#!/bin/bash
#
# health-report.sh
#  Simple shell script to email basic server health information
#
# Changelog
#  2014-03-27 - Nathan Isburgh <nathan@edgecloud.com>
#             * Initial version
#             * Implements a top report, and a df report
#

# Debug flag?  1=on, 0=off
DEBUG=1

# Additional user-customized variables...

#
# END OF CONFIGURATION VARIABLES
# NO MORE EDITS BEYOND THIS POINT
#

# Functions...

#
# fail [exit code] [exit message]
#
# Common exit codes:
#  1 - Invalid arguments
#  2 - Missing arguments
#  3 - Missing software
#
fail() {
  cleanup
  ECODE=${1:-1}
  EMSG=$2
  if [ -n "$EMSG" ]
  then
    echo $EMSG > /dev/stderr
  fi
  exit $ECODE
}

succeed() {
  cleanup
  exit
}

cleanup() {
  # Clean up temp files
  # Close out logs
  # Disconnect from remote resources
  return
}

#
# debug "message"
#
debug() {
  if [ $DEBUG -eq 1 ]
  then
    printf "*** [%s] %s\n" "$(date +%r)" "$1" > /dev/stderr
  fi
}

usage() {
  cat << eof
  $0 [-tdmc] [-r date] [email]
    -t          Generate a top report
    -d          Generate a df -h report
    -m          Generate a memory report
    -c          Run in collect-only mode
    -r date     Email report for given date
    email       Address to send report
eof
}

check-email() {
  # Check that email is supplied when required
  if [ -z "$EMAIL" ]
  then
    usage
    fail 2 "Please supply an email address for the report"
  fi
}

top-report() {
  echo -e "\nTop Report\n--------------------------------------" >> $TMPFILE
  top -bn 1 >> $TMPFILE
}

df-report() {
  echo -e "\nDF Report\n---------------------------------------" >> $TMPFILE
  df -h >> $TMPFILE
}

mem-report() {
  echo -e "\nMemory Report\n-----------------------------------" >> $TMPFILE
  ps -Ao comm -o pmem | tail -n +2 | sort -nrk 2 >> $TMPFILE
}

# Main body...

TOPREPORT=0
DFREPORT=0
MEMREPORT=0
COLLECT=0
REPORT=0
DATE=$(date +%F)

while getopts ":tdmcr:" opt; do
  case $opt in
    t)
      TOPREPORT=1
      ;;
    d)
      DFREPORT=1
      ;;
    m)
      MEMREPORT=1
      ;;
    c)
      COLLECT=1
      ;;
    r)
      REPORT=1
      DATE="$OPTARG"
      ;;
    \?)
      usage
      fail 1 "Invalid option: -$OPTARG"
      ;;
    :)
      usage
      fail 1 "Option -$OPTARG requires an argument."
      ;;
  esac
done

# Sanity checks..
if [ $REPORT -eq 1 -a $COLLECT -eq 1 ]
then
  fail 4 "Can not collect and report at same time"
fi

# Sanity checks..
echo "$DATE" | egrep -q '^[0-9]{4}-[0-9]{2}-[0-9]{2}$'
if [ $? -ne 0 ]
then
  fail 20 "Invalid date ( Need: YYYY-MM-DD ): $DATE"
fi

eval EMAIL=\$$OPTIND
TMPFILE=$(mktemp)
LOGFILE="/tmp/health-report.$DATE"

# Runs the reports, collecting results into TMPFILE
if [ $TOPREPORT -eq 1 ]
then
  top-report
fi
if [ $DFREPORT -eq 1 ]
then
  df-report
fi
if [ $MEMREPORT -eq 1 ]
then
  mem-report
fi

#
# DONE 1) No -c and no -r ( original form ) ( email required )
# DONE 2) Yes -c and no -r ( collect only mode ) ( email NOT required )
# 3) No -c and yes -r ( report only mode ) ( email required )
# XXX NOT PRACTICAL 4) Yes -c and yes -r ( Collect *and* report ) ( email required )
#

# Collection mode -- append current reports to LOGFILE
if [ $COLLECT -eq 1 ]
then
  date >> $LOGFILE
  echo '===========================================' >> $LOGFILE
  cat $TMPFILE >> $LOGFILE
elif [ $REPORT -eq 0 ]
then
  # Not collection, nor reporting mode ( original mode )
  check-email
  cat $TMPFILE | mailx -s "Health report - $DATE" $EMAIL
else
  # Report mode
  LOGFILE="/tmp/health-report.$DATE"
  if [ -e "$LOGFILE" ]
  then
    check-email
    cat $LOGFILE | mailx -s "Health report - $DATE" $EMAIL
  else
    fail 10 "Invalid report date: $DATE"
  fi
fi

succeed