add -sum-field option

.gitignore

@@ -0,0 +1 @@
+ethflux

README.md

@@ -6,7 +6,8 @@
 ## Getting the code
 
 ```
-go get github.com/DCSO/ethflux.git
+cd ethflux
+go get ./...
 ```
 
 ## Building
@@ -20,13 +21,17 @@ will produce an `ethflux` binary.
 ## Usage
 
 ```
-Usage: ethflux [-help] [-quiet] [-measurement=string] <iface pattern>
+Usage: ethflux [-help] [-quiet] [-hostname] [-measurement=string] [-sum-field=name=regex ...] <iface pattern>
   -help
     	show help
+  -hostname
+    	use os.Hostname() rather than FQDN
   -measurement string
     	name of measurement to use in line (default "ethtool")
   -quiet
     	do not show warnings
+  -sum-field value
+    	add a derived field as name=regex, summing all fields matching regex (can be repeated)
 ```
 The interface parameter supports regular expressions, e.g. `wl.*` would match `wlp4s0` etc.
 

ethflux.go

@@ -10,19 +10,57 @@ import (
 	"net"
 	"os"
 	"regexp"
+	"strings"
 
 	"github.com/DCSO/fluxline"
-	log "github.com/Sirupsen/logrus"
 	"github.com/safchain/ethtool"
+	log "github.com/sirupsen/logrus"
 )
 
+// sumField describes a derived field that is computed as the sum of all
+// existing fields whose name matches Pattern.
+type sumField struct {
+	Name    string
+	Pattern *regexp.Regexp
+}
+
+// sumFieldsFlag allows the -sum-field flag to be specified multiple times,
+// each in the form name=regex.
+type sumFieldsFlag []sumField
+
+func (s *sumFieldsFlag) String() string {
+	parts := make([]string, len(*s))
+	for i, f := range *s {
+		parts[i] = fmt.Sprintf("%s=%s", f.Name, f.Pattern.String())
+	}
+	return strings.Join(parts, ",")
+}
+
+func (s *sumFieldsFlag) Set(value string) error {
+	idx := strings.Index(value, "=")
+	if idx < 0 {
+		return fmt.Errorf("invalid -sum-field value %q, expected format name=regex", value)
+	}
+	name := value[:idx]
+	pattern := value[idx+1:]
+	re, err := regexp.Compile(pattern)
+	if err != nil {
+		return fmt.Errorf("invalid regex in -sum-field %q: %w", value, err)
+	}
+	*s = append(*s, sumField{Name: name, Pattern: re})
+	return nil
+}
+
 func main() {
 
 	msmt := flag.String("measurement", "ethtool",
 		"name of measurement to use in line")
 	help := flag.Bool("help", false, "show help")
 	quiet := flag.Bool("quiet", false, "do not show warnings")
 	useHostname := flag.Bool("hostname", false, "use os.Hostname() rather than FQDN")
+	var sumFields sumFieldsFlag
+	flag.Var(&sumFields, "sum-field",
+		"add a derived field as name=regex, summing all fields matching regex (can be repeated)")
 	flag.Parse()
 
 	argsWithoutProg := flag.Args()
@@ -33,7 +71,7 @@ func main() {
 	}
 
 	if *help {
-		fmt.Fprintln(os.Stderr, "Usage: ethflux [-help] [-quiet] [-hostname] [-measurement=string] <iface pattern>")
+		fmt.Fprintln(os.Stderr, "Usage: ethflux [-help] [-quiet] [-hostname] [-measurement=string] [-sum-field=name=regex ...] <iface pattern>")
 		flag.PrintDefaults()
 		os.Exit(1)
 	}
@@ -77,6 +115,16 @@ func main() {
 			log.Fatal(err)
 		}
 
+		for _, sf := range sumFields {
+			var sum uint64
+			for k, v := range stats {
+				if sf.Pattern.MatchString(k) {
+					sum += v
+				}
+			}
+			stats[sf.Name] = sum
+		}
+
 		stringStats := make(map[string]string)
 		for k, v := range stats {
 			stringStats[k] = fmt.Sprintf("%d", v)

go.mod

@@ -0,0 +1,14 @@
+module github.com/DCSO/ethflux
+
+go 1.26.3
+
+require (
+	github.com/DCSO/fluxline v0.0.0-20200907065040-78686e5e68f6
+	github.com/safchain/ethtool v0.7.0
+	github.com/sirupsen/logrus v1.9.4
+)
+
+require (
+	github.com/Showmax/go-fqdn v1.0.0 // indirect
+	golang.org/x/sys v0.38.0 // indirect
+)

go.sum

@@ -0,0 +1,18 @@
+github.com/DCSO/fluxline v0.0.0-20200907065040-78686e5e68f6 h1:ILpYBsvnQwnM7PvDKoLjLx47tE0jPsR/oX3CvhuhJG4=
+github.com/DCSO/fluxline v0.0.0-20200907065040-78686e5e68f6/go.mod h1:PvQC78r0wMuOsJ8Sl9isIEYR+00WKI/gliLjVYfDVjQ=
+github.com/Showmax/go-fqdn v1.0.0 h1:0rG5IbmVliNT5O19Mfuvna9LL7zlHyRfsSvBPZmF9tM=
+github.com/Showmax/go-fqdn v1.0.0/go.mod h1:SfrFBzmDCtCGrnHhoDjuvFnKsWjEQX/Q9ARZvOrJAko=
+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/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/safchain/ethtool v0.7.0 h1:rlJzfDetsVvT61uz8x1YIcFn12akMfuPulHtZjtb7Is=
+github.com/safchain/ethtool v0.7.0/go.mod h1:MenQKEjXdfkjD3mp2QdCk8B/hwvkrlOTm/FD4gTpFxQ=
+github.com/sirupsen/logrus v1.9.4 h1:TsZE7l11zFCLZnZ+teH4Umoq5BhEIfIzfRDZ1Uzql2w=
+github.com/sirupsen/logrus v1.9.4/go.mod h1:ftWc9WdOfJ0a92nsE2jF5u5ZwH8Bv2zdeOC42RjbV2g=
+github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
+github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+golang.org/x/sys v0.38.0 h1:3yZWxaJjBmCWXqhN1qh02AkOnCQ1poK6oF+a7xWL6Gc=
+golang.org/x/sys v0.38.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=