add probe_ip_addr_hash to detect if the IP changes (#584)

* add probe_ip_addr_hash to detect if the IP changes

Signed-off-by: Wing924 <weihe924stephen@gmail.com>

diff --git a/prober/utils.go b/prober/utils.go
index d1d0388555ccece06750fbc70449ed869c5d1580..98c9152ea36efa0d643467c103353e06a40b7ae0 100644 (file)
--- a/prober/utils.go
+++ b/prober/utils.go
@@ -16,6 +16,7 @@ package prober
 import (
        "context"
        "fmt"
+       "hash/fnv"
        "net"
        "time"
 
@@ -37,8 +38,14 @@ func chooseProtocol(ctx context.Context, IPProtocol string, fallbackIPProtocol b
                Name: "probe_ip_protocol",
                Help: "Specifies whether probe ip protocol is IP4 or IP6",
        })
+
+       probeIPAddrHash := prometheus.NewGauge(prometheus.GaugeOpts{
+               Name: "probe_ip_addr_hash",
+               Help: "Specifies the hash of IP address. It's useful to detect if the IP address changes.",
+       })
        registry.MustRegister(probeIPProtocolGauge)
        registry.MustRegister(probeDNSLookupTimeSeconds)
+       registry.MustRegister(probeIPAddrHash)
 
        if IPProtocol == "ip6" || IPProtocol == "" {
                IPProtocol = "ip6"
@@ -71,6 +78,7 @@ func chooseProtocol(ctx context.Context, IPProtocol string, fallbackIPProtocol b
                        if ip.IP.To4() != nil {
                                level.Info(logger).Log("msg", "Resolved target address", "ip", ip.String())
                                probeIPProtocolGauge.Set(4)
+                               probeIPAddrHash.Set(ipHash(ip.IP))
                                return &ip, lookupTime, nil
                        }
 
@@ -81,6 +89,7 @@ func chooseProtocol(ctx context.Context, IPProtocol string, fallbackIPProtocol b
                        if ip.IP.To4() == nil {
                                level.Info(logger).Log("msg", "Resolved target address", "ip", ip.String())
                                probeIPProtocolGauge.Set(6)
+                               probeIPAddrHash.Set(ipHash(ip.IP))
                                return &ip, lookupTime, nil
                        }
 
@@ -100,6 +109,13 @@ func chooseProtocol(ctx context.Context, IPProtocol string, fallbackIPProtocol b
        } else {
                probeIPProtocolGauge.Set(6)
        }
+       probeIPAddrHash.Set(ipHash(fallback.IP))
        level.Info(logger).Log("msg", "Resolved target address", "ip", fallback.String())
        return fallback, lookupTime, nil
 }
+
+func ipHash(ip net.IP) float64 {
+       h := fnv.New32a()
+       h.Write(ip)
+       return float64(h.Sum32())
+}