From 077d8a829dfd964060a94e04c44c01ba58c10831 Mon Sep 17 00:00:00 2001
From: Ahmet Alp Balkan <ahmetb@google.com>
Date: Sun, 12 Apr 2020 17:57:27 -0700
Subject: [PATCH] Re-introduce DEBUG env var stack traces

Signed-off-by: Ahmet Alp Balkan <ahmetb@google.com>
---
 cmd/kubectx/env.go        |  3 +++
 cmd/kubectx/flags.go      |  7 +++----
 cmd/kubectx/flags_test.go |  7 +++++--
 cmd/kubectx/main.go       | 14 ++++++++------
 4 files changed, 19 insertions(+), 12 deletions(-)

diff --git a/cmd/kubectx/env.go b/cmd/kubectx/env.go
index 0bbcda9..98319b0 100644
--- a/cmd/kubectx/env.go
+++ b/cmd/kubectx/env.go
@@ -14,6 +14,9 @@ const (
 	// EnvForceColor describes the "internal" environment variable to force
 	// color usage to show current context in a list.
 	EnvForceColor = `_KUBECTX_FORCE_COLOR`
+
+	// EnvDebug describes the internal environment variable for more verbose logging.
+	EnvDebug = `DEBUG`
 )
 
 func useColors() bool {
diff --git a/cmd/kubectx/flags.go b/cmd/kubectx/flags.go
index 11603c9..87cd7c7 100644
--- a/cmd/kubectx/flags.go
+++ b/cmd/kubectx/flags.go
@@ -1,11 +1,10 @@
 package main
 
 import (
+	"fmt"
 	"io"
 	"os"
 	"strings"
-
-	"github.com/pkg/errors"
 )
 
 type Op interface {
@@ -50,9 +49,9 @@ func parseArgs(argv []string) Op {
 		}
 
 		if strings.HasPrefix(v, "-") && v != "-" {
-			return UnsupportedOp{Err: errors.Errorf("unsupported option %s", v)}
+			return UnsupportedOp{Err: fmt.Errorf("unsupported option '%s'", v)}
 		}
 		return SwitchOp{Target: argv[0]}
 	}
-	return UnsupportedOp{Err: errors.New("too many arguments")}
+	return UnsupportedOp{Err: fmt.Errorf("too many arguments")}
 }
diff --git a/cmd/kubectx/flags_test.go b/cmd/kubectx/flags_test.go
index 6c6128c..a4990b6 100644
--- a/cmd/kubectx/flags_test.go
+++ b/cmd/kubectx/flags_test.go
@@ -1,10 +1,10 @@
 package main
 
 import (
+	"fmt"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
-	"github.com/pkg/errors"
 )
 
 func Test_parseArgs_new(t *testing.T) {
@@ -60,7 +60,10 @@ func Test_parseArgs_new(t *testing.T) {
 			want: RenameOp{"a", "."}},
 		{name: "unrecognized flag",
 			args: []string{"-x"},
-			want: UnsupportedOp{Err: errors.Errorf("unsupported option \"-x\"")}},
+			want: UnsupportedOp{Err: fmt.Errorf("unsupported option \"-x\"")}},
+		{name: "too many args",
+			args: []string{"a", "b", "c"},
+			want: UnsupportedOp{Err: fmt.Errorf("too many arguments")}},
 		// TODO add more UnsupportedOp cases
 
 		// TODO consider these cases
diff --git a/cmd/kubectx/main.go b/cmd/kubectx/main.go
index 45767fd..c9657ec 100644
--- a/cmd/kubectx/main.go
+++ b/cmd/kubectx/main.go
@@ -9,18 +9,20 @@ import (
 )
 
 func main() {
-	// parse command-line flags
-	var op Op
-	op = parseArgs(os.Args[1:])
-
+	op := parseArgs(os.Args[1:])
 	if err := op.Run(os.Stdout, os.Stderr); err != nil {
 		printError(os.Stderr, err.Error())
-		os.Exit(1)
+
+		if _, ok := os.LookupEnv(EnvDebug); ok {
+			// print stack trace in verbose mode
+			fmt.Fprintf(os.Stderr, "[DEBUG] error: %+v\n", err)
+		}
+		defer os.Exit(1)
 	}
 }
 
 func printError(w io.Writer, format string, args ...interface{}) {
-	fmt.Fprintf(os.Stderr, color.RedString("error: ")+format+"\n", args...)
+	fmt.Fprintf(w, color.RedString("error: ")+format+"\n", args...)
 }
 
 func printWarning(w io.Writer, format string, args ...interface{}) {