populate error to error_class mapping once

engine/apps/slack/client.py

@@ -8,13 +8,7 @@
 from slack_sdk.http_retry import HttpRequest, HttpResponse, RetryHandler, RetryState, default_retry_handlers
 from slack_sdk.web import SlackResponse, WebClient
 
-from apps.slack.errors import (
-    SlackAPIError,
-    SlackAPIRatelimitError,
-    SlackAPIServerError,
-    SlackAPITokenError,
-    UnexpectedResponse,
-)
+from apps.slack.errors import SlackAPIRatelimitError, SlackAPIServerError, SlackAPITokenError, get_error_class
 
 if typing.TYPE_CHECKING:
     from apps.slack.models import SlackTeamIdentity
@@ -138,7 +132,7 @@ def api_call(self, *args, **kwargs) -> SlackResponse:
             )
 
             # narrow down the error
-            error_class = self._get_error_class(e.response)
+            error_class = get_error_class(e.response)
 
             # mark / unmark token as revoked
             if error_class is SlackAPITokenError:
@@ -149,19 +143,6 @@ def api_call(self, *args, **kwargs) -> SlackResponse:
             # raise the narrowed down error class
             raise error_class(e.response) from e
 
-    @staticmethod
-    def _get_error_class(response: UnexpectedResponse | SlackResponse) -> typing.Type[SlackAPIError]:
-        """Get an appropriate error class for the response"""
-
-        if isinstance(response, dict):  # UnexpectedResponse
-            return SlackAPIServerError
-
-        for error_class in SlackAPIError.__subclasses__():
-            if response["error"] in error_class.errors:
-                return error_class
-
-        return SlackAPIError
-
     def _mark_token_revoked(self) -> None:
         if not self.slack_team_identity.detected_token_revoked:
             self.slack_team_identity.detected_token_revoked = timezone.now()

engine/apps/slack/errors.py

@@ -14,7 +14,7 @@ class UnexpectedResponse(typing.TypedDict):
 class SlackAPIError(Exception):
     """
     Base class for Slack API errors. To add a new error class, add a new subclass of SlackAPIError in this file.
-    See apps.slack.client.SlackClient._get_error_class for more details on how these are raised.
+    See get_error_class at the end of this file for more details on how these are raised.
     """
 
     errors: tuple[str, ...]
@@ -94,3 +94,17 @@ class SlackAPICannotDMBotError(SlackAPIError):
 
 class SlackAPIMethodNotSupportedForChannelTypeError(SlackAPIError):
     errors = ("method_not_supported_for_channel_type",)
+
+
+_error_to_error_class = {
+    error: error_class for error_class in SlackAPIError.__subclasses__() for error in error_class.errors
+}
+
+
+def get_error_class(response: UnexpectedResponse | SlackResponse) -> typing.Type[SlackAPIError]:
+    """Get an appropriate error class for the response"""
+
+    if isinstance(response, dict):  # UnexpectedResponse
+        return SlackAPIServerError
+
+    return _error_to_error_class.get(response["error"], SlackAPIError)