rules_buf fails on Linux ARM64 due to incorrect binary naming

[jaeyeom]

Summary

rules_buf fails to download buf binaries on Linux ARM64 systems because it uses the wrong naming convention. The rules look for linux-arm64 but buf releases use Linux-aarch64 for Linux ARM64 platforms.

Environment

• OS: Linux ARM64 (Android Termux)
• Architecture: aarch64
• Bazel version: 7.4.1
• rules_buf version: 0.4.0

Error

WARNING: Download from https://github.com/bufbuild/buf/releases/download/v1.54.0/protoc-gen-buf-lint-linux-arm64 failed: class java.io.FileNotFoundException GET returned 404 Not Found

Root Cause

The buf project releases binaries with these naming conventions:

• macOS ARM64: buf-Darwin-arm64
• Linux ARM64: buf-Linux-aarch64
• Linux x86_64: buf-Linux-x86_64

However, rules_buf tries to download using linux-arm64 instead of Linux-aarch64.

Actual Release Assets

From buf v1.54.0 releases:

• buf-Darwin-arm64 (macOS ARM64)
• buf-Linux-aarch64 (Linux ARM64)
• protoc-gen-buf-lint-Linux-aarch64 (Linux ARM64)
• protoc-gen-buf-breaking-Linux-aarch64 (Linux ARM64)

Suggested Fix

In the toolchain.bzl file, the platform detection logic should map:

• Darwin + arm64 → Darwin-arm64
• Linux + arm64 → Linux-aarch64 (not linux-arm64)

Workaround

Until fixed, users on Linux ARM64 need to manually download and configure the buf binaries.

References

• Buf releases: https://github.com/bufbuild/buf/releases
• toolchain.bzl source: https://github.com/bufbuild/rules_buf/blob/main/buf/internal/toolchain.bzl

[srikrsna-buf]

We already map arm64 to aarch64 here, can you tell me the ctx.os.name and ctx.os.arch that you see in your environment?

[jaeyeom]

@srikrsna-buf Thank you for your response. But somehow it's trying to download the wrong one.

Error downloading [https://github.com/bufbuild/buf/releases/download/v1.54.0/protoc-gen-buf-lint-linux-arm64]

I'm struggling to extract ctx.os.name and ctx.os.arch value. Could you help me how to extract them?

uname -s tells Linux. (with capital L)

But even though, as you said, this should never be possible? But it happens... I'm using the latest release.

[srikrsna-buf]

Hey @jaeyeom I tried to reproduce this in a linux arm64 virtual machine and it downloads using the correct url. Are you on the latest version?

[jaeyeom]

Hey @jaeyeom I tried to reproduce this in a linux arm64 virtual machine and it downloads using the correct url. Are you on the latest version?

Thank you for your effort. As you see in the environment section, it is 0.4.0.

I guess my environment (Termux) is a little different from some other environments. I'll try to debug it on my side.