Make everything build strings instead of printing

cmd/breathe.go

@@ -2,6 +2,7 @@ package lumecmd
 
 import (
 	"flag"
+	"fmt"
 
 	"git.kill0.net/chill9/lifx-go"
 )
@@ -102,7 +103,7 @@ func BreatheCmd(ctx Context) (int, error) {
 	}
 
 	p = NewPrinter(format)
-	p.Results(r.Results)
+	fmt.Print(p.Results(r.Results))
 
 	return ExitSuccess, nil
 }

cmd/help.go

@@ -3,6 +3,7 @@ package lumecmd
 import (
 	"fmt"
 	"sort"
+	"strings"
 )
 
 func NewCmdHelp() Command {
@@ -16,15 +17,21 @@ func NewCmdHelp() Command {
 
 func HelpCmd(ctx Context) (int, error) {
 	if len(ctx.Args) == 0 {
-		printHelp(commandRegistry)
+		fmt.Print(printHelp(commandRegistry))
 	} else if len(ctx.Args) >= 1 {
-		printCmdHelp(ctx.Args[0])
+		if cmdHelp, err := printCmdHelp(ctx.Args[0]); err == nil {
+			fmt.Print(cmdHelp)
+		} else {
+			fmt.Print(err)
+		}
 	}
 
 	return ExitSuccess, nil
 }
 
-func printHelp(commands map[string]Command) {
+func printHelp(commands map[string]Command) string {
+	var b strings.Builder
+
 	var maxLen, cmdLen int
 	var keys []string
 
@@ -36,34 +43,45 @@ func printHelp(commands map[string]Command) {
 		}
 	}
 
-	fmt.Printf("usage:\n  lume <command> [<args...>]")
+	fmt.Fprintf(&b, "usage:\n  lume <command> [<args...>]")
-	fmt.Println()
+	fmt.Fprintln(&b)
-	fmt.Println("\ncommands:")
+	fmt.Fprintln(&b, "\ncommands:")
 
 	sort.Strings(keys)
+
 	for _, k := range keys {
 		c := commands[k]
-		fmt.Printf("  %-*s    %s\n", maxLen, c.Name, c.Short)
+		fmt.Fprintf(&b, "  %-*s    %s\n", maxLen, c.Name, c.Short)
-	}
 	}
 
-func printCmdHelp(name string) error {
+	return b.String()
+}
+
+func printCmdHelp(name string) (string, error) {
+	var b strings.Builder
+
 	subCmd, ok := commandRegistry[name]
+
 	if !ok {
-		return fmt.Errorf("unknown commnnd: %s\n", name)
+		return "", fmt.Errorf("unknown commnnd: %s\n", name)
 	}
 
 	if subCmd.Use != "" {
-		fmt.Printf("usage:\n  lume %s %s\n", subCmd.Name, subCmd.Use)
+		fmt.Fprintf(&b, "usage:\n  lume %s %s\n", subCmd.Name, subCmd.Use)
 	} else {
-		fmt.Printf("usage:\n  lume %s\n", subCmd.Name)
+		fmt.Fprintf(&b, "usage:\n  lume %s\n", subCmd.Name)
 	}
 
 	if subCmd.Flags != nil {
-		fmt.Println()
+		out := subCmd.Flags.Output()
-		fmt.Print("flags:\n")
+		defer subCmd.Flags.SetOutput(out)
+
+		fmt.Fprintln(&b)
+		fmt.Fprint(&b, "flags:\n")
+
+		subCmd.Flags.SetOutput(&b)
 		subCmd.Flags.PrintDefaults()
 	}
 
-	return nil
+	return b.String(), nil
 }

cmd/ls.go

@@ -2,6 +2,7 @@ package lumecmd
 
 import (
 	"flag"
+	"fmt"
 )
 
 func NewCmdLs() Command {
@@ -42,7 +43,7 @@ func LsCmd(ctx Context) (int, error) {
 	}
 
 	p = NewPrinter(format)
-	p.Lights(lights)
+	fmt.Print(p.Lights(lights))
 
 	return ExitSuccess, nil
 }

cmd/poweroff.go

@@ -2,6 +2,7 @@ package lumecmd
 
 import (
 	"flag"
+	"fmt"
 
 	"git.kill0.net/chill9/lifx-go"
 )
@@ -48,7 +49,7 @@ func PoweroffCmd(ctx Context) (int, error) {
 	}
 
 	p = NewPrinter(format)
-	p.Results(r.Results)
+	fmt.Print(p.Results(r.Results))
 
 	return ExitSuccess, nil
 }

cmd/poweron.go

@@ -2,6 +2,7 @@ package lumecmd
 
 import (
 	"flag"
+	"fmt"
 
