RFC: Add linux-musl-x64 Runtime Support #496
Comments
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Currently there is no reliable way to detect libc vs musl during a .Net restore operation and therefore no reliable way to ensure the correct libpact binary is restored. That makes this issue currently infeasible until a reliable way of doing that detection is found. |
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Could you please help me understand why it is preferred to restore the correct pact_ffi package over picking the correct one at runtime? |
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That's the design of the FFI packaging, so that the correct binary is restored to the bin folder when the NuGet is installed. That means we're leaning on existing features provided in MSBuild instead of rolling our own detection code, which is bound to be worse. I'm not sure how runtime vs restore time is a distinction here anyway? Either way there's no reliable way to detect libc vs musl, because if there was you could use it with either style. Both call in to .Net APIs to determine the OS/arch currently, but there's no API to determine libc vs musl. I can understand why that is also - .Net itself doesn't need to worry about that because your code is all IL and it's the installed runtime that matters. Given we're doing native interop though then it does matter to us, so the missing API matters. |
## Rationale pact-reference has introduced musl and arm64 based ffi libraries for linux - pact-foundation/pact-reference#416 Tracking Issue - pact-foundation/devrel#30 ## Issues Resolved fixes pact-foundation#498 fixes pact-foundation#496 fixes pact-foundation#500 fixes pact-foundation#374 fixes pact-foundation#387 ## Backwards Compatibility Linux glibc based hosts take precedence, so if any error occurs during musl detection. I do not anticipate breaking changes for users ## Implementation notes ### .NET notes - Docs - [Uses MSBuild Exec task](https://learn.microsoft.com/en-us/visualstudio/msbuild/exec-task?view=vs-2022) - MSBuild Blog Posts - [Cross-Platform Build Events in .NET Core using MSBuild](https://jeremybytes.blogspot.com/2020/05/cross-platform-build-events-in-net-core.html) - [MSBuild 101: Using the exit code from a command](https://www.creepingcoder.com/2020/06/01/msbuild-101-using-the-exit-code-from-a-command/) - Stack OverFlow - [Set PropertyGroup property to Exec output](https://stackoverflow.com/questions/76583824/set-propertygroup-property-to-exec-output) - .NET runtime musl detection code - https://github.com/dotnet/runtime/blob/a50ba0669353893ca8ade8568b0a7d210b5a425f/src/mono/llvm/llvm-init.proj\#L7 - https://github.com/dotnet/runtime/blob/a50ba0669353893ca8ade8568b0a7d210b5a425f/src/libraries/Common/tests/TestUtilities/System/PlatformDetection.Unix.cs\#L78t ### Conditions for execution musl detection will run if - if linux - if /lib/ld-musl-(x86_64|aarch64).so.1 exists - if ldd bin/sh | grep musl is true (musl lib is loaded, rather than glibc) will continue on error, reverting back to glibc based libaries. ### Supported musl targets should work for multiple musl based distroes if - /lib/ld-musl-(x86_64|aarch64).so.1 exists - ldd is available (available by default in alpine images) Tested on Alpine ARM64 / AMD64. ## Caveats - [.NET does not run under QEMU](https://github.com/dotnet/core/blob/main/release-notes/8.0/supported-os.md#qemu) affecting the ability to test multi-arch from a single system - .NET restore can take a long time when running under containers. - [Workaround](NuGet/Home#13062 (comment)): Set `DOTNET_NUGET_SIGNATURE_VERIFICATION` to `false` ## Compatibility ### Operating System Due to using a shared native library instead of C# for the main Pact logic only certain OSs are supported: | OS | Arch | Support | | ------------ | ----------- | -------------------------------------------------------------------| | Windows | x86 | ❌ No | | Windows | x64 | ✔️ Yes | | Linux (libc) | x86 | ❌ No | | Linux (libc) | x64 | ✔️ Yes | | Linux (musl) | x64 | ✔️ Yes (Tier 2)* | | Linux (libc) | ARM | ✔️ Yes (Tier 3)* | | Linux (musl) | ARM | ✔️ Yes (Tier 3)* | | OSX | x64 | ✔️ Yes | | OSX | ARM (M1/M2) | ✔️ Yes | #### Support - Tier 1 - Established - Full CI/CD support. - Users should not encounter issues - Full reproducible examples running in CI, should be provided by users raising issues - If using musl targets, users should attempt the same test on a libc target (such as debian) - Tier 2 - Recently introduced - Full CI/CD support. - Users may encounter issues - Full reproducible examples running in CI, should be provided by users raising issues - If using musl targets, users should attempt the same test on a libc target (such as debian) - Tier 3 - Recently introduced, No/limited CI/CD support. - Users may encounter issues - Full reproducible examples which can be run by maintainers locally, should be provided by users raising issues
Previous issues
Add
linux-musl-x64Runtime SupportIs your feature request related to a problem? Please describe.
According to Compatibility / Operating System page Linux (musl) is not supported, however starting with Pact FFI Library 0.4.17 the
libpact_ffi-linux-aarch64-musl.soandlibpact_ffi-linux-x86_64-musl.soshared libraries are part of releases.Describe the solution you'd like
Update pact-net to use latest Pact FFI Library 0.4.19 which has the
libpact_ffishared libraries and extend the NuGet package with additional runtime targets.Breaking Changes
No
Potential Downsides/Caveats
n/a
Describe alternatives you've considered
n/a
Additional context
After replacing the
runtimes/linux-x64/native/libpact_ffi.sofile added by PactNet 5.0.0-beta.2 package with libpact_ffi-linux-x86_64-musl.so I was able to successfully run pact-net tests inside Docker usingmcr.microsoft.com/dotnet/sdk:6.0.421-alpine3.19-amd64The text was updated successfully, but these errors were encountered: