feat(helptext): detect terminal width

If the io.writer given to help text is the terminal, read its width. otherwise, use a default.

Author: hannahhoward

cli/helptext.go

@@ -4,21 +4,23 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"os"
 	"sort"
 	"strings"
 	"text/template"
 
-	"github.com/ipfs/go-ipfs-cmds"
+	cmds "github.com/ipfs/go-ipfs-cmds"
+	"golang.org/x/crypto/ssh/terminal"
 )
 
 const (
-	terminalWidth = 100
-	requiredArg   = "<%v>"
-	optionalArg   = "[<%v>]"
-	variadicArg   = "%v..."
-	shortFlag     = "-%v"
-	longFlag      = "--%v"
-	optionType    = "(%v)"
+	defaultTerminalWidth = 80
+	requiredArg          = "<%v>"
+	optionalArg          = "[<%v>]"
+	variadicArg          = "%v..."
+	shortFlag            = "-%v"
+	longFlag             = "--%v"
+	optionType           = "(%v)"
 
 	whitespace = "\r\n\t "
 
@@ -117,6 +119,19 @@ SUBCOMMANDS
 var longHelpTemplate *template.Template
 var shortHelpTemplate *template.Template
 
+func getTerminalWidth(out io.Writer) int {
+	file, ok := out.(*os.File)
+	if ok {
+		if terminal.IsTerminal(int(file.Fd())) {
+			width, _, err := terminal.GetSize(int(file.Fd()))
+			if err == nil {
+				return width
+			}
+		}
+	}
+	return defaultTerminalWidth
+}
+
 func init() {
 	longHelpTemplate = template.Must(template.New("longHelp").Parse(longHelpFormat))
 	shortHelpTemplate = template.Must(template.New("shortHelp").Parse(shortHelpFormat))
@@ -163,7 +178,7 @@ func LongHelp(rootName string, root *cmds.Command, path []string, out io.Writer)
 		MoreHelp:    (cmd != root),
 	}
 
-	width := terminalWidth - len(indentStr)
+	width := getTerminalWidth(out) - len(indentStr)
 
 	if len(cmd.Helptext.LongDescription) > 0 {
 		fields.Description = cmd.Helptext.LongDescription
@@ -224,7 +239,7 @@ func ShortHelp(rootName string, root *cmds.Command, path []string, out io.Writer
 		MoreHelp:    (cmd != root),
 	}
 
-	width := terminalWidth - len(indentStr)
+	width := getTerminalWidth(out) - len(indentStr)
 
 	// autogen fields that are empty
 	if len(cmd.Helptext.Usage) > 0 {

cli/helptext_test.go

@@ -4,7 +4,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/ipfs/go-ipfs-cmds"
+	cmds "github.com/ipfs/go-ipfs-cmds"
 )
 
 func TestSynopsisGenerator(t *testing.T) {
@@ -22,6 +22,7 @@ func TestSynopsisGenerator(t *testing.T) {
 			},
 		},
 	}
+	terminalWidth := 100
 	syn := generateSynopsis(terminalWidth, command, "cmd")
 	t.Logf("Synopsis is: %s", syn)
 	if !strings.HasPrefix(syn, "cmd ") {

go.mod

@@ -6,4 +6,5 @@ require (
 	github.com/ipfs/go-log v0.0.1
 	github.com/rs/cors v1.6.0
 	github.com/texttheater/golang-levenshtein v0.0.0-20180516184445-d188e65d659e
+	golang.org/x/crypto v0.0.0-20190513172903-22d7a77e9e5f
 )

go.sum

@@ -27,9 +27,18 @@ github.com/texttheater/golang-levenshtein v0.0.0-20180516184445-d188e65d659e h1:
 github.com/texttheater/golang-levenshtein v0.0.0-20180516184445-d188e65d659e/go.mod h1:XDKHRm5ThF8YJjx001LtgelzsoaEcvnA7lVWz9EeX3g=
 github.com/whyrusleeping/go-logging v0.0.0-20170515211332-0457bb6b88fc h1:9lDbC6Rz4bwmou+oE6Dt4Cb2BGMur5eR/GYptkKUVHo=
 github.com/whyrusleeping/go-logging v0.0.0-20170515211332-0457bb6b88fc/go.mod h1:bopw91TMyo8J3tvftk8xmU2kPmlrt4nScJQZU2hE5EM=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/crypto v0.0.0-20190513172903-22d7a77e9e5f h1:R423Cnkcp5JABoeemiGEPlt9tHXFfw5kvc0yqlxRPWo=
+golang.org/x/crypto v0.0.0-20190513172903-22d7a77e9e5f/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/net v0.0.0-20190227160552-c95aed5357e7 h1:C2F/nMkR/9sfUTpvR3QrjBuTdvMUC/cFajkphs1YLQo=
 golang.org/x/net v0.0.0-20190227160552-c95aed5357e7/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3 h1:0GoQqolDA55aaLxZyTzK/Y2ePZzZTUrRacwib7cNsYQ=
+golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190222072716-a9d3bda3a223/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20190302025703-b6889370fb10 h1:xQJI9OEiErEQ++DoXOHqEpzsGMrAv2Q2jyCpi7DmfpQ=
 golang.org/x/sys v0.0.0-20190302025703-b6889370fb10/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d h1:+R4KGOnez64A81RvjARKc4UT5/tI9ujCIVX+P5KiHuI=
+golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/tools v0.0.0-20180221164845-07fd8470d635/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=