require effective config for slots ttl

agent/nix_builder_autoscaler/cli.py

@@ -96,10 +96,7 @@ def _slot_age_seconds(slot: dict[str, Any]) -> float | None:
     return (datetime.now(UTC) - dt).total_seconds()
 
 
-def _slot_ttl(slot: dict[str, Any], policy: dict[str, Any] | None, active_slots: int) -> str:
-    if policy is None:
-        return "-"
-
+def _slot_ttl(slot: dict[str, Any], policy: dict[str, Any], active_slots: int) -> str:
     capacity = policy.get("capacity")
     scheduler = policy.get("scheduler")
     if not isinstance(capacity, dict) or not isinstance(scheduler, dict):
@@ -138,7 +135,7 @@ def _slot_ttl(slot: dict[str, Any], policy: dict[str, Any] | None, active_slots:
     return "-"
 
 
-def _print_slots(data: list[dict[str, Any]], policy: dict[str, Any] | None = None) -> None:
+def _print_slots(data: list[dict[str, Any]], policy: dict[str, Any]) -> None:
     active_slots = sum(1 for slot in data if str(slot.get("state", "")) not in {"empty", "error"})
     rows: list[list[str]] = []
     for slot in data:
@@ -193,16 +190,15 @@ def _print_status_summary(data: dict[str, Any]) -> None:
     _print_table(["metric", "value"], rows)
 
 
-def _get_effective_config(socket_path: str) -> dict[str, Any] | None:
-    try:
+def _get_effective_config(socket_path: str) -> dict[str, Any]:
     status, data = _uds_request(socket_path, "GET", "/v1/config/effective")
-    except OSError:
-        return None
     if status < 200 or status >= 300:
-        return None
+        msg = "failed to fetch effective config"
+        raise RuntimeError(msg)
     if isinstance(data, dict):
         return data
-    return None
+    msg = "invalid effective config payload"
+    raise RuntimeError(msg)
 
 
 def _bulk_slot_action(socket_path: str, action: str) -> dict[str, Any]:
@@ -395,7 +391,11 @@ def main() -> None:
         print(json.dumps(data, indent=2))
     elif args.command == "slots":
         if isinstance(data, list):
+            try:
                 policy = _get_effective_config(args.socket)
+            except RuntimeError as err:
+                print(str(err))
+                raise SystemExit(1) from err
             _print_slots(data, policy)
         else:
             _print_error(data)

agent/nix_builder_autoscaler/tests/test_cli.py

@@ -7,7 +7,13 @@ from datetime import UTC, datetime, timedelta
 import pytest
 
 from nix_builder_autoscaler import cli
-from nix_builder_autoscaler.cli import _parse_args, _print_slots, _print_status_summary, _slot_ttl
+from nix_builder_autoscaler.cli import (
+    _get_effective_config,
+    _parse_args,
+    _print_slots,
+    _print_status_summary,
+    _slot_ttl,
+)
 
 
 def test_parse_args_without_command_prints_help_and_exits_zero(
@@ -149,3 +155,15 @@ def test_print_slots_includes_ttl_column(capsys: pytest.CaptureFixture[str]) ->
     out = capsys.readouterr().out
     assert "ttl" in out
     assert "slot001" in out
+
+
+def test_get_effective_config_raises_on_non_2xx(monkeypatch: pytest.MonkeyPatch) -> None:
+    def _fake_request(socket_path: str, method: str, path: str, body=None):  # noqa: ANN001
+        assert socket_path == "/tmp/sock"
+        assert method == "GET"
+        assert path == "/v1/config/effective"
+        return 404, {"error": "not found"}
+
+    monkeypatch.setattr(cli, "_uds_request", _fake_request)
+    with pytest.raises(RuntimeError, match="failed to fetch effective config"):
+        _get_effective_config("/tmp/sock")