Fix range header to correctly fetch latest logs (#6202)

* Fix range header to correctly fetch latest logs

Add a colon before line numbers to indicate that no cursor is used.
This makes the range header work when fetching latest logs from
systemd-journal-gatewayd.

* Fix pytest

Author: agners

supervisor/api/host.py

@@ -267,7 +267,7 @@ async def advanced_logs_handler(
             # entries=cursor[[:num_skip]:num_entries]
             range_header = f"entries=:-{lines - 1}:{SYSTEMD_JOURNAL_GATEWAYD_LINES_MAX if follow else lines}"
         elif latest:
-            range_header = f"entries=0:{SYSTEMD_JOURNAL_GATEWAYD_LINES_MAX}"
+            range_header = f"entries=:0:{SYSTEMD_JOURNAL_GATEWAYD_LINES_MAX}"
         elif RANGE in request.headers:
             range_header = request.headers[RANGE]
         else:

tests/api/__init__.py

@@ -64,7 +64,7 @@ async def common_test_api_advanced_logs(
     logs_call = journald_logs.call_args_list[1]
     assert logs_call[1]["params"]["SYSLOG_IDENTIFIER"] == syslog_identifier
     assert logs_call[1]["params"]["CONTAINER_LOG_EPOCH"] == "12345"
-    assert logs_call[1]["range_header"] == "entries=0:18446744073709551615"
+    assert logs_call[1]["range_header"] == "entries=:0:18446744073709551615"
 
     journald_logs.reset_mock()