unavailable

Unavailable

Unavailable is a tiny, simple Go program to print out a program is unavailable for a certain platform.

For example:

helm v3.6.1 is unavailable for linux/riscv64

It is designed to be built in a Dockerfile as an alternative to a program if this program is not supported for a certain architecture.

To reduce the complexity of the Dockerfile if/else block in a RUN instruction, the build.sh script can be pipe to sh with:

wget -qO- https://raw.githubusercontent.com/qdm12/binpot/main/unavailable/build.sh | \
  sh -s -- "programName v9.9.9" "linux/riscv64"

The script requires:

• xcputranslate (see one of the Dockerfiles on how-to)
• wget
• go
• Argument 1 as the program name
• ${TARGETPLATFORM} to be set

It will:

1. Clear the current working directory
2. Download the main.go file
3. Cross build the binary, setting the program name and platform in the binary with -ldflags
4. Write the binary to /tmp/bin with 500 permissions.

Concrete example

You can see its usage in some of the Dockerfiles where not all architectures are supported by the program, such as for dlv.

Relevant section for dlv:

ARG TARGETPLATFORM
RUN export GOARCH="$(xcputranslate translate -field arch -targetplatform ${TARGETPLATFORM})" && \
    export GOARM="$(xcputranslate translate -field arm -targetplatform ${TARGETPLATFORM})" && \
    if [ "${TARGETPLATFORM}" = "linux/amd64" ] || [ "${TARGETPLATFORM}" = "linux/arm64" ]; then \
        echo "Building for ${TARGETPLATFORM}..." && \
        COMMIT="$(git rev-parse --short HEAD)" && \
        DATE="$(date +%Y-%m-%dT%T%z)" && \
        go build -trimpath -ldflags="-s -w" -o /tmp/bin ./cmd/dlv && \
        chmod 500 /tmp/bin && \
        exit 0; \
    fi && \
    wget -qO- https://raw.githubusercontent.com/qdm12/binpot/main/unavailable/build.sh | \
       sh -s -- "dlv ${VERSION}" "${TARGETPLATFORM}"

If you build it for linux/amd64, the final /tmp/bin program will be the actual dlv binary.

Otherwise, if you build it for linux/arm/v7 for example, it will be this unavailable program showing: dlv v1.6.1 is unavailable for linux/arm/v7.