 	"git.kill0.net/chill9/lifx-go"
 )
@@ -48,7 +49,7 @@ func PoweronCmd(ctx Context) (int, error) {
 	}
 
 	p = NewPrinter(format)
-	p.Results(r.Results)
+	fmt.Print(p.Results(r.Results))
 
 	return ExitSuccess, nil
 }

cmd/print.go

@@ -2,7 +2,8 @@ package lumecmd
 
 import (
 	"fmt"
-	"os"
+	"io"
+	"strings"
 	"time"
 
 	"git.kill0.net/chill9/lifx-go"
@@ -11,8 +12,8 @@ import (
 )
 
 type Printer interface {
-	Results(results []lifx.Result)
+	Results(results []lifx.Result) string
-	Lights(lights []lifx.Light)
+	Lights(lights []lifx.Light) string
 }
 
 type defaultPrinter struct{}
@@ -28,17 +29,19 @@ func NewPrinter(format string) Printer {
 	}
 }
 
-func (dp *defaultPrinter) Results(results []lifx.Result) {
+func (dp *defaultPrinter) Results(results []lifx.Result) string {
+	var b strings.Builder
+
 	sortResults(results)
 
-	table := tablewriter.NewWriter(os.Stdout)
+	table := tablewriter.NewWriter(&b)
 	_, rows := makeResultsTable(results)
 
 	for _, v := range rows {
 		table.Append(v)
 	}
 
-	fmt.Printf("total %d\n", len(results))
+	fmt.Fprintf(&b, "total %d\n", len(results))
 	table.SetAlignment(tablewriter.ALIGN_LEFT)
 	table.SetAutoWrapText(false)
 	table.SetBorder(false)
@@ -49,12 +52,16 @@ func (dp *defaultPrinter) Results(results []lifx.Result) {
 	table.SetRowSeparator("")
 	table.SetTablePadding(" ")
 	table.Render()
+
+	return b.String()
 }
 
-func (tp *tablePrinter) Results(results []lifx.Result) {
+func (tp *tablePrinter) Results(results []lifx.Result) string {
+	var b strings.Builder
+
 	sortResults(results)
 
-	table := tablewriter.NewWriter(os.Stdout)
+	table := tablewriter.NewWriter(&b)
 	hdr, rows := makeResultsTable(results)
 
 	for _, v := range rows {
@@ -63,19 +70,23 @@ func (tp *tablePrinter) Results(results []lifx.Result) {
 
 	table.SetHeader(hdr)
 	table.Render()
+
+	return b.String()
 }
 
-func (dp *defaultPrinter) Lights(lights []lifx.Light) {
+func (dp *defaultPrinter) Lights(lights []lifx.Light) string {
+	var b strings.Builder
+
 	sortLights(lights)
 
-	table := tablewriter.NewWriter(os.Stdout)
+	table := tablewriter.NewWriter(&b)
 	_, rows := makeLightsTable(lights)
 
 	for _, v := range rows {
 		table.Append(v)
 	}
 
-	fmt.Printf("total %d\n", len(lights))
+	fmt.Fprintf(&b, "total %d\n", len(lights))
 	table.SetAlignment(tablewriter.ALIGN_LEFT)
 	table.SetAutoWrapText(false)
 	table.SetBorder(false)
@@ -86,12 +97,16 @@ func (dp *defaultPrinter) Lights(lights []lifx.Light) {
 	table.SetRowSeparator("")
 	table.SetTablePadding(" ")
 	table.Render()
+
+	return b.String()
 }
 
-func (tp *tablePrinter) Lights(lights []lifx.Light) {
+func (tp *tablePrinter) Lights(lights []lifx.Light) string {
+	var b strings.Builder
+
 	sortLights(lights)
 
-	table := tablewriter.NewWriter(os.Stdout)
+	table := tablewriter.NewWriter(&b)
 	hdr, rows := makeLightsTable(lights)
 
 	for _, v := range rows {
@@ -100,6 +115,8 @@ func (tp *tablePrinter) Lights(lights []lifx.Light) {
 
 	table.SetHeader(hdr)
 	table.Render()
+
+	return b.String()
 }
 
 func ColorizeIndicator(s string) string {
@@ -138,6 +155,11 @@ func PrintfWithIndent(indent int, format string, a ...interface{}) (n int, err e
 	return fmt.Printf(format, a...)
 }
 
