refactor: never panic with errors

Signed-off-by: Massimiliano Giovagnoli <me@maxgio.it>

go.mod

@@ -3,6 +3,7 @@ module github.com/maxgio92/proxy-kubeconfig-generator
 go 1.18
 
 require (
+	github.com/pkg/errors v0.9.1
 	k8s.io/api v0.24.1
 	k8s.io/apimachinery v0.24.1
 	k8s.io/client-go v0.24.1

go.sum

@@ -225,6 +225,7 @@ github.com/onsi/gomega v1.7.1/go.mod h1:XdKZgCCFLUoM/7CFJVPcG8C1xQ1AJ0vpAezJrB7J
 github.com/onsi/gomega v1.10.1 h1:o0+MgICZLuZ7xjH7Vx6zS/zcu93/BEp1VwkIW1mEXCE=
 github.com/onsi/gomega v1.10.1/go.mod h1:iN09h71vgCQne3DLsj+A5owkum+a2tYe+TOCB1ybHNo=
 github.com/peterbourgon/diskv v2.0.1+incompatible/go.mod h1:uqqh8zWWbv1HBMNONnaR/tNboyR3/BZd58JJSHlUSCU=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
 github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=

main.go

@@ -17,6 +17,8 @@ package main
 import (
 	"flag"
 	"fmt"
+	"github.com/pkg/errors"
+	"os"
 
 	"k8s.io/client-go/kubernetes"
 
@@ -43,34 +45,39 @@ func main() {
 
 	if *serviceAccountName == "" {
 		flag.Usage()
-		panic(fmt.Errorf("missing service account name"))
+		fmt.Println(errors.New("missing service account name"))
+		os.Exit(1)
 	}
 
 	if *server == "" {
-		flag.Usage()
-		panic(fmt.Errorf("missing server url"))
+		fmt.Println(errors.New("missing server url"))
+		os.Exit(1)
 	}
 
 	if *serverTLSSecretName == "" {
 		flag.Usage()
-		panic(fmt.Errorf("missing server TLS secret name"))
+		fmt.Println(errors.New("missing server TLS secret name"))
+		os.Exit(1)
 	}
 
 	config, err := utils.BuildClientConfig()
 	if err != nil {
-		panic(err)
+		fmt.Println(errors.Wrap(err, "error building client config"))
+		os.Exit(1)
 	}
 
 	clientset := kubernetes.NewForConfigOrDie(config)
 
 	tenantConfig, err := generator.GenerateProxyKubeconfigFromSA(clientset, *serviceAccountName, *namespace, *server, *serverTLSSecretName, *serverTLSSecretCAKey, *serverTLSSecretNamespace, *kubeconfigSecretKey)
 	if err != nil {
-		panic(err)
+		fmt.Println(errors.Wrap(err, "error generating kubeconfig from service account"))
+		os.Exit(1)
 	}
 
 	err = utils.CreateKubeconfigSecret(clientset, tenantConfig, *namespace, *serviceAccountName+"-kubeconfig", *kubeconfigSecretKey)
 	if err != nil {
-		panic(err)
+		fmt.Println(errors.Wrap(err, "error creating kubeconfig secret"))
+		os.Exit(1)
 	}
 
 	fmt.Println("Proxy kubeconfig Secret created")