0}}
             collection_formats=collection_formats)
 {{/operation}}
 {{/operations}}

modules/openapi-generator/src/main/resources/python/api_client.mustache

@@ -107,7 +107,7 @@ class ApiClient(object):
             query_params=None, header_params=None, body=None, post_params=None,
             files=None, response_type=None, auth_settings=None,
             _return_http_data_only=None, collection_formats=None,
-            _preload_content=True, _request_timeout=None):
+            _preload_content=True, _request_timeout=None, _host=None):
 
         config = self.configuration
 
@@ -154,7 +154,11 @@ class ApiClient(object):
             body = self.sanitize_for_serialization(body)
 
         # request url
+        if _host is None:
             url = self.configuration.host + resource_path
+        else:
+            # use server/host defined in path or operation instead
+            url = _host + resource_path
 
         # perform request and return response
         response_data = {{#asyncio}}await {{/asyncio}}{{#tornado}}yield {{/tornado}}self.request(
@@ -296,7 +300,7 @@ class ApiClient(object):
                  body=None, post_params=None, files=None,
                  response_type=None, auth_settings=None, async_req=None,
                  _return_http_data_only=None, collection_formats=None,
-                 _preload_content=True, _request_timeout=None):
+                 _preload_content=True, _request_timeout=None, _host=None):
         """Makes the HTTP request (synchronous) and returns deserialized data.
 
         To make an async_req request, set the async_req parameter.
@@ -339,7 +343,7 @@ class ApiClient(object):
                                    body, post_params, files,
                                    response_type, auth_settings,
                                    _return_http_data_only, collection_formats,
-                                   _preload_content, _request_timeout)
+                                   _preload_content, _request_timeout, _host)
         else:
             thread = self.pool.apply_async(self.__call_api, (resource_path,
                                            method, path_params, query_params,
@@ -348,7 +352,9 @@ class ApiClient(object):
                                            response_type, auth_settings,
                                            _return_http_data_only,
                                            collection_formats,
-                                           _preload_content, _request_timeout))
+                                           _preload_content,
+                                           _request_timeout,
+                                           _host))
         return thread
 
     def request(self, method, url, query_params=None, headers=None,

modules/openapi-generator/src/test/resources/3_0/petstore-with-fake-endpoints-models-for-testing.yaml

@@ -30,6 +30,9 @@ paths:
                   string:
                     $ref: '#/components/schemas/Foo'
   /pet:
+    servers:
+    - url: 'http://petstore.swagger.io/v2'
+    - url: 'http://path-server-test.petstore.local/v2'
     post:
       tags:
         - pet

samples/client/petstore/python-asyncio/README.md

@@ -51,6 +51,7 @@ import petstore_api
 from petstore_api.rest import ApiException
 from pprint import pprint
 
+
 # create an instance of the API class
 api_instance = petstore_api.AnotherFakeApi(petstore_api.ApiClient(configuration))
 body = petstore_api.Client() # Client | client model
@@ -158,16 +159,19 @@ Class | Method | HTTP request | Description
 - **API key parameter name**: api_key
 - **Location**: HTTP header
 
+
 ## api_key_query
 
 - **Type**: API key
 - **API key parameter name**: api_key_query
 - **Location**: URL query string
 
+
 ## http_basic_test
 
 - **Type**: HTTP basic authentication
 
+
 ## petstore_auth
 
 - **Type**: OAuth

samples/client/petstore/python-asyncio/docs/AnotherFakeApi.md

@@ -15,6 +15,7 @@ To test special tags
 To test special tags and operation ID starting with number
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time

samples/client/petstore/python-asyncio/docs/FakeApi.md

@@ -27,6 +27,7 @@ creates an XmlItem
 this route creates an XmlItem
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -74,6 +75,7 @@ No authorization required
 Test serialization of outer boolean types
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -121,6 +123,7 @@ No authorization required
 Test serialization of object with outer number type
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -168,6 +171,7 @@ No authorization required
 Test serialization of outer number types
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -215,6 +219,7 @@ No authorization required
 Test serialization of outer string types
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -262,6 +267,7 @@ No authorization required
 For this test, the body for this request much reference a schema named `File`.
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -306,6 +312,7 @@ No authorization required
 
