Building / Installing Go on the Raspberry Pi or Ubuntu

## Building-Installing_Go_on_the_RPi_or_Ubuntu.bash
###############################################################################
# Building Go on the Raspberry Pi
###############################################################################
# Based on the work of Dave Cheney
#   http://dave.cheney.net/2015/09/04/building-go-1-5-on-the-raspberry-pi
# Also info in the docs:
#   https://github.com/golang/go/blob/master/src/make.bash
###############################################################################

### Set project area
export MYPROJROOT=~/Projects
export MYPKGNAME=go
export MYPKGVER=1.10.1
export MYPKGOS=linux
export MYPKGARCH=armv6l  # Pi, etc.
#export MYPKGARCH=amd64  # Intel architectures
export MYPKGDEST=/usr/local/${MYPKGNAME}-${MYPKGVER}

### Preparation
mkdir -p ${MYPROJROOT}
cd ${MYPROJROOT}
rm -rf ${MYPKGNAME} ${MYPKGNAME}-${MYPKGVER}

### Obtaining binaries to use
  ### Option 1: Using the pre-compiled version (1.6.x and later!):

    # Get the release binaries
    cd ${MYPROJROOT}
    wget https://storage.googleapis.com/golang/go${MYPKGVER}.${MYPKGOS}-${MYPKGARCH}.tar.gz
    tar xzf ${MYPKGNAME}${MYPKGVER}.${MYPKGOS}-${MYPKGARCH}.tar.gz
    mv ${MYPKGNAME} ${MYPKGNAME}-${MYPKGVER}

  ### Option 2: Building from source:

    # Lower the ulimit to prevent problems
    ulimit -s
    ulimit -s 1024
    ulimit -s

    # Get the source
    cd ${MYPROJROOT}
    wget https://storage.googleapis.com/golang/go${MYPKGVER}.src.tar.gz
    tar xzf ${MYPKGNAME}${MYPKGVER}.src.tar.gz
    mv ${MYPKGNAME} ${MYPKGNAME}-${MYPKGVER}

    # Bootstrapping
    export MYBOOTSTRAP=/usr/local/${MYPKGNAME}
    if [ ! -d ${MYBOOTSTRAP} ]; then
        # Never had Go installed
        cd ${MYPROJROOT}
        wget http://dave.cheney.net/paste/go-linux-arm-bootstrap-c788a8e.tbz  # For ARM
        tar xjf go-linux-arm-bootstrap-c788a8e.tbz
        export MYBOOTSTRAP=${MYPROJROOT}/go-linux-arm-bootstrap
    fi
    echo ${MYBOOTSTRAP}

    # Build Go
    cd ${MYPROJROOT}/${MYPKGNAME}-${MYPKGVER}/src
    env GO_TEST_TIMEOUT_SCALE=10 GOROOT_BOOTSTRAP=${MYBOOTSTRAP} GOROOT_FINAL=${MYPKGDEST} ./all.bash

### Install the package
cd ${MYPROJROOT}
sudo rm -rf /usr/local/${MYPKGNAME}-${MYPKGVER}
sudo cp -rp ${MYPROJROOT}/${MYPKGNAME}-${MYPKGVER} /usr/local
sudo chown root:staff /usr/local/${MYPKGNAME}-${MYPKGVER}
#sudo chown root:root /usr/local/${MYPKGNAME}-${MYPKGVER}  # Ubuntu
sudo chmod -R g-s /usr/local/${MYPKGNAME}-${MYPKGVER}
sudo rm /usr/local/${MYPKGNAME}
sudo ln -s /usr/local/${MYPKGNAME}-${MYPKGVER} /usr/local/${MYPKGNAME}

### Test the installation

# Ensure the package is in your path (e.g., edit your .profile, then source it with `. ~/.profile`)
export PATH=$PATH:/usr/local/go/bin

cd $HOME
go version
    go version goX.Y.Z linux/arm
    # Note: if you get something like "go: cannot find GOROOT directory: /foo/bar/blah"
    # ensure that path exists. GOROOT_FINAL mediates that (above)

### Clean up
rm -rf ${MYPROJROOT}/${MYPKGNAME}-${MYPKGVER}