Re: how to create and test a new service definition

[Ludovic Courtès]

Vincent Legoll <address@hidden> skribis:

>> The best way to test your code is to write an ‘operating-system’
>> declaration that uses the new service and to instantiate it in a VM with
>> ‘guix system vm’.
>
> Should that be working properly (out-of-the-box) when you're already in
> a qemu VM (recursive virtualization) ?
>
> I ask because I'm getting:
>
> [...]
> ERROR: qemu failed "qemu-system-x86_64"

What were the lines above this one?  This tool tries to use KVM if it
seems available.  Maybe in your case it “seems” to be available (as in
/dev/kvm exists) but is actually unusable?

>> Once you’ve done that, you can also write an automated test for the new
>> service; see <https://gnu.org/s/guix/news/guixsd-system-tests.html>.
>
> I'm far from there, I have a *really* hard time getting back to guixsd. For
> instance it took me very long time to find back the GUIX_PACKAGE_PATH
> env var. This looks under-documented, or I don't understand how one is to
> work on custom or new packages, etc...

‘GUIX_PACKAGE_PATH’ is documented at
<https://www.gnu.org/software/guix/manual/html_node/Package-Modules.html#index-GUIX_005fPACKAGE_005fPATH>.

The workflow for defining packages is described at
<https://www.gnu.org/software/guix/manual/html_node/Defining-Packages.html>,
and that for contributing them is at
<https://www.gnu.org/software/guix/manual/html_node/Submitting-Patches.html>.

There’s probably room for improvement though.  What changes/additions
would you suggest?

> guix edit is throwing me :
> E166: Can't open linked file for writing

This error does not come from ‘guix edit’, but maybe from your editor.
As for why the file is read-only, see
<https://www.gnu.org/software/guix/manual/html_node/Invoking-guix-edit.html>.

HTH,
Ludo’.