profile symlink structure

profile symlink structure

[vapnik spaknik]

Hi,
    please could someone help me understand how guix organizes profile symlinks?
I can't find a full explanation anywhere.
So far I have figured out the following on my foreign distro:

- original profile directories are named like: /gnu/store/<UID>-profile
- /var/guix/profiles/per-user/<USR>/ contains symlinks to the profiles in /gnu/store associated with user <USR>
- symlinks in /var/guix/profiles/per-user/<USR>/ seem to take one of the following forms:

  current-guix
  current-guix-<N>-link
  guix-profile
  guix-profile-<N>-link

the ones with a number <N> in their name refer to the <N>th generation of a profile with the same name apart from the <N>-link part. 
 - "guix-profile" is a symlink to the currently used generation for the profile used by "guix package" for the user
 - "current-guix" is a symlink to the currently used generation for the profile used by "guix pull" for the user
 - ~/.guix-profile is a symlink to the current profile used by "guix package", i.e. /var/guix/profiles/per-user/<USR>/guix-profile
 - ~/.config/guix/current is a symlink to the profile used by "guix pull" 

Now this is where I'm confused.. I was expecting ~/.config/guix/current to link to /var/guix/profiles/per-user/<USR>/current-guix where <USR> is the current user. However, in my case it links to /var/guix/profiles/per-user/root/current-guix, i.e. the profile for the root user, even though there are several "current-guix" symlinks for <USR>, i.e. links of the form /var/guix/profiles/per-user/<USR>/current-guix*.
Could this be due to running "sudo guix pull" or "sudo -i guix pull"?

Also, what determines which profile symlinks are placed in /var/guix/gcroots/auto? I read elsewhere that these symlinks will be automatically removed as soon as any of them are broken. 
In my case that directory only contains symlinks to /var/guix/profiles/per-user/*/current-guix* symlinks, one of which is missing (/var/guix/profiles/per-user/root/current-guix-1-link), and there is another link to ~/.config/guix/current-1-link which itself links directly to a profile in /gnu/store

I suspect that the previously mentioned anomalies are the reason why "guix pull" fails for me with the following error when run as <USR>:

> guix pull: error: symlink: File exists: "/var/guix/profiles/per-user/<USR>/current-guix-1-link" 

and which may have been caused by interrupting a "guix pull".

I guess I can probably fix that problem by deleting current-guix-1-link, but I would really like to know how the symlinking works exactly, so that I'm prepared for potential future problems of this kind. 

Thankyou,

Joe Bloggs

Re: profile symlink structure

[Pierre Neidhardt]

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vapnik spaknik <vapniks@yahoo.com> writes:

> Could this be due to running "sudo guix pull" or "sudo -i guix pull"?

Did you run `sudo guix pull`?  If so, you should probably not! :)

> Also, what determines which profile symlinks are placed in /var/guix/gcroots/auto? I read elsewhere that these symlinks will be automatically removed as soon as any of them are broken. 
See my other email.   `guix package --profile=...` is one of the
commands that creates auto GC roots.

> In my case that directory only contains symlinks to /var/guix/profiles/per-user/*/current-guix* symlinks, one of which is missing (/var/guix/profiles/per-user/root/current-guix-1-link), and there is another link to ~/.config/guix/current-1-link which itself links directly to a profile in /gnu/store
>
> I suspect that the previously mentioned anomalies are the reason why "guix pull" fails for me with the following error when run as <USR>:
>
>> guix pull: error: symlink: File exists: "/var/guix/profiles/per-user/<USR>/current-guix-1-link" 
>
> and which may have been caused by interrupting a "guix pull".

The symlinking operations should be atomic, thus this can not happen.
I suspect that your error is due to calling `sudo guix pull`.

Cheers!

-- 
Pierre Neidhardt
https://ambrevar.xyz/

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Re: profile symlink structure

[vapnik spaknik via]

 
> On Monday, May 25, 2020, 09:03:44 AM GMT+1, Pierre Neidhardt <mail@ambrevar.xyz> wrote:
> vapnik spaknik <vapniks@yahoo.com> writes:

>> In my case that directory only contains symlinks to /var/guix/profiles/per-user/*/current-guix* symlinks, one of which is missing (/var/guix/profiles/per-user/root/current-guix-1-link), and there is another link to ~/.config/guix/current-1-link which itself links directly to a profile in /gnu/store
>>
>> I suspect that the previously mentioned anomalies are the reason why "guix pull" fails for me with the following error when run as <USR>:
>>
>>> guix pull: error: symlink: File exists: "/var/guix/profiles/per-user/<USR>/current-guix-1-link"
>>
>> and which may have been caused by interrupting a "guix pull".
>
> The symlinking operations should be atomic, thus this can not happen.
> I suspect that your error is due to calling `sudo guix pull`.

OK, so I checked the manual again, and found out that I'm supposed to run `sudo -i guix pull`, not `sudo guix pull` or `guix pull`. I've was trying both of the latter two commands which would explain the unnecessary /var/guix/profiles/per-user/ben/current-guix* symlinks (due to `guix pull`) and /root/.config/guix/* symlinks (due to `sudo guix pull`). 
Running `sudo -i guix pull` it seems to work.

  

Re: profile symlink structure

[vapnik spaknik via]

 

> On Monday, May 25, 2020, 09:03:44 AM GMT+1, Pierre Neidhardt <mail@ambrevar.xyz> wrote:

> The symlinking operations should be atomic, thus this can not happen.
> I suspect that your error is due to calling `sudo guix pull`.

> Cheers!

Another question; what is the purpose of the *.lock files in the symlink directories exactly, and how are they used?
I guess it has something to do with atomic transactions, but the .lock files appear to be untouched after several updates as the modification times are unchanged. 

--
  

Re: profile symlink structure

[Pierre Neidhardt]

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vapnik spaknik <vapniks@yahoo.com> writes:

> OK, so I checked the manual again, and found out that I'm supposed to
> run `sudo -i guix pull`, not `sudo guix pull` or `guix pull`. I've was
> trying both of the latter two commands which would explain the
> unnecessary /var/guix/profiles/per-user/ben/current-guix* symlinks
> (due to `guix pull`) and /root/.config/guix/* symlinks (due to `sudo
> guix pull`).

Only on a foreign distribution.  On Guix System, `guix pull' (without
sudo) is enough.

-- 
Pierre Neidhardt
https://ambrevar.xyz/

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