diff --git a/.gitignore b/.gitignore
index 31a72c46..b7d995e7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,13 +2,16 @@
 __pycache__
 .DS_Store
 .vscode
+.idea
 .pypirc
 */tmp/*
 build/*
 dist/*
 *.egg-info
 .python-version
-logs/%
+logs
 .coverage
 locustfile.py
 site/
+poetry.lock
+reports
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
index ccea9762..9d2b70c5 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,16 @@
 # Release History
 
+## 2.2.6 (2019-09-18)
+
+**Added**
+
+- config variables support parsing from function
+
+**Changed**
+
+- remove unused import
+- adjust code format
+
 ## 2.2.5 (2019-07-28)
 
 **Added**
diff --git a/httprunner/__init__.py b/httprunner/__init__.py
index 567610eb..7fbb6af4 100644
--- a/httprunner/__init__.py
+++ b/httprunner/__init__.py
@@ -1,4 +1,4 @@
-__version__ = "2.2.5"
+__version__ = "2.2.6"
 __description__ = "One-stop solution for HTTP(S) testing."
 
 __all__ = ["__version__", "__description__"]
diff --git a/httprunner/cli.py b/httprunner/cli.py
index f6000427..97b4b3ad 100644
--- a/httprunner/cli.py
+++ b/httprunner/cli.py
@@ -1,5 +1,6 @@
 # encoding: utf-8
 
+
 def main_hrun():
     """ API test: parse command line options and run commands.
     """
@@ -11,7 +12,7 @@ def main_hrun():
     from httprunner.compat import is_py2
     from httprunner.validator import validate_json_file
     from httprunner.utils import (create_scaffold, get_python2_retire_msg,
-                                prettify_json_file)
+                                  prettify_json_file)
 
     parser = argparse.ArgumentParser(description=__description__)
     parser.add_argument(
diff --git a/httprunner/loader.py b/httprunner/loader.py
index 1df7a8a3..bf93b81e 100644
--- a/httprunner/loader.py
+++ b/httprunner/loader.py
@@ -17,10 +17,12 @@ try:
 except AttributeError:
     pass
 
+
 ###############################################################################
-##   file loader
+#   file loader
 ###############################################################################
 
+
 def _check_format(file_path, content):
     """ check testcase format if valid
     """
@@ -239,9 +241,10 @@ def locate_file(start_path, file_name):
 
 
 ###############################################################################
-##   debugtalk.py module loader
+#   debugtalk.py module loader
 ###############################################################################
 
+
 def load_module_functions(module):
     """ load python module functions.
 
@@ -290,9 +293,10 @@ def load_debugtalk_functions():
 
 
 ###############################################################################
-##   testcase loader
+#   testcase loader
 ###############################################################################
 
+
 project_mapping = {}
 tests_def_mapping = {
     "PWD": None,
@@ -720,14 +724,16 @@ def load_api_folder(api_folder_path):
         if isinstance(api_items, list):
             for api_item in api_items:
                 key, api_dict = api_item.popitem()
-                api_id = api_dict.get("id") or api_dict.get("def") or api_dict.get("name")
+                api_id = api_dict.get("id") or api_dict.get("def") \
+                    or api_dict.get("name")
                 if key != "api" or not api_id:
                     raise exceptions.ParamsError(
                         "Invalid API defined in {}".format(api_file_path))
 
                 if api_id in api_definition_mapping:
                     raise exceptions.ParamsError(
-                        "Duplicated API ({}) defined in {}".format(api_id, api_file_path))
+                        "Duplicated API ({}) defined in {}".format(
+                            api_id, api_file_path))
                 else:
                     api_definition_mapping[api_id] = api_dict
 
@@ -745,7 +751,8 @@ def locate_debugtalk_py(start_path):
     """ locate debugtalk.py file
 
     Args:
-        start_path (str): start locating path, maybe testcase file path or directory path
+        start_path (str): start locating path,
+            maybe testcase file path or directory path
 
     Returns:
         str: debugtalk.py file path, None if not found
@@ -769,7 +776,8 @@ def load_project_tests(test_path, dot_env_path=None):
         dot_env_path (str): specified .env file path
 
     Returns:
-        dict: project loaded api/testcases definitions, environments and debugtalk.py functions.
+        dict: project loaded api/testcases definitions,
+            environments and debugtalk.py functions.
 
     """
     # locate debugtalk.py file
@@ -876,6 +884,7 @@ def load_tests(path, dot_env_path=None):
     }
 
     def __load_file_content(path):
+        loaded_content = None
         try:
             loaded_content = load_test_file(path)
         except exceptions.FileFormatError:
diff --git a/httprunner/parser.py b/httprunner/parser.py
index 4a85ac65..29b0a666 100644
--- a/httprunner/parser.py
+++ b/httprunner/parser.py
@@ -2,11 +2,10 @@
 
 import ast
 import builtins
-import os
 import re
 
 from httprunner import exceptions, utils, validator
-from httprunner.compat import basestring, builtin_str, numeric_types, str
+from httprunner.compat import basestring, numeric_types, str
 
