Use a specific exception for worker start-up

This lets the exception class deal with sorting into tags and
context for Sentry.

Author: jonathansick

src/noteburst/exceptions.py

@@ -15,6 +15,7 @@
     "NoteburstClientRequestError",
     "NoteburstError",
     "NoteburstWorkerError",
+    "NoteburstWorkerStartupError",
     "TaskError",
 ]
 
@@ -38,6 +39,38 @@ def __init__(
             self.contexts = contexts
 
 
+class NoteburstWorkerStartupError(NoteburstWorkerError):
+    """Error raised when the worker fails to start."""
+
+    def __init__(
+        self,
+        msg: str,
+        *,
+        last_username: str,
+        attempted_usernames: list[str],
+        image_selector: str,
+        image_reference: str | None,
+        user_token_scopes: list[str],
+    ) -> None:
+        super().__init__(
+            msg,
+            tags={
+                "username": last_username,
+                "image_selector": image_selector,
+                "image_reference": image_reference or "N/A",
+            },
+            contexts={
+                "noteburst_worker": {
+                    "username": last_username,
+                    "attempted_usernames": attempted_usernames,
+                    "user_token_scopes": user_token_scopes,
+                    "image_selector": image_selector,
+                    "image_reference": image_reference or "N/A",
+                }
+            },
+        )
+
+
 class TaskError(Exception):
     """Error related to Arq task execution."""
 

src/noteburst/worker/main.py

@@ -28,7 +28,7 @@
     WorkerConfig,
     WorkerKeepAliveSetting,
 )
-from noteburst.exceptions import NoteburstWorkerError
+from noteburst.exceptions import NoteburstWorkerStartupError
 
 from .functions import keep_alive, nbexec, ping, run_python
 from .identity import IdentityClaimError, IdentityManager
@@ -85,8 +85,10 @@ async def startup(ctx: dict[Any, Any]) -> None:
 
     # Loop with different identities until we get a successful spawn
     spawn_exception: Exception | None = None
+    attempted_usernames: list[str] = []
     while True:
         try:
+            attempted_usernames.append(identity.username)
             nublado_pod = await NubladoPod.spawn(
                 identity=identity,
                 nublado_image=config.nublado_image,
@@ -117,22 +119,14 @@ async def startup(ctx: dict[Any, Any]) -> None:
             identity = await identity_manager.get_next_identity(identity)
         except IdentityClaimError:
             # No more identities available, so we can't spawn a pod
-            raise NoteburstWorkerError(
+            raise NoteburstWorkerStartupError(
                 "Failed to start up Noteburst worker. Could not spawn a "
                 "Nublado pod with any identity.",
-                tags={
-                    "username": identity.username,
-                    "image_selector": config.image_selector,
-                    "image_reference": config.image_reference or "N/A",
-                },
-                contexts={
-                    "nublado": {
-                        "username": identity.username,
-                        "user_token_scopes": config.parsed_worker_token_scopes,
-                        "image_selector": config.image_selector,
-                        "image_reference": config.image_reference,
-                    }
-                },
+                last_username=identity.username,
+                attempted_usernames=attempted_usernames,
+                image_selector=config.image_selector,
+                image_reference=config.image_reference,
+                user_token_scopes=config.parsed_worker_token_scopes,
             ) from spawn_exception
 
     ctx["nublado_client"] = nublado_pod.nublado_client