#!/bin/bash
#
# egdbback, copyright 2005-2008 Egressive Limited, http://egressive.com
#
# this script runs periodic database backups...
#
#==========================================
# The Variables - these must be define
#   before they're referenced
#==========================================
VERSION="0.3"
EGDB_NAME=`basename $0`
EGDB_DIR=/etc/egscripts/egdbback
EGDB_CMD=$EGDB_DIR/egdbback
EGDB_CONF_DIR=$EGDB_DIR/conf
SITE_CONF="$EGDB_CONF_DIR/site.conf"
# the appropriate mysql paths
MYDIR=/var/lib/mysql
#
# this provides values for MACHINE_NAME and EMAIL
. $SITE_CONF
#
LOGS=/var/log
LOG=$LOGS/egdbback.log
#==========================================
# Defaults - these shouldn't need changing
#==========================================
PERIODS="hourly daily weekly monthly yearly"
hourlyNUM="24"
dailyNUM="7"
weeklyNUM="4"
monthlyNUM="12"
yearlyNUM="7"

hourlyNEXT="daily"
dailyNEXT="weekly"
weeklyNEXT="monthly"
monthlyNEXT="yearly"

# required programs
MAIL=`which mail`
GREP=`which grep`
LS=`which ls`
ID=`which id`
DATE=`which date`
DF=`which df`
GZIP=`which gzip`
GZIPSUF=gz
RM=`which rm`
LN=`which ln`
CUT=`which cut`
AWK=`which awk`
# determine today's date
TODAY=`$DATE '+%Y-%m-%d-%a'`
# determine today's date
NOW=`$DATE '+%H-%M-%S'`
# a timestamp for logging purposes
TIMESTAMP=`$DATE '+%Y-%m-%d %H:%M.%S'`
# temporary holding point for email
TMP_DIR=/tmp
TMP_EMAIL=$TMP_DIR/$EGDB_NAME"_tmp_email_"$TODAY.$TIME
#
#==========================================
#  MySQL vars...
MYTMP=$MYBKP/tmp-$DATE
MYDUMP=`which mysqldump`
MYSQL=`which mysql`
MYSHOW=`which mysqlshow`
#==========================================
#  The Functions - these have to be defined
#    before they're called!  Note, refer
#   to them without the "()" and provide
#   up to one argument, referred to as "$@"
#   in the function...
#==========================================
#
# function to direct a message...
message() {
  # a timestamp for logging purposes
  timestamp
  if test -w $LOG ; then
    echo "$EGDB_NAME: $TIMESTAMP $@" >> $LOG
  fi
  if test -w $TMP_EMAIL ; then
    echo "$EGDB_NAME: $TIMESTAMP $@" >> $TMP_EMAIL
  fi
  verbose "$TIMESTAMP $@"
}
#
# function to direct a message...
verbose() {
  if test $VERBOSE ; then
    echo "$@"
  fi
}
#
# insert a blank line into the log and on the console
insert_blank() {
  echo "" >> $TMP_EMAIL
  verbose ""
}
#
# update date and time info..
today() {
  # determine today's date
  TODAY=`$DATE '+%Y-%m-%d-%a'`
}
#
#
now() {
  # determine today's date
  NOW=`$DATE '+%H-%M-%S'`
}
#
#
timestamp() {
  # a timestamp for logging purposes
  TIMESTAMP=`$DATE  '+%Y-%m-%d %H:%M.%S'`
}
#
# create the temporary email file
create_tmp_email() {
  if test -d $TMP_DIR ; then
    if test -w $TMP_DIR ; then
      touch $TMP_EMAIL 2>&1
    else
      error "Email tmp directory $TMP_DIR is not writable"
    fi
  else
    error "Email tmp directory $TMP_DIR does not exist"
  fi
  
  if test -w $TMP_EMAIL ; then
    message "created temporary email $TMP_EMAIL"
  else
    error "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_TO"
    if test $ERROR_STATUS == 1 ; then
      EMAIL_SUBJ="[ERROR] $MACHINE_NAME $DEFAULT_EMAIL_SUBJ"
    else
      EMAIL_SUBJ="[SUCCESS] $MACHINE_NAME $DEFAULT_EMAIL_SUBJ"
    fi
    # check space again to see how close things are to full
    
