Golang version switcher. Activate by `goswitch 1.4` or `goswitch list`. See help at `goswitch help`.

goswitch.sh

#!/bin/bash
#
# Author: Jason Giedymin <[email protected]>
# Copyright 2014 Jason Giedymin
# License: Apache2
#
# Basic goswitch script to swtich between two gopath roots.
# This script can be useful if you have a basic structure
# and your build scripts don't have knowledge of where
# your golibs are installed.
#
# This script is especially useful if you have a custom
# golang compiler and you need a clean userland install 
# without command path trickery.
#
#
# Requirements:
#
# - mkdir ~/local/lib/golang
# - mkdir ~/local/usr/golang
# - mkdir ~/.go
# - put all the golang versions you want in ~/local/lib/golang
# - modify your shell profile and set:
#   - GOROOT=~/.go/bin
#   - GOPATH=~/.go/workspace
#

# App Vars
# Note: standard installs use /usr/local/go/, however userland is better.
GOROOT=${GOROOT-~/.go/bin}
GOPATH=${GOPATH-~/.go/workspace}

# Directory where all the golang versions reside
GO_LIB_ROOT=~/local/lib/golang
GO_WORKSPACE_ROOT=~/local/usr/golang

# tput colors
T_OK=2
T_WARN=5
T_ERROR=1
T_RESET=0

rmGo(){
  # These should exist but for safety they're checked.
  if [ -e $GOPATH ]; then
    rm -R $GOPATH
  fi

  if [ -e $GOROOT ]; then
    rm -R $GOROOT
  fi
}

log() {
  echo "$(tput setaf $1)$2 $(tput setaf $T_RESET)"
}

askCreate() {
  log $T_WARN "Would you like me to create [$1] for you? [yn]:"
  read create
  if [ "$create" == "y" ]; then
    mkdir -p $1
  else
    log $T_ERROR "User aborted. Please create workspace manually."
    exit 1;
  fi
}

goswitch() {
  local version=$1
  local link_version=go.$version
  local link=$GO_LIB_ROOT/$link_version
  local workspace_link=$GO_WORKSPACE_ROOT/$link_version

  if [ ! -e $link ]; then
    log $T_ERROR "Specified go version: [$version] could not be found at [$link]."
    exit 1;
  fi; # else proceed

  if [ ! -e $workspace_link ]; then
    log $T_ERROR "Specified go workspace for version: [$version] could not be found at [$workspace_link]."
    askCreate $workspace_link
  fi; # else proceed

  rmGo
  ln -sf $link $GOROOT
  ln -sf $workspace_link $GOPATH

  log $T_OK "Switched to go $version which resides in $link"
}

list() {
  ls -x $GO_LIB_ROOT | sed 's/go.//g'
}

help() {
  log $T_OK "------------------- Commands -------------------"
  log $T_OK " help  : this help screen"
  log $T_OK " list  : lists all versions of go available"
  echo
  log $T_OK "otherwise pass the version to goswitch:"
  log $T_OK "    goswitch 1.4"
  echo
  log $T_OK "other examples:"
  log $T_OK "    goswitch list"
}

main() {
  case "$1" in
    list)
      $1
      ;;
    help)
      $1
      ;;
    *)
      if [ $# -gt 0 ]; then
        goswitch $1
      else
        log $T_ERROR "\nInvalid Usage!\n"
        help
      fi
      ;;
  esac
}

main $@