Difference between revisions of "Neon/Snap"

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__TOC__
 
__TOC__
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== Reading Material ==
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* Snap & Snapcraft Documentation: https://docs.snapcraft.io
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* Snap Guide: [[Guidelines_and_HOWTOs/Snap]]
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* Content Snap: [[Neon/Snap/KF5Content]]
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* Current notes on state of Snaps https://notes.kde.org/p/neon-snaps
  
 
== Usage ==
 
== Usage ==
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and install suitable packages for the current content-snap SDK. By and large this is optional though.
 
and install suitable packages for the current content-snap SDK. By and large this is optional though.
  
To build run
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To build you need a working snapd (for containerized use LXD is recommended because it has native systemd support).  You'll also want latest snapcraft:  <code>snap install --classic snapcraft</code>
{{Input|1=<nowiki>
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SNAPCRAFT_PARTS_URI=https://metadata.neon.kde.org/snap/parts.yaml snapcraft</nowiki>}}
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Building is done by running {{Input|1=<nowiki>snap run snapcraft --destructive-mode</nowiki>}}
  
The environment variable sets a different remote parts URI to load the -dev and -env parts from. Long term these should be
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It's destructive because it needs to change your system. By default snapcraft since 2019 would try to throw builds in  a VM, since snaps mostly need neon's repos to build that isn't useful for us in its current form.
added to the upstream default parts.yaml though.
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== Snapd Problems ==
 
== Snapd Problems ==
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(upstream issues ought to be filed/subscribed to and mentioned here)
 
(upstream issues ought to be filed/subscribed to and mentioned here)
  
# <strike>Content snap not getting installed if snap depending on it gets installed
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# Theming [is kind of addressed by XDG Settings portal]
## https://bugs.launchpad.net/snapcraft/+bug/1711329
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## https://github.com/snapcore/snapd/compare/master...mvo5:default-plugin-provider?expand=1</strike>
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# <strike>Installing a content snap into the core ISO requires snapd which requires systemd which cannot (?) run in a docker/lxc/chroot</strike> snap download can be used to "preseed" snaps
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# Theming
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## How to get theme settings from the host into the snap?
 
## How to get theme settings from the host into the snap?
 
## QtStyles are binary plugins and so even when we know which style is configured on the host we cannot just load it
 
## QtStyles are binary plugins and so even when we know which style is configured on the host we cannot just load it
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### gdb/valgrind/strace need to be in the snap to be reachable
 
### gdb/valgrind/strace need to be in the snap to be reachable
 
## Possibly needs a way to catch and send cores and then retrace them server-side with (externally) generated debug symbol dumps?
 
## Possibly needs a way to catch and send cores and then retrace them server-side with (externally) generated debug symbol dumps?
# <strike>xdg-desktop-portals (with patches) + snapd (with patches). Needs landing or something
 
## FIleIO
 
## Printing (cups-control gives printer management access which I think we do not need; it is also not auto-connected which makes it useless from a user pov)
 
## wip https://forum.snapcraft.io/t/xdg-desktop-portal-proof-of-concept-demo/1027</strike>
 
 
# Discover Software Center integration isn't at the level of PackageKit or Flatpak. Mostly boils down to some appstream support
 
# Discover Software Center integration isn't at the level of PackageKit or Flatpak. Mostly boils down to some appstream support
 
## we are lacking appstream ids, useful for de-duplication
 
## we are lacking appstream ids, useful for de-duplication
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## https://bugs.launchpad.net/snapcraft/+bug/1711333
 
## https://bugs.launchpad.net/snapcraft/+bug/1711333
 
## https://forum.snapcraft.io/t/use-a-separate-manifest-file-or-save-everything-in-snap-snapcraft-yaml/1152
 
## https://forum.snapcraft.io/t/use-a-separate-manifest-file-or-save-everything-in-snap-snapcraft-yaml/1152
# <strike>Dolphin and kfileopen are cluttered with loopback mounts from snapd  https://bugs.launchpad.net/ubuntu/+source/snapcraft/+bug/1714941</strike> Kai made a fairly general prupose fix for this in solid, which is technically the wrong level to fix this on but good enough for us
 