    message "Printing disk space for reference purposes:"
    DISK_SPACE=`$DF`
    message "$DISK_SPACE"
    # send it to each email address in the list...
    for EMAIL_ADD in $EMAIL_TO
    do
      RES=`$MAIL -s "$EMAIL_SUBJ" $EMAIL_ADD < $TMP_EMAIL`
      if test -z $RES ; then
        if test $ERROR_STATUS == 1 ; then
          message "Error email report successfully sent to $EMAIL_ADD"
        else
          message "Email report successfully sent to $EMAIL_ADD"
        fi
      else
        if ! test $ERROR_STATUS == 1 ; then
          error "Email report send to $EMAIL_ADD failed with this message: $RES"
        fi
      fi
    done
    if test -w $TMP_EMAIL ; then
      $RM $TMP_EMAIL 2>&1
    else
      if ! test $ERROR_STATUS == 1 ; then
        error "Failed to remove email message file, $TMP_EMAIL: permission denied."
      fi
    fi
    if test -f $TMP_EMAIL ; then
      error "Failed to remove email message file $TMP_EMAIL for an unknown reason"
    else
      message "successfully removed temporary email  $TMP_EMAIL"
    fi
  else
    if ! test $ERROR_STATUS == 1 ; then
      error "Email message file, $TMP_EMAIL, does not exist."
    fi
  fi
}
#
# function to direct an error...
error() {
  #
  # recognise that the system experienced
  # an error and send out a special email, and halt
  # the program!
  timestamp
  ERROR_STATUS=1
  #
  # get current user details
  USER_DETAILS=`$ID`
  if test -w $LOG ; then
    echo "$EGDB_NAME: **ERROR** $TIMESTAMP $@" >> $LOG
    echo "$EGDB_NAME: user details - $USER_DETAILS" >> $LOG
  fi
  if test -w $TMP_EMAIL ; then
    echo "$EGDB_NAME: **ERROR** $TIMESTAMP $@" >> $TMP_EMAIL
    echo "  user details: $USER_DETAILS" >> $LOG
  fi
  verbose "$TIMESTAMP **ERROR** $@"
  verbose "  user details: $USER_DETAILS"
  send_email_report
  exit 1   
}
#
#  build list of backup configuration files
get_confs() {
  CONFS=`$LS -1 $EGDB_CONF_DIR/$CONF_ROOT*.conf 2>&1`
  TEST=`echo $CONFS | $GREP -c "No such file or directory" -`
  if test $TEST == 1 ; then
    error "No configuration files found with root $CONF_ROOT in $EGDB_CONF_DIR"
  fi
}
# delete old backups
delete_old() {
  for PERIOD in $PERIODS
  do
    BU_TO_KEEP=$((${PERIOD}NUM))
    echo "keeping $BU_TO_KEEP files for $PERIOD"
    PATTERN="$FROOT-*.*"
    PRUNEABLES=`$LS -tr1 $BU_DIR/$PATTERN`
    #echo "pruneable files: $PRUNEABLES"
    NUM=0
    for FILE in $PRUNEABLES
    do
      NUM=$(($NUM + 1))
      if test $NUM -gt $BU_TO_KEEP ; then
        echo "removing $FILE ($NUM/$BU_TO_KEEP)"
        $RM $FILE
#      else
#        echo "not removing $FILE ($NUM/$BU_TO_KEEP)"
      fi
    done
  done
}
#
# convert last monthly into daily, daily->weekly, weekly->monthly, monthly->yearly
roll_over() {
  # First figure out if this backup is a "roll" one
  # by conducting a few tests
  hourly_ROLL=0
  daily_ROLL=0
  weekly_ROLL=0
  monthly_ROLL=0
  # hour of the day 0-23
  if test `$DATE '+%k'` -eq "0" ; then 
    message "it's time to create a new daily backup!"
    hourly_ROLL=1
  fi
  # day of the week 0-6
  if test `$DATE '+%w'` -eq "0" ; then  
    message "it's time to create a new weekly backup!"
    daily_ROLL=1
  fi
  # day of month 0-31ish
  if test `$DATE '+%d'` -eq "00" ; then  
    message "it's time to create a new monthly backup!"
    weekly_ROLL=1
  fi
  # day of year 0-366ish
  if test `$DATE '+%j'` -eq "000" ; then  
    message "it's time to create a new yearly backup!"
    monthly_ROLL=1
  fi  
  for PERIOD in $PERIODS
  do
    ROLL=$((${PERIOD}_ROLL))
    echo "checking $PERIOD for rollover: $ROLL"
    if test $ROLL -eq "1" ; then
      echo "rollover for $PERIOD"
      # Use the dynamic variable approach...
      VAR=${PERIOD}NEXT
      # ...to set value of NEXT to the *value* of $VAR
      eval NEXT=\$$VAR
      if ! test -z $NEXT; then
	echo "rolling $PERIOD to the value of $VAR ($NEXT)"
	# get the root name for the most recent $PERIOD file
	PATTERN="$FROOT-*.*"
        PERIOD_FILES=`$LS -qt1 $BU_DIR/$PATTERN`
        echo "\$?=$?"
        # only proceed with the copy if there's a suitable file
        if test $? ; then 
	for FILE in $PERIOD_FILES 
          do
	          echo "copying $FILE"
	          break
          done
          # the echo "" is required to launch awk properly...
          NEW_FILE=`echo "" | $AWK -v fn=$FILE -v nxt="NEXT" '{ 
	    split(fn,filepath,"/"); 
	    filename = filepath[length(filepath)]; 
	    split(filename,filenameparts,"-"); 
	    filecut = length(filenameparts[1]); 
	    pathcut = length(filename); 
	    path = substr(fn,1,length(fn)-pathcut); 
	    subname = substr(filename, filecut + 1); 
	    print path nxt subname; }'`
          echo "to $NEW_FILE"
          $CP $FILE $NEW_FILE
        else
          echo "there's no suitable file to copy!"
        fi
      else
        echo "there is no 'next' for $PERIOD"
      fi
    else
      echo "no rollover for $PERIOD this time"
    fi    
  done
}
#
#  Make sure there's sufficient disk space (or at least that it's not full!)
check_space() {
  RES=`$DF -h`
  #message "$RES"
  TEST=0
  PCENT="100%"
  TEST=`echo "$RES" | $GREP -c "$PCENT"`
  if test $TEST == 1  ; then
    PART_LINE=`echo "$RES" | $GREP "$PCENT"`
    # get the device name which is showing $PCENT
    TEST=`echo $PART_LINE | $CUT -f 1 -d ' '`
    # if it has a partition number in the name, it's probably a block
    # device rather than, say, a CDROM...
    TEST2=`echo $TEST | $GREP -c [0-9]`
    echo "Test2 = $TEST2"
    if test $TEST2 == 1 ; then
      error "Partition $TEST is full - detail: $PART_LINE"
    else
      message "false alarm - it's only the $TEST volume..."
    fi
  fi
}
#
#  this is where we do all the backup-related stuff - what ebu used to do...
do_backup() {
  # first, find out what dbs there are
  DBLIST=`$MYSHOW -u $USER -p$PASSWORD | $AWK '{ if ($2!~/^$/&&$2!="Databases") { print $2;}}'`
  #message "List of databases: $DBLIST"
  # for each db in the list, create a compressed backup in the right place
  message "creating a backup of the MySQL databases on $MACHINE_NAME..."
  for DB in $DBLIST
  do
    FROOT=hourly-$DB
    # work out which backups should be turned into dailies, weeklies, monthlies, etc.
    roll_over
    # we only create hourlies
    now
    today
    FNAME=$FROOT-$TODAY.$NOW
    # --opt is same as  --add-drop-table --add-locks --all --extended-insert --quick --lock-tables
    CMD="$MYDUMP -u $USER -p$PASSWORD --opt $DB"
    # create the new backup!
    if test $DRY_RUN == 1 ; then
      message "I would be doing this (if it was not a dry run):" 
      message "$CMD > $BU_DIR/$FNAME"
    else
      message "backing up table $DB..."
      message "running $MYDUMP with user $USER, creating $BU_DIR/$FNAME"
      $CMD  > $BU_DIR/$FNAME
      if test -f $BU_DIR/$FNAME ; then
        $GZIP $BU_DIR/$FNAME
      else
        error "backup sql file, $BU_DIR/$FNAME, doesn't exist!"
      fi
    fi
    # delete old backups, so that only BU_TO_KEEP of them are stored at once
    delete_old
  done
}
#========================================
#  The Error Checking
#========================================
#
# first, check that all the necessary files and stuff are there and usable
#
# if the log doesn't exist, create it
if ! test -f $LOG ; then
  message "creating non-existent log file $LOG"
  RET=`touch $LOG 2>&1 /dev/null`
  TEST=`echo $RET | $GREP -c "Permission denied" -`
  if test $TEST == 1 ; then
    error "Failed to create log file $LOG, user cannot write to that directory"
  fi
fi
# checking whether it's there an is writable
if ! test -w $LOG ; then
  error "Log file $LOG not writable"
fi

