Re: bug#26608: channels.scm supporting substitutes

[zimoun]

Hi,

On Wed, 4 Dec 2019 at 22:50, Nome Grey <address@hidden> wrote:

> I also noticed often the substitute is not chosen when the server is having 
> congestion issues.

I do not understand what this means.


The tool to know if the build farm has already built the package is
"guix weather". If it is not built yet, then you have only two
choices: 1. build it yourself or 2. wait. There are discussions to
share more in distributed fashion via IPFS -- which will partially
diminish the time to wait between when the package is included to the
tree and when the binary is available -- and a patch already exists in
the Bug Tracker; but it lacks tests and feedback. Note also that not
enough of us use "guix publish". ;-)


> $ guix install ungoogled-chromium --dry-run
> The following package would be upgraded:
>    ungoogled-chromium 74.0.3729.131-0.9e33022 → 78.0.3904.108-0.8f06513 
> /gnu/store/wcjr5n9ljvbw6ak3705pqs7y6n3fk934-ungoogled-chromium-78.0.3904.108-0.8f06513
>
> The following derivation would be built:
>    /gnu/store/akzyrbp4pirvxjss0s41fv3ggpy70a8q-profile.drv
> 82.1 MB would be downloaded:
>    /gnu/store/9aiizpqhpiixds5x52w67q7p3wxsz1db-libcdio-paranoia-10.2+2.0.0
>    /gnu/store/ghj6k72hpvilkv53hx2frz5a5qazvrk2-libcdio-2.1.0
>    /gnu/store/mpsjsddxbzjncvrxqll59lmwad6yygl0-ffmpeg-4.2.1
>    
> /gnu/store/wcjr5n9ljvbw6ak3705pqs7y6n3fk934-ungoogled-chromium-78.0.3904.108-0.8f06513
> The following profile hooks would be built:
>    /gnu/store/71fl8l2n2l01yjd2ajqz1qs7a5f0g8ar-gtk-im-modules.drv
>    /gnu/store/7nrwf66l0r9vdzcxyl56xzkrm3dj5bhl-gtk-icon-themes.drv
>    /gnu/store/f3xpxb5a79xvxxaav7zvmg1lmsslxz8f-xdg-mime-database.drv
>    /gnu/store/g1acs7i62984xkwkwshyirinqzvf20xl-glib-schemas.drv
>    /gnu/store/k0xp9xvc8njzqzwy7ndj7w5p8kk4ljcv-ca-certificate-bundle.drv
>    /gnu/store/n4zwqdspgy8dnfmz7y0sv425mc81mm87-fonts-dir.drv
>    /gnu/store/qmb0w52ys35l7hdrbkx3vwbsd2b31nj3-manual-database.drv
>    /gnu/store/syspl3xawhbpynvjn6a5n34fyap7awap-xdg-desktop-database.drv
>    /gnu/store/vpy3llakmf6kfb2gf93309m8wdrkhjvc-info-dir.drv


So this will download what you want. :-)
Everything is available, AFAICT.
No issue, no workaround.


> Yeah, they both resolve to 141.80.181.40 over here.  I think berlin is maybe 
> left over from when hydra was in use, not sure.  I was kind of assuming they 
> were the same and may have confused things not clarifying that.

AFAIU, it is a bit more complicated. It is the same build farm but
then some network configuration is different (CDN available or not,
etc.). In short: use ci.guix.gnu.org.


>> > By only upgrading to releases with substitutes available, fewer builds are 
>> > required on the local system, which can still be occasionally brought up 
>> > to date.  The user channel filters the official channel, to hide releases 
>> > without substitutes built yet.
>>
>> I am not sure it works as you think.
>
> That is how the specialized channels.scm they were discussing in the bugs is 
> supposed to work.  Following ludo's lead was how I managed to find this way 
> to use the substitute for ungoogled-chromium.

I am not sure to understand. Maybe you should read (again?) the manual
about channels and derivations. It is one better source of information
than any bug report where hypothetical had been discussed. The manual
explains for sure how Guix works; bug reports not always, they are not
a reliable source of information, IMHO.


> But yeah I'm not really sure where the package index is stored to directly 
> connect it to guix pull's behavior and such.  It's guesswork for me for sure.

AFAIU, the package index lives under ~/.config/guix/current. But it is
not important, IMO.


>> I am checking why Guix claims the substitute is not available for i686
>> when it really is.
>
> If it's not because the ci server was overloaded, maybe it is that one of the 
> inputs to the package has been updated, such that a new derivation than the 
> one built is used now?

No. I do not know if it comes from "-s i686-linux" because I running
on a x86 system, or other.
The point is: the derivation that my system computes is different of
the derivation that I expect.

--8<---------------cut here---------------start------------->8---
guix build ungoogled-chromium -s i686-linux -n -d
/gnu/store/45cfay69pp6prky2kw0r21nv5lp3xgs9-ungoogled-chromium-78.0.3904.108-0.8f06513.drv
--8<---------------cut here---------------start------------->8---

instead of 
/gnu/store/wcjr5n9ljvbw6ak3705pqs7y6n3fk934-ungoogled-chromium-78.0.3904.108-0.8f06513


All the best,
simon