lolaus.sh

#!/usr/bin/env bash

help() {
  cat <<EOF
Simple monorepo lifecycle/pipeline tool for running one or more commands on one
or more directories that have diffs compared to an ansector. The primary
use case is for selective CI jobs within a trunk based workflow.

Takes two arguments, <glob> <command>. The command is invoked from each
directory context matching the glob.

Usage:
  lolaus "./tests/* :(top,exclude)**requirements.txt" ls
  lolaus "**" pwd
  lolaus "*/*/package.json" npm test & lolaus "*/*/requirements.txt" "python test.py"
  lolaus "apps/*/index.js"
  lolaus "**" ls target-branch other-branch
EOF
  exit 1
}

# lolaus <cmd> [glob] [target_ref] [source_ref]
function main() {

  [[ $1 == "-h" || $1 == "--help" ]] && help

  local GLOB
  GLOB=${1:-'**'}

  local CMD
  CMD="$2"

  local TARGET_REF
  TARGET_REF=$(get-target-ref "$3")
  [[ ${DEBUG} =~ ^(true|TRUE) ]] && echo target: $TARGET_REF

  local SOURCE_REF
  SOURCE_REF=$(get-source-ref "$4")
  [[ ${DEBUG} =~ ^(true|TRUE) ]] && echo source: $SOURCE_REF

  local CONCESTOR
  CONCESTOR=$(get-concestor $TARGET_REF $SOURCE_REF)
  [[ ${DEBUG} =~ ^(true|TRUE) ]] && echo concestor: $CONCESTOR

  local DIFFS
  DIFFS=$(get-diffs $CONCESTOR $SOURCE_REF)
  [[ ${DEBUG} =~ ^(true|TRUE) ]] && echo diffs: $DIFFS

  local DIRS
  DIRS=$(files-to-dirs "$DIFFS")
  [[ ${DEBUG} =~ ^(true|TRUE) ]] && echo dirs: $DIRS

  [[ x"$2" == "x" ]] && echo "$DIRS" || cmd-runner "$CMD" "$DIRS"

}

# Invokes the provided command in each provided direcotry
# cmd-runner <cmd> <dirs>
cmd-runner() {
  : ${1? "Please provide comands to run."}
  : ${2? "Please provide directories to run in."}

  local cmd
  cmd="$1"

  declare -a local dirs
  dirs=($2)

  for d in "${dirs[@]}"; do
    [[ ! -d $d ]] && echo "cmd-runner only works on dirs, not: $d" && exit 1

    local cmds="cd $d; $cmd"
    output="$(eval "$cmds" 2>&1)"

    [[ x"$output" == "x" ]] && output="$cmd produced no output"

    [[ $d == "$PWD" ]] && d='./'
    relative=${d/$(echo "$PWD/")/}
    echo -e "$(tput smso)  $relative  $(tput sgr0)\n$output\n"
  done
}

# Returns list of sorted and unique containing directories from a list of files.
# files-to-dirs <files>
files-to-dirs() {
  declare -a local files
  files=($1)

  local path
  path=$(pwd)

  declare -a local dirs
  declare -a local sorted

  for file in "${files[@]}"; do

    if [ -n "${file##*/*}" ]; then
      dirs+=("$path")
    else
      dirs+=("$path/${file%/*}")
    fi

  done

  IFS=$'\n' sorted=($(sort -u <<<"${dirs[*]}"))
  unset IFS

  echo "${sorted[*]}"
}

# Determines the closest common ansester from two git refs with a default
# strategy of 'fork-point'
# get-concestor <LEFT_REF> <RIGHT_REF> [STRATEGY]
get-concestor() {
  local left_ref=${1}
  local right_ref=${2}
  local strategy=${3:-'fp'}
  local concestor

  case ${strategy} in
    fp) concestor=$(git merge-base --fork-point $left_ref $right_ref) ;;
  esac

  echo $concestor
}

# Returns a list of files with diffs between two git refs with optional glob.
# get-diffs <left_ref> <right_ref> [glob]
get-diffs() {
  local left_ref=$1
  local right_ref=$2
  local glob=${3:-"**"}

  local diffs
  diffs=$(git diff --name-only $left_ref..$right_ref -- $glob)

  echo $diffs
}

# Returns the verified git reference to target. Defaults to current ref.
# get-source-ref [branch name]
get-source-ref() {
  local ref=$1

  if [ ! -z "$ref" ]; then

    if ! git rev-parse --quiet --verify $ref &>/dev/null; then
      echo "Source git ref, $ref, is not valid"
      exit 1
    fi

  else

    ref=$(git symbolic-ref --short HEAD)

  fi

  echo $ref
}

# Returns the verified git reference to target. Default to 'next' then 'master'
# get-target-ref [branch name]
get-target-ref() {
  local REF=$1

  if [ ! -z "$ref" ]; then

    if ! git rev-parse --quiet --verify $ref &>/dev/null; then
      echo "Targeted git ref, $ref, is not valid"
      return 1
    fi

  else

    if git rev-parse --quiet --verify next &>/dev/null; then
      ref='next'
    elif git rev-parse --quiet --verify master &>/dev/null; then
      ref='master'
    else
      return 1
    fi

  fi

  echo $ref
}

main "$@"