#!/bin/bash

#
# this waits for changes in files passed in params and sends php-fpm a USR1
# signal to reload the logfiles
#
# we need to watch the containing directories and filter events by files, as
# when a file is open while being deleted (as it happens with php-fpm
# logfiles), inotify fails to register a delete_self event, for some reason.
#
function watch_logfiles {

    # inform
    echo "+-- watching for changes in watchfile(s):"

    # prepare the watch files array
    unset WATCH_FILES
    WATCH_FILES=()
    
    # build the egrep filter
    # start off with the general events happening directly on watched directories
    EGREP_FILTER="^(.+ (DELETE_SELF|MOVE_SELF|UNMOUNT)"
    
    # get the watch files; filter out `/dev/null`s we don't need
    for WATCH_FILE in "$@"; do
        if [ ! $WATCH_FILE = "/dev/null" ]; then
            WATCH_FILES+=("$WATCH_FILE")
            echo "    +-- $WATCH_FILE"
            # add filter for the particular filee in its directory
            # TODO: escape regex special chars in filenames!
            EGREP_FILTER="${EGREP_FILTER}|$( dirname "$WATCH_FILE" )/ (MOVED_FROM|DELETE) $( basename "$WATCH_FILE" )"
        fi
    done
    
    # do we actually have any files to watch?
    if [ ${#WATCH_FILES[@]} = 0 ]; then 
        echo "    +-- no files to watch."
        return 0
    fi
    
    # finish the regex with a nice dollar sign
    EGREP_FILTER="$EGREP_FILTER)$"

    # loopy-loop!
    while true; do
        echo "    +-- checking watchfiles..."
        for WATCH_FILE in "${WATCH_FILES[@]}"; do
            # if the file is not there, create
            if [ ! -e "$( dirname "$WATCH_FILE" )" ]; then
                echo "        +-- waiting for missing watch file directory: $( dirname "$WATCH_FILE" )"
                sleep 1
                continue 2 # we want to break out to the outer loop, and then to continue
            fi
        done
        echo "    +-- watchfiles ok, setting the watches for dirs containing ${WATCH_FILES[*]}"
        
        # monitor for events on directories *containing* the files we want to watch
        # grep only the events we want
        # and then act upon them
        #
        # using pure egrep confuses read in the next piped step, so we need to work
        # around that via a minimal while look; not elegant, but works
        inotifywait -m \
            -e delete_self \
            -e move_self \
            -e unmount \
            -e delete \
            -e moved_from \
            -q $( dirname "${WATCH_FILES[@]}" ) \
            |   while true; do egrep -m 1 "$EGREP_FILTER"; done \
            |   while true; do
                    read -r AN_EVENT
                    echo "    +-- event: $AN_EVENT"
                    echo "        sending USR1 to php-fpm (pid $( cat "$PHP_PID_FILE" ))..."
                    kill -USR1 "$( cat "$PHP_PID_FILE" )"
                    # TODO handle DELETE_SELF, MOVE_SELF, UNMOUNT
                done
    done
}

function abort {
    # kill php-fpm if it is running
    [ -s $PHP_PID_FILE ] && kill -USR1 "$( cat "$PHP_PID_FILE" )"
    # inform
    echo
    echo "* * * ABORTED * * *"
    echo
    exit 0
}

# trap whatever we need to trap
trap abort SIGHUP SIGINT SIGQUIT SIGTERM SIGSTOP SIGKILL

# we need root
if [[ `whoami` != "root" ]]; then
  echo "we need root, and we are: $( whoami ); exiting!.."
  exit 1
fi

# sanity check
if [[ "$PHP_APP_NAME" == "" || "$PHP_APP_USER" == "" || "$PHP_APP_GROUP" == "" || "$PHP_APP_DIR" == "" ]]; then
  echo '$PHP_APP_NAME, $PHP_APP_USER, $PHP_APP_GROUP or $PHP_APP_DIR are not set'
  exit 2
fi