 # use $$ to escape $ notation
 dolloar_regex_compile = re.compile(r"\$\$")
@@ -872,10 +871,23 @@ def __prepare_config(config, project_mapping, session_variables_set=None):
     """
     # get config variables
     raw_config_variables = config.pop("variables", {})
-    raw_config_variables_mapping = utils.ensure_mapping_format(raw_config_variables)
+
     override_variables = utils.deepcopy_dict(project_mapping.get("variables", {}))
     functions = project_mapping.get("functions", {})
 
+    if isinstance(raw_config_variables, basestring) and function_regex_compile.match(raw_config_variables):
+        # config variables are generated by calling function
+        # e.g.
+        # "config": {
+        #     "name": "basic test with httpbin",
+        #     "variables": "${gen_variables()}"
+        # }
+        raw_config_variables_mapping = parse_lazy_data(
+            prepare_lazy_data(raw_config_variables, functions_mapping=functions)
+        )
+    else:
+        raw_config_variables_mapping = utils.ensure_mapping_format(raw_config_variables)
+
     # override config variables with passed in variables
     raw_config_variables_mapping.update(override_variables)
 
diff --git a/httprunner/response.py b/httprunner/response.py
index 5cf20189..5ab5ac33 100644
--- a/httprunner/response.py
+++ b/httprunner/response.py
@@ -6,8 +6,6 @@ import jsonpath
 
 from httprunner import exceptions, logger, utils
 from httprunner.compat import OrderedDict, basestring, is_py2
-from requests.models import PreparedRequest
-from requests.structures import CaseInsensitiveDict
 
 
 text_extractor_regexp_compile = re.compile(r".*\(.*\).*")
@@ -112,7 +110,7 @@ class ResponseObject(object):
                 "content.person.name.first_name"
 
         """
-        # string.split(sep=None, maxsplit=-1) -> list of strings
+        # string.split(sep=None, maxsplit=1) -> list of strings
         # e.g. "content.person.name" => ["content", "person.name"]
         try:
             top_query, sub_query = field.split('.', 1)
diff --git a/pyproject.toml b/pyproject.toml
index 02d00a78..db5bae3a 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "httprunner"
-version = "2.2.5"
+version = "2.2.6"
 description = "One-stop solution for HTTP(S) testing."
 license = "Apache-2.0"
 readme = "README.md"
diff --git a/tests/debugtalk.py b/tests/debugtalk.py
index 74b9a3d3..dd89e8be 100644
--- a/tests/debugtalk.py
+++ b/tests/debugtalk.py
@@ -111,3 +111,10 @@ def alter_response(response):
 def alter_response_error(response):
     # NameError
     not_defined_variable
+
+
+def gen_variables():
+    return {
+        "var_a": 1,
+        "var_b": 2
+    }
diff --git a/tests/test_parser.py b/tests/test_parser.py
index 5391ebc2..6f76148e 100644
--- a/tests/test_parser.py
+++ b/tests/test_parser.py
@@ -1,5 +1,4 @@
 import os
-import re
 import time
 import unittest
 
@@ -561,7 +560,6 @@ class TestParserBasic(unittest.TestCase):
         )
 
     def test_parse_data_functions(self):
-        import random, string
         functions_mapping = {
             "gen_random_string": gen_random_string
         }
diff --git a/tests/test_runner.py b/tests/test_runner.py
index 4b684c1d..df8c734d 100644
--- a/tests/test_runner.py
+++ b/tests/test_runner.py
@@ -336,4 +336,47 @@ class TestRunner(ApiServerUnittest):
         parsed_testcases = parser.parse_tests(tests_mapping)
         parsed_testcase = parsed_testcases[0]
         test_runner = runner.Runner(parsed_testcase["config"])
-        test_runner.run_test(parsed_testcase["teststeps"][0])
\ No newline at end of file
+        test_runner.run_test(parsed_testcase["teststeps"][0])
+
+    def test_run_testcase_config_variables_parsed_from_function(self):
+        testcases = [
+            {
+                "config": {
+                    "name": "basic test with httpbin",
+                    "base_url": HTTPBIN_SERVER,
+                    "variables": "${gen_variables()}"
+                },
+                "teststeps": [
+                    {
+                        "name": "modify request headers",
+                        "base_url": HTTPBIN_SERVER,
+                        "request": {
+                            "url": "/anything",
+                            "method": "POST",
+                            "headers": {
+                                "user_agent": "iOS/10.3",
+                                "os_platform": "ios"
+                            },
+                            "data": "a=1&b=2"
+                        },
+                        "validate": [
+                            {"check": "status_code", "expect": 200}
+                        ]
+                    }
+                ]
+            }
+        ]
+        tests_mapping = {
+            "project_mapping": {
+                "functions": self.debugtalk_functions
+            },
+            "testcases": testcases
+        }
+        parsed_testcases = parser.parse_tests(tests_mapping)
+        parsed_testcase = parsed_testcases[0]
+        test_runner = runner.Runner(parsed_testcase["config"])
+        test_runner.run_test(parsed_testcase["teststeps"][0])
+        test_variables_mapping = test_runner.session_context.test_variables_mapping
+        self.assertEqual(test_variables_mapping["var_a"], 1)
+        self.assertEqual(test_variables_mapping["var_b"], 2)
+        self.assertEqual(test_variables_mapping["request"]["data"], "a=1&b=2")