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -354,6 +361,7 @@ To test \"client\" model
 To test \"client\" model
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -481,6 +489,7 @@ To test enum parameters
 To test enum parameters
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -542,6 +551,7 @@ Fake endpoint to test group parameters (optional)
 Fake endpoint to test group parameters (optional)
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -597,6 +607,7 @@ No authorization required
 test inline additionalProperties
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -642,6 +653,7 @@ No authorization required
 test json serialization of form data
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time

samples/client/petstore/python-asyncio/docs/StoreApi.md

@@ -18,6 +18,7 @@ Delete purchase order by ID
 For valid response try integer IDs with value < 1000. Anything above 1000 or nonintegers will generate API errors
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -116,6 +117,7 @@ Find purchase order by ID
 For valid response try integer IDs with value <= 5 or > 10. Other values will generated exceptions
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -162,6 +164,7 @@ No authorization required
 Place an order for a pet
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time

samples/client/petstore/python-asyncio/docs/UserApi.md

@@ -22,6 +22,7 @@ Create user
 This can only be done by the logged in user.
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -67,6 +68,7 @@ No authorization required
 Creates list of users with given input array
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -112,6 +114,7 @@ No authorization required
 Creates list of users with given input array
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -159,6 +162,7 @@ Delete user
 This can only be done by the logged in user.
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -204,6 +208,7 @@ No authorization required
 Get user by user name
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -250,6 +255,7 @@ No authorization required
 Logs user into the system
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -298,6 +304,7 @@ No authorization required
 Logs out current logged in user session
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -341,6 +348,7 @@ Updated user
 This can only be done by the logged in user.
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time

samples/client/petstore/python-asyncio/petstore_api/api_client.py

@@ -109,7 +109,7 @@ class ApiClient(object):
             query_params=None, header_params=None, body=None, post_params=None,
             files=None, response_type=None, auth_settings=None,
             _return_http_data_only=None, collection_formats=None,
-            _preload_content=True, _request_timeout=None):
+            _preload_content=True, _request_timeout=None, _host=None):
 
         config = self.configuration
 
@@ -156,7 +156,11 @@ class ApiClient(object):
             body = self.sanitize_for_serialization(body)
 
         # request url
+        if _host is None:
             url = self.configuration.host + resource_path
+        else:
+            # use server/host defined in path or operation instead
+            url = _host + resource_path
 
         # perform request and return response
         response_data = await self.request(
@@ -289,7 +293,7 @@ class ApiClient(object):
                  body=None, post_params=None, files=None,
                  response_type=None, auth_settings=None, async_req=None,
                  _return_http_data_only=None, collection_formats=None,
-                 _preload_content=True, _request_timeout=None):
+                 _preload_content=True, _request_timeout=None, _host=None):
         """Makes the HTTP request (synchronous) and returns deserialized data.
 
         To make an async_req request, set the async_req parameter.
@@ -332,7 +336,7 @@ class ApiClient(object):
                                    body, post_params, files,
                                    response_type, auth_settings,
                                    _return_http_data_only, collection_formats,
-                                   _preload_content, _request_timeout)
+                                   _preload_content, _request_timeout, _host)
         else:
             thread = self.pool.apply_async(self.__call_api, (resource_path,
                                            method, path_params, query_params,
@@ -341,7 +345,9 @@ class ApiClient(object):
                                            response_type, auth_settings,
                                            _return_http_data_only,
                                            collection_formats,
-                                           _preload_content, _request_timeout))
+                                           _preload_content,
+                                           _request_timeout,
+                                           _host))
         return thread
 
     def request(self, method, url, query_params=None, headers=None,

samples/client/petstore/python-asyncio/petstore_api/configuration.py

@@ -59,10 +59,8 @@ class Configuration(six.with_metaclass(TypeWithDefault, object)):
         self.username = ""
         # Password for HTTP basic authentication
         self.password = ""
-
+        # access token for OAuth/Bearer
-        # access token for OAuth
         self.access_token = ""
-
         # Logging Settings
         self.logger = {}
         self.logger["package_logger"] = logging.getLogger("petstore_api")
@@ -236,7 +234,6 @@ class Configuration(six.with_metaclass(TypeWithDefault, object)):
                     'key': 'Authorization',
                     'value': self.get_basic_auth_token()
                 },
-
             'petstore_auth':
                 {
                     'type': 'oauth2',
@@ -244,7 +241,6 @@ class Configuration(six.with_metaclass(TypeWithDefault, object)):
                     'key': 'Authorization',
                     'value': 'Bearer ' + self.access_token
                 },
-
         }
 
     def to_debug_report(self):
@@ -281,7 +277,7 @@ class Configuration(six.with_metaclass(TypeWithDefault, object)):
         servers = self.get_host_settings()
 
         # check array index out of bound
-        if index < 0 or index > len(servers):
+        if index < 0 or index >= len(servers):
             raise ValueError(
                 "Invalid index {} when selecting the host settings. Must be less than {}"  # noqa: E501
                 .format(index, len(servers)))

samples/client/petstore/python-tornado/README.md

@@ -51,6 +51,7 @@ import petstore_api
 from petstore_api.rest import ApiException
 from pprint import pprint
 
