Munin contributed plugins

#!/usr/bin/env bash

# vim: expandtab:ts=4:sw=4

: << =cut

=head1 NAME

http_response - Monitor HTTP response statistics

=head1 CONFIGURATION

The following environment variables are used

 sites       - Sites to check

                 - separated by spaces

                 - can contain basic auth credentials

                 - defaults to "http://localhost/"

 max_time    - Timeout for each site check in seconds

                 - defaults to 5 seconds

 short_label - Switch for shortening the label below the graph

                 - defaults to false

=head2 CONFIGURATION EXAMPLE

 [http_response]

  env.sites http://example.com/ https://user:secret@example2.de

  env.max_time 20

  env.short_label true

=head1 PREREQUISITES

This plugin needs at least bash version 4 to run

=head1 NOTES

This plugin unifies the functionalities of the following plugins into one

multigraph plugin

 http_loadtime     - https://gallery.munin-monitoring.org/plugins/munin/http_loadtime/

 http_responsecode - https://gallery.munin-monitoring.org/plugins/munin-contrib/http_responsecode/

In contrast to using these two plugins with the same configuration, this plugin

performs only one request per site and munin run to gather its statistics.

=head1 AUTHOR

Copyright (C) 2020 Klaus Sperner

=head1 LICENSE

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; version 2 dated June,

1991.

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, write to the Free Software

Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

=head1 MAGIC MARKERS

 #%# family=manual

=cut

. "$MUNIN_LIBDIR/plugins/plugin.sh"

readonly uri_regex='^(https?://)([^:]*):(.*)@(.*)$'

strip_credentials_from_url() {

    if [[ "$1" =~ $uri_regex ]]; then

        echo "${BASH_REMATCH[1]}${BASH_REMATCH[4]}"

    else

        echo "$1"

    fi

}

extract_username_from_url() {

    if [[ "$1" =~ $uri_regex ]]; then

        echo "${BASH_REMATCH[2]}"

    else

        echo ""

    fi

}

extract_password_from_url() {

    if [[ "$1" =~ $uri_regex ]]; then

        echo "${BASH_REMATCH[3]}"

    else

        echo ""

    fi

}

compute_label() {

    if [[ "${short_label,,}" == "true" || "${short_label,,}" == "yes" ]]; then

        if [[ ${#1} -gt 33 ]]; then

            echo "${1:0:30}..."

        else

            echo "$1"

        fi

    else

        echo "$1"

    fi

}

if [[ "${BASH_VERSINFO:-0}" -lt 4 ]]; then

    >&2 echo "The plugin http_response needs at least bash version 4"

    exit 1

fi

sites=${sites:-"http://localhost/"}

max_time=${max_time:-5}

short_label=${short_label:-"false"}

if [[ "$1" == "config" ]]; then

    echo 'multigraph http_response_code'

    echo 'graph_args --base 1000 -l 0 -u 511'

    echo 'graph_title HTTP Response Codes'

    echo 'graph_vlabel Repsonse Code'

    echo 'graph_category network'

    echo 'graph_info This graph shows HTTP response code statistics'

    echo 'graph_printf %3.0lf'

    for site in $sites; do

        site_without_credentials=$( strip_credentials_from_url "$site" )

        siteid="$( clean_fieldname "$site_without_credentials" )"

        echo "$siteid.label $( compute_label "$site_without_credentials" )"

        echo "$siteid.info HTTP response code statistics for $site_without_credentials"

        echo "$siteid.critical 99:399";

    done

    echo 'multigraph http_response_time'

    echo 'graph_args --base 1000 -l 0'

    echo 'graph_title HTTP Response Times'

    echo 'graph_vlabel Response Time in seconds'

    echo 'graph_category network'

    echo 'graph_info This graph shows HTTP response time statistics'

    for site in $sites; do

        site_without_credentials=$( strip_credentials_from_url "$site" )

        siteid="$( clean_fieldname "$site_without_credentials" )"

        echo "$siteid.label $( compute_label "$site_without_credentials" )"

        echo "$siteid.info HTTP response time statistics for $site_without_credentials"

    done

    exit 0

fi

declare -A response_codes

declare -A response_times

for site in $sites; do

    site_without_credentials=$( strip_credentials_from_url "$site" )

    username=$( extract_username_from_url "$site" )

    password=$( extract_password_from_url "$site" )

    curl_config_file=""

    curl_auth_opt=()

    if [ -n "$username" ]; then

        if [ -z "$password" ]; then

            >&2 echo "Invalid configuration: username specified without password"

            exit 1

        fi

        curl_config_file=$(mktemp) || exit 1

        trap 'rm -f "$curl_config_file"' EXIT

        echo "user=${username}:${password}" >> "$curl_config_file"

        curl_auth_opt=(--config "$curl_config_file")

    fi

    siteid="$( clean_fieldname "$site_without_credentials" )"

    statuscode=

    loadtime=

    start=$(date +%s.%N)

    statuscode=$( curl "${curl_auth_opt[@]}" --write-out '%{http_code}' --max-time "$max_time" --silent --output /dev/null "$site_without_credentials" )

    returncode=$?

    loadtime=$( echo "$start" "$(date +%s.%N)" | awk '{ print($2 - $1); }' )

    if [[ $returncode -ne 0 ]]; then

        loadtime=0

    fi

    response_codes+=(["$siteid"]="$statuscode")

    response_times+=(["$siteid"]="$loadtime")

    if [ -n "$curl_config_file" ]; then

        rm -f "$curl_config_file"

    fi

done

echo 'multigraph http_response_code'

for siteid in "${!response_codes[@]}"; do

    echo "${siteid}.value ${response_codes[${siteid}]}"

done

echo 'multigraph http_response_time'

for siteid in "${!response_times[@]}"; do

    echo "${siteid}.value ${response_times[${siteid}]}"

done