Allow using the kiosk on platforms without DBus

[knuton]

We previously added support for using the kiosk without connman installed, but it still crashed when started on systems without DBus (i.e. any non-Linux platform).

With this change we add a stub implementation of the core proxy abstraction, which is going to provide safe no-op responses on non-Linux platforms, allowing to use the kiosk, albeit without proxy support.

Checklist

• Changelog updated
• Code documented
• User manual updated

[knuton]

@krksgbr Are you able to run the kiosk on macOS with these changes?

[knuton]

I tried to add a simple smoke test to verify that the kiosk can run on macOS, but there seems to be another error after the proxy/DBus issue is resolved.

I am not sure whether this is due to something in the GitHub runner env, or an additional problem with running on macOS.

This PR is blocked until a macOS user looks at it on their machine.

[krksgbr]

Strangely, I can't build the nix-shell of the kiosk on macOS. I'm not sure what's different in my environment from GitHub's runner's, but it's already surprising that it matters.

I tried different versions of nixpkgs: 24.05-pre, the 23.11-darwin branch, but they also didn't work.

What's also strange is that attempting to build the shell produced two different errors for the same derivation on two different attempts.

First run:

> Running phase: pythonImportsCheckPhase
> Executing pythonImportsCheckPhase
> Check whether the following modules can be imported: PyQt6.QtWebEngineCore PyQt6.QtWebEngineQuick PyQt6.QtWebEngineWidgets
> /nix/store/4gj9qic1i6dd004f2zgqlmjjxd0qsclc-python-imports-check-hook.sh/nix-support/setup-hook: line 10:  4118 Killed: 9               /nix/store/2inzdrr9fql5512ykfzp32zgr4ss7bma-python3-3.11.8/bin/python3.11 -c 'import os; import importlib; list(map(lambda mod: importlib.import_module(mod), os.environ["pythonImportsCheck"].split()))'
For full logs, run 'nix log /nix/store/lghg9h6h7h42nn30bd3xb3kciab09zr0-python3.11-PyQt6_WebEngine-6.6.0.drv'.

Second run:

