Default substitute URLs

Default substitute URLs

[Ludovic Courtès]

Hello!

If there are no objections, I’d like to change the default substitute
URLs to just “https://mirror.hydra.gnu.org”.

Currently it’s “https://mirror.hydra.gnu.org https://hydra.gnu.org” (see
config-daemon.ac), but the second URL is redundant and can only cause
slowness (if a substitute is missing on the mirror, the other machine is
queried but it likely lacks it as well.)

Since guix-maintenance commit 539f7351d749e25c73e90877ea159d495ed4d4b0,
mirror.hydra.gnu.org caches build logs as well, which removes the main
reason for keeping hydra.gnu.org among the substitute URLs.

Thoughts?

Ludo’.

Re: Default substitute URLs

[Andreas Enge]

On Tue, Jul 12, 2016 at 10:52:49AM +0200, Ludovic Courtès wrote:
> If there are no objections, I’d like to change the default substitute
> URLs to just “https://mirror.hydra.gnu.org”.

How about adding/replacing by https://mirror.guixsd.org? It would be good
to (also) have a mirror URL under our control, so we could act quickly in
case of a problem independently of the FSF sysadmins.

Andreas

Re: Default substitute URLs

[Ludovic Courtès]

Andreas Enge <andreas@enge.fr> skribis:

> On Tue, Jul 12, 2016 at 10:52:49AM +0200, Ludovic Courtès wrote:
>> If there are no objections, I’d like to change the default substitute
>> URLs to just “https://mirror.hydra.gnu.org”.
>
> How about adding/replacing by https://mirror.guixsd.org? It would be good
> to (also) have a mirror URL under our control, so we could act quickly in
> case of a problem independently of the FSF sysadmins.

I prefer to keep the mirror.hydra.gnu.org name, I think it’s clearer.

Ludo’.

Re: Default substitute URLs

[Andreas Enge]

On Wed, Jul 13, 2016 at 02:46:55PM +0200, Ludovic Courtès wrote:
> I prefer to keep the mirror.hydra.gnu.org name, I think it’s clearer.

Could there not be two, both of which would be checked, so if a package is not
found on the first one, it is searched on the second one? This would make things
more resilient.

Andreas

Re: Default substitute URLs

[Efraim Flashner]

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On Thu, Jul 14, 2016 at 05:48:54PM +0200, Andreas Enge wrote:
> On Wed, Jul 13, 2016 at 02:46:55PM +0200, Ludovic Courtès wrote:
> > I prefer to keep the mirror.hydra.gnu.org name, I think it’s clearer.
> 
> Could there not be two, both of which would be checked, so if a package is not
> found on the first one, it is searched on the second one? This would make things
> more resilient.
> 
> Andreas
> 

I don't believe it's currently possible to list more than one substitute
url with --substitute-urls=

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Re: Default substitute URLs

[Ludovic Courtès]

Andreas Enge <andreas@enge.fr> skribis:

> On Wed, Jul 13, 2016 at 02:46:55PM +0200, Ludovic Courtès wrote:
>> I prefer to keep the mirror.hydra.gnu.org name, I think it’s clearer.
>
> Could there not be two, both of which would be checked, so if a package is not
> found on the first one, it is searched on the second one? This would make things
> more resilient.

Yes, that’s why we currently have mirror.* followed by hydra.*.

But given that the former is a mirror of the latter, which clients do
not know, it’s a bit silly: when mirror.* lacks an item, clients try
hydra.* but are very unlikely to get a positive answer there.  However,
they pay an extra network query.

Having several URLs pointing to the same server would be similarly
inefficient.

Hope this clarifies things.

Ludo’.

Re: Default substitute URLs

[Ludovic Courtès]

Efraim Flashner <efraim@flashner.co.il> skribis:

> I don't believe it's currently possible to list more than one substitute
> url with --substitute-urls=

Of course it’s possible, hence the plural.  :-)  (It’s even the default,
which is the whole point of this discussion.  ;-))

Ludo’.

Re: Default substitute URLs

[Andreas Enge]

On Fri, Jul 15, 2016 at 04:10:40PM +0200, Ludovic Courtès wrote:
> Having several URLs pointing to the same server would be similarly
> inefficient.

Indeed. So we could modify this again if we ever have distinct mirror
machines, not just distinct names.

Andreas