app-control

#!/bin/bash
# Control the operation of Python applications.
# Usage: app-control APP_NAME ACTION
# Actions:
#   cron: Cron job tasks for the application.
#   kill: Kill the application (in case it has hung).
#   restart: Gracefully restart the application (uWSGI reload).
#   start: Start the application.
#   status: Status of the application (values: `running`, `stopped`, `crashed`).
#   stop: Stop the application.


APPS_DIR="$HOME/apps"
__DIR__="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
. $__DIR__/_easycli


# HELPERS

function _date() {
  date '+%Y-%m-%d %H:%M:%S'
}


function _error() {
  echo -e "\e[31mERROR: $1\e[0m"
  exit 1
}


function _log() {
  [ $IS_CRON = false ] && echo "[app: $APP_NAME] $1"
}


function _isRunning() {
  # [ -n "$PID" ] && (ps -u `whoami` -o pid= | grep "^`whoami`\s+${PID}$" &> /dev/null)
  [ -n "$PID" ] && [ "`ps -p $PID -o user=`" = "`whoami`" ]
}


# COMMANDS

## Cron job tasks for the application.
function command_cron() {
  IS_CRON=true
  command_start
}


## Kill the application (in case it has hung).
function command_kill() {
  kill -9 $PID
  _log "Killed uWSGI at `_date`."
  rm -f $PID_FILE
}


## List available applications.
function command_list() {
  ls $APPS_DIR
}


## Gracefully restart the application (uWSGI reload).
function command_restart() {
  if _isRunning; then
    $BIN_DIR/uwsgi --reload $PID_FILE
  else
    _log "uWSGI is not running so start it instead."
    command_start
  fi
}


## Start the application.
function command_start() {
  if _isRunning; then
    _log "uWSGI already running."
  else
    mkdir -p `dirname $PID_FILE`
    $BIN_DIR/uwsgi --ini $APP_DIR/uwsgi.ini
    _log "Started uWSGI at `_date`."
  fi
}


## Status of the application (values: `running`, `stopped`, `crashed`).
function command_status() {
  if _isRunning; then
    echo "running"
  else
    [ -z "$PID" ] && echo "stopped" || echo "crashed"
  fi
}


## Stop the application.
function command_stop() {
  if _isRunning; then
    $BIN_DIR/uwsgi --stop $PID_FILE
    sleep 3
    _isRunning && command_kill || _log "Stopped uWSGI at `_date`."
  else
    [ -f "$PID_FILE" ] && _log "uWSGI not running." || _log "No PID file."
  fi

  rm -f $PID_FILE
}


# EXECUTION

# Validate script arguments.
if [ $# -lt 2 ]; then
  [ "$1" == "list" ] && { command_list; exit; }
  easycli_display_usage
  exit 1
fi

# Initialization.
APP_NAME=$1
ACTION=$2
ACTION_FUNCTION="command_$ACTION"

APP_DIR="$APPS_DIR/$APP_NAME"
BIN_DIR="$APP_DIR/venv/bin"
PID_FILE="$APP_DIR/tmp/uwsgi.pid"
[ -f "$PID_FILE" ] && PID=`cat $PID_FILE` || PID=
IS_CRON=false

# Check if app exists.
[ -d "$APP_DIR" ] || { _error "App '$APP_NAME' does not exist."; }

# Execute action.
declare -F "$ACTION_FUNCTION" &> /dev/null
[ $? = 0 ] && $ACTION_FUNCTION || _error "Unknown action '$ACTION'."