ci: retry if rate limited in roulette (#19523)

[skip ci]

.github/helper/roulette.py

@@ -4,8 +4,10 @@ import re
 import shlex
 import subprocess
 import sys
+import time
 import urllib.request
 from functools import lru_cache
+from urllib.error import HTTPError
 
 
 @lru_cache(maxsize=None)
@@ -15,11 +17,25 @@ def fetch_pr_data(pr_number, repo, endpoint=""):
 	if endpoint:
 		api_url += f"/{endpoint}"
 
-	req = urllib.request.Request(api_url)
-	res = urllib.request.urlopen(req)
+	res = req(api_url)
 	return json.loads(res.read().decode("utf8"))
 
 
+def req(url):
+	"Simple resilient request call to handle rate limits."
+	retries = 0
+	while True:
+		try:
+			req = urllib.request.Request(url)
+			return urllib.request.urlopen(req)
+		except HTTPError as exc:
+			if exc.code == 403 and retries < 5:
+				retries += 1
+				time.sleep(retries)
+				continue
+			raise
+
+
 def get_files_list(pr_number, repo="frappe/frappe"):
 	return [change["filename"] for change in fetch_pr_data(pr_number, repo, "files")]