snap: Make external dependencies actually work
Git:
- Set GIT_EXEC_PATH and include usr/lib/git-core so that git can find the
git-remote-https helper (needed by e.g. "go mod download").
Go:
- Put Go in its own snap part, and use stage-snaps instead of build-snaps
so that it is included in the final snap.
- Set GOCACHE to a writable directory. (In a previous commit,
HOME is set to $SNAP_REAL_HOME which is unwritable.)
Hugo:
- Patch config/security/securityConfig.go "[security.exec] osEnv" whitelist
(during snap build) so that external dependencies can use the required
environment variables to run properly from within the snap.
Asciidoctor:
- Replace shebang line in asciidoctor so it can find the ruby executable.
- Set RUBYLIB so that Ruby can find its libraries.
Caveat/TODO: The Ruby version is hardcoded in our custom RUBYLIB.
Embedded Dart Sass:
- Download from GitHub and install it, for amd64 and arm64 only.
Node.js:
- Remove my incomplete include list so that npx is actually installed.
- Set npm_config_{cache,init_module,userconfig} to writable locations.
Pandoc:
- Set pandoc_datadir so that Pandoc can find its data files.
rst2html:
- Install python3-docutils package for rst2html, rst2html5, etc.
- Set PYTHONHOME so that Python can find its libraries.
Note that asciidoctor, pandoc and rst2html are not in Hugo’s default
"[security.exec] allow" whitelist, and the snap package does not change
that default, so they still needed to be whitelisted manually in
config.toml if necessary by the end user.
Special thanks to Joe Mooring (@jmooring) for meticulously diagnosing
the issue and providing a comprehensive test repository at
https://github.com/jmooring/hugo-snap-test without which I would not
have been able to understand and resolve the issue.
Fixes #9078
