check_systemctl

#!/bin/bash

# 1.0.1: Removed double quote in service status, double quote might be bad interpreted by scripts such as custom notification script.
# 1.0: Initial script

SCRIPT_VERSION=1.0.1
MAINTAINER_NAME="Mickael Ange"
MAINTAINER_EMAIL_ADDRESS=akiran28@hotmail.com

SCRIPT_HOSTNAME=$(hostname)
SCRIPT_DIR=$(pwd)
WHOAREU=$(whoami)
SCRIPT_NAME=$0
PARAM=$@

VERSION_TO_DISPLAY="Script Version: $SCRIPT_VERSION\nMaintainer: $MAINTAINER_NAME <$MAINTAINER_EMAIL_ADDRESS>"

GET_VERSION=false
RUNNING_STATUS="active"
STOPPED_STATUS="inactive"
FAILED_STATUS="failed"
DEFAULT_EXPECTED_STATUS=$RUNNING_STATUS

# Nagios Exit Codes
EXIT_OK=0
EXIT_WARNING=1
EXIT_CRITICAL=2
EXIT_UNKNOWN=3

f_display_usage() {
    cat << EOF
    Check service status with systemctl.
    USAGE: $0 -s <service_name> [OPTIONS]
    OPTIONS:
        -e | --expected-status
            The expected service status: $RUNNING_STATUS | $STOPPED_STATUS.
            Defaults: $DEFAULT_EXPECTED_STATUS

        -h | --help
            Display this help.

        -s | --service
            The name of the service to check, e.g. nginx or nginx.service.

        -v | --version
            Display script version.        
EOF
}

f_log() {
    msg="$1"
    level=$2
    msg_to_log_in_console="$level - $msg"
    echo -e "$msg_to_log_in_console"
}

f_log_unknown() {
    f_log "$1" "UNKNOWN"
    f_display_usage
    exit $EXIT_UNKNOWN 
}

f_log_ok() {
    f_log "$1" "OK"
    exit $EXIT_OK
}

f_log_warning() {
    f_log "$1" "WARNING"
    exit $EXIT_WARNING
}

f_log_critical() {
    f_log "$1" "CRITICAL"
    exit $EXIT_CRITICAL
}


f_parse_parameters() {
# Define long options
    long_opts="expected-status:,help,service:,version"
    
    # read the options
    params=`getopt -o e:hs:v --long $long_opts -n $SCRIPT_NAME -- $PARAM`
    eval set -- "$params"
    
    while true ; do
        case "$1" in
            -e|--expected-status)
                EXPECTED_STATUS="$2" 
                shift
        ;;
            -h|--help)
                f_log_unknown "Display help"
        ;;
            -s|--service)
                SERVICE_NAME="$2"
                shift
        ;;
            -v|--version)   # Get the version of the script
                GET_VERSION=true
        ;;
            --) break 
        ;;
                # Handle unknown option
            *)  f_log_unknown "Unknown option: $1, exited.."
        ;;
        esac
        shift
    done
        
    # Validate parsed parameters
    f_validate_parameters
}

f_diplay_script_version(){
   f_log_unknown "$VERSION_TO_DISPLAY"
}

f_validate_parameters() {
    # Display script version
    if $GET_VERSION; then
        f_diplay_script_version
        exit $EXIT_UNKNOWN
    fi

    # Check service name
    if [ -z "$SERVICE_NAME" ]; then
        f_log_unknown "Service name is mandatory, you must provide one in command line with option -s or --service."
    fi

    if [ -z "$EXPECTED_STATUS" ]; then
        EXPECTED_STATUS=$DEFAULT_EXPECTED_STATUS
    fi
    if [ "$EXPECTED_STATUS" != "$RUNNING_STATUS" ] && [ "$EXPECTED_STATUS" != "$STOPPED_STATUS" ]; then
       f_log_unknown "Expected status -e should be $RUNNING_STATUS or $STOPPED_STATUS (actual: $EXPECTED_STATUS)"
    fi

}
f_check_service_status() {
    SERVICE_STATUS=`systemctl is-active $SERVICE_NAME`
    STATUS_MSG="Systemctl - Service $SERVICE_NAME is in state $SERVICE_STATUS (expected status is $EXPECTED_STATUS)"
    if [ "$SERVICE_STATUS" = "$EXPECTED_STATUS" ]; then
        f_log_ok "$STATUS_MSG"
    else
        f_log_critical "$STATUS_MSG"
    fi
}

f_parse_parameters

f_check_service_status
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