Make the output machine readable (ddo#18)

* Use go module instead of gopkg, add gitignore for binary

* Added flags which force the output into the desired metric

* Adding non-zero return codes for when the program fails

* Added a silent switch to surpress the status message to make it more machine readable.

* Updated the README with additional arguments

* Ran fmt

Co-authored-by: Mike Hix <mhix@newrelic.com>

.gitignore

@@ -1,3 +1,4 @@
+fast
 build/docker/fast
 build/snap/*
-!build/snap/snapcraft.yaml
+!build/snap/snapcraft.yaml

README.md

@@ -60,6 +60,23 @@ yay -S fast || paru -S fast
 go get -u github.com/ddo/fast
 ```
 
+## Usage
+To use simply invoke `fast` with no arguments.
+```
+$ ./fast
+ -> 340.37 Mbps
+```
+By default fast will print status messages as it progresses and will display a pleasing spinning bar. It will also find the unit of measure most appropriate for your use case.
+
+If you don't want the extra output and you only want the end result, you can use the `--silent` option. Additionally you can force the output into the desired units with the `-k`, `-m`, or `-g` flags.
+
+| Flag     | Description |
+| -------  | ----------- |
+| --silent | Hides status information and only displays the end result |
+| -k       | Forces output into Kbps |
+| -m       | Forces output into Mbps |
+| -g       | Forces output into Gbps |
+
 ## Build
 
 #### Docker

fast.go

@@ -1,25 +1,41 @@
 package main
 
 import (
+	"flag"
 	"fmt"
+	"os"
 	"time"
 
 	"github.com/ddo/go-fast"
 	"github.com/ddo/go-spin"
 )
 
 func main() {
+	var kb, mb, gb, silent bool
+	flag.BoolVar(&kb, "k", false, "Format output in Kbps")
+	flag.BoolVar(&mb, "m", false, "Format output in Mbps")
+	flag.BoolVar(&gb, "g", false, "Format output in Gbps")
+	flag.BoolVar(&silent, "silent", false, "Surpress all output except for the final result")
+
+	flag.Parse()
+
+	if kb && (mb || gb) || (mb && kb) {
+		fmt.Println("You may have at most one formating switch. Choose either -k, -m, or -g")
+		os.Exit(-1)
+	}
+
 	status := ""
 	spinner := spin.New("")
 
 	// output
 	ticker := time.NewTicker(100 * time.Millisecond)
-
-	go func() {
-		for range ticker.C {
-			fmt.Printf("%c[2K %s  %s\r", 27, spinner.Spin(), status)
-		}
-	}()
+	if !silent {
+		go func() {
+			for range ticker.C {
+				fmt.Printf("%c[2K %s  %s\r", 27, spinner.Spin(), status)
+			}
+		}()
+	}
 	// output
 
 	fastCom := fast.New()
@@ -28,7 +44,7 @@ func main() {
 	err := fastCom.Init()
 	if err != nil {
 		fmt.Println(err)
-		return
+		os.Exit(1)
 	}
 
 	status = "connecting"
@@ -37,7 +53,7 @@ func main() {
 	urls, err := fastCom.GetUrls()
 	if err != nil {
 		fmt.Println(err)
-		return
+		os.Exit(1)
 	}
 
 	status = "loading"
@@ -46,36 +62,72 @@ func main() {
 	KbpsChan := make(chan float64)
 
 	go func() {
+		var value, units string
 		for Kbps := range KbpsChan {
-			status = format(Kbps)
-		}
+			value, units = format(Kbps, kb, mb, gb)
+			// don't print the units of measurement if explicitly asked for
+			if kb || mb || gb {
+				status = fmt.Sprintf("%s", value)
+			} else {
+				status = fmt.Sprintf("%s %s", value, units)
+			}
 
-		fmt.Printf("\r%c[2K -> %s\n", 27, status)
+		}
+		if silent {
+			fmt.Printf("%s\n", status)
+		} else {
