#!/usr/bin/env bash

# This is meant to be executed periodically. It will check if the application is
# running. If it's not, it will start it.

# on crontab:
#    * * * * * /bin/bash -l -c '/path/to/watchdog/watchdog.sh'

app="<%= app %>"
user="<%= user %>"
dir="/home/$user/$app/current"
log="$dir/log/$app.log"
touch $log # ensure existence

# test proof of life
alive="$dir/tmp/alive"
if [ -f $alive ]; then
  mtime=$(ls -l --time-style=+%s $alive | awk '{print $6}')
  let "last = $(date +%s) - 60"
  [ $mtime -gt $last ] && exit
fi
touch $alive # ensure existence

# start in an erlang VM
cmd="erl -boot $dir/boot/start -config $dir/boot/sys -env ERL_LIBS $dir/lib"
cmd="$cmd -name $app@localhost -noshell"

echo "$(date) Running: $cmd" >> $log

$cmd 2>&1 >> $log &

########################################
#
#     Some ways to run your app:
#
#     To run (embedded erlang):
#     ```
#         run_erl -daemon /home/$user/$app/pipes/ /home/$user/$app/log
#           "erl -boot $dir/boot/start
#                -config $dir/boot/sys
#                -env ERL_LIBS $dir/lib
#                -sname $app"
#     ```
#
#     To connect (embedded erlang):
#     ```
#         to_erl /home/$user/$app/pipes/erlang.pipe.1
#     ```
#
#     To run (interactive erlang):
#     ```
#         erl -boot $dir/boot/start
#             -config $dir/boot/sys
#             -env ERL_LIBS $dir/lib
#             -name $app@localhost
#     ```
#
#     To run (interactive elixir, using app's own `iex`):
#     ```
#         erl -boot $dir/boot/start
#             -config $dir/boot/sys
#             -env ERL_LIBS $dir/lib
#             -name $app@localhost
#             -noshell -user Elixir.IEx.CLI -extra --no-halt
#     ```
#
#     To run (detached elixir):
#     ```
#         iex --erl "-boot $dir/boot/start
#                    -config $dir/boot/sys
#                    -env ERL_LIBS $dir/lib"
#             --name $app@localhost
#             --detached
#     ```
#
#     To run (detached erlang):
#     ```
#         erl -boot $dir/boot/start
#             -config $dir/boot/sys
#             -env ERL_LIBS $dir/lib
#             -name $app@localhost
#             -detached
#     ```
#
#     To connect (interactive elixir):
#     ```
#         iex --remsh $app@localhost --sname connector
#     ```
#
#     To connect (interactive erlang):
#     ```
#         erl -remsh $app@localhost -sname connector
#     ```
#
#     To connect (interactive elixir, using app's own `iex`):
#     ```
#         erl -remsh $app@localhost -sname connector
#         # and then ...
#         ($app@localhost)1> 'Elixir.IEx':start().
#     ```
#