89 lines
1.7 KiB
Go
89 lines
1.7 KiB
Go
package main
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import (
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"context"
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"flag"
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"fmt"
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"os"
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"github.com/nberlee/go-netstat/netstat"
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"github.com/prometheus/client_golang/prometheus"
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"github.com/prometheus/common/expfmt"
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)
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var (
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maybe_port = flag.Uint("port", 8500, "Port to monitor")
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)
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func main() {
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flag.Parse()
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// Check port number before attempting to cast it to a uint16
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if *maybe_port < 1 || *maybe_port > 65535 {
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fmt.Fprintln(os.Stderr, "Invalid port number")
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os.Exit(1)
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}
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port := uint16(*maybe_port)
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reg := prometheus.NewRegistry()
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open_consul_connections := prometheus.NewGauge(prometheus.GaugeOpts{
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Subsystem: "consul",
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Name: "open_tcp_connections",
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Help: "Number of open consul tcp connections",
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ConstLabels: prometheus.Labels{
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"port": fmt.Sprintf("%d", port),
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},
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})
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reg.MustRegister(open_consul_connections)
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open_consul_connections.Set(float64(ConsulConnectionCount(port)))
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metricFamilies, err := reg.Gather()
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if err != nil {
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panic(err)
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}
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for _, mf := range metricFamilies {
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expfmt.MetricFamilyToText(os.Stdout, mf)
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}
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}
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// Filters
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func PortFilter(port uint16) func(s *netstat.SockTabEntry) bool {
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return func(s *netstat.SockTabEntry) bool {
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return s.LocalEndpoint.Port == port
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}
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}
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func StateFilter(s *netstat.SockTabEntry) bool {
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return s.State == netstat.Established
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}
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func ConsulConnectionCount(port uint16) int {
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ctx := context.Background()
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features := netstat.EnableFeatures{
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TCP: true,
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TCP6: true,
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UDP: true,
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UDP6: true,
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PID: true,
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}
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targetFilterFn := PortFilter(port)
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resp, err := netstat.Netstat(ctx, features, func(ste *netstat.SockTabEntry) bool {
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return targetFilterFn(ste) && StateFilter(ste)
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})
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if err != nil {
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fmt.Fprintf(os.Stderr, "Error: %v\n", err)
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return 0
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}
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return len(resp)
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}
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