I believe we (the IT lot) made way too many incompatible ways to package software, and there is a whole industry built around its packaging and repackaging.
What should have been a mundane task, dealt with once and for good is a steaming mess of competing projects with increasingly byzantine architectures.
The goal of Squash App is to show that:
- We already had all of the required tools to neatly package software before containers, snap, flatpak, etc. were a thing.
- One app - one (fast to mount/decompress & run) file and a signature for it. All you need is 1 or 2 files.
- Simple file formats existing in the wild for over a decade is a win for end user (squashfs image format, gpg signature).
- One compressed file - a multitude of platforms (OS and virtual or real hardware architectures) to run on. A single squashfs can easily represent "fat binary" by using a portable loader shell script as /bin/init.
The ingredients:
- squashfs - a compressed filesystem
- gpg - a tool to easily encrypt and sign/verify files
- squash - a simple portable
/bin/shscript to run, verify, sign and (re)pack squashfs images of apps, depends on the former 2 tools - any web server or network fileshare to serve the signed squashfs files to the end user
- any of your usual file system and command-line tools
./squash pack examples/hello
... # (shows packing progress or asks for squashfs-tools to be installed)
./squash run examples/hello.squash.app
... # caches the image in $HOME/.squash-apps and unpacks to run the app, ultimately displaying "Hello, world"
# as a short-cut run command may be omited
./squash examples/hello.squash.app
... # since it's 2nd time should display "Running from cache (last modified <date-time>)" to stderr and runs the same Hello, world sample
A brief TODO list
- more examples and how-tos for established languages and build tools
- outline how to build multi-platform and multi-arch images
- squash should provide simple sign/verify/keygen helper "commands" forwarding to gpg, of course
- squash script should easily be able to export/import squashfs app image from/to
.tarcompatible with OCI and runnable as container with runc and friends - run in a unikernel-style by tacking on a suitable bootloader+kernel combo
- run as true unikernel on KVM/Xen/etc., by utilizing some of ideas of unikraft and related projects
- try to find even more simple and efficient ways to run it removing excessive moving parts or supporting more targets with single image file