Get JupyterHub XSRF token from each redirect hop

This is similar to what we're already doing for logging into JupyterLab.
Adam found this is necessary for logging into JupyterHub as well, see
https://rubinobs.atlassian.net/browse/DM-45523

changelog.d/20240802_135738_jsick_DM_45563.md

@@ -0,0 +1,17 @@
+<!-- Delete the sections that don't apply -->
+
+### Backwards-incompatible changes
+
+-
+
+### New features
+
+-
+
+### Bug fixes
+
+- When logging into JupyterHub, a Noteburst now looks for XRSF tokens from each redirect.
+
+### Other changes
+
+-

src/noteburst/jupyterclient/jupyterlab.py

@@ -483,16 +483,30 @@ def _extract_xsrf(self, response: Response) -> str | None:
     async def log_into_hub(self) -> None:
         """Log into JupyterHub or raise a JupyterError."""
         self.logger.debug("Logging into JupyterHub")
-        r = await self.http_client.get(self.url_for("hub/home"))
-        # JupyterHub returns a 302 redirect to the login page on success,
-        # but we don't want to follow that redirect. This request is just
-        # to set cookies.
-        if r.status_code >= 400:
-            raise JupyterError.from_response(self.user.username, r)
+        url = self.url_for("hub/home")
+        r = await self.http_client.get(url, follow_redirects=False)
+        while r.is_redirect:
+            xsrf = self._extract_xsrf(r)
+            if xsrf and xsrf != self._lab_xsrf:
+                self._hub_xsrf = xsrf
+            next_url = urljoin(url, r.headers["Location"])
+            r = await self.http_client.get(next_url, follow_redirects=False)
+        r.raise_for_status()
         xsrf = self._extract_xsrf(r)
-        if xsrf:
+        if xsrf and xsrf != self._lab_xsrf:
             self._hub_xsrf = xsrf
 
+        if not self._hub_xsrf:
+            raise JupyterError(
+                reason="No XSRF token found for JupyterHub",
+                url=url,
+                username=self.user.username,
+                status=r.status_code,
+                method="GET",
+                body=r.text,
+            )
+        self.logger.debug("Logged into JupyterHub with XSRF token")
+
     async def log_into_lab(self) -> None:
         """Log into JupyterLab or raise a JupyterError."""
         self.logger.debug("Logging into JupyterLab")

src/noteburst/worker/main.py

@@ -140,7 +140,7 @@ def create_message(message: str) -> SlackMessage:
         )
 
 
-async def shutdown(ctx: dict[Any, Any]) -> None:  # noqa: PLR0912
+async def shutdown(ctx: dict[Any, Any]) -> None:
     """Clean up the worker context on shutdown."""
     if "logger" in ctx:
         logger = ctx["logger"]