#!/bin/bash

# Maintenance:
# * Recfactored from original version (2016-07-04) on 2017-04-07 by Sebastian J.
#   Bronner <sebastian@bronner.name>.
# * Modified: 2017-05-19 by Sebastian J. Bronner

DEFAULT_BINDIR='$HOME/secondo/bin'

function die {
  for arg
  do
    echo "$arg" >&2
  done
  echo >&2
  echo "Usage  : $0 <conffile> <action>" >&2
  echo "Details: $0 --help" >&2
  exit 1
}

function printUsage {
  cat << EOF
Usage: $0 <conffile> <action>

<action> can be start, stop, check, update, or mkdbdir:"
'start'   starts the monitors in <conffile>.
'stop'    stops any running monitors in <conffile>.
'check'   shows the status of the monitors in <conffile>.
'update'  updates Secondo via CVS on all <server>s in <conffile>.
'mkdbdir' creates the database directories specified in <conffile>.

Each line within <conffile> has to be in the following format:
<server> <conffile> [<bindir> [<dbdir> [<port> [<user>]]]]

<server>: the hostname where the monitor should be run
<config>: configuration file to use, must exist on server side
<bin>   : the Secondo bin directory containing the SecondoMonitor executable
<home>  : overwrite the database directory specified in the configuration file
          if not used, but later arguments should be set, use a dollar sign as
          place holder
<port>  : overwrite the monitor port specified in the configuration file if not
          used, but later arguments should be set, use a dollar sign as place
          holder
<user>  : user with which to run command on the remote machine, including the
          monitor
EOF
  exit
}

function startLine {
  echo -n "$userhost${port:+:}$port ... "
  ssh "$userhost" 'bash -s' << EOF
set -e
. \$HOME/.secondorc
cd ${bindir:-$DEFAULT_BINDIR}
port=${port:-\$(sed -rn 's/^SecondoPort=([^#[:space:]]*)[[:space:]]*(#.*$)?/\1/p' $conffile)}
test "\$TMPDIR" || export TMPDIR=/tmp
tmpfile="\$TMPDIR/SM_\$port.lck"
if [ -e "\$tmpfile" ]
then
  echo "failed! A SecondoMonitor (pid \$(cat "\$tmpfile")) is already running on port \$port."
  exit
fi
nohup ./SecondoMonitor -s -c $conffile ${dbdir:+-d }$dbdir ${port:+-p }$port > SecondoMonitor.log 2>&1 &
pid=\$!
echo \$pid > "\$tmpfile"
if ps --no-headers -p \$pid > /dev/null
then
  echo "started with pid \$pid$(test "$port" || echo " on port \$port")."
else
  echo "failed! The SecondoMonitor process (pid \$pid) disappeared unexpectedly."
  rm "\$tmpfile"
fi
EOF
  test $? -eq 0 || echo 'failed!'
}

function stopLine {
  echo -n "$userhost${port:+:}$port ... "
  ssh "$userhost" 'bash -s' << EOF
set -e
cd ${bindir:-$DEFAULT_BINDIR}
port=${port:-\$(sed -rn 's/^SecondoPort=([^#[:space:]]*)[[:space:]]*(#.*$)?/\1/p' $conffile)}
test "\$TMPDIR" || export TMPDIR=/tmp
tmpfile="\$TMPDIR/SM_\$port.lck"
if [ ! -e "\$tmpfile" ]
then
  echo "done. No SecondoMonitor was found running on port \$port."
  exit
fi
pid=\$(cat "\$tmpfile")
if ! pgid=\$(ps --no-headers -p \$pid -o pgid)
then
  echo "done. No SecondoMonitor was found with pid \$pid."
  rm "\$tmpfile"
  exit
fi
pgid=\$(echo \$pgid)
if kill -s 9 -\$pgid
then
  echo "done."
  rm "\$tmpfile"
else
  echo "failed! The SecondoMonitor on port \$port with pid \$pid could not be killed."
fi
EOF
  test $? -eq 0 || echo 'failed!'
}

function checkLine {
  echo -n "$userhost${port:+:}$port ... "
  ssh "$userhost" 'bash -s' << EOF
set -e
cd ${bindir:-$DEFAULT_BINDIR}
port=${port:-\$(sed -rn 's/^SecondoPort=([^#[:space:]]*)[[:space:]]*(#.*$)?/\1/p' $conffile)}
test "\$TMPDIR" || export TMPDIR=/tmp
tmpfile="\$TMPDIR/SM_\$port.lck"
if [ ! -e "\$tmpfile" ]
then
  echo "NOT RUNNING!$(test "$port" || echo " (port \$port)")"
  exit
fi
pid=\$(cat "\$tmpfile")
if ps --no-headers -p \$pid > /dev/null
then
  echo "running with pid \$pid$(test "$port" || echo " on port \$port")."
else
  echo "NOT RUNNING! (pid \$pid$(test "$port" || echo ", port \$port")), removing marker."
  rm "\$tmpfile"
fi
EOF
  test $? -eq 0 || echo 'ERROR!'
}

function updateLine {
  # Check whether $userhost was already updated and update the list of already
  # updated userhosts and their update status.
  for u in "${updated[@]}"
  do
    test "$u" == "$userhost" && return
  done
  n=${#updated[@]}
  updated[n]="$userhost"
  status[n]='not started'

  # Label the output.
  echo
  echo "> > > $userhost < < <"
  echo

  # Determine $remotedir.
  if [ "$bindir" ]
  then
    remotedir="${bindir%/bin}"
  else
    remotedir="$(ssh "$userhost" '. $HOME/.bashrc; echo $SECONDO_BUILD_DIR')"
    if [ -z "$remotedir" ]
    then
      echo "Can't determine SECONDO_BUILD_DIR for $userhost!"
      status[n]='aborted, no SECONDO_BUILD_DIR'
      return
    fi
  fi
  echo "Remote SECONDO_BUILD_DIR: $remotedir"

  # Copy current makefile.algebras to $userhost.
  scp "$SECONDO_BUILD_DIR/makefile.algebras" "$userhost:$remotedir/"
  status[n]='aborted, copied makefile.algebras'

  # Run the update.
  ssh "$userhost" 'bash -s' << EOF
set -e
. \$HOME/.secondorc
cd $remotedir
cvs update -PdA
make
EOF
  test $? == 0 && status[n]='complete' || status[n]='aborted with remote errors'
}

function mkdbdirLine {
  test -z "$dbdir" && echo "no dbdir specified in line '$*'." && return
  ssh "$userhost" mkdir -p "$dbdir"
}

# Check <conffile> specified on commandline.
test "$1" || die "No <conffile> was specified."
test "$1" == '--help' && printUsage
test -r "$1" || die "Unable to read <conffile> '$1'."

# Check <action> specified on commandline.
test "$2" || die "No <action> was specified."
method="${2}Line"
declare -f "$method" > /dev/null || die "The <action> '$2' is not valid."

# Execute <action> for every line in <conffile>.
while read server conffile bindir dbdir port user rest
do
  test "$server" || return  # empty line
  test -z "$conffile" && echo "Invalid format in line '$*'." && return
  test "$bindir" == '$' && unset bindir
  test "$dbdir" == '$' && unset dbdir
  test "$port" == '$' && unset port
  test "$user" == '$' && unset user
  userhost="$user${user:+@}$server"
  $method
done < $1

# Perform some post-action stuff.
if [ "$2" == 'update' ]
then
  echo
  echo 'Update Summary'
  echo
  for((i=0; i<${#updated[@]}; i++))
  do
    echo "${updated[i]}: ${status[i]}"
  done
fi

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