# info
echo "\$PHP_APP_NAME         :: $PHP_APP_NAME"
echo "\$PHP_APP_USER         :: $PHP_APP_USER"
echo "\$PHP_APP_GROUP        :: $PHP_APP_GROUP"
echo "\$PHP_APP_DIR          :: $PHP_APP_DIR"
echo "\$PHP_LISTEN           :: $PHP_LISTEN"
echo "\$PHP_ACCESS_LOG       :: $PHP_ACCESS_LOG"
echo "\$PHP_ERROR_LOG        :: $PHP_ERROR_LOG"
echo "\$PHP_SLOW_LOG         :: $PHP_SLOW_LOG"
echo "\$PHP_SLOW_LOG_TIMEOUT :: $PHP_SLOW_LOG_TIMEOUT"
echo "\$PHP_PID_FILE         :: $PHP_PID_FILE"

# do we have UID/GID number given explicitly?
if [[ "$PHP_APP_UID" != "" ]]; then
  echo "\$PHP_APP_UID          :: $PHP_APP_UID"
fi
if [[ "$PHP_APP_GID" != "" ]]; then
  echo "\$PHP_APP_GID          :: $PHP_APP_GID"
fi


# get group data, if any, and check if the group exists
if GROUP_DATA=`getent group "$PHP_APP_GROUP"`; then
  # it does! do we have the gid given?
  if [[ "$PHP_APP_GID" != "" ]]; then
    # we do! do these match?
    if [[ `echo "$GROUP_DATA" | cut -d ':' -f 3` != "$PHP_APP_GID" ]]; then
      # they don't. we have a problem
      echo "ERROR: group $PHP_APP_GROUP already exists, but with a different gid (`echo "$GROUP_DATA" | cut -d ':' -f 3`) than provided ($PHP_APP_GID)!"
      exit 3
    fi
  fi
  # if no gid given, the existing group satisfies us regardless of the GID

# group does not exist
else
  # do we have the gid given?
  GID_ARGS=""
  if [[ "$PHP_APP_GID" != "" ]]; then
    # we do! does a group with a given id exist?
    if getent group "$PHP_APP_GID" >/dev/null; then
      echo "ERROR: a group with a given id ($PHP_APP_GID) already exists, can't create group $PHP_APP_GROUP with this id"
      exit 4
    fi
    # prepare the fragment of the groupadd command
    GID_ARGS="-g $PHP_APP_GID"
  fi
  # we either have no GID given (and don't care about it), or have a GID given that does not exist in the system
  # great! let's add the group
  groupadd $GID_ARGS "$PHP_APP_GROUP"
fi


# get user data, if any, and check if the user exists
if USER_DATA=`id -u "$PHP_APP_USER" 2>/dev/null`; then
  # it does! do we have the uid given?
  if [[ "$PHP_APP_UID" != "" ]]; then
    # we do! do these match?
    if [[ "$USER_DATA" != "$PHP_APP_UID" ]]; then
      # they don't. we have a problem
      echo "ERROR: user $PHP_APP_USER already exists, but with a different uid ("$USER_DATA") than provided ($PHP_APP_UID)!"
      exit 5
    fi
  fi
  # if no uid given, the existing user satisfies us regardless of the uid
  # but is he in the right group?
  adduser "$PHP_APP_USER" "$PHP_APP_GROUP"

# user does not exist
else
  # do we have the uid given?
  UID_ARGS=""
  if [[ "$PHP_APP_UID" != "" ]]; then
    # we do! does a group with a given id exist?
    if getent passwd "$PHP_APP_UID" >/dev/null; then
      echo "ERROR: a user with a given id ($PHP_APP_UID) already exists, can't create user $PHP_APP_USER with this id"
      exit 6
    fi
    # prepare the fragment of the useradd command
    UID_ARGS="-u $PHP_APP_UID"
  fi
  # we either have no UID given (and don't care about it), or have a UID given that does not exist in the system
  # great! let's add the user
  useradd $UID_ARGS -r -g "$PHP_APP_GROUP" "$PHP_APP_USER"
fi

