Support extra envvars per snap (New)

[Hook25]

Description

Some libraries are not the default locations and, without ldconfig support, which we don't have in snaps, we don't have an easy way to point to them.
The old approach was to add them to the wrapper common, but this leads to:

• code duplication, all frontends have a copy of this file
• forced inheritance, Checkbox itself and all jobs of all providers see this variables and are influenced by them
• broken w/ the new interface. Now that custom frontends no longer have an independent agent, this mechanism to define these variables doesn't work anymore.

This introduces a new mechanism, in the form of a file in the root of the snap with a very simple sintax and comments support. This file is supposed to be created during snap creation and is in the form of:

# comments
VARIABLE_NAME+=value

Resolved issues

Fixes: CHECKBOX-2172

Documentation

Added a HowTo that expains how to use the new packaging feature

Tests

Tested on a rebuilt version of Checkbox24. Use this command to run the test

snap download --edge checkbox24
unsquashfs checkbox24*.snap
cd squashfs-root
snap try --devmode .
checkbox24.checkbox run fwts
# ^^^ this fails
# lets patch it

Add this file under squashfs-root

#fwts is in /lib/fwts instead of /lib
LD_LIBRARY_PATH+=/lib/fwts
# lapack and blas are pulled by opencv and install libraries in a directory
LD_LIBRARY_PATH+=/usr/lib/x86_64-linux-gnu/lapack
LD_LIBRARY_PATH+=/usr/lib/x86_64-linux-gnu/blas
GI_TYPELIB_PATH+=/usr/lib/girepository-1.0
GI_TYPELIB_PATH+=/usr/lib/x86_64-linux-gnu/girepository-1.0

Now patch the snap and run the test(assuming ../checkbox points to checkbox repo at this branch

cp -rT ../checkbox/checkbox-ng/checkbox_ng/ `find . -name "checkbox_ng"`; cp -rT ../checkbox/checkbox-ng/plainbox/ `find . -name "plainbox"`; checkbox24.checkbox run fwts

[codecov]

Codecov Report

❌ Patch coverage is 88.31169% with 9 lines in your changes missing coverage. Please review.
✅ Project coverage is 55.32%. Comparing base (bf63c5f) to head (24fe25e).
⚠️ Report is 4 commits behind head on main.

Files with missing lines	Patch %	Lines
checkbox-ng/plainbox/impl/execution.py	54.54%	5 Missing ⚠️
checkbox-ng/plainbox/impl/secure/providers/v1.py	90.90%	3 Missing and 1 partial ⚠️

❌ Your patch status has failed because the patch coverage (88.31%) is below the target coverage (90.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2325      +/-   ##
==========================================
+ Coverage   55.25%   55.32%   +0.06%     
==========================================
  Files         413      413              
  Lines       44457    44524      +67     
  Branches     8195     8213      +18     
==========================================
+ Hits        24566    24634      +68     
+ Misses      19031    19029       -2     
- Partials      860      861       +1     

Flag	Coverage Δ
checkbox-ng	71.82% <88.31%> (+0.12%)	⬆️
provider-base	32.17% <ø> (ø)

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[fernando79513]

Good job here. I just have a couple of questions/suggestions, but it looks good in general (appart from the path bug)

[fernando79513]

LGTM +1!
Good job, thanks!
👍