bash script for pushing a directory in your repo to the gh-pages branch, and for initializing orphaned gh-pages branches

gh-pages-submodule-deploy

#!/usr/bin/env bash
# Copyright (c) 2021 Matthew Strasiotto
# This work is licensed under the terms of the MIT license.  
# For a copy, see <https://opensource.org/licenses/MIT>.

function ascend_to_root {
  local top_level="$(pwd)"

  if top_level="$(git rev-parse --show-toplevel 2>/dev/null)" ; then
    cd "$top_level"
    return 0
  else
    echo "not in a repo"
    return 1
  fi
}

function gh-pages_submodule_exists {
  if [ "$#" -ne "1" ]; then
    echo "gh-pages_submodule_exists takes path to submodule as arg"
    return 2
  fi
  local status=$(git submodule status "$1" | grep '(heads/gh-pages)')

  if [ -z "$status" ]; then
    return 1
  fi



  return 0
}

function deploy_site {
  local submodule_path="${1:-./docs}"
  ascend_to_root
  
  if ! gh-pages_submodule_exists; then
    echo "no gh-pages submodule found!"
    echo "try calling: scriptname init_submodules"
    return 2
  fi

  local current_sha="$(git log -1 --format='%h')"
  local current_branch="$(git rev-parse --abbrev-ref HEAD)"
  local commit_msg=""

  read -d '' commit_msg << EOF
Publish from $current_branch @ $current_sha on $(date)
EOF

  cd "$submodule_path" 
  git add --all 
  git commit -m "$commit_msg"
  git push origin HEAD:gh-pages
}

function get_current_origin {
  git remote -v    | \
    grep "(push)"  | \
    cut -f2 | cut -f1 -d' '
}

function gh-pages_branch_init { 
    if git ls-remote --quiet --exit-code --heads origin gh-pages; then
        echo "gh-pages branch found, will try to use that"
        return 0
    fi
    
    echo "initializing orphaned gh-pages branch"
    if ! git diff-index --quiet HEAD --; then
        echo "Please stash or discard changes in working tree before trying to initialize empty gh-pages branch"
        exit 3
    fi
    
    git checkout --orphan gh-pages
    git reset --hard
    git commit --allow-empty -m "Initialize gh-pages"
    git push -u origin gh-pages
    git checkout "$previous_branch"
  }

function init_submodules {
  ascend_to_root
  
  local status="$(git submodule status)"
  local submodule_path="${1:-./docs}"
  
  local previous_branch="$(git branch --show-current)"
  
  local origin="$(get_current_origin)"
  
  if ! gh-pages_submodule_exists; then
    echo "No submodule exists"
    echo "Will attempt to init submodule at: origin@gh-pages"
    
    gh-pages_branch_init
    
    git submodule add --branch gh-pages -- "$origin" "$submodule_path"
  fi
  
  git submodule update --init --recursive
}

command="${1:-deploy_site}"
shift

($command $@)

Usage:

./gh-pages-submodule-deploy init_submodule <optional path, default: ./docs>
# will make a submodule at repo-root/<path>

./gh-pages-submodule-deploy deploy-site <optional path, default: ./docs>
# will push whatever is in <path> to gh-pages