Implement interval output (closes #1)

Author: dkorunic

README.md

@@ -30,15 +30,16 @@ NAME
   pktstat
 
 FLAGS
-  -?, --help               display help
-  -v, --add_vlan           if true, add VLAN header
-  -j, --json               if true, output in JSON format
-      --version            display program version
-  -s, --snaplen INT        snaplen (if <= 0 uses 65535) (default: 0)
-  -b, --bufsize INT        interface buffersize in MB (default: 8)
-  -f, --filter STRING      BPF filter
-  -i, --iface STRING       interface to read from (default: any)
-  -t, --timeout DURATION   timeout for packet capture (default: 0s)
+  -?, --help                display help
+  -v, --add_vlan            if true, add VLAN header
+  -j, --json                if true, output in JSON format
+      --version             display program version
+  -s, --snaplen INT         snaplen (if <= 0 uses 65535) (default: 0)
+  -b, --bufsize INT         interface buffersize in MB (default: 8)
+  -f, --filter STRING       BPF filter
+  -i, --iface STRING        interface to read from (default: en0)
+  -t, --timeout DURATION    timeout for packet capture (default: 10m0s)
+  -l, --interval DURATION   interval between packet capture output (default: 0s)
 ```
 
 By default pktstat listens to all interfaces without any BPF filter. It is possible to specify interface with `--iface` and specify a BPF filter either including or excluding needed traffic, for instance `--filter "not port 22"`.
@@ -47,6 +48,8 @@ Timeout `--timeout` will stop execution after a specified time, but it is also p
 
 With `--json` it is possible to get traffic statistics in JSON format.
 
+Interval `--interval` when it is greater than zero (and less than timeout duration) will make program output statistics for every such duration until program exit.
+
 ## Star History
 
 [![Star History Chart](https://api.star-history.com/svg?repos=dkorunic/pktstat,dkorunic/pktstat-bpf&type=Date)](https://star-history.com/#dkorunic/pktstat&dkorunic/pktstat-bpf&Date)

flags.go

@@ -42,7 +42,7 @@ var (
 	iface, filter                      *string
 	snaplen, bufferSize                *int
 	addVLAN, version, help, jsonOutput *bool
-	timeout                            *time.Duration
+	timeout, interval                  *time.Duration
 )
 
 func parseFags() {
@@ -61,6 +61,7 @@ func parseFags() {
 	iface = fs.String('i', "iface", findFirstEtherIface(), "interface to read from")
 
 	timeout = fs.Duration('t', "timeout", defaultTimeout, "timeout for packet capture")
+	interval = fs.Duration('l', "interval", 0, "interval between packet capture output")
 
 	var err error
 
@@ -86,4 +87,8 @@ func parseFags() {
 	if *snaplen <= 0 {
 		*snaplen = 65535
 	}
+
+	if *timeout > 0 && *interval > 0 && *interval >= *timeout {
+		*interval = 0
+	}
 }

go.mod

@@ -5,17 +5,17 @@ go 1.24
 toolchain go1.24.0
 
 require (
-	github.com/KimMachineGun/automemlimit v0.7.2
+	github.com/KimMachineGun/automemlimit v0.7.4
 	github.com/goccy/go-json v0.10.5
 	github.com/google/gopacket v1.1.19
 	github.com/hako/durafmt v0.0.0-20210608085754-5c1018a4e16b
 	github.com/peterbourgon/ff/v4 v4.0.0-alpha.4
 	go.uber.org/automaxprocs v1.6.0
-	golang.org/x/net v0.41.0
+	golang.org/x/net v0.42.0
 )
 
 require (
 	github.com/pbnjay/memory v0.0.0-20210728143218-7b4eea64cf58 // indirect
 	github.com/stretchr/testify v1.8.4 // indirect
