Merge ~r00ta/maas:lp-2058037-3.5 into maas:3.5

[Jacopo Rota]

fix: lp-2058037. Ensure get-bootresourcefile-endpoints activity fails if the region is not exposing its ip yet.

(cherry-picked from 81a99768c3098a9fbd76f8de1e27ea8433af04ba)

[Jacopo Rota (r00ta)]

self approving backport

review: Approve

[MAAS Lander (maas-lander)]

UNIT TESTS
-b lp-2058037-3.5 lp:~r00ta/maas/+git/maas into -b 3.5 lp:~maas-committers/maas

STATUS: SUCCESS
COMMIT: 63a95907a74e79ac7f503e479141d44897c7cd27

review: Approve

diff --git a/src/maasserver/workflow/bootresource.py b/src/maasserver/workflow/bootresource.py
index 4c76a5e..4097f7e 100644
--- a/src/maasserver/workflow/bootresource.py
+++ b/src/maasserver/workflow/bootresource.py
@@ -97,13 +97,21 @@ class BootResourcesActivity(MAASAPIClient):
     async def get_bootresourcefile_endpoints(self) -> dict[str, list]:
         url = f"{self.url}/api/2.0/regioncontrollers/"
         regions = await self.request_async("GET", url)
-        return {
-            r["system_id"]: [
-                compose_URL("http://:5240/MAAS/boot-resources/", src)
-                for src in r["ip_addresses"]
-            ]
-            for r in regions
-        }
+        regions_endpoints = {}
+        for region in regions:
+            # https://bugs.launchpad.net/maas/+bug/2058037
+            if region["ip_addresses"]:
+                regions_endpoints[region["system_id"]] = [
+                    compose_URL("http://:5240/MAAS/boot-resources/", src)
+                    for src in region["ip_addresses"]
+                ]
+            else:
+                raise ApplicationError(
+                    f"Could not retrieve the IP addresses of the region controller '{region['system_id']}' from the API. This "
+                    f"activity will be retried until we have the IP for all the region controllers.",
+                    non_retryable=False,
+                )
+        return regions_endpoints
 
     @activity.defn(name="download-bootresourcefile")
     async def download_bootresourcefile(