# <strike>Live images should be able to turn off Snap updates</strike> We've done this by aggressively disabling snapd components. Starting a snap will still cause the update, but that is nothing we can prevent outside snapd
 
## https://bugs.launchpad.net/ubuntu/+source/casper/+bug/1723094
 
  
 
== Snapcraft Problems ==
 
== Snapcraft Problems ==
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## Talking with snapcraft developers, they suggested using "install: ctest ." much like in here: https://snapcraft.io/docs/build-snaps/node
 
## Talking with snapcraft developers, they suggested using "install: ctest ." much like in here: https://snapcraft.io/docs/build-snaps/node
 
## Implemented here: https://cgit.kde.org/scratch/apol/kf5-snap-env.git/plain/README.md
 
## Implemented here: https://cgit.kde.org/scratch/apol/kf5-snap-env.git/plain/README.md
# <strike>Content snap has "external" dev tarball which we utilize to build snaps off of the content snap, problem is that snapcraft does not like files diverging, so whenever a snap stages-packages something that is in the dev tarball (e.g. as part of a runtime dep) but binary different (e.g. newer build) the snapcraft will fail. On auto generated snaps this was worked around by maintaining an exclusion list of packages to not install, this may be auto-injectable into manual builds BUT won't be doable for non-infrastructure builds (i.e. a dev running snapcraft on their system).</strike>
 
 
# Content snap has problems
 
# Content snap has problems
 
## Make sure that on cleanbuilds we get the deps from the Neon repo instead of ubuntu (for the things Neon implements)
 
## Make sure that on cleanbuilds we get the deps from the Neon repo instead of ubuntu (for the things Neon implements)
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### https://github.com/snapcore/snapcraft/issues/1694
 
### https://github.com/snapcore/snapcraft/issues/1694
 
## Should be extracting the icon and desktop file from the package. Now it's copied in the packaging.
 
## Should be extracting the icon and desktop file from the package. Now it's copied in the packaging.
# Icons do not appear to get installed into hicolor nor hardcoded absolute paths in the desktop files, making icon availability entirely theme-dependent.
 
 
# GPG verification of incoming content is not supported. This breaks the signing chain from tag -> tarball -> pkg -> user. Only applies to tarballs. [Supposedly the tarball is somewhere in the build tree, so we could build custom rigging to download the gpg after snapcraft ran and verify the tarball snapcraft got is the signed one and abort if not]
 
# GPG verification of incoming content is not supported. This breaks the signing chain from tag -> tarball -> pkg -> user. Only applies to tarballs. [Supposedly the tarball is somewhere in the build tree, so we could build custom rigging to download the gpg after snapcraft ran and verify the tarball snapcraft got is the signed one and abort if not]
  
== Troubleshooting ==
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== Other Problems ==
# on <2.26.0 We need to umount the snap if it was already installed: sudo umount /run/snapd/ns/dolphin.mnt
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# kdoctools requires docbook-* packages in /usr always https://bugs.kde.org/show_bug.cgi?id=406177

Latest revision as of 15:03, 10 April 2019

Reading Material

Usage

To use them

https://apachelog.wordpress.com/2017/01/30/kde-applications-in-ubuntu-snap-store/

sudo snap install kblocks

No sudo

To drop the requirement to have to sudo everything you need to login using ubuntu login credentials first.

sudo snap login

After that you should have a ~/.snap/auth.json file and snap should work without sudo.

Building

The snapcraft.yamls we have in our packaging repositories are generally meant to be built via our tooling and the respective Jenkins jobs. Generally they can however also be built manually as the tooling only extends them a bit to build from git and install suitable packages for the current content-snap SDK. By and large this is optional though.