-	golang.org/x/sys v0.33.0 // indirect
+	golang.org/x/sys v0.34.0 // indirect
 )

go.sum

@@ -1,5 +1,5 @@
-github.com/KimMachineGun/automemlimit v0.7.2 h1:DyfHI7zLWmZPn2Wqdy2AgTiUvrGPmnYWgwhHXtAegX4=
-github.com/KimMachineGun/automemlimit v0.7.2/go.mod h1:QZxpHaGOQoYvFhv/r4u3U0JTC2ZcOwbSr11UZF46UBM=
+github.com/KimMachineGun/automemlimit v0.7.4 h1:UY7QYOIfrr3wjjOAqahFmC3IaQCLWvur9nmfIn6LnWk=
+github.com/KimMachineGun/automemlimit v0.7.4/go.mod h1:QZxpHaGOQoYvFhv/r4u3U0JTC2ZcOwbSr11UZF46UBM=
 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/goccy/go-json v0.10.5 h1:Fq85nIqj+gXn/S5ahsiTlK3TmC85qgirsdTP/+DeaC4=
@@ -28,13 +28,13 @@ golang.org/x/lint v0.0.0-20200302205851-738671d3881b/go.mod h1:3xt1FjdF8hUf6vQPI
 golang.org/x/mod v0.1.1-0.20191105210325-c90efee705ee/go.mod h1:QqPTAvyqsEbceGzBzNggFXnrqF1CaUcvgkdR5Ot7KZg=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
-golang.org/x/net v0.41.0 h1:vBTly1HeNPEn3wtREYfy4GZ/NECgw2Cnl+nK6Nz3uvw=
-golang.org/x/net v0.41.0/go.mod h1:B/K4NNqkfmg07DQYrbwvSluqCJOOXwUjeb/5lOisjbA=
+golang.org/x/net v0.42.0 h1:jzkYrhi3YQWD6MLBJcsklgQsoAcw89EcZbJw8Z614hs=
+golang.org/x/net v0.42.0/go.mod h1:FF1RA5d3u7nAYA4z2TkclSCKh68eSXtiFwcWQpPXdt8=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.33.0 h1:q3i8TbbEz+JRD9ywIRlyRAQbM0qF7hu24q3teo2hbuw=
-golang.org/x/sys v0.33.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
+golang.org/x/sys v0.34.0 h1:H5Y5sJ2L2JRdyv7ROF1he/lPdvFsd0mJHFw2ThKHxLA=
+golang.org/x/sys v0.34.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/tools v0.0.0-20200130002326-2f3ba24bd6e7/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

main.go

@@ -124,12 +124,16 @@ func main() {
 	signalCh := make(chan os.Signal, 1)
 	signal.Notify(signalCh, os.Interrupt, syscall.SIGTERM, syscall.SIGINT)
 
-	go func() {
-		s := <-signalCh
-		fmt.Fprintf(os.Stderr, "Received %v signal, trying to exit...\n", s)
-		cancel()
-		close(statCh)
-	}()
+	go func(ctx context.Context) {
+		select {
+		case <-ctx.Done():
+			return
+		case s := <-signalCh:
+			fmt.Fprintf(os.Stderr, "Received %v signal, trying to exit...\n", s)
+			cancel()
+			close(statCh)
+		}
+	}(c1)
 
 	if *timeout > 0 {
 		go func() {
@@ -139,11 +143,21 @@ func main() {
 		}()
 	}
 
+	if *interval > 0 {
+		go func(ctx context.Context) {
+			for {
+				select {
+				case <-ctx.Done():
+					return
+				default:
+					time.Sleep(*interval)
+					outputStats(startTime, statMap, totalPackets, totalBytes)
+				}
+			}
+		}(c1)
+	}
+
 	wg.Wait()
 
-	if *jsonOutput {
-		outputJSON(startTime, statMap, totalPackets, totalBytes)
-	} else {
-		outputPlain(startTime, statMap, totalPackets, totalBytes)
-	}
+	outputStats(startTime, statMap, totalPackets, totalBytes)
 }

output.go

@@ -126,3 +126,17 @@ func (s *statJSON) MarshalJSON() ([]byte, error) {
 		Proto: s.Proto.String(),
 	})
 }
+
+// outputStats outputs the collected statistics in either plain text or JSON format.
+//
+// startTime: the start time of the statistics collection.
+// statMap: a map containing statistical data.
+// totalPackets: total number of packets.
+// totalBytes: total number of bytes.
+func outputStats(startTime time.Time, statMap StatMap, totalPackets uint64, totalBytes uint64) {
+	if *jsonOutput {
+		outputJSON(startTime, statMap, totalPackets, totalBytes)
+	} else {
+		outputPlain(startTime, statMap, totalPackets, totalBytes)
+	}
+}