#!/bin/bash
# Fred Denis -- Jan 2019 -- fred.denis3@gmail.com -- http://unknowndba.blogspot.com
# rac-mon.sh - A script to monitor a RAC / GI 12c using rac-status.sh (https://goo.gl/EwDeKn)
# Copyright (C) 2021 Fred Denis
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <https://www.gnu.org/licenses/>.
#
#
# More info and git repo: https://goo.gl/EwDeKn -- https://github.com/freddenis/oracle-scripts
#
# The current script version is 20211111
#
# History :
#
# 20211111 - Fred Denis - GPLv3 licence
# 20190913 - Fred Denis - rac-status options can be passed as a parameter (-o)
# 20190118 - Fred Denis - Initial Release
#
#
# Variables
#
       REFERENCE="${HOME}/rac-status_reference"         # The reference file where is saved the good status of your cluster
       RACSTATUS="${HOME}/rac-status.sh"                # The rac-status.sh script location
             TMP=$(mktemp)                              # A tempfile
            TMP2=$(mktemp)                              # Another tempfile
 AUTO_CREATE_REF="Yes"                                  # If yes, create the reference file if it does not exist (for first execution)
         OPTIONS="-a -w0"                               # Options to use with rac-status.sh
#
# Email alerting
#
         EMAILTO="youremail@company.com"                # The email to send the alert to
EMAIL_ON_FAILURE="No"                                   # Default behavior to send an email if an error is detected (-e option) - put Yes to always send emails
EMAIL_ON_SUCCESS="No"                                   # Default behavior to send an email even if no error is detected (-s option) - put Yes to always send emails
FAILURE_SUBJECT="Error : Cluster status at "`date`      # Subject of the email sent
SUCCESS_SUBJECT="OK : Cluster status at "`date`         # Subject of the email sent
#
# usage function
#
usage() {
printf "\n\033[1;37m%-8s\033[m\n" "NAME"                ;
cat << END
    `basename $0` - A quick and efficient RAC/GI 12c monitoring tool based on rac-status.sh (https://goo.gl/LwQC1N)
END

printf "\n\033[1;37m%-8s\033[m\n" "SYNOPSIS"            ;
cat << END
    $0 [-e] [-s] [-h]
END

printf "\n\033[1;37m%-8s\033[m\n" "DESCRIPTION"         ;
cat << END
    `basename $0` needs the rac-status.sh script to be downloaded and working (https://goo.gl/LwQC1N)

    `basename $0` executes rac-status.sh $OPTIONS and compares its output with a previously saved good status of your cluster
    If no reference file exists, `basename $0` will create it for you at the location pointed by the REFERENCE variable.

    If `basename $0` finds differences betwen the current status of the cluster and the good status from the reference file,
    you will be prompted about it and `basename $0` will exit 1. If no difference found, you will be prompted about it and `basename $0` will exit 0.

    `basename $0` can also send emails about this depending on the -e and -s option as well as the EMAIL_ON_FAILURE and EMAIL_ON_SUCCESS variables.
END

printf "\n\033[1;37m%-8s\033[m\n" "OPTIONS"             ;
cat << END
    -e    Sends an email to the email(s) defined in the EMAILTO parameter if an issue has been detected in the cluster
    -s    Sends an email to the email(s) defined in the EMAILTO parameter on success (even if no error has been detected)

          If you want to modify the script default to always send emails and not have to specify -e or -s,
          just change the values of these parameters on top of the script like this:
              EMAIL_ON_FAILURE="Yes"
              EMAIL_ON_SUCCESS="Yes"
    -o    Specify the options to use for rac-status
              $ ./rac-mon.sh -s -o "-a -w0"

