parse and use --kubeconfig flag, fix #9

cmd/tubectl/complete.go

@@ -29,7 +29,7 @@ func matchResources(resources []Resource, params *ParamsMatch) ([]Resource, erro
 
 func completeParams(client string, params *Params) (*Params, error) {
 	if params.CompleteContext {
-		contexts, err := parseKubernetesContexts()
+		contexts, err := parseKubernetesContexts(params.Kubeconfig)
 		if err != nil {
 			return params, err
 		}

cmd/tubectl/kube.go

@@ -16,8 +16,16 @@ type Resource struct {
 	Namespace string
 }
 
-func parseKubernetesContexts() ([]string, error) {
-	config, err := clientcmdapi.NewDefaultClientConfigLoadingRules().Load()
+func parseKubernetesContexts(kubeconfig string) ([]string, error) {
+	loader := clientcmdapi.NewDefaultClientConfigLoadingRules()
+	if kubeconfig != "" {
+		loader.Precedence = append(
+			[]string{kubeconfig},
+			loader.Precedence...,
+		)
+	}
+
+	config, err := loader.Load()
 	if err != nil {
 		return nil, karma.Format(
 			err,
@@ -38,7 +46,10 @@ func parseKubernetesContexts() ([]string, error) {
 func requestNamespaces(client string, params *Params) ([]string, error) {
 	// omit namespace argument because requesting list of them
 	cmd, args := getCommand(
-		client, buildArgContext(params.Context), "", "",
+		client, 
+		buildArgKubeconfig(params.Kubeconfig),
+		buildArgContext(params.Context),
+		"", "",
 		"get", "namespaces", "-o", "json",
 	)
 
@@ -76,6 +87,7 @@ func requestNamespaces(client string, params *Params) ([]string, error) {
 func requestResources(client string, params *Params) ([]Resource, error) {
 	cmd, args := getCommand(
 		client,
+		buildArgKubeconfig(params.Kubeconfig),
 		buildArgContext(params.Context),
 		buildArgNamespace(params.Namespace),
 		buildArgAllNamespaces(params.AllNamespaces),
@@ -133,12 +145,16 @@ func unmarshalResources(contents []byte) ([]Resource, error) {
 
 func getCommand(
 	client string,
-	argContext,
+	argKubeconfig string,
+	argContext string,
 	argNamespace string,
 	argAllNamespaces string,
 	value ...string,
 ) (*exec.Cmd, []string) {
 	args := []string{}
+	if argKubeconfig != "" {
+		args = append(args, argKubeconfig)
+	}
 	if argContext != "" {
 		args = append(args, argContext)
 	}
@@ -155,6 +171,14 @@ func getCommand(
 	return exec.Command(client, args...), append([]string{client}, args...)
 }
 
+func buildArgKubeconfig(value string) string {
+	if value != "" {
+		return "--kubeconfig=" + value
+	}
+
+	return ""
+}
+
 func buildArgContext(value string) string {
 	if value != "" {
 		return "--context=" + value

cmd/tubectl/main.go

@@ -152,6 +152,10 @@ func main() {
 func syscallExec(client string, params *Params) {
 	args := []string{client}
 
+	if arg := buildArgKubeconfig(params.Kubeconfig); arg != "" {
+		args = append(args, arg)
+	}
+
 	if arg := buildArgContext(params.Context); arg != "" {
 		args = append(args, arg)
 	}

cmd/tubectl/params.go

@@ -15,7 +15,8 @@ type Params struct {
 	Namespace         string
 	AllNamespaces     bool
 
-	Match *ParamsMatch
+	Match      *ParamsMatch
+	Kubeconfig string
 }
 
 type ParamsMatch struct {
@@ -46,6 +47,8 @@ const (
 	FlagNamespaceShort      = "-n"
 	FlagNamespaceShortValue = "-n="
 	FlagAllNamespaces       = "--all-namespaces"
+	FlagKubeconfig          = "--kubeconfig"
+	FlagKubeconfigValue     = "--kubeconfig="
 )
 
 var (
@@ -74,6 +77,18 @@ func parseParams(raw []string) *Params {
 			continue
 		}
 
+		if params.Kubeconfig == "" {
+			var usedNext bool
+			params.Kubeconfig, usedNext = parseKubeconfig(value, raw, index)
+			if usedNext {
+				index++
+			}
+
+			if params.Kubeconfig != "" {
+				continue
+			}
+		}
+
 		if params.Context == "" {
 			var usedNext bool
 			params.Context, usedNext = parseContext(value, raw, index)
@@ -239,6 +254,27 @@ func parseContext(
 	return "", false
 }
 
+func parseKubeconfig(
+	value string,
+	args []string,
+	index int,
+) (name string, usedNext bool) {
+	if value == FlagKubeconfig {
+		if index+1 <= len(args)-1 {
+			return args[index+1], true
+		}
+
+		return "", false
+	}
+
+	if len(value) > len(FlagKubeconfigValue) &&
+		strings.HasPrefix(value, FlagKubeconfigValue) {
+		return value[len(FlagKubeconfigValue):], false
+	}
+
+	return "", false
+}
+
 func parseNamespace(
 	value string,
 	args []string,

cmd/tubectl/params_test.go

@@ -316,6 +316,27 @@ func TestParams_Suites(t *testing.T) {
 				Args: []string{"blah%"},
 			},
 		},
+		{
+			[]string{"--kubeconfig=x", "a"},
+			&Params{
+				Args:       []string{"a"},
+				Kubeconfig: "x",
+			},
+		},
+		{
+			[]string{"--kubeconfig", "x", "a"},
+			&Params{
+				Args:       []string{"a"},
+				Kubeconfig: "x",
+			},
+		},
+		{
+			[]string{"--kubeconfig", "x", "a", "--kubeconfig=y", "z"},
+			&Params{
+				Args:       []string{"a", "--kubeconfig=y", "z"},
+				Kubeconfig: "x",
+			},
+		},
 		//
 	}
 

cmd/tubectl/task.go

@@ -30,6 +30,10 @@ func getTask(client string, params *Params, resource Resource) Task {
 	return func(writer io.Writer) error {
 		values := []string{}
 
+		if arg := buildArgKubeconfig(params.Kubeconfig); arg != "" {
+			values = append(values, arg)
+		}
+
 		if arg := buildArgContext(params.Context); arg != "" {
 			values = append(values, arg)
 		}