popufare/server/scripts/autocfg_svn.sh

#!/bin/bash
#
# Copyright (c) 2021 Clementine Computing LLC.
#
# This file is part of PopuFare.
#
# PopuFare is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# PopuFare is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with PopuFare.  If not, see <https://www.gnu.org/licenses/>.
#


verbose=0
httpd_user="apache"
svn_dir="/home/bus/current_config"
deploy_dir="/home/bus/new_bus/devel"
deploy_cmd="deploy_config.sh"

prog_name="${0##*/}"
lockfile_name="/tmp/$prog_name.pid_lock"

try_and_get_lock() {

  if [ -f $lockfile_name ]; then
    lock_pid="`cat $lockfile_name`"
    echo "ERROR: An instance of $prog_name is already running with PID $lock_pid." 2>&1
    exit 1
  else
    echo $$ > $lockfile_name
                if [ "$verbose" = "1" ]; then
            echo "Got lock: $lockfile_name for PID $$"
                fi
  fi

}

release_lock() {

  if [ -f $lockfile_name ]; then

    lock_pid="`cat $lockfile_name`"

    if [ "$lock_pid" -eq "$$" ]; then
                        
      rm -f $lockfile_name
                        if [ "$verbose" = "1" ]; then
              echo "Released lock: $lockfile_name for PID $$"  
                        fi
    else
      echo "WARNIG: release_lock() called for lock $lockfile_name belonging to PID $lock_pid.  Lock not removed." 2>&1
    fi

  else
    echo "WARNIG: release_lock() called for nonexistent lock $lockfile_name" 2>&1 
  fi

}

export_and_cleanup() {

  #Make sure we can execute commands as the subversion user (by trying to run /bin/true using sudo -u (see comment below)
  if sudo -u $httpd_user /bin/true; then

    $deploy_dir/webui/export_bus_files.php

    #    This is _CRITICAL_ because if we do the export but can't remove the dropfiles
    #we will keep running the export every single time through the loop, which is _bad_.
    #To make sure this condition is met, the following line should be present in the 
    #/etc/sudoers file.
    #
    #%apache    ALL=(apache)       NOPASSWD: ALL
    #
    sudo -u $httpd_user rm -f /tmp/new_drivers_exist /tmp/new_paddles_exist

  else
    echo -e "WARNIG: User \"$USER\" not permitted to execute commands as \"$httpd_user\" using sudo -u\nNot exporting paddles and drivers because drop files cannot be removed afterwards." 2>&1
  fi

}

cruft_remover() {
        svn ls $1 | sed s:/$::g | sort > /tmp/oldlist
        ls $1 | sed s:/$::g | sort > /tmp/newlist
        for i in `diff /tmp/oldlist /tmp/newlist | grep "< " | sed s/^\<\ //g`; do svn rm $1/$i; done
  rm -f /tmp/oldlist /tmp/newlist
}

get_rev() {
  svn info | egrep "^Revision: [0-9]+$" | egrep -o "[0-9]+$"
}



######################################### ENTRY POINT #####################################################

#Try and get a lock (bad things happen if two of this process try and run at once...
try_and_get_lock

#Change to the configuration sandbox that contains the current config snapshot
pushd $svn_dir > /dev/null

#Ask SVN what our old [current as of right before we start making changes] revision is...
old_rev=`get_rev`

#See if we need to pump the database for new paddles or drivers or we've been forced...
if [ "$1" = "-f" ] || [ -f /tmp/new_drivers_exist ] || [ -f /tmp/new_paddles_exist ] ; then
  
  #If this is the case, we want to do the export and remove the dropfiles when we're done...
  export_and_cleanup
fi

#Attempt to add all files in this directory (most will be ignored because they're already under version control)
svn add * -q 2>/dev/null

#Commit these added and/or changed files...
svn commit --non-interactive -m "added stuff." -q

#Remove any files from subversion that are no longer present
cruft_remover .

#Commit these removals
svn commit --non-interactive -m "removed cruft." -q

#    Perform an SVN update to catch any structure changes, or any files added from elsewhere.
#This also effectively brings this sandbox up to the latest revision.
svn update --non-interactive -q

#Ask SVN what our new [after any changes have been applied] revision is...
new_rev=`get_rev`

#If these revision numbers differ, that means we need to push a new configuration out to the clients.
if [ "$new_rev" != "$old_rev" ]; then

  #Change our working directory to the working directory of the deploy script
  pushd $deploy_dir > /dev/null

    #    Signal to the deploy script that we are using an external verion control system and we want to
    #have our SVN revision number included in the config version string.
    export deploy_rev="$new_rev"

    #Execute the deploy script and tell it to go look in the SVN sandbox for its component config files
    ./$deploy_cmd $svn_dir
    
                if [ "$verbose" = "1" ]; then
                        echo "Configuration deployed."
                fi

  popd > /dev/null
else
        if [ "$verbose" = "1" ]; then
                echo "No changes have been made."
        fi
fi

#Release our lock so that we can run another day (or minute as the case may be...
release_lock

popd > /dev/null