#!/bin/bash
#
# This script dumps the osl db on new.egressive.com
# and pipes the results into an appropriately named/dated
# file...
#
# The following options must be specified in .conf files
# in a directory designated with the -c switch.
#
# # backup directory
# BU_DIR=/storage/warhol/pgsql/daily
# # the database details
# SERVER=localhost
# USER=root
# PASSWORD=
# # names of the databases to backup
# DBS="osl osltest egressive seradigm egressive_accounts"
# # email address to send reports to, and subject
# EMAIL=dlane@egressive.com
# EMAIL_SUBJ="Postgres daily OSL Backup Report"
# # backup identifier
# BU_IDENT=daily
# # number of backups for each db to keep
# BU_TO_KEEP=7
# # output for debugging...
VERBOSE=0
#
# Stuff that should be universal for this install...
# where we can find this app...
MAIN_DIR=/etc/pgdbbackup
# determine today's date
DATE=`date   '+%Y-%m-%d-%a'`
# determine today's date
TIME=`date   '+%H-%M-%S'`
# temporary holding point for email
TMP_EMAIL=/tmp/tmp_pgdbbackup_email.$DATE_$TIME
# log file
LOG=/var/log/epgdbbackup.log
#
# Commands
# gzip command
GZIP=`which gzip`
# grep command
GREP=`which grep`
# email program
MAIL=`which mail`
# database dump utility
PGDUMP=`which pg_dump`
DEF_ARGS="-C -d -O -x"
#
# pattern for "ls" command to build list of
# pruneable backup files...
# -1t = 1 column, ordered by time of last mod
PRUNEABLES_CMD="ls -1t"
# function to direct a message...
message() {
  #
  # a timestamp for logging purposes
  TIMESTAMP=`date  '+%Y-%m-%d %H:%M.%S'`
  echo "$0: $TIMESTAMP $@" >> $LOG
  if test -f $TMP_EMAIL ; then
    echo "$0: $TIMESTAMP $@" >> $TMP_EMAIL
  fi
  verbose "$TIMESTAMP $@"
}
# create the temporary email file
create_tmp_email() {
  touch $TMP_EMAIL
  if test -f $TMP_EMAIL ; then
    message "created temporary email  $TMP_EMAIL"
  else
    message "failed to create temporary email  $TMP_EMAIL"
  fi
}
# send the contents of the temporary file to the
# designated report recipient
send_email_report() {
  if test -f $TMP_EMAIL ; then
    message "sending email report to $EMAIL"
    $MAIL -s "$EMAIL_SUBJ" $EMAIL < $TMP_EMAIL
    rm $TMP_EMAIL
    if test -f $TMP_EMAIL ; then
      message "failed to remove temporary email  $TMP_EMAIL"
    else
      message "successfully removed temporary email  $TMP_EMAIL"
    fi
    message "email report successfully sent"
  fi
}
# insert a blank line into the log and on the console
insert_blank() {
  echo "" >> $LOG
  verbose ""
}
# function to direct a message...
verbose() {
  if test $VERBOSE = 1 ; then
    echo "$@"
  fi
}
#
# delete old backups
delete_old() {
  #
  if test -n $BU_FROOT && test -n $BU_TO_KEEP ; then
    # pattern to search for to build the list...
    PATTERN="$BU_DIR/$BU_FROOT-*.*"
    # build the list, with the suffix...
    PRUNEABLES=`$PRUNEABLES_CMD $PATTERN`
    if  test "$?" -eq "0" ; then
      message "pruning older files based on $PATTERN.$BU_SUFFIX"
      message "keeping last $BU_TO_KEEP backups"
      #
      # set counter
      NUM=0
      # go through the list of files and remove those we don't want
      for PRUNEABLE in $PRUNEABLES
      do
        NUM=$(($NUM + 1))
        if test $NUM -gt $BU_TO_KEEP ; then
          message "deleting $PRUNEABLE"
          rm $PRUNEABLE 2>&1 > /dev/null
        else
          message "keeping $PRUNEABLE"
        fi
      done
    fi
  else
    message "keeping older backups, missing backup_root_filename..."
  fi
}

#
# cycle through the command line options
while test $# -ne 0 ; do
  case $1 in
    --config|-c)
      shift # shift from the flag to the value
      verbose "setting configuration directory to $1"
      BU_CONFDIR=$1
    ;;
  esac
  shift
done
#
#
# create the blank email report
create_tmp_email
#
# run through the various configuration files
message "looking for configuration files in $BU_CONFDIR"
if test -d $MAIN_DIR/$BU_CONFDIR ; then
  CONFS=`ls -1 $MAIN_DIR/$BU_CONFDIR/*.conf`
  message "found these config files: $CONFS"
  for CONF in $CONFS
  do
    if test -f $CONF ; then
      message "processing $CONF configuration file"
      # source the configuration file
      source $CONF
      # go to the backup directory
      cd $BU_DIR
      # set up database access info
      export PGUSER=$USER
      export PGPASSWORD=$PASSWORD
      message "starting backup of databases $DBS"
      #
      # dump the database
      for DB in $DBS
      do
        # a timestamp for logging purposes
        STAMP=`date  '+%Y-%m-%d_%H-%M-%S'`
        # create a root filename
        BU_FROOT=$DB-$BU_IDENT
        # delete stale backups
        delete_old
        # generate the filename
        FILENAME=$BU_FROOT-$STAMP.sql
        message "backing up database '$DB' into file $FILENAME"
        # dump the data into the file
        $PGDUMP $DEF_ARGS -h $SERVER -f $FILENAME $DB
        message "completed backup of '$DB'"
        # compress the backup
        message "compressing $FILENAME"
        $GZIP $FILENAME
        # vaccuum the database
      done
      message "completed backup of databases: $DBS"
      # return to where you started from...
      cd $OLDPWD
    fi
  done
  message "read config files in $BU_CONF directory"
else
  message "config directory $BU_CONF doesn't exist!"
  exit 1
fi
# sent resulting email report
send_email_report
exit 0