#========================================
#  The Functional Part of the Script
#========================================
#  set variable defaults
ERROR_STATUS=0  # initially assume no errors
VERBOSE=0  # initially assume quiet output
CONF_ROOT="hourly" # set it to something we know so we can test if it's changed
DRY_RUN=0 # assume this is not a dry run...
CURRENT_LINK="none"
MODE=help
#  process any arguments
while test $# -ne 0 ; do  # while there are arguments
  message "argument: $1"
  case $1 in
    --help|-h|-?)
      verbose "setting mode to HELP"
      MODE=help
      ;;
    --verbose|-v)
      verbose "setting verbostity to ON"
      VERBOSE=1
      ;;
    --dryrun)
      verbose "setting dryrun to ON"
      DRY_RUN=1
      ;;
    *)
      verbose "unknown option: $1"
      message "unknown option: $1"
      MODE=help
      ;;
   esac
   shift
done 
if ! test $MODE == "help" ; then
  MODE=run
fi
#
#  set things in motion based on the script arguments
case $MODE in
  run)
    create_tmp_email
    get_confs
    #  run backup for each file
    for BU_CONF in $CONFS
    do
      message "do backup with conf: $BU_CONF"
      . $BU_CONF  # grab the current variables for this conf file...
      do_backup
      # put a space in the email to separate tasks
      insert_blank
    done
    #
    #  send the resulting email
    send_email_report
    ;;
  help)
    if test $CONF_ROOT; then
      echo "error: please specify a period for egbackup"
    fi
    echo ""
    echo "$EGDB_NAME, version $VERSION, copyright 2005-7 Egressive Ltd, http://egressive.com"
    echo "==================="
    echo "usage: $EGDB_NAME"
    echo "== options =="
    echo "-v or --verbose -  give extra feedback on progress to stdout"
    echo "-c or --configroot config_filename - root for configuration filenames"
    echo "--dryrun - do everything else, but *don't* delete anything or run the backup"
    echo ""
  ;;
esac