# do we need particular packages installed?
if [ ! -z ${INSTALL_PACKAGES+x} ]; then
  # aye, install them
  echo
  echo "* * * WARNING: INSTALL_PACKAGES envvar support is deprecated and will soon be removed!"
  echo "* * * WARNING: use INSTALL_PACKAGES build arg instead!"
  echo
  DEBIAN_FRONTEND=noninteractive apt-get -q update && apt-get -q -y --no-install-recommends install $INSTALL_PACKAGES && apt-get -q clean && apt-get -q -y autoremove
fi

# log, run and data
mkdir -p /var/log/php-fpm
mkdir -p /var/run/php-fpm
mkdir -p $PHP_APP_DIR
chown $PHP_APP_USER:$PHP_APP_GROUP /var/log/php-fpm
chown $PHP_APP_USER:$PHP_APP_GROUP /var/run/php-fpm
chown $PHP_APP_USER:$PHP_APP_GROUP $PHP_APP_DIR

# PHP-FPM pool configuration.
# expects configuration in /etc/php5/fpm/pool.d/$PHP_APP_NAME.conf file
if [ -s /etc/php5/fpm/pool.d/$PHP_APP_NAME.conf ]; then
    echo "config file /etc/php5/fpm/pool.d/$PHP_APP_NAME.conf found, ignoring any PHP_* env vars!"
else
    # if that file does not exist or is empty, it creates it with config from envvars
    echo "config file /etc/php5/fpm/pool.d/$PHP_APP_NAME.conf not found, setting up from PHP_* env vars!"
    mv /etc/php5/fpm/pool.d/pool.conf /etc/php5/fpm/pool.d/$PHP_APP_NAME.conf
    echo "+-- pool name..."
    sed -i "s/pool_name/$PHP_APP_NAME/g" /etc/php5/fpm/pool.d/$PHP_APP_NAME.conf
    echo "+-- user..."
    sed -i "s/app_user/$PHP_APP_USER/g" /etc/php5/fpm/pool.d/$PHP_APP_NAME.conf
    echo "+-- group..."
    sed -i "s/app_group/$PHP_APP_GROUP/g" /etc/php5/fpm/pool.d/$PHP_APP_NAME.conf
    echo "+-- listen..."
    sed -i -r -e "s@^listen = .*@listen = $PHP_LISTEN@g" /etc/php5/fpm/pool.d/$PHP_APP_NAME.conf
    # access and slowlog locations
    echo "+-- access log..."
    sed -i -r -e "s@^access\.log = .*@access.log = \"$PHP_ACCESS_LOG\"@g" /etc/php5/fpm/pool.d/$PHP_APP_NAME.conf
    echo "+-- slowlog..."
    sed -i -r -e "s@^slowlog = .*@slowlog = \"$PHP_SLOW_LOG\"@g" /etc/php5/fpm/pool.d/$PHP_APP_NAME.conf
    echo "+-- slowlog timeout..."
    sed -i -r -e "s@^request_slowlog_timeout = .*@request_slowlog_timeout = \"$PHP_SLOW_LOG_TIMEOUT\"@g" /etc/php5/fpm/pool.d/$PHP_APP_NAME.conf
fi

# Change the default error location.
echo "+-- error log..."
sed -i "s@error_log = /var/log/php5-fpm.log@error_log = \"$PHP_ERROR_LOG\"@g" /etc/php5/fpm/php-fpm.conf

# Change the default pidfile location.
echo "+-- pidfile..."
sed -i "s@pid = .*@pid = $PHP_PID_FILE@g" /etc/php5/fpm/php-fpm.conf

# let's run the darn thing,
# if there is anything to run that is
if [ $# -ne 0 ]; then

    # watch the files
    watch_logfiles "$PHP_ACCESS_LOG" "$PHP_ERROR_LOG" "$PHP_SLOW_LOG" &
    sleep 1

    echo "+-- running command:"
    echo "    $@"
    exec "$@"
else
    echo "+-- no command specified."
fi