+
 # create an instance of the API class
 api_instance = petstore_api.AnotherFakeApi(petstore_api.ApiClient(configuration))
 body = petstore_api.Client() # Client | client model
@@ -158,16 +159,19 @@ Class | Method | HTTP request | Description
 - **API key parameter name**: api_key
 - **Location**: HTTP header
 
+
 ## api_key_query
 
 - **Type**: API key
 - **API key parameter name**: api_key_query
 - **Location**: URL query string
 
+
 ## http_basic_test
 
 - **Type**: HTTP basic authentication
 
+
 ## petstore_auth
 
 - **Type**: OAuth

samples/client/petstore/python-tornado/docs/AnotherFakeApi.md

@@ -15,6 +15,7 @@ To test special tags
 To test special tags and operation ID starting with number
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time

samples/client/petstore/python-tornado/docs/FakeApi.md

@@ -27,6 +27,7 @@ creates an XmlItem
 this route creates an XmlItem
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -74,6 +75,7 @@ No authorization required
 Test serialization of outer boolean types
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -121,6 +123,7 @@ No authorization required
 Test serialization of object with outer number type
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -168,6 +171,7 @@ No authorization required
 Test serialization of outer number types
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -215,6 +219,7 @@ No authorization required
 Test serialization of outer string types
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -262,6 +267,7 @@ No authorization required
 For this test, the body for this request much reference a schema named `File`.
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -306,6 +312,7 @@ No authorization required
 
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -354,6 +361,7 @@ To test \"client\" model
 To test \"client\" model
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -481,6 +489,7 @@ To test enum parameters
 To test enum parameters
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -542,6 +551,7 @@ Fake endpoint to test group parameters (optional)
 Fake endpoint to test group parameters (optional)
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -597,6 +607,7 @@ No authorization required
 test inline additionalProperties
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -642,6 +653,7 @@ No authorization required
 test json serialization of form data
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time

samples/client/petstore/python-tornado/docs/StoreApi.md

@@ -18,6 +18,7 @@ Delete purchase order by ID
 For valid response try integer IDs with value < 1000. Anything above 1000 or nonintegers will generate API errors
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -116,6 +117,7 @@ Find purchase order by ID
 For valid response try integer IDs with value <= 5 or > 10. Other values will generated exceptions
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -162,6 +164,7 @@ No authorization required
 Place an order for a pet
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time

samples/client/petstore/python-tornado/docs/UserApi.md

@@ -22,6 +22,7 @@ Create user
 This can only be done by the logged in user.
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -67,6 +68,7 @@ No authorization required
 Creates list of users with given input array
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -112,6 +114,7 @@ No authorization required
 Creates list of users with given input array
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -159,6 +162,7 @@ Delete user
 This can only be done by the logged in user.
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -204,6 +208,7 @@ No authorization required
 Get user by user name
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -250,6 +255,7 @@ No authorization required
 Logs user into the system
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -298,6 +304,7 @@ No authorization required
 Logs out current logged in user session
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time
@@ -341,6 +348,7 @@ Updated user
 This can only be done by the logged in user.
 
