[Rust][FFI] Add native library support for Linux musl (Alpine)#412
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Add x86_64-unknown-linux-musl and aarch64-unknown-linux-musl matrix rows to release-ffi.yml, cross-compiled with cargo-zigbuild on the existing linux-ubuntu-latest runners. Uses RUSTFLAGS=-C target-feature=-crt-static so the libs link musl dynamically, correct for Alpine hosts. Document the musl cross-compile in the FFI README. Mirrors the JNI musl support from #347. Fixes #411 Signed-off-by: Zlata Stefanovic <zlata.stefanovic@databricks.com>
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| ### New Features and Improvements | ||
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| - Build the FFI library for Linux musl targets (`x86_64-unknown-linux-musl`, `aarch64-unknown-linux-musl`), enabling C/C++ and Go-on-Alpine consumers to link `libzerobus_ffi.a` / `libzerobus_ffi.so` on musl-based (Alpine) containers. Artifacts ship in the `linux-musl-x86_64` / `linux-musl-aarch64` directories. Mirrors the JNI musl support added in #347. |
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I don't think we need the last sentence.
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| - name: Install Zig (musl cross-builds) | ||
| if: matrix.zigbuild | ||
| uses: mlugg/setup-zig@a67e68dc5c8281d9608136d3d7ca1b282213e4ac # v2.0.1 |
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why not the latest (v2.2.1)
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No good reason, it was just the one used by Teodor, changed it now in both workflows.
Signed-off-by: Zlata Stefanovic <zlata.stefanovic@databricks.com>
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What changes are proposed in this pull request?
WHAT: Builds the C FFI library (
rust/ffi) for Linux musl targets so it works on Alpine / musl-based containers:x86_64-unknown-linux-muslandaarch64-unknown-linux-muslmatrix rows to.github/workflows/release-ffi.yml, cross-compiled withcargo-zigbuildon the existingdatabricks-protected-runner-group / linux-ubuntu-latestrunners (no dedicated Alpine runner). Builds withRUSTFLAGS=-C target-feature=-crt-staticso the libs link musl dynamically, which is correct for dynamically-linked Alpine hosts. The crate'scrate-type = ["staticlib", "cdylib"]means onecargo zigbuildrun emits bothlibzerobus_ffi.aandlibzerobus_ffi.so. Artifacts upload asffi-linux-musl-x86_64/ffi-linux-musl-aarch64.rust/ffi/README.md.rust/ffi/NEXT_CHANGELOG.mdentry.WHY: The FFI library was previously built only for glibc targets, so the glibc-linked artifacts do not load or link on Alpine. This is the FFI counterpart to #324 (Java request), which was implemented for JNI in #347 but left the FFI build unchanged — so direct C/C++ consumers on Alpine were still unsupported. This PR mirrors the #347 workflow approach for FFI.
The Java side of #347 also had a runtime
NativeLoader(it bundles all platforms in one JAR and selects the lib at load time). The FFI library has no runtime loader — C/C++ consumers link thelinux-musl-*directory they download directly — so there is no analogous code to add here. Per scope decision, therelease-go.yml/ Go-on-Alpine path (which needs cgo build-tag plumbing to distinguish musl from glibc) is left to a separate change.Fixes #411
How is this tested?
Triggered & passed - https://github.com/databricks/zerobus-sdk/actions/runs/28018404039
CI/packaging change only — no unit-testable code paths. Validated the
release-ffi.ymlYAML parses and that the new matrix rows reuse the existingPrepare artifacts/Upload artifactsteps (keyed offmatrix.artifact_dir/static_lib/dynamic_lib). The workflow isworkflow_dispatch-triggered; a manualrelease-ffi.ymlrun is the end-to-end verification, mirroring how #347 was validated via a triggeredrelease-jni.ymlrun.