gvm.sh

#!/usr/bin/env bash

set -e

usage()
{
    echo "GVM is a simple golang version manager written in bash."
    echo "$(basename $0) -v <version>"
}

setversion()
{
    if [[ -z ${WANTED} ]]; then
        usage
        exit 1
    fi
    
    go version 2&>1 > /dev/null || bootstrap

    if [[ ! -d ${HOME}/sdk/go${WANTED} ]]; then
        go get golang.org/dl/go${WANTED}
        go${WANTED} download
    fi

    pushd ${HOME}/sdk > /dev/null
    rm -f active
    ln -s go${WANTED} active
    popd > /dev/null
}

bootstrap()
{
    os=$(uname)
    arch="386"
    
    case ${os} in
        Darwin)
            arch="amd64"
        ;;
        Linux)
            # TODO: armv6l support
            if [[ "$(uname -m)" == "x86_64" ]]; then
                arch="amd64"
            fi
        ;;
    esac
    
    mkdir -p ${HOME}/sdk
    pushd ${HOME}/sdk > /dev/null
    curl -o go.tar.gz https://dl.google.com/go/go${WANTED}.${os}-${arch}.tar.gz
    tar xf go.tar.gz
    mv go go${WANTED}
    rm -f go.tar.gz
    popd > /dev/null
}

while getopts ":v:h" opt; do
    case ${opt} in
        h)
            usage
            exit 0
        ;;
        v)
            WANTED=${OPTARG}
            setversion
        ;;
    esac
done

if [[ ${PATH} != *"${HOME}/sdk/active/bin"* ]]; then
    echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
    echo "Runtime set, add it to your path"
    echo "export PATH=\${PATH}:\${HOME}/sdk/active/bin"
    echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
fi