 ### Example
+
 ```python
 from __future__ import print_function
 import time

samples/client/petstore/python-tornado/petstore_api/api_client.py

@@ -111,7 +111,7 @@ class ApiClient(object):
             query_params=None, header_params=None, body=None, post_params=None,
             files=None, response_type=None, auth_settings=None,
             _return_http_data_only=None, collection_formats=None,
-            _preload_content=True, _request_timeout=None):
+            _preload_content=True, _request_timeout=None, _host=None):
 
         config = self.configuration
 
@@ -158,7 +158,11 @@ class ApiClient(object):
             body = self.sanitize_for_serialization(body)
 
         # request url
+        if _host is None:
             url = self.configuration.host + resource_path
+        else:
+            # use server/host defined in path or operation instead
+            url = _host + resource_path
 
         # perform request and return response
         response_data = yield self.request(
@@ -291,7 +295,7 @@ class ApiClient(object):
                  body=None, post_params=None, files=None,
                  response_type=None, auth_settings=None, async_req=None,
                  _return_http_data_only=None, collection_formats=None,
-                 _preload_content=True, _request_timeout=None):
+                 _preload_content=True, _request_timeout=None, _host=None):
         """Makes the HTTP request (synchronous) and returns deserialized data.
 
         To make an async_req request, set the async_req parameter.
@@ -334,7 +338,7 @@ class ApiClient(object):
                                    body, post_params, files,
                                    response_type, auth_settings,
                                    _return_http_data_only, collection_formats,
-                                   _preload_content, _request_timeout)
+                                   _preload_content, _request_timeout, _host)
         else:
             thread = self.pool.apply_async(self.__call_api, (resource_path,
                                            method, path_params, query_params,
@@ -343,7 +347,9 @@ class ApiClient(object):
                                            response_type, auth_settings,
                                            _return_http_data_only,
                                            collection_formats,
-                                           _preload_content, _request_timeout))
+                                           _preload_content,
+                                           _request_timeout,
+                                           _host))
         return thread
 
     def request(self, method, url, query_params=None, headers=None,

samples/client/petstore/python-tornado/petstore_api/configuration.py

@@ -59,10 +59,8 @@ class Configuration(six.with_metaclass(TypeWithDefault, object)):
         self.username = ""
         # Password for HTTP basic authentication
         self.password = ""
-
+        # access token for OAuth/Bearer
-        # access token for OAuth
         self.access_token = ""
-
         # Logging Settings
         self.logger = {}
         self.logger["package_logger"] = logging.getLogger("petstore_api")
@@ -236,7 +234,6 @@ class Configuration(six.with_metaclass(TypeWithDefault, object)):
                     'key': 'Authorization',
                     'value': self.get_basic_auth_token()
                 },
-
             'petstore_auth':
                 {
                     'type': 'oauth2',
@@ -244,7 +241,6 @@ class Configuration(six.with_metaclass(TypeWithDefault, object)):
                     'key': 'Authorization',
                     'value': 'Bearer ' + self.access_token
                 },
-
         }
 
     def to_debug_report(self):
@@ -281,7 +277,7 @@ class Configuration(six.with_metaclass(TypeWithDefault, object)):
         servers = self.get_host_settings()
 
         # check array index out of bound
-        if index < 0 or index > len(servers):
+        if index < 0 or index >= len(servers):
             raise ValueError(
                 "Invalid index {} when selecting the host settings. Must be less than {}"  # noqa: E501
                 .format(index, len(servers)))

samples/client/petstore/python/petstore_api/api_client.py

@@ -109,7 +109,7 @@ class ApiClient(object):
             query_params=None, header_params=None, body=None, post_params=None,
             files=None, response_type=None, auth_settings=None,
             _return_http_data_only=None, collection_formats=None,
-            _preload_content=True, _request_timeout=None):
+            _preload_content=True, _request_timeout=None, _host=None):
 
         config = self.configuration
 
@@ -156,7 +156,11 @@ class ApiClient(object):
             body = self.sanitize_for_serialization(body)
 
         # request url
+        if _host is None:
             url = self.configuration.host + resource_path
+        else:
+            # use server/host defined in path or operation instead
+            url = _host + resource_path
 
         # perform request and return response
         response_data = self.request(
@@ -289,7 +293,7 @@ class ApiClient(object):
                  body=None, post_params=None, files=None,
                  response_type=None, auth_settings=None, async_req=None,
                  _return_http_data_only=None, collection_formats=None,
-                 _preload_content=True, _request_timeout=None):
+                 _preload_content=True, _request_timeout=None, _host=None):
         """Makes the HTTP request (synchronous) and returns deserialized data.
 
         To make an async_req request, set the async_req parameter.
@@ -332,7 +336,7 @@ class ApiClient(object):
                                    body, post_params, files,
                                    response_type, auth_settings,
                                    _return_http_data_only, collection_formats,
-                                   _preload_content, _request_timeout)
+                                   _preload_content, _request_timeout, _host)
         else:
             thread = self.pool.apply_async(self.__call_api, (resource_path,
                                            method, path_params, query_params,
@@ -341,7 +345,9 @@ class ApiClient(object):
