Support Alpine Linux (inadvertently to conform with libc for embedded systems)

[ghost]

musl (for Alpine), μClibc (for Alpine and Lilblue) and Newlib (for AmigaOS, Cygwin and PlayStation Portable) are standard C library implementations for embedded systems, which don't include Memory Management Unit (MMU).

If .NET team has plans to target microcontrollers/embedded-systems with coreclr, please provide support for those platforms.

Note that static lib libnix is also available for AmigaOS: http://cahirwpz.users.sourceforge.net/libnix/Description.html#Description (or https://github.com/cahirwpz/m68k-amigaos-toolchain)

Here is a list of major C standard libraries implementations: http://en.wikipedia.org/wiki/C_standard_library#Implementations

[ghuntley]

coreclr on embeded? This will be an interesting discussion to follow.

@jasonwilliams200OK are you aware of the .NET micro-framework - http://www.netmf.com/gadgeteer/ which is open source and available on GitHub @ http://netmf.github.io/

That well be an interesting discussion to follow.

Indeed. :)

/cc @smaillet-ms your thoughts?

[helloitszak]

I've been trying to get CoreCLR to build on Alpine and am stuck trying to compile libunwind. Seems that doesn't play nice with musl, specifically it doesn't have execinfo.h. Haven't looked much into any workarounds.

My goal is to eventually see if I can get ASP.NET vNext running on here, as Alpine is great for super lightweight Docker images (https://github.com/gliderlabs/docker-alpine)

[luisrudge]

Running on alpine would be awesome, since the docker image is very tiny!

Update: I have upstreamed all the local patches for Alpine Linux, one of the smallest Linux distro (~80 MBs ISO) that relies on musl-libc. It builds 99% of the CoreCLR without LLDB and event tracing (LIBLLTNG) support at the moment.

PRs: dotnet/coreclr#5726, dotnet/coreclr#5727, dotnet/coreclr#5728, dotnet/coreclr#5729, dotnet/coreclr#5730, dotnet/coreclr#5731.

This work is based on @benpye's original PR dotnet/coreclr#2262.

[smaillet-ms]

This is definitely interesting work. It is important to point out to those who may be following from the NETMF realms that this is NOT NETMF, but rather a port of CoreCLR to this platform. The discussion here is available due to common interests and a bit of high level overlap (embedded and .NET)

All the above mentioned PRs are merged.

Result is 💯 %

Repo successfully built.
Product binaries are available at /root/coreclr/bin/Product/Linux.x64.Debug
alp:~/coreclr#

As of this moment, CoreCLR (without lldbplugin) and CoreFX native both build on Alpine Linux. ⚡

Once lldb package is made available (i.e. very soon), I will rebuild CoreCLR and CoreFX native and post the test results with steps-by-step gist notes on how to build these from scratch installation here.

FYI: @barthalion, @benpye, @ellismg

Thanks to @barthalion for porting LLDB to Alpine Linux: https://pkgs.alpinelinux.org/packages?name=lldb. 🎉 ⭐

Now CoreCLR master builds on Alpine with lldbplugin (without missing anything).

Running the PAL suites revealed 12 failures: https://github.com/dotnet/coreclr/issues/5872.

Will run the managed test suite once PAL suite failures are sorted out.

[benpye]

👍 for getting this working!

With dotnet/coreclr#5872 closed, these are the final steps to build CoreCLR on Alpine Linux: https://gist.github.com/jasonwilliams200OK/7d6f5594d3bf697a27c9c1036d349fce and running the PAL tests. Note that CoreFX native also builds on Alpine. Now the verification (running full managed assemblies tests suite) and packaging parts are remaining.

While ISO is 87MB with still lots of auxiliary stuff bundled in, the minimal Alpine is just 5MB in size (aka slimmest Linux with smallest footprints) used by docker: https://hub.docker.com/_/alpine/:/ (see description) .. the next in line is TinyCore Linux, which is 11 MB in size, but depends on glibc (i was trying to build working clang38 on it but Alpine is already 2x slimmer than TC 😉 ) ..

For packaging, would be really nice to get someone from dotnet team to provide RID for Alpine Linux and APKBUILD script in dotnet/core-setup repo so we can build that project on Alpine... (we can help with APKBUILD script but please unblock us on core-setup)

Reference: https://wiki.alpinelinux.org/wiki/APKBUILD_Reference
Examples: https://github.com/alpinelinux/aports/search?q=filename:apkbuild

cc: @jkotas, @ericstj, can Alpine get special love for dotnet core v1.0-RTM? long shot, but hopefully not impossible! 😊

[jkotas]

@jasonwilliams200OK v1.0-RTM is out the door. It would be for the update that comes next.

@joshfree @Petermarcu How can we get started on adding Alpine Linux to the list of the officially supported distros?

@jkotas, yup but the distros packaging systems can still get v1.0 at any point. For example, lldb38 was released couple of months back but aports (Alpine packaging sys) got it 9 days ago. :)

[Petermarcu]

Is the key blocker right now the RID for Alpine?

[Petermarcu]

In other words, an entry here... https://github.com/dotnet/corefx/blob/master/pkg/Microsoft.NETCore.Platforms/runtime.json

@jasonwilliams200OK you said please unblock you on core-setup. Is the RID issue whats blocking you?

[ericstj]

Folks can ammend the RID graph in their own package to try things out; any package with a runtime.json will get merged into the graph. We shouldn't be defining a RID compatibility relationship in the central MS.NETCore.Platforms until we have a chance to assess the compatibility of the distro with others/versions. That's ok to do in prerelease so long as we test it out and vet it before shipping stable.