We are given a log file that contains a sequence of events related to an update process on a device. The log is from the perspective of an automated test system (autotest) that is monitoring the update process. The key events in the log: 1. The test system is trying to establish an SSH connection to the device at 192.168.231.225. Initially, the connection is down, so it tries to start a new connection. 2. At 04:38:48, there's a timeout error waiting for the main SSH connection to come up. 3. Then, at 04:39:06, we see that the device has switched slots (likely due to an update) and the test breaks out of a waiting loop. 4. The test then checks the status of the update engine by running `update_engine_client --status` via SSH. The output shows that the update is in the DOWNLOADING state with progress at about 13%. 5. The test then retrieves the update_engine log and we see the log entries from the device's update_engine daemon. The update_engine log shows: - The update_engine starts at 04:39:01. - It identifies that the device is booted from slot A (slot 0). - It's an unofficial build, so periodic update checks are blocked. - It begins an update for a DLC (Downloadable Content) called "timeofday-dlc". The download URL is provided, and the download completes successfully (HTTP 200) at 04:39:05, with 23064576 bytes downloaded. - After verifying the hash, the DLC is mirrored and set to Active. - Then, the update_engine starts another update for a different DLC: "ml-dlc-a97333ed-3157-49a3-b503-2d2d3f23c81d". The log shows the installation starting for this DLC. However, the test then fails because it cannot find the update_engine logs to verify the update. The last lines in the log are: ``` 06/05 04:39:09.952 DEBUG| test:0439| Test failed due to update_engine logs are missing. Cannot verify update.. Exception log follows the after_iteration_hooks. ``` This indicates that the test expected to find update_engine logs for the entire update process, but at the time it checked (04:39:09), the log for the second DLC update was not available (or the test looked in the wrong place). But note: the test did retrieve the update_engine log at 04:39:09.856 (the file `update_engine.20250604-213901`). However, that log only covers the first DLC (timeofday-dlc) and the beginning of the second DLC (ml-dlc). The second DLC update was still in progress when the test checked. The test then, at 04:39:09.920, runs `ls -t -1 /var/log/update_engine/` and gets only one log file: `update_engine.20250604-213901`. This is the same log that was previously retrieved. The test then fails because it expects to see logs for the entire update (which might include multiple log files or a more recent one) but only one is present. It's possible that the update_engine daemon rotates logs and the test expects a new log for the second update? However, the log we see spans from 04:39:01 to 04:39:07 (and beyond, but the test only retrieved up to 04:39:09.913 in the log). The test failure message says "update_engine logs are missing", meaning it couldn't find the logs it expected. Alternatively, the test might be looking for a log entry that confirms the entire update (including the second DLC) completed, but the log we have only shows the start of the second DLC update. Given the information, the problem appears to be that the test is failing because it cannot find the expected update_engine logs to verify the update. This could be because: - The test is not waiting long enough for the update to complete and the logs to be written. - The update_engine log rotation might have occurred and the test is not accounting for the latest log file. - The test expects a specific log entry that is not present in the retrieved log. However, from the provided log, we can see that the update_engine was in the middle of updating the second DLC when the test checked. The test then immediately tried to get the logs again and found only one log file, which it had already retrieved. The test code seems to be in a state where it breaks out of the waiting loop because it detected a slot switch (which happened for the first DLC) but then it tries to verify the entire update (which includes multiple DLCs) and fails because the second DLC update was still ongoing and the logs were not complete. In summary, the issue is that the test did not wait for the entire update (all DLCs) to complete before attempting to verify the logs. It only waited for the first DLC to complete and the slot switch, but then proceeded to check the logs while the second DLC update was still in progress. Recommendation: The test should wait until the update_engine status indicates that the update is fully completed (e.g., IDLE) and then verify the logs. 翻译成中文