bootstrap.sh

#!/usr/bin/env bash

set -e
set -o pipefail

OS="$(uname -s)"
ARCH="$(uname -m)"

PROGRAM_NAME="bindl"
REPOSITORY="bindl-dev/${PROGRAM_NAME}"

WORKDIR="$(mktemp -d /tmp/bootstrap-${PROGRAM_NAME}-XXXXX)"

ARCHIVE="${PROGRAM_NAME}-${OS}-${ARCH}.tar.gz"

OUTDIR="${OUTDIR:-$(pwd)}"
TAG="${TAG:-latest}"

function log() {
  echo -e "[\e[1;34mbootstrap\e[0m] $1"
}

function prompt() {
  if [ -t 0 ]; then
    read -p "Proceed? (y/N) " answer </dev/tty
    if [ $answer != "y" ]; then
      echo "Aborted: only 'y' is accepted answer to continue (received '${answer}')"
      exit 1
    fi
  else
    log "Detected non-interactive mode, prompt implictly proceeds"
    return
  fi
}

function copy_local() {
  set +e
  exe=$(which ${PROGRAM_NAME} 2>/dev/null)
  set -e

  if [ -z $exe ]; then
    return
  fi

  dst=$(realpath ${OUTDIR}/${PROGRAM_NAME})

  if [ $exe == $dst ]; then
    log "Found ${PROGRAM_NAME} in ${OUTDIR}, my job here is done."
    exit 0
  fi

  log "I found ${exe}, I will now create symbolic link to ${OUTDIR}"
  ln -s ${exe} ${dst} || return
  log "Done!"
  exit 0
}

log "Hello! The sole purpose of my existence is to bootstrap ${PROGRAM_NAME}."

copy_local

log "I have found myself in ${ARCH} machine running ${OS}."
log "I expect the archive to be named ${ARCHIVE}."

prompt

log "Working in ${WORKDIR}"
pushd "${WORKDIR}" >/dev/null
  log "Downloading (1/2): checksums.txt"
  curl --silent --location --remote-name "https://github.com/${REPOSITORY}/releases/${TAG}/download/checksums.txt"

  log "Downloading (2/2): ${ARCHIVE}"
  curl --silent --location --remote-name "https://github.com/${REPOSITORY}/releases/${TAG}/download/${ARCHIVE}"

  downloaded=$(ls -A | tr '\n' ' ')
  log "Downloaded: ${downloaded}"

  log "Verifying checksums"
  shasum --algorithm 256 --check checksums.txt --ignore-missing

  tar -xzf ${ARCHIVE} ${PROGRAM_NAME}

  log "Printing program version"
  ./${PROGRAM_NAME} version
popd >/dev/null

trap "rm -r ${WORKDIR}" EXIT

mv ${WORKDIR}/${PROGRAM_NAME} ${OUTDIR}/.
log "Done! The binary is in ${OUTDIR}"