#!/bin/sh
#
#Get OS Release information and output it in prometheus text format to be ingested
#
#Currently supports:
# - Any Linux Distro with /etc/os-release file (most modern Linux Distros)

#node_release_info
node_release_info="node_release_info{} 0"

if [[ -f "/etc/os-release" ]]; then
        #The following fields are not gathered as they do not provide any useful information
        #ANSI_COLOR=,HOME_URL=, DOCUMENTATION_URL=, SUPPORT_URL=, BUG_REPORT_URL=, PRIVACY_POLICY_URL=,LOGO=

        #Read file into array
        IFS=$'\r\n' GLOBIGNORE='*' command eval 'node_release=($(cat /etc/os-release))'

        #Regex fields for parsing file/array
        NAME_REGEX="^NAME=.*"
        VERSION_REGEX="^VERSION=.*"
        ID_REGEX="^ID=.*"
        ID_LIKE_REGEX="^ID_LIKE=.*"
        VERSION_CODENAME_REGEX="^VERSION_CODENAME=.*"
        VERSION_ID_REGEX="^VERSION_ID=.*"
        PRETTY_NAME_REGEX="^PRETTY_NAME=.*"
        CPE_NAME_REGEX="^CPE_NAME=.*"
        BUILD_ID_REGEX="^BUILD_ID=.*"
        VARIENT_REGEX="^VARIENT=.*"
        VARIENT_ID_REGEX="^VARIENT_ID=.*"

        #Loop through file/array
        for i in "${node_release[@]}"
        do
                if [[ "$i" =~ $NAME_REGEX ]]; then
                        IFS="=" read _ name <<< $i
                        IFS='"' read _ name <<< $name
                elif [[ "$i" =~ $VERSION_REGEX ]]; then
                        IFS="=" read _ version <<< $i
                        IFS='"' read _ version <<< $version
                elif [[ "$i" =~ $ID_REGEX ]]; then
                        IFS="=" read _ id <<< $i
                        IFS='"' read _ id <<< $id
                elif [[ "$i" =~ $ID_LIKE_REGEX ]]; then
                        IFS="=" read _ id_like <<< $i
                        IFS='"' read _ id_like <<< $id_like
                elif [[ "$i" =~ $VERSION_CODENAME_REGEX ]]; then
                        IFS="=" read _ version_codename <<< $i
                        IFS='"' read _ version_codename <<< $version_codename
                elif [[ "$i" =~ $VERSION_ID_REGEX ]]; then
                        IFS="=" read _ version_id <<< $i
                        IFS='"' read _ version_id <<< $version_id
                elif [[ "$i" =~ $PRETTY_NAME_REGEX ]]; then
                        IFS="=" read _ pretty_name <<< $i
                        IFS='"' read _ pretty_name <<< $pretty_name
                elif [[ "$i" =~ $CPE_NAME_REGEX ]]; then
                        IFS="=" read _ cpe_name <<< $i
                        IFS='"' read _ cpe_name <<< $cpe_name
                elif [[ "$i" =~ $BUILD_ID_REGEX ]]; then
                        IFS="=" read _ build_id <<< $i
                        IFS='"' read _ build_id <<< $build_id
                elif [[ "$i" =~ $VARIENT_REGEX ]]; then
                        IFS="=" read _ varient <<< $i
                        IFS='"' read _ varient <<< $varient
                elif [[ "$i" =~ $VARIENT_ID_REGEX ]]; then
                        IFS="=" read _ varient_id <<< $i
                        IFS='"' read _ varient_id <<< $varient_id
                fi
        done

        #build node release string
        node_release_info="node_release_info{name=\"${name}\",version=\"${version}\",id=\"${id}\",id_like=\"${id_like}\",version_codename=\"${version_codename}\",version_id=\"${version_id}\",pretty_name=\"${pretty_name}\",cpe_name=\"${cpe_name}\",build_id=\"${build_id}\",varient=\"${varient}\",varient_id=\"${varient_id}\"} 1"
fi

echo "# HELP node_release_info Labeled OS information as provided by the OS specific release file."
echo "# TYPE node_release_info gauge"
echo $node_release_info