ERROR Backend subprocess exited when trying to invoke build_wheel
error: builder for '/nix/store/lghg9h6h7h42nn30bd3xb3kciab09zr0-python3.11-PyQt6_WebEngine-6.6.0.drv' failed with exit code 1;
       last 10 log lines:
       > rm -f QtWebEngineCore
       > clang++ -stdlib=libc++ -undefined dynamic_lookup -bundle -o QtWebEngineCore sipQtWebEngineCorecmodule.o sipQtWebEngineCoreQMap0100QByteArray0100QByteArray.o sipQtWebEngineCoreQHash0100QByteArray0100QByteArray.o sipQtWebEngineCoreQList0100QWebEngineScript.o sipQtWebEngineCoreQMultiMap0100QByteArray0100QByteArray.o sipQtWebEngineCoreQMap0100QString0100QString.o sipQtWebEngineCoreQList0100QWebEngineHistoryItem.o sipQtWebEngineCoreQFlags0100QWebEngineUrlSchemeFlag.o sipQtWebEngineCoreQFlags0100QWebEnginePageFindFlag.o sipQtWebEngineCoreQFlags0100QWebEngineFileSystemAccessRequestAccessFlag.o sipQtWebEngineCoreQFlags0100QWebEngineContextMenuRequestMediaFlag.o sipQtWebEngineCoreQFlags0100QWebEngineContextMenuRequestEditFlag.o sipQtWebEngineCoreQWebEngineUrlSchemeHandler.o sipQtWebEngineCoreQWebEngineUrlScheme.o sipQtWebEngineCoreQWebEngineUrlRequestJob.o sipQtWebEngineCoreQWebEngineUrlRequestInterceptor.o sipQtWebEngineCoreQWebEngineUrlRequestInfo.o sipQtWebEngineCoreQWebEngineSettings.o sipQtWebEngineCoreQWebEngineScriptCollection.o sipQtWebEngineCoreQWebEngineScript.o sipQtWebEngineCoreQWebEngineRegisterProtocolHandlerRequest.o sipQtWebEngineCoreQWebEngineQuotaRequest.o sipQtWebEngineCoreQWebEngineProfile.o sipQtWebEngineCoreQWebEnginePage.o sipQtWebEngineCoreQWebEngineNotification.o sipQtWebEngineCoreQWebEngineNewWindowRequest.o sipQtWebEngineCoreQWebEngineNavigationRequest.o sipQtWebEngineCoreQWebEngineLoadingInfo.o sipQtWebEngineCoreQWebEngineHttpRequest.o sipQtWebEngineCoreQWebEngineHistory.o sipQtWebEngineCoreQWebEngineHistoryModel.o sipQtWebEngineCoreQWebEngineHistoryItem.o sipQtWebEngineCoreQWebEngineGlobalSettingsDnsMode.o sipQtWebEngineCoreQWebEngineGlobalSettings.o sipQtWebEngineCoreQWebEngineFullScreenRequest.o sipQtWebEngineCoreQWebEngineFindTextResult.o sipQtWebEngineCoreQWebEngineFileSystemAccessRequest.o sipQtWebEngineCoreQWebEngineDownloadRequest.o sipQtWebEngineCoreQWebEngineCookieStoreFilterRequest.o sipQtWebEngineCoreQWebEngineCookieStore.o sipQtWebEngineCoreQWebEngineContextMenuRequest.o sipQtWebEngineCoreQWebEngineClientCertificateStore.o sipQtWebEngineCoreQWebEngineClientCertificateSelection.o sipQtWebEngineCoreQWebEngineCertificateError.o  -F/nix/store/0dc1zcczqabfhxvk6drdm27ynrzq83bf-qtwebengine-6.6.1/lib -F/nix/store/hfds24mlnlvrpjqg3sqmp9r9fdk2zwzb-qtdeclarative-6.6.1/lib -F/nix/store/vc0w6gjdvhhvdny563bd86vazcgny96d-qtbase-6.6.1/lib -F/nix/store/zkhizkq76s7zlf39a4wji93mdkgx1mih-qtwebchannel-6.6.1/lib -F/nix/store/achvrh9q66lkwi22lmn8f661f3z4lkws-qtpositioning-6.6.1/lib -framework QtWebEngineCore /nix/store/hfds24mlnlvrpjqg3sqmp9r9fdk2zwzb-qtdeclarative-6.6.1/lib/QtQuick.framework/Versions/A/QtQuick /nix/store/hfds24mlnlvrpjqg3sqmp9r9fdk2zwzb-qtdeclarative-6.6.1/lib/QtQmlModels.framework/Versions/A/QtQmlModels /nix/store/zkhizkq76s7zlf39a4wji93mdkgx1mih-qtwebchannel-6.6.1/lib/QtWebChannel.framework/Versions/A/QtWebChannel /nix/store/hfds24mlnlvrpjqg3sqmp9r9fdk2zwzb-qtdeclarative-6.6.1/lib/QtQml.framework/Versions/A/QtQml /nix/store/achvrh9q66lkwi22lmn8f661f3z4lkws-qtpositioning-6.6.1/lib/QtPositioning.framework/Versions/A/QtPositioning -framework QtQuick -framework QtOpenGL -framework QtGui -framework AppKit -framework ImageIO -framework Metal -framework QtQmlModels -framework QtWebChannel -framework QtQml -framework QtNetwork -framework QtPositioning -framework QtCore -framework IOKit -framework DiskArbitration -framework AGL -framework OpenGL
       > /nix/store/c4nif4ydhhsdnjal038wkmi4x3mz88ff-clang-wrapper-16.0.6/bin/ld: line 269:  7182 Killed: 9               /nix/store/8kkn9qqg1mnny41cc8i33ws9ilmxyww1-cctools-binutils-darwin-16.0.6-973.0.1/bin/ld @<(printf "%q\n" ${extraBefore+"${extraBefore[@]}"} ${params+"${params[@]}"} ${extraAfter+"${extraAfter[@]}"})
       > clang-16: error: linker command failed with exit code 137 (use -v to see invocation)
       > make[1]: *** [Makefile:367: QtWebEngineCore.plugin/Contents/MacOS/QtWebEngineCore] Error 1
       > make[1]: Leaving directory '/private/tmp/nix-build-python3.11-PyQt6_WebEngine-6.6.0.drv-0/tmpr8tnaost/QtWebEngineCore'
       > make: *** [Makefile:52: sub-QtWebEngineCore-make_first-ordered] Error 2
       > _in_process.py: 'make' failed returning 2
       >
       > ERROR Backend subprocess exited when trying to invoke build_wheel
       For full logs, run 'nix log /nix/store/lghg9h6h7h42nn30bd3xb3kciab09zr0-python3.11-PyQt6_WebEngine-6.6.0.drv'.

I'll continue investigating.

[krksgbr]

The same issue is reported here:
NixOS/nixpkgs#275464

According to one of the comments it's an aarch64-darwin specific problem.
Unfortunately there's not enough information to get further with this and currently it doesn't seem pressing for us to dig deeper.

[krksgbr]

clang-16: error: linker command failed with exit code 137 (use -v to see invocation)
This seems to be an out of memory error. I'm building on a machine with 32GB of RAM so that's interesting.

[knuton]

I rebased after #164 being merged, maybe this helps somehow.

[krksgbr]

I rebased after #164 being merged, maybe this helps somehow.

Unfortunately this didn't help as it's the webengine bindings that fail to build.

[krksgbr]

@knuton I've amended your work here and created a separate shell for running the kiosk on macOS:

knuton/playos@multi-platform-kiosk...krksgbr:playos:kiosk-on-macos

This gets the job done until the upstream issues are fixed. How should we proceed? Should I push my changes to this PR or should I open a new one?

[knuton]

Cool 👌

As your approach goes well beyond the goal of this PR, which only aimed to address the proxy issue, I think a new PR would make sense.