[bug] when select multi agents to execute download command will only download one file

[heheda123123]

1 select multi agents
2 right click - Agents - Execute command - input "download /etc/passwd"
3 in the Downloads tab will have multi rows , but they are the same file
4 in the ~/dist/data/download in server , there is only one file

[heheda123123]

This bug is not caused by the UI showing duplicate entries. The UI creates one download entry per fileId, so when the same command is sent to multiple agents, multiple rows are expected.

The real problem is in the server-side download storage logic. When a download starts, the local filename is generated from a hash of time.Now().Unix() plus the original basename. Since
time.Now().Unix() only has second-level precision, multiple agents downloading a file with the same name within the same second can end up with exactly the same local path.

In the reported reproduction path, the operator selects multiple agents and uses the right-click "Execute command" action. The client does not execute the command in true parallel, but it dispatches it
in a very tight loop, one agent after another. In practice, that is fast enough that multiple agents often start the download within the same second. When that happens, the server creates the same
destination filename more than once, and later os.Create(...) truncates or overwrites the previous file.

That is why the Downloads tab can show multiple download records, while the server's data/download directory contains only one final file. The database keeps separate rows because they are keyed by
FileId, but those rows may still point to the same LocalPath.

English Summary

Root cause: the server-side download filename is not unique enough.

The saved filename is derived from a second-resolution timestamp plus the original filename, so multiple agents downloading the same file in the same second can collide on the same local path.

Impact:

• multiple download records appear in the UI
• only one file may remain on disk
• active downloads may overwrite each other

Recommended fix:
use a truly unique value in the saved filename, such as fileId + "_" + baseName or agentId + "_" + fileId + "_" + baseName.