Bash script to run rails migrations singly interactively

run-migrations-singly

#!/usr/bin/env bash
# run-migrations-singly

PROG=${0##*/}
DIR=${0%/*}

export PATH=$PATH:$HOME/bin:$HOME/lib
# see github.com/aks/bash-lib
source talk-utils.sh
source run-utils.sh

status_log=migration_statuses.log

usage() {
  cat 1>&2 <<EOF
usage: $PROG [-hnv] [STARTDATE [ENDDATE]]
Run rails migrations from STARTDATE until ENDDATE, if given.  If a date is
omitted, all available down migrations are used.

Options
  -h    show this help
  -n    no run; show commands but don't run them
  -v    be verbose
EOF
  exit
}

migration_statuses() {
  talk "Fetching migration statuses in $status_log .."
  safe_run "bundle exec rake db:migrate:status"
}

prompt_yes_or_no() {
  local ans=
  while [[ -z "$ans" ]]; do
    read -e -p "Run? [yNq]" ans
    [[ -z "$ans" ]] && ans=no
    case "$ans" in
      yes|y|YES|Y)
        return 0 ;;
      no|n|NO|n)
        return 1 ;;
      quit|q|QUIT|q)
        talk "Quit!"
        exit ;;
      *)
        ans=
        talk "Please answer yes or no" ;;
    esac
  done
}

start_yet() {
  test_limit '>' "$@"
}

not_done_yet() {
  test_limit '<' "$@"
}

# test_limit ver lim op
test_limit() {
  local op="$1" ver="$2" lim="$3"
  if eval "[[ -z \"$lim\" || ( \"$ver\" $op \"$lim\" || \"$ver\" = \"$lim\" ) ]]" ; then
    return 0
  else
    return 1
  fi
}

skipped_line() {
  if (( skipping )) ; then
    if (( verbose )) ; then
      talkf "%s (skipped)\n" "$line"
    fi
    return 0
  fi
  skipping=1
  return 1
}

skipping_msg() {
  (( verbose )) || return 0
  talk "$line"
  talk "$1"
}


#  up     20180309183346  Add index to site instruction type
#  down    20180312232945  Change alternate formats table all ids to bigints stage 1

run_migrations_up_iteratively() {
  local startdate="$1"
  local enddate="$2"
  local line skipping=0
  local updown version message
  exec 3<$status_log                  # open fd 3 on the status log
  while read -u 3 line ; do
    if [[ "$line" =~ (down|up)\ *([0-9]{14})\ *([^\ ].*)$ ]] ; then
      updown="${BASH_REMATCH[1]}"
      version="${BASH_REMATCH[2]}"
      message="${BASH_REMATCH[2]}"
      case "$updown" in
      down)
        if start_yet "$version" "$startdate" ; then
          if not_done_yet "$version" "$enddate" ; then
            talk "$line"
            if prompt_yes_or_no ; then
              run_migration "$version"
            else
              talk "Skipped $version"
            fi
          else # done
            skipped_line && continue
            skipping_msg "Skipping this and remaining migrations" || break
          fi
        else # not started yet?
          skipped_line && continue
          skipping_msg "Skipping this and others until $startdate .." || break
        fi
        ;;
      up)
        (( verbose )) && talk "$line"
        ;;
      esac
    else
      (( verbose )) && talk "$line"
    fi
  done
  exec 3<&-                         # close fd 3
}

run_migration() {
  run "bundle exec rake db:migrate:up VERSION=\"$1\""
}

norun= verbose=

while getopts 'hnv' opt ; do
  case "$opt" in
    h) usage ;;
    n) norun=1 ;;
    v) verbose=1 ;;
  esac
done
shift $(( OPTIND - 1 ))

case $# in
  2) startdate="$1" enddate="$2" ;;
  1) startdate="$1" enddate=     ;;
  0) startdate=     enddate=     ;;
esac

if [[ ! -e $status_log ]] || find $status_log -mtime +1 1 >& /dev/null ; then
  migration_statuses >$status_log 
fi
run_migrations_up_iteratively "$startdate" "$enddate"
exit