add error handler

console.go

@@ -25,7 +25,7 @@ func Execute(ctx context.Context, cmd *Command, opts ...func(*App)) {
 	New(opts...).exec(ctx, cmd)
 }
 
-// Run current command by input and output/
+// Run current command by input and output.
 func Run(ctx context.Context, cmd *Command, in input.Input, out output.Output) error {
 	def := input.NewDefinition()
 

input/wrap/input.go

@@ -40,6 +40,10 @@ func (i *Input) Bind(ctx context.Context, def *input.Definition) error {
 	return i.bindOptions(ctx, def)
 }
 
+func (i *Input) build(ctx context.Context) error {
+	return nil
+}
+
 func (i *Input) bindOptions(ctx context.Context, def *input.Definition) error {
 	for _, name := range def.Options() {
 		opt, err := def.Option(name)

output/output.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"io"
+	"os"
 )
 
 type Verbosity int
@@ -16,46 +17,50 @@ const (
 	VerbosityTrace
 )
 
+func writeError(n int, err error) {
+	fmt.Fprint(os.Stderr, err)
+}
+
 type Output func(ctx context.Context, verb Verbosity, msg string, args ...KeyValue) (int, error)
 
 func (o Output) Print(ctx context.Context, args ...interface{}) {
-	o(ctx, VerbosityNorm, fmt.Sprint(args...))
+	writeError(o(ctx, VerbosityNorm, fmt.Sprint(args...)))
 }
 
 func (o Output) PrintKV(ctx context.Context, msg string, kv ...KeyValue) {
-	o(ctx, VerbosityNorm, msg, kv...)
+	writeError(o(ctx, VerbosityNorm, msg, kv...))
 }
 
 func (o Output) Printf(ctx context.Context, format string, args ...interface{}) {
-	o(ctx, VerbosityNorm, fmt.Sprintf(format, args...))
+	writeError(o(ctx, VerbosityNorm, fmt.Sprintf(format, args...)))
 }
 
 func (o Output) Println(ctx context.Context, args ...interface{}) {
-	o(ctx, VerbosityNorm, fmt.Sprintln(args...))
+	writeError(o(ctx, VerbosityNorm, fmt.Sprintln(args...)))
 }
 
 func (o Output) Info(ctx context.Context, args ...interface{}) {
-	o(ctx, VerbosityInfo, fmt.Sprint(args...))
+	writeError(o(ctx, VerbosityInfo, fmt.Sprint(args...)))
 }
 
 func (o Output) InfoKV(ctx context.Context, msg string, kv ...KeyValue) {
-	o(ctx, VerbosityInfo, msg, kv...)
+	writeError(o(ctx, VerbosityInfo, msg, kv...))
 }
 
 func (o Output) Debug(ctx context.Context, args ...interface{}) {
-	o(ctx, VerbosityDebug, fmt.Sprint(args...))
+	writeError(o(ctx, VerbosityDebug, fmt.Sprint(args...)))
 }
 
 func (o Output) DebugKV(ctx context.Context, msg string, kv ...KeyValue) {
-	o(ctx, VerbosityDebug, msg, kv...)
+	writeError(o(ctx, VerbosityDebug, msg, kv...))
 }
 
 func (o Output) Trace(ctx context.Context, args ...interface{}) {
-	o(ctx, VerbosityTrace, fmt.Sprint(args...))
+	writeError(o(ctx, VerbosityTrace, fmt.Sprint(args...)))
 }
 
 func (o Output) TraceKV(ctx context.Context, msg string, kv ...KeyValue) {
-	o(ctx, VerbosityTrace, msg, kv...)
+	writeError(o(ctx, VerbosityTrace, msg, kv...))
 }
 
 func (o Output) Write(b []byte) (int, error) {

output/writer/output.go

@@ -11,6 +11,8 @@ import (
 	"gitoa.ru/go-4devs/console/output"
 )
 
+const newline = "\n"
+
 func Stderr() output.Output {
 	return New(os.Stderr, String)
 }
@@ -25,13 +27,12 @@ func Buffer(buf *bytes.Buffer) output.Output {
 
 func String(_ output.Verbosity, msg string, kv ...output.KeyValue) string {
 	if len(kv) > 0 {
-		newline := ""
-		if msg[len(msg)-1:] == "\n" {
-			newline = "\n"
+		nline := ""
+		if msg[len(msg)-1:] == newline {
+			nline = newline
 		}
 
-		return "msg=\"" + strings.TrimSpace(msg) + "\", " + output.KeyValues(kv).String() + newline
-
+		return "msg=\"" + strings.TrimSpace(msg) + "\", " + output.KeyValues(kv).String() + nline
 	}
 
 	return msg