Fix GLIBC Compatibility Issue for nostcat in Alpine-based Docker Image

[imksoo]

Issue:

The nostcat binary, when executed in the existing Alpine-based Docker image, encounters an issue due to the absence of required GLIBC versions (2.32, 2.33, 2.34). Alpine, by default, uses musl libc, which is not compatible with glibc-dependent binaries. This results in the following error when running nostcat:

/usr/local/bin/nostcat: /usr/glibc-compat/lib/libc.so.6: version `GLIBC_2.33' not found (required by /usr/local/bin/nostcat)
/usr/local/bin/nostcat: /usr/glibc-compat/lib/libc.so.6: version `GLIBC_2.32' not found (required by /usr/local/bin/nostcat)
/usr/local/bin/nostcat: /usr/glibc-compat/lib/libc.so.6: version `GLIBC_2.34' not found (required by /usr/local/bin/nostcat)

Proposed Solution:

This PR addresses the issue by introducing a multi-stage Docker build process. The key steps are:

1. GLIBC Extraction: We use gcr.io/distroless/cc-debian12:latest-amd64 as a source to extract the GLIBC library. This distroless image is based on Debian 12 and contains the necessary GLIBC versions.

2. Copy to Alpine Image: The extracted GLIBC files are then copied to the Alpine-based runtime image at /usr/glibc-compat/lib/. This allows the nostcat binary to access the required GLIBC versions within the Alpine environment.

Implementation:

# Download glibc library from distroless container image
FROM gcr.io/distroless/cc-debian12:latest-amd64 AS glibc
# ... existing steps ...
# Copy the GLIBC files to the final image
COPY --from=glibc /lib/x86_64-linux-gnu/* /usr/glibc-compat/lib/

Benefits:

• Compatibility: Ensures that nostcat runs successfully in the lightweight Alpine container by resolving the GLIBC version mismatch.
• Minimal Changes: The change is minimal and isolated, avoiding a complete overhaul of the existing Docker setup.

Considerations:

• This solution focuses on resolving the immediate compatibility issue. However, for long-term maintenance, considering a glibc-based image or removing the glibc dependency in nostcat might be beneficial.

I look forward to your feedback on this proposed fix and am happy to make further modifications as needed.