From feaa701874549aee58ff589e3a7a85e5eb544451 Mon Sep 17 00:00:00 2001
From: Kazuhiro Sera <seratch@gmail.com>
Date: Wed, 22 Apr 2020 12:41:27 +0900
Subject: [PATCH] Add a sample for #497

---
 integration_tests/samples/issues/issue_497.py | 106 ++++++++++++++++++
 1 file changed, 106 insertions(+)
 create mode 100644 integration_tests/samples/issues/issue_497.py

diff --git a/integration_tests/samples/issues/issue_497.py b/integration_tests/samples/issues/issue_497.py
new file mode 100644
index 000000000..a12c75bc2
--- /dev/null
+++ b/integration_tests/samples/issues/issue_497.py
@@ -0,0 +1,106 @@
+# ------------------
+# Only for running this script here
+import asyncio
+import logging
+import sys
+from os.path import dirname
+
+sys.path.insert(1, f"{dirname(__file__)}/../../..")
+logging.basicConfig(level=logging.DEBUG)
+# ------------------
+
+# ---------------------
+# Flask App
+# ---------------------
+
+# pip3 install flask
+from flask import Flask, make_response
+
+app = Flask(__name__)
+logger = logging.getLogger(__name__)
+
+import os
+
+from slack import WebClient
+from slack.errors import SlackApiError
+
+singleton_client = WebClient(token=os.environ["SLACK_BOT_TOKEN"], run_async=False)
+
+singleton_loop = asyncio.new_event_loop()
+singleton_async_client = WebClient(
+    token=os.environ["SLACK_BOT_TOKEN"],
+    run_async=True,
+    loop=singleton_loop
+)
+
+
+@app.route("/sync/singleton", methods=["GET"])
+def singleton():
+    try:
+        response = singleton_client.chat_postMessage(
+            channel="#random",
+            text="You used the singleton WebClient for posting this message!"
+        )
+        return str(response)
+    except SlackApiError as e:
+        return make_response(str(e), 400)
+
+
+@app.route("/sync/per-request", methods=["GET"])
+def per_request():
+    try:
+        client = WebClient(
+            token=os.environ["SLACK_BOT_TOKEN"],
+            run_async=False
+        )
+        response = client.chat_postMessage(
+            channel="#random",
+            text="You used a new WebClient for posting this message!"
+        )
+        return str(response)
+    except SlackApiError as e:
+        return make_response(str(e), 400)
+
+
+# This doesn't work
+@app.route("/async/singleton", methods=["GET"])
+def singleton_async():
+    try:
+        future = singleton_async_client.chat_postMessage(
+            channel="#random",
+            text="You used the singleton WebClient for posting this message!"
+        )
+        # blocking here!!!
+        # as described at https://github.com/slackapi/python-slackclient/issues/497
+        # until this completion, other simultaneous requests get "RuntimeError: This event loop is already running"
+        response = singleton_loop.run_until_complete(future)
+        return str(response)
+    except SlackApiError as e:
+        return make_response(str(e), 400)
+
+
+@app.route("/async/per-request", methods=["GET"])
+def per_request_async():
+    try:
+        # This is not optimal and the host should have a large number of FD (File Descriptor)
+        loop_for_this_request = asyncio.new_event_loop()
+
+        async_client = WebClient(
+            token=os.environ["SLACK_BOT_TOKEN"],
+            run_async=True,
+            loop=loop_for_this_request
+        )
+        future = async_client.chat_postMessage(
+            channel="#random",
+            text="You used the singleton WebClient for posting this message!"
+        )
+        response = loop_for_this_request.run_until_complete(future)
+        return str(response)
+    except SlackApiError as e:
+        return make_response(str(e), 400)
+
+
+if __name__ == "__main__":
+    # export FLASK_ENV=development
+    # python3 integration_tests/samples/issues/issue_497.py
+    app.run(debug=True, host="localhost", port=3000)