Add aiohttp version validation (ref slackapi#912)

setup.py

@@ -295,7 +295,9 @@ def run(self):
         "optional": [
             # async modules depend on aiohttp
             "aiodns>1.0",
-            "aiohttp>=3,<4",
+            # We recommend using 3.7.1+ for RTMClient
+            # https://github.com/slackapi/python-slack-sdk/issues/912
+            "aiohttp>=3.7.3,<4",
             # used only under slack_sdk/*_store
             "boto3<=2",
             # InstallationStore/OAuthStateStore

slack_sdk/aiohttp_version_checker.py

@@ -0,0 +1,23 @@
+import logging
+from typing import Callable
+
+
+def _print_warning_log(message: str) -> None:
+    logging.getLogger(__name__).warning(message)
+
+
+def validate_aiohttp_version(
+    aiohttp_version: str, print_warning: Callable[[str], None] = _print_warning_log,
+):
+    if aiohttp_version is not None:
+        elements = aiohttp_version.split(".")
+        if len(elements) >= 3:
+            # patch version can be a non-numeric value
+            major, minor, patch = int(elements[0]), int(elements[1]), elements[2]
+            if major <= 2 or (
+                major == 3 and (minor == 6 or (minor == 7 and patch == "0"))
+            ):
+                print_warning(
+                    "We highly recommend upgrading aiohttp to 3.7.3 or higher versions."
+                    "An older version of the library may not work with the Slack server-side in the future."
+                )

slack_sdk/rtm/__init__.py

@@ -16,9 +16,13 @@
 import aiohttp
 
 import slack_sdk.errors as client_err
+from slack_sdk.aiohttp_version_checker import validate_aiohttp_version
 from slack_sdk.web.legacy_client import LegacyWebClient as WebClient
 
 
+validate_aiohttp_version(aiohttp.__version__)
+
+
 class RTMClient(object):  # skipcq: PYL-R0205
     """An RTMClient allows apps to communicate with the Slack Platform's RTM API.
 

tests/test_aiohttp_version_checker.py

@@ -0,0 +1,42 @@
+import logging
+import unittest
+
+from slack_sdk.aiohttp_version_checker import validate_aiohttp_version
+
+
+class TestAiohttpVersionChecker(unittest.TestCase):
+    def setUp(self):
+        self.logger = logging.getLogger(__name__)
+
+    def tearDown(self):
+        pass
+
+    def test_not_recommended_versions(self):
+        state = {"counter": 0}
+
+        def print(message: str):
+            state["counter"] = state["counter"] + 1
+
+        validate_aiohttp_version("2.1.3", print)
+        self.assertEqual(state["counter"], 1)
+        validate_aiohttp_version("3.6.3", print)
+        self.assertEqual(state["counter"], 2)
+        validate_aiohttp_version("3.7.0", print)
+        self.assertEqual(state["counter"], 3)
+
+    def test_recommended_versions(self):
+        state = {"counter": 0}
+
+        def print(message: str):
+            state["counter"] = state["counter"] + 1
+
+        validate_aiohttp_version("3.7.1", print)
+        self.assertEqual(state["counter"], 0)
+        validate_aiohttp_version("3.7.3", print)
+        self.assertEqual(state["counter"], 0)
+        validate_aiohttp_version("3.8.0", print)
+        self.assertEqual(state["counter"], 0)
+        validate_aiohttp_version("4.0.0", print)
+        self.assertEqual(state["counter"], 0)
+        validate_aiohttp_version("4.0.0rc1", print)
+        self.assertEqual(state["counter"], 0)