To build you need a working snapd (for containerized use LXD is recommended because it has native systemd support). You'll also want latest snapcraft: snap install --classic snapcraft

Building is done by running
snap run snapcraft --destructive-mode

It's destructive because it needs to change your system. By default snapcraft since 2019 would try to throw builds in a VM, since snaps mostly need neon's repos to build that isn't useful for us in its current form.

Snapd Problems

(upstream issues ought to be filed/subscribed to and mentioned here)

  1. Theming [is kind of addressed by XDG Settings portal]
    1. How to get theme settings from the host into the snap?
    2. QtStyles are binary plugins and so even when we know which style is configured on the host we cannot just load it
    3. Icon themes in /usr/share and ~/.local cannot be accessed from inside snaps
    4. Same for mouse cursor themes
    5. Same for fonts
    6. upstream is aware and working on it
    7. https://bugs.launchpad.net/ubuntu/+source/snapd/+bug/1585332
  2. Hard to debug applications
    1. We have huge wrapper scripts that are required for applications to run properly
      1. https://cgit.kde.org/scratch/apol/kf5-snap-env.git/tree/
      2. https://forum.snapcraft.io/t/custom-environment-variables-for-parts/1639/10
    2. It's hard to reach out to debugging tools
      1. should be easy-ish to use gdb-server
      2. gdb/valgrind/strace need to be in the snap to be reachable
    3. Possibly needs a way to catch and send cores and then retrace them server-side with (externally) generated debug symbol dumps?
  3. Discover Software Center integration isn't at the level of PackageKit or Flatpak. Mostly boils down to some appstream support
    1. we are lacking appstream ids, useful for de-duplication
    2. cannot use snaps for the featured applications list (apps are listed as appstream ids)
    3. AppStream ID as id for reviews https://forum.snapcraft.io/t/best-way-to-key-a-snap-for-reviewing/854/2
    4. https://forum.snapcraft.io/t/support-for-appstream-id/2327
  4. No source code storage/retrieval for snaps
    1. https://bugs.launchpad.net/snapcraft/+bug/1711333
    2. https://forum.snapcraft.io/t/use-a-separate-manifest-file-or-save-everything-in-snap-snapcraft-yaml/1152

Snapcraft Problems

  1. No real way to run unit tests through snapcraft
    1. Talking with snapcraft developers, they suggested using "install: ctest ." much like in here: https://snapcraft.io/docs/build-snaps/node
    2. Implemented here: https://cgit.kde.org/scratch/apol/kf5-snap-env.git/plain/README.md
  2. Content snap has problems
    1. Make sure that on cleanbuilds we get the deps from the Neon repo instead of ubuntu (for the things Neon implements)
    2. Related https://bugs.kde.org/show_bug.cgi?id=385062
    3. https://bugs.launchpad.net/snapcraft/+bug/1719928
  3. Lack of Appstream support
    1. Substantial metadata duplication. snap metadata excessively duplicates appstream metadata such as license, summary, version, icon. Makes it undesirable to maintain the data in snapcraft.yaml so it will simply go out of date at some point.
      1. https://forum.snapcraft.io/t/extracting-existing-data-from-projects-to-feed-into-snap-yaml/2285
      2. https://github.com/snapcore/snapcraft/issues/1694
    2. Should be extracting the icon and desktop file from the package. Now it's copied in the packaging.
  4. GPG verification of incoming content is not supported. This breaks the signing chain from tag -> tarball -> pkg -> user. Only applies to tarballs. [Supposedly the tarball is somewhere in the build tree, so we could build custom rigging to download the gpg after snapcraft ran and verify the tarball snapcraft got is the signed one and abort if not]

Other Problems

  1. kdoctools requires docbook-* packages in /usr always https://bugs.kde.org/show_bug.cgi?id=406177

This page was last modified on 10 April 2019, at 15:03. Content is available under Creative Commons License SA 4.0 unless otherwise noted.