83 lines
2.4 KiB
Bash
83 lines
2.4 KiB
Bash
#!/bin/sh
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defaults () {
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if [ -z $PROMETHEUS_PORT ]; then
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PROMETHEUS_PORT=9100
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fi
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if [ -z $PROMETHEUS_METRIC_NAME ]; then
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PROMETHEUS_METRIC_NAME="metrics_sh"
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fi
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}
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start () {
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readonly prometheus_report_header="# TYPE metrics_sh gauge"
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readonly prometheus_stats_file=$TEMP_DIR/$(unique_id)_prometheus
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readonly prometheus_httpd_fifo=$TEMP_DIR/$(unique_id)_prometheus_fifo
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touch $prometheus_stats_file
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mkfifo $prometheus_httpd_fifo
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prometheus_httpd &
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prometheus_stats_file_monitor &
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}
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report () {
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local metric=$1
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local value=$2
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printf "%s{metric=\"%s\"} %s %s\n" "$PROMETHEUS_METRIC_NAME" "$metric" \
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"$value" "$(unix_timestamp)000" >> $prometheus_stats_file
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}
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stop () {
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if [ ! -z $prometheus_stats_file ] && [ -f $prometheus_stats_file ]; then
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rm $prometheus_stats_file
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fi
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if [ ! -z $prometheus_httpd_fifo ] && [ -p $prometheus_httpd_fifo ]; then
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rm $prometheus_httpd_fifo
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fi
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}
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prometheus_httpd () {
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echo "Serving prometheus HTTP endpoint at http://localhost:$PROMETHEUS_PORT/metrics"
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while true; do
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local REQUEST RESPONSE
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cat $prometheus_httpd_fifo | nc -l $PROMETHEUS_PORT | while read line; do
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line=$(echo "$line" | tr -d '[\r\n]')
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# extract the request
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if echo "$line" | grep -qE '^GET /'; then
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REQUEST=$(echo "$line" | cut -d ' ' -f2)
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# end of request
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elif [ "x$line" = x ]; then
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if echo $REQUEST | grep -qE '^/metrics'; then
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RESPONSE=$(cat $prometheus_stats_file)
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# clear
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printf "" > $prometheus_stats_file
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printf "HTTP/1.1 200 OK\nContent-Type: text/plain\n\n%s\n%s\n" \
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"$prometheus_report_header" "$RESPONSE" > $prometheus_httpd_fifo
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else
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printf "HTTP/1.1 404 Not Found\nLocation: %s\n\n%s\n" \
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"$REQUEST" "404 Not Found" > $prometheus_httpd_fifo
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fi
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fi
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done
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done
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}
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prometheus_stats_file_monitor () {
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while true; do
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local bytes=$(ls -l $prometheus_stats_file | awk '{ print $5 }')
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# clear file if bigger than 5MB
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if [ $bytes -gt 5000000 ]; then
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printf "" > $prometheus_stats_file
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fi
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sleep 120
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done
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}
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docs () {
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echo "Provide HTTP endpoint for Prometheus (http://prometheus.io)."
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echo "Exposes metrics of type gauges in the following format:"
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echo "$PROMETHEUS_METRIC_NAME{metric=\"<metric>\"} <value> <timestamp>"
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echo "PROMETHEUS_PORT=$PROMETHEUS_PORT"
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echo "PROMETHEUS_METRIC_NAME=$PROMETHEUS_METRIC_NAME"
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} |