[pve-devel] [RFC PATCH storage] pvesm export: convert dd's \r in status=progress output to \n

[Fabian Grünbichler]

On January 16, 2025 9:13 am, Dominik Csapak wrote:
> On 1/15/25 12:28, Thomas Lamprecht wrote:
>> Am 15.01.25 um 10:59 schrieb Dominik Csapak:
>>> pvesm export is mostly used for (remote) migrations, where the
>>> status progress output lands in a task log. For task logs we want to
>>> have line based output (since it's not a terminal), but dd uses \r
>>> to overwrite the same line which does not work in every situation, e.g.
>>> browsers sometimes simply don't show them, making the dd output a long
>>> line instead of separate ones.
>>>
>>> To fix this, use run_command's `errfunc` to log the lines. run_command
>>> will split also on \r, but with warn we print a \n so this does the
>>> conversion.
>>>
>>> This fixes an issue where the remote migration task log on PDM does not
>>> display that part in new lines. (ExtJS works because it does things
>>> differently and some browser quirks convert \r to \n)
>>>
>>> Signed-off-by: Dominik Csapak <d.csapak at proxmox.com>
>>> ---
>>> Not sure if we want to take this approach because we lose the
>>> functionalty of overwriting progress on the terminal.
>> 
>> FWIW, you could test with `-t STDERR` if the std error FD is a terminal
>> and differ between replacing \r or not.
>> 
> 
> not sure if that would work here since we do quite some redirection for
> the worker task (to be able to display + putting it in the task log at
> the same time), but yes, I'll try that
> 
>>>
>>> AFAICS there is no easy way to only do this for the task log, since
>>> we simply pipe the output fh of the worker task to the task log fh.
>>>
>>> Alternatively we could patch the task log api to parse \r as newlines or
>>> patch the yew widget toolkit to replace \r with \n.
>> 
>> Wouldn't be one alternative also be to do that in the UI?
> 
> thats what i meant in that sentence. (replacing in yew widget toolkit)

one issue with that though would be that the line (in the task log/API
response) can get really long? not sure whether/where that might cause
problems..