+func FprintfWithIndent(w io.Writer, indent int, format string, a ...interface{}) (n int, err error) {
+	format = fmt.Sprintf("%*s%s", indent, "", format)
+	return fmt.Fprintf(w, format, a...)
+}
+
 func makeLightsTable(lights []lifx.Light) (hdr []string, rows [][]string) {
 	hdr = []string{"", "ID", "Location", "Group", "Label", "Last Seen", "Power"}
 

cmd/setcolor.go

@@ -130,7 +130,7 @@ func SetColorCmd(ctx Context) (int, error) {
 
 	if !fast {
 		p = NewPrinter(format)
-		p.Results(r.Results)
+		fmt.Print(p.Results(r.Results))
 	}
 
 	return ExitSuccess, nil

cmd/setstate.go

@@ -2,6 +2,7 @@ package lumecmd
 
 import (
 	"flag"
+	"fmt"
 
 	"git.kill0.net/chill9/lifx-go"
 )
@@ -96,7 +97,7 @@ func SetStateCmd(ctx Context) (int, error) {
 
 	if !fast {
 		p = NewPrinter(format)
-		p.Results(r.Results)
+		fmt.Print(p.Results(r.Results))
 	}
 
 	return ExitSuccess, nil

cmd/setwhite.go

@@ -2,6 +2,7 @@ package lumecmd
 
 import (
 	"flag"
+	"fmt"
 
 	"git.kill0.net/chill9/lifx-go"
 )
@@ -114,7 +115,7 @@ func SetWhiteCmd(ctx Context) (int, error) {
 
 	if !fast {
 		p = NewPrinter(format)
-		p.Results(r.Results)
+		fmt.Print(p.Results(r.Results))
 	}
 
 	return ExitSuccess, nil

cmd/show.go

@@ -3,6 +3,7 @@ package lumecmd
 import (
 	"flag"
 	"fmt"
+	"strings"
 )
 
 const Tabstop int = 2
@@ -26,6 +27,8 @@ func NewCmdShow() Command {
 
 func ShowCmd(ctx Context) (int, error) {
 	var indent int
+	var b strings.Builder
+
 	c := ctx.Client
 	selector := ctx.Flags.String("selector")
 	lights, err := c.ListLights(selector)
@@ -38,7 +41,8 @@ func ShowCmd(ctx Context) (int, error) {
 