+			fmt.Printf("\r%c[2K -> %s\n", 27, status)
+		}
 	}()
 
 	err = fastCom.Measure(urls, KbpsChan)
+	ticker.Stop()
 	if err != nil {
 		fmt.Println(err)
+		os.Exit(1)
 	}
 
-	ticker.Stop()
 	return
 }
 
-func format(Kbps float64) string {
+func formatGbps(Kbps float64) (string, string, float64) {
+	f := "%.2f"
+	unit := "Gbps"
+	value := Kbps / 1000000
+	return f, unit, value
+}
+func formatMbps(Kbps float64) (string, string, float64) {
+	f := "%.2f"
+	unit := "Mbps"
+	value := Kbps / 1000
+	return f, unit, value
+}
+func formatKbps(Kbps float64) (string, string, float64) {
+	f := "%.f"
 	unit := "Kbps"
-	f := "%.f %s"
-
-	if Kbps > 1000000 { // Gbps
-		f = "%.2f %s"
-		unit = "Gbps"
-		Kbps /= 1000000
+	value := Kbps
+	return f, unit, value
+}
 
+func format(Kbps float64, kb bool, mb bool, gb bool) (string, string) {
+	var value float64
+	var unit string
+	var f string
+
+	if kb {
+		f, unit, value = formatKbps(Kbps)
+	} else if mb {
+		f, unit, value = formatMbps(Kbps)
+	} else if gb {
+		f, unit, value = formatGbps(Kbps)
+	} else if Kbps > 1000000 { // Gbps
+		f, unit, value = formatGbps(Kbps)
 	} else if Kbps > 1000 { // Mbps
-		f = "%.2f %s"
-		unit = "Mbps"
-		Kbps /= 1000
+		f, unit, value = formatMbps(Kbps)
+	} else {
+		f, unit, value = formatKbps(Kbps)
 	}
 
-	return fmt.Sprintf(f, Kbps, unit)
+	strValue := fmt.Sprintf(f, value)
+	return strValue, unit
 }

go.mod

@@ -0,0 +1,11 @@
+module github.com/ddo/fast
+
+require (
+	github.com/ddo/go-fast v0.0.0-20180221183904-3a2f747dc782
+	github.com/ddo/go-spin v0.0.0-20160718105357-ab0a40e623c0
+	github.com/ddo/pick-json v0.0.0-20170207095303-c8760e09e0fe
+	github.com/ddo/rq v0.0.0-20180104074423-d8ad0e0faf64
+	golang.org/x/net v0.0.0-20180218175443-cbe0f9307d01
+	gopkg.in/ddo/go-dlog.v2 v2.1.0
+	gopkg.in/ddo/pick.v1 v1.2.2
+)

go.sum

@@ -0,0 +1,14 @@
+github.com/ddo/go-fast v0.0.0-20180221183904-3a2f747dc782 h1:eLUvgFAzID11rBj2McGOWobrw0e6tVsKEAk2/zTB35w=
+github.com/ddo/go-fast v0.0.0-20180221183904-3a2f747dc782/go.mod h1:FSWBFAxOhcfYWUc6RaycgBezryVDAD0ECXTc9zxp/Xg=
+github.com/ddo/go-spin v0.0.0-20160718105357-ab0a40e623c0 h1:IXCsXx3/itag1jdJ6Pdk96BRuYRHJvcVxn9zMVutt7I=
+github.com/ddo/go-spin v0.0.0-20160718105357-ab0a40e623c0/go.mod h1:F4meHnXw8Iq/mjLWPtyMXrxm0xtANYOhyCeqBvbjPs8=
+github.com/ddo/pick-json v0.0.0-20170207095303-c8760e09e0fe h1:/8DxbVJzB+Rx2wgJ1VGb3ziwGlI2VB3bWqtoldtalUU=
+github.com/ddo/pick-json v0.0.0-20170207095303-c8760e09e0fe/go.mod h1:vhvQl0uhd1j+zZPJhH0mZ1Moz14khMTXkCkNDXavk1Q=
+github.com/ddo/rq v0.0.0-20180104074423-d8ad0e0faf64 h1:ccuGArPA2AQwyfbpnC2NCWCvqypJFhn6eEvpwYDJPf8=
+github.com/ddo/rq v0.0.0-20180104074423-d8ad0e0faf64/go.mod h1:XIayI7kdKklkc7yyWDBYMJLbK/AO4AchQUxdoSFcn+k=
+golang.org/x/net v0.0.0-20180218175443-cbe0f9307d01 h1:po1f06KS05FvIQQA2pMuOWZAUXiy1KYdIf0ElUU2Hhc=
+golang.org/x/net v0.0.0-20180218175443-cbe0f9307d01/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+gopkg.in/ddo/go-dlog.v2 v2.1.0 h1:SrIltB+SYmJLJZp/5vGKGLUpk2VCfLUM1V3jGs7RSh4=
+gopkg.in/ddo/go-dlog.v2 v2.1.0/go.mod h1:CENm6saSBTtC4/HLiyEnKte/MHgJ/LECoptlS6oHBVI=
+gopkg.in/ddo/pick.v1 v1.2.2 h1:5Ue60YhDOzjwaQp3vwHwyuJ4ufj4DyKIxn95W4G7iZI=
+gopkg.in/ddo/pick.v1 v1.2.2/go.mod h1:AgGJKIMzwG3nzr1OX4nqa2+J27vPZXFgFnEWI3zh8Ow=