Sort source names

Sort the list of source names to make the label value consistent.
* Bump time Go mod.

Fixes: #25

Signed-off-by: SuperQ <superq@gmail.com>

collector/sources.go

@@ -18,6 +18,7 @@ import (
 	"fmt"
 	"math"
 	"net"
+	"sort"
 	"strings"
 
 	"github.com/facebook/time/ntp/chrony"
@@ -122,6 +123,7 @@ func (e Exporter) getSourcesMetrics(ch chan<- prometheus.Metric, client chrony.C
 		sourceAddress := r.IPAddr.String()
 		// Ignore reverse lookup errors.
 		sourceNames, _ := net.LookupAddr(sourceAddress)
+		sort.Strings(sourceNames)
 		sourceName := strings.Join(sourceNames, ",")
 
 		if r.Mode == chrony.SourceModeRef && r.IPAddr.To4() != nil {

go.mod

@@ -4,7 +4,7 @@ go 1.19
 
 require (
 	github.com/alecthomas/kingpin/v2 v2.3.2
-	github.com/facebook/time v0.0.0-20230328101046-54fdb4d16625
+	github.com/facebook/time v0.0.0-20230529151911-512b3b30ab23
 	github.com/go-kit/log v0.2.1
 	github.com/prometheus/client_golang v1.16.0
 	github.com/prometheus/common v0.44.0

go.sum

@@ -12,8 +12,8 @@ github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ3
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/facebook/time v0.0.0-20230328101046-54fdb4d16625 h1:n9sqA4q62V8p3b7hcotw23eP1k3KETSJpJdO6uzPYCk=
-github.com/facebook/time v0.0.0-20230328101046-54fdb4d16625/go.mod h1:dfouHrgxDA7FxAzPYOFIGHFcrFlG2trLpeLtA5+hs+Q=
+github.com/facebook/time v0.0.0-20230529151911-512b3b30ab23 h1:2bNmQUpwOmOwPrUFts4znQaefE8fYMzf3yutKzWztWM=
+github.com/facebook/time v0.0.0-20230529151911-512b3b30ab23/go.mod h1:dfouHrgxDA7FxAzPYOFIGHFcrFlG2trLpeLtA5+hs+Q=
 github.com/go-kit/log v0.2.1 h1:MRVx0/zhvdseW+Gza6N9rVzU/IVzaeE1SFI4raAhmBU=
 github.com/go-kit/log v0.2.1/go.mod h1:NwTd00d/i8cPZ3xOwwiv2PO5MOcx78fFErGNcVmBjv0=
 github.com/go-logfmt/logfmt v0.5.1 h1:otpy5pqBCBZ1ng9RQ0dPu4PN7ba75Y/aA+UpowDyNVA=