 	for i, l := range lights {
 		indent = 0
-		fmt.Printf(
+		fmt.Fprintf(
+			&b,
 			"%s Light ID: %s, %s, Power: %s\n",
 			ColorizeIndicator(l.Power),
 			l.Id,
@@ -46,41 +50,43 @@ func ShowCmd(ctx Context) (int, error) {
 			ColorizePower(l.Power),
 		)
 		indent += Tabstop + 2
-		PrintfWithIndent(indent, "Label: %s, ID: %s\n", l.Label, l.Id)
+		FprintfWithIndent(&b, indent, "Label: %s, ID: %s\n", l.Label, l.Id)
-		PrintfWithIndent(indent, "UUID: %s\n", l.UUID)
+		FprintfWithIndent(&b, indent, "UUID: %s\n", l.UUID)
-		PrintfWithIndent(indent, "Location: %s, ID: %s\n", l.Location.Name, l.Location.Id)
+		FprintfWithIndent(&b, indent, "Location: %s, ID: %s\n", l.Location.Name, l.Location.Id)
-		PrintfWithIndent(indent, "Group: %s, ID: %s\n", l.Group.Name, l.Group.Id)
+		FprintfWithIndent(&b, indent, "Group: %s, ID: %s\n", l.Group.Name, l.Group.Id)
-		PrintfWithIndent(indent, "Color: Hue: %.1f, Saturation: %.1f%%, Kelvin: %d\n",
+		FprintfWithIndent(&b, indent, "Color: Hue: %.1f, Saturation: %.1f%%, Kelvin: %d\n",
 			*l.Color.H, *l.Color.S, *l.Color.K)
-		PrintfWithIndent(indent, "Brightness: %.1f%%\n", l.Brightness*100)
+		FprintfWithIndent(&b, indent, "Brightness: %.1f%%\n", l.Brightness*100)
 		if l.Effect != "" {
-			PrintfWithIndent(indent, "Effect: %s\n", l.Effect)
+			FprintfWithIndent(&b, indent, "Effect: %s\n", l.Effect)
 		}
-		PrintfWithIndent(indent, "Product: %s\n", l.Product.Name)
+		FprintfWithIndent(&b, indent, "Product: %s\n", l.Product.Name)
-		PrintfWithIndent(indent, "Capabilities: ")
+		FprintfWithIndent(&b, indent, "Capabilities: ")
-		fmt.Printf("Color: %s, ", YesNo(l.Product.Capabilities.HasColor))
+		fmt.Fprintf(&b, "Color: %s, ", YesNo(l.Product.Capabilities.HasColor))
-		fmt.Printf("Variable Color Temp: %s, ", YesNo(l.Product.Capabilities.HasVariableColorTemp))
+		fmt.Fprintf(&b, "Variable Color Temp: %s, ", YesNo(l.Product.Capabilities.HasVariableColorTemp))
-		fmt.Printf("IR: %s, ", YesNo(l.Product.Capabilities.HasIR))
+		fmt.Fprintf(&b, "IR: %s, ", YesNo(l.Product.Capabilities.HasIR))
-		fmt.Printf("Chain: %s, ", YesNo(l.Product.Capabilities.HasChain))
+		fmt.Fprintf(&b, "Chain: %s, ", YesNo(l.Product.Capabilities.HasChain))
-		fmt.Printf("Multizone: %s, ", YesNo(l.Product.Capabilities.HasMultizone))
+		fmt.Fprintf(&b, "Multizone: %s, ", YesNo(l.Product.Capabilities.HasMultizone))
-		fmt.Printf("Min Kelvin: %.1f, ", l.Product.Capabilities.MinKelvin)
+		fmt.Fprintf(&b, "Min Kelvin: %.1f, ", l.Product.Capabilities.MinKelvin)
-		fmt.Printf("Max Kelvin: %.1f ", l.Product.Capabilities.MaxKelvin)
+		fmt.Fprintf(&b, "Max Kelvin: %.1f ", l.Product.Capabilities.MaxKelvin)
-		fmt.Println()
+		fmt.Fprintln(&b)
 		// List applicable selectors (most to least specific)
-		PrintfWithIndent(indent, "Selectors:\n")
+		FprintfWithIndent(&b, indent, "Selectors:\n")
 		indent += Tabstop
-		PrintfWithIndent(indent, "id:%s\n", l.Id)
+		FprintfWithIndent(&b, indent, "id:%s\n", l.Id)
-		PrintfWithIndent(indent, "label:%s\n", l.Label)
+		FprintfWithIndent(&b, indent, "label:%s\n", l.Label)
-		PrintfWithIndent(indent, "group_id:%s\n", l.Group.Id)
+		FprintfWithIndent(&b, indent, "group_id:%s\n", l.Group.Id)
-		PrintfWithIndent(indent, "group:%s\n", l.Group.Name)
+		FprintfWithIndent(&b, indent, "group:%s\n", l.Group.Name)
-		PrintfWithIndent(indent, "location_id:%s\n", l.Location.Id)
+		FprintfWithIndent(&b, indent, "location_id:%s\n", l.Location.Id)
-		PrintfWithIndent(indent, "location:%s\n", l.Location.Name)
+		FprintfWithIndent(&b, indent, "location:%s\n", l.Location.Name)
 		indent -= Tabstop
-		PrintfWithIndent(indent, "Last Seen: %s (%.1fs ago)\n", l.LastSeen, l.SecondsLastSeen)
+		FprintfWithIndent(&b, indent, "Last Seen: %s (%.1fs ago)\n", l.LastSeen, l.SecondsLastSeen)
 
 		if i < len(lights)-1 {
-			fmt.Println()
+			fmt.Fprintln(&b)
 		}
+
+		fmt.Print(b.String())
 	}
 	return ExitSuccess, nil
 }

cmd/toggle.go

@@ -2,6 +2,7 @@ package lumecmd
 
 import (
 	"flag"
+	"fmt"
 )
 
 func NewCmdToggle() Command {
@@ -45,7 +46,7 @@ func ToggleCmd(ctx Context) (int, error) {
 	}
 
 	p = NewPrinter(format)
-	p.Results(r.Results)
+	fmt.Print(p.Results(r.Results))
 
 	return ExitSuccess, nil
 }

cmd/validate.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"flag"
 	"fmt"
+	"strings"
 
 	"git.kill0.net/chill9/lifx-go"
 )
@@ -23,10 +24,11 @@ func NewCmdValidate() Command {
 }
 
 func ValidateCmd(ctx Context) (int, error) {
+	var b strings.Builder
 	c := ctx.Client
 
 	if len(ctx.Args) != 1 {
-		printCmdHelp(ctx.Name)
+		fmt.Print(printCmdHelp(ctx.Name))
 		return ExitFailure, nil
 	}
 
@@ -38,11 +40,12 @@ func ValidateCmd(ctx Context) (int, error) {
 	}
 
 	if validColor, ok := i.(*lifx.HSBKColor); ok {
-		fmt.Print(validColor)
+		fmt.Fprintln(&b, validColor)
 	} else {
 		return ExitFailure, errors.New("go type %T but wanted *HSBKColor")
 	}
-	fmt.Println()
+
+	fmt.Print(b.String())
 
 	return ExitSuccess, nil
 }