    -h    Show this help

END

exit 567
}
#
# Show the version of the script (-V)
#
show_version() {
        VERSION=$(awk '{if ($0 ~ /^# 20[0-9][0-9][0-1][0-9]/) {print $2; exit}}' $0)
        printf "\n\t\033[1;36m%s\033[m\n" "The current version of "`basename $0`" is "$VERSION"."          ;
}
#
# Command line options
#
while getopts "esho:V" OPT; do
    case ${OPT} in
    e)  EMAIL_ON_FAILURE="Yes"                               ;;
    s)  EMAIL_ON_SUCCESS="Yes"                               ;;
    o)           OPTIONS="${OPTARG}"                         ;;
    V)  show_version; exit 567                               ;;
    h)  usage                                                ;;
    \?) echo "Invalid option: -$OPTARG" >&2; usage           ;;
    esac
done
#
# Variables verification
#
if [[ ! -x "${RACSTATUS}" ]]; then
    cat << !
    Cannot find $RACSTATUS or $RACSTATUS is not executable; the rac-status.sh script is needed and needs to be executable to run this script, to fix this issue:
        - Please have a look at https://goo.gl/LwQC1N and downloada rac-status.sh
        - Adjust the RACSTATUS variable on top of this script to point to the location you saved rac-status.sh
        - Make $RACSTATUS executable:
            $ chmod u+x $RACSTATUS
!
        exit 456
fi
if [[ ! -f "${REFERENCE}" ]]; then                                            # No reference file, we cannot continue
    if [[ "${AUTO_CREATE_REF}" == "Yes" ]]; then                         # Reference file does not exist, we create it
        printf "\t%s" "No reference file found at $REFERENCE, creating it . . ."
        ${RACSTATUS} ${OPTIONS} > "${REFERENCE}"
        if [ $? -eq 0 ]; then
            printf "\t\033[1;32m%-8s\033[m\n" "OK"          ;
        else
            printf "\t\033[1;31m%-8s\n" "Error $ERR"          ;
            printf "%s\033[m\n" "Could not create $REFERENCE using $RACSTATUS ${OPTIONS} > $REFERENCE; cannot continue."
            exit 444
        fi
    else
        cat << !
            Cannot find the ${REFERENCE} file. A status reference file is needed to be able to compare the current status of the cluster with
            Please initialize this reference file as below:
            $ $RACSTATUS ${OPTIONS} > $REFERENCE
!
            exit 123
    fi
fi
#
# Check the current status of the cluster
#
${RACSTATUS} ${OPTIONS} > "${TMP}"
if [ $? -ne 0 ]; then
    cat << !
    There was an error executing ${RACSTATUS}, please try executing it manually first and reach out to the author if it doesn't work.
!
fi
#
# Check for any difference between the reference file $REFERENCE and the current status from $TMP
#
diff "${REFERENCE}" "${TMP}" > "${TMP2}" 2>&1
if [ $? -eq 0 ]; then                            # All good
    cat << !
    No change has been identified across the cluster, all good !
!
    if [[ "${EMAIL_ON_SUCCESS}" == "Yes" ]]; then
        printf "\t%s" "Sending en email to " ${EMAILTO} " . . ."
        echo "No change has been identified across the cluster, all good !" | mailx -s "${SUCCESS_SUBJECT}" ${EMAILTO}
        if [ $? -eq 0 ]; then
            printf "\t\033[1;32m%-8s\033[m\n" "OK"          ;
        else
            printf "\t\033[1;31m%-8s\n" "Error $ERR"          ;
            printf "%s\033[m\n" "There was an issue sending an email using mailx -s ${SUCCESS_SUBJECT} ${EMAILTO}"
            exit 555
        fi
    fi
    RET=0
else                            # Something is wrong, we send an email about it
    cat << !
    The below changes have been identified across the cluster:
!
    cat "${TMP2}"
    if [[ "${EMAIL_ON_FAILURE}" = "Yes" ]]; then
        printf "\t%s" "Sending en email to " ${EMAILTO} " . . ."
        # Remove colors from the file before sending the email
        cat "${TMP2}" | sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[m|K]//g" | mailx -s "${FAILURE_SUBJECT}" "${EMAILTO}"
        if [ $? -eq 0 ]; then
            printf "\t\033[1;32m%-8s\033[m\n" "OK"          ;
        else
            printf "\t\033[1;31m%-8s\n" "Error $ERR"          ;
            printf "%s\033[m\n" "There was an issue sending an email using mailx -s ${FAILURE_SUBJECT} ${EMAILTO}"
            exit 666
        fi
    fi
    RET=1
fi
#
# Delete the tempfiles
#
for F in "${TMP}" "${TMP2}"; do 
    rm -f "${F}"
done

exit "${RET}"
#*********************************************************************************************************
#                               E N D     O F      S O U R C E
#*********************************************************************************************************