                                            response_type, auth_settings,
                                            _return_http_data_only,
                                            collection_formats,
-                                           _preload_content, _request_timeout))
+                                           _preload_content,
+                                           _request_timeout,
+                                           _host))
         return thread
 
     def request(self, method, url, query_params=None, headers=None,

samples/openapi3/client/petstore/python/petstore_api/api/pet_api.py

@@ -68,6 +68,12 @@ class PetApi(object):
                  returns the request thread.
         """
 
+        local_var_hosts = ['http://petstore.swagger.io/v2', 'http://path-server-test.petstore.local/v2']  # noqa: E501
+        local_var_host = local_var_hosts[0]
+        if kwargs.get('_host_index'):
+            if int(kwags.get('_host_index')) < 0 or int(kawgs.get('_host_index')) >= len(local_var_hosts):
+                raise ValueError("Invalid host index. Must be 0 <= index < %s" % len(local_var_host))
+            local_var_host = local_var_hosts[int(kwargs.get('_host_index'))]
         local_var_params = locals()
 
         all_params = ['pet']  # noqa: E501
@@ -77,7 +83,7 @@ class PetApi(object):
         all_params.append('_request_timeout')
 
         for key, val in six.iteritems(local_var_params['kwargs']):
-            if key not in all_params:
+            if key not in all_params and key != "_host_index":
                 raise TypeError(
                     "Got an unexpected keyword argument '%s'"
                     " to method add_pet" % key
@@ -124,6 +130,7 @@ class PetApi(object):
             _return_http_data_only=local_var_params.get('_return_http_data_only'),  # noqa: E501
             _preload_content=local_var_params.get('_preload_content', True),
             _request_timeout=local_var_params.get('_request_timeout'),
+            _host=local_var_host,
             collection_formats=collection_formats)
 
     def delete_pet(self, pet_id, **kwargs):  # noqa: E501
@@ -546,6 +553,12 @@ class PetApi(object):
                  returns the request thread.
         """
 
+        local_var_hosts = ['http://petstore.swagger.io/v2', 'http://path-server-test.petstore.local/v2']  # noqa: E501
+        local_var_host = local_var_hosts[0]
+        if kwargs.get('_host_index'):
+            if int(kwags.get('_host_index')) < 0 or int(kawgs.get('_host_index')) >= len(local_var_hosts):
+                raise ValueError("Invalid host index. Must be 0 <= index < %s" % len(local_var_host))
+            local_var_host = local_var_hosts[int(kwargs.get('_host_index'))]
         local_var_params = locals()
 
         all_params = ['pet']  # noqa: E501
@@ -555,7 +568,7 @@ class PetApi(object):
         all_params.append('_request_timeout')
 
         for key, val in six.iteritems(local_var_params['kwargs']):
-            if key not in all_params:
+            if key not in all_params and key != "_host_index":
                 raise TypeError(
                     "Got an unexpected keyword argument '%s'"
                     " to method update_pet" % key
@@ -602,6 +615,7 @@ class PetApi(object):
             _return_http_data_only=local_var_params.get('_return_http_data_only'),  # noqa: E501
             _preload_content=local_var_params.get('_preload_content', True),
             _request_timeout=local_var_params.get('_request_timeout'),
+            _host=local_var_host,
             collection_formats=collection_formats)
 
     def update_pet_with_form(self, pet_id, **kwargs):  # noqa: E501

samples/openapi3/client/petstore/python/petstore_api/api_client.py

@@ -109,7 +109,7 @@ class ApiClient(object):
             query_params=None, header_params=None, body=None, post_params=None,
             files=None, response_type=None, auth_settings=None,
             _return_http_data_only=None, collection_formats=None,
-            _preload_content=True, _request_timeout=None):
+            _preload_content=True, _request_timeout=None, _host=None):
 
         config = self.configuration
 
@@ -156,7 +156,11 @@ class ApiClient(object):
             body = self.sanitize_for_serialization(body)
 
         # request url
+        if _host is None:
             url = self.configuration.host + resource_path
+        else:
+            # use server/host defined in path or operation instead
+            url = _host + resource_path
 
         # perform request and return response
         response_data = self.request(
@@ -289,7 +293,7 @@ class ApiClient(object):
                  body=None, post_params=None, files=None,
                  response_type=None, auth_settings=None, async_req=None,
                  _return_http_data_only=None, collection_formats=None,
-                 _preload_content=True, _request_timeout=None):
+                 _preload_content=True, _request_timeout=None, _host=None):
         """Makes the HTTP request (synchronous) and returns deserialized data.
 
         To make an async_req request, set the async_req parameter.
@@ -332,7 +336,7 @@ class ApiClient(object):
                                    body, post_params, files,
                                    response_type, auth_settings,
                                    _return_http_data_only, collection_formats,
-                                   _preload_content, _request_timeout)
+                                   _preload_content, _request_timeout, _host)
         else:
             thread = self.pool.apply_async(self.__call_api, (resource_path,
                                            method, path_params, query_params,
@@ -341,7 +345,9 @@ class ApiClient(object):
                                            response_type, auth_settings,
                                            _return_http_data_only,
                                            collection_formats,
-                                           _preload_content, _request_timeout))
+                                           _preload_content,
+                                           _request_timeout,
+                                           _host))
         return thread
 
     def request(self, method, url, query_params=None, headers=None,