[bug#30647] [PATCH] guix build: Support '--remote-log-file=PACKAGE'.

[Ludovic Courtès]

Hey Tobias,

Tobias Geerinckx-Rice <address@hidden> skribis:

> On 2018-02-28 23:13, address@hidden wrote:
>> What did you think of having ‘--log-file’ transparently fall back to
>> searching for log files on substitute servers?
>>
>> I find it handy, but also wondered if it might surprise users that such
>> a trivially-looking option connects to external servers.
>
> It would pleasantly surprise me :-)

Good.  :-)

> TBH, I don't see the difference between this & all other actions that
> already connect to external servers.
>
> Is this different? Will it ignore ’--no-substitutes’, or ping servers
> outside of user-approved substitute-urls? Does it need to?

It’s not really different, indeed.  (The only thing is that the list of
substitute URLs that is used by ‘--log-file’ can differ from that of
guix-daemon; but that’s a bug, really.)

>> I thought about having it print something when it does so.
>
> Like a progress bar? Seems more eye-catching than yet another
> warning. Or something more permanent in/next to the downloaded log?

‘--log-file’ just probes remote servers without actually downloading the
log, so a progress bar wouldn’t be useful.

I was thinking of a message like:

  info: looking for build log at https://…/log/…-foo

Ludo’.