refactor: set Retry-After header directly

frappe/app.py

@@ -394,12 +394,6 @@ def handle_exception(e):
 	elif http_status_code == 429:
 		response = frappe.rate_limiter.respond()
 
-	elif http_status_code == 503:
-		retry_after = getattr(e, "retry_after", 10)
-		response = frappe.utils.response.report_error(503)
-		if response:
-			response.headers["Retry-After"] = str(retry_after)
-
 	else:
 		response = ErrorPage(
 			http_status_code=http_status_code, title=_("Server Error"), message=_("Uncaught Exception")

frappe/concurrency_limiter.py

@@ -72,9 +72,9 @@ def concurrent_limit(limit: int | None = None, wait_timeout: int | None = None):
 			if not acquired:
 				from frappe.exceptions import ServiceUnavailableError
 
-				retry_after = max(1, int(effective_wait))
 				exc = ServiceUnavailableError(frappe._("Server is busy. Please try again in a few seconds."))
-				exc.retry_after = retry_after
+				retry_after = max(1, int(effective_wait))
+				frappe.local.response_headers.set("Retry-After", str(retry_after))
 				raise exc
 
 			try:

frappe/exceptions.py

@@ -87,14 +87,7 @@ class TooManyRequestsError(Exception):
 
 
 class ServiceUnavailableError(Exception):
-	"""Raised when a concurrency limit is exceeded for an endpoint.
-
-	Set :attr:`retry_after` (seconds) before raising so that the response
-	includes a ``Retry-After`` header.
-	"""
-
 	http_status_code = 503
-	retry_after: int = 10
 
 
 class ImproperDBConfigurationError(Exception):

frappe/tests/test_concurrency_limiter.py

@@ -91,9 +91,8 @@ class TestConcurrentLimit(IntegrationTestCase):
 			del frappe.local.request
 			frappe.cache.delete(key)
 
-	def test_service_unavailable_has_correct_http_status_and_retry_after(self):
+	def test_service_unavailable_has_correct_http_status(self):
-		"""The raised exception must carry http_status_code=503 and retry_after
+		"""The raised exception must carry http_status_code=503."""
-		equal to the configured wait_timeout."""
 		TIMEOUT = 1
 
 		@concurrent_limit(limit=1, wait_timeout=TIMEOUT)
@@ -110,7 +109,6 @@ class TestConcurrentLimit(IntegrationTestCase):
 				fn()
 			exc = ctx.exception
 			self.assertEqual(exc.http_status_code, 503)
-			self.assertEqual(exc.retry_after, TIMEOUT)
 		finally:
 			del frappe.local.request
 			frappe.cache.delete(key)