hal-sync

#!/bin/bash

set ${CHANG_SET:--eu}

RED='\033[0;31m'
GREEN='\033[0;32m'
YELLOW='\033[0;33m'
NO_COLOR='\033[0m'
CLEAR_LINE='\r\033[K'
DIM='\e[2m'
STEP_LINE=false

fail() {
  printf "${CLEAR_LINE}${RED}⚡️  ${@:?}${NO_COLOR}\n" 1>&2
  exit 1
}

step() {
  STEP_LINE=true
  style=$(${VERBOSE} && printf ${YELLOW} || printf ${DIM})
  printf "${CLEAR_LINE}${NO_COLOR}${style}▷ ${@:?}${NO_COLOR}" 1>&2
}

finish_step_line() {
  printf "$(${STEP_LINE} && echo "\n")" 1>&2
  STEP_LINE=false
}

start_server() {
  require_changignore
  stop_server
  create_volume_if_not_exists
  docker run \
    -d \
    -v $(docker_volume):/chang \
    -e CHANG_UID=${CHANG_UID} \
    -e CHANG_GID=${CHANG_GID} \
    -p 127.0.0.1::${CHANG_SYNC_SERVER_PORT} \
    --name $(docker_container) \
    ${DOCKER_IMAGE} > /dev/null
  test_server 50
}

stop_server() {
  if server_exists; then
    docker rm -f $(docker_container) >/dev/null 2>&1
  fi
}

server_exists() {
  ! test -z $(docker ps -aq --filter name=^/$(docker_container)$ 2>/dev/null)
}

server_running() {
  ! test -z $(docker ps -q --filter name=^/$(docker_container)$)
}

initial_sync() {
  chang_unison $(${VERBOSE} || echo -silent) -batch -ignorelocks -ignorearchives -force "${APP_PATH}" -perms -1
  code=$?
  case $code in
    0) step "Initial sync finished";;
    1) fail "Initial sync failed because some files were skipped";;
    2) fail "Failures occurred during initial sync";;
    3) fail "Fatal error occured during initial sync";;
    *) fail "Unison server returned unknown exit code: ${code}";;
  esac
}

docker_volume() {
  if [[ -z ${DOCKER_VOLUME:-} ]]; then
    project_name=${APP_PATH##*/}
    [[ -z ${project_name//[a-zA-Z0-9_-]/} ]] || project_name=""
    path_hash=$(path_hash $project_name)
    DOCKER_VOLUME="chang-sync${project_name:+_${project_name}}_${path_hash}"
  fi
  echo ${DOCKER_VOLUME}
}

path_hash() {
  echo ${1:?} | shasum - | head -c 8
}

docker_container() {
  docker_volume
}

container_port() {
  if [[ -z ${CONTAINER_PORT:-} ]]; then
    CONTAINER_PORT=`docker port $(docker_container) ${CHANG_SYNC_SERVER_PORT}/tcp 2>/dev/null | sed -E 's/.*127.0.0.1://'`
    [[ -n ${CONTAINER_PORT} ]] || fail "Unison server has gone away"
  fi
  echo ${CONTAINER_PORT}
}

server_url() {
  echo socket://127.0.0.1:$(container_port)//chang
}

test_server() {
  tests=${1:-1}
  for _ in $(seq 1 ${tests}); do
    if unison $(${VERBOSE} || echo -silent) -testserver ${APP_PATH} $(server_url) 2>/dev/null; then
      return 0
    fi
    sleep 1
  done
  return 1
}

chang_unison() {
  eval unison \
    $(changignore) \
    -root "${APP_PATH}" \
    -root $(server_url) \
    -perms 7 \
    "${@}"
}

require_changignore() {
  [[ -f .changignore || -f .chang/ignore ]] || fail "Chang-sync requires .changignore file to be present"
}

changignore() {
  changignorefile=$(test -f .changignore && echo .changignore || echo .chang/ignore)
  while read ignore || [ -n "${ignore}" ]; do
    echo -n "-ignore='${ignore}' "
  done < ${changignorefile}
}

sync() {
  trap stop_server INT TERM EXIT
  chang_unison $(${VERBOSE} || echo -silent) -repeat watch -prefer ${APP_PATH} -killserver -perms -1
}

sync_daemon() {
  sync | read fail_fast & disown
}

create_volume_if_not_exists() {
  local name=$(docker_volume)
  if ! docker volume ls -q | grep -q "^${name}$"; then
    docker run --rm \
      --volume "${name}":/volume \
      ${CHANG_MIN_IMAGE} \
      chown ${CHANG_UID}:${CHANG_GID} /volume
  fi
}

start() {
  if ! server_running; then
    step "Starting chang-sync"
    start_server
    step "Performing initial sync"
    initial_sync
    sync_daemon
    step "Chang-sync started"
  fi
  finish_step_line
}

stop() {
  stop_server
}

verbose() {
  VERBOSE=true
  step "Starting chang-sync in verbose mode"
  stop_server
  step "Docker volume name: ${NO_COLOR}$(docker_volume)"
  finish_step_line
  step "Starting chang-sync container"
  start_server
  step "Performing initial sync"
  finish_step_line
  initial_sync
  step "Running chang-sync in verbose mode"
  finish_step_line
  sync
}

DOCKER_IMAGE="majkel/chang-sync"
CHANG_SYNC_SERVER_PORT=5000
CHANG_UID=${CHANG_UID:-1000}
CHANG_GID=${CHANG_GID:-1000}
CHANG_PWD="${CHANG_PWD:-$(pwd -P)}"
APP_PATH="${CHANG_PWD}"
VERBOSE=false

case "${@:-}" in
  ""|start)
    start
    echo $(docker_volume)
    ;;
  stop)
    stop
    ;;
  verbose)
    verbose
    ;;
  restart)
    stop
    start
    ;;
  *)
    fail "Usage: chang-sync [start|stop|restart|verbose]"
    ;;
esac