osbuild2: add support for org.osbuild.systemd-logind stage

Add support for the `org.osbuild.systemd-logind` osbuild stage [1],
which allows one to configure systemd-logind by creating
configuration drop-ins.

Add unit test cases for the newly added stage.

[1] https://github.com/osbuild/osbuild/pull/668

Signed-off-by: Tomas Hozza <thozza@redhat.com>

internal/osbuild2/stage.go

@@ -101,6 +101,8 @@ func (stage *Stage) UnmarshalJSON(data []byte) error {
 		options = new(RHSMStageOptions)
 	case "org.osbuild.systemd":
 		options = new(SystemdStageOptions)
+	case "org.osbuild.systemd-logind":
+		options = new(SystemdLogindStageOptions)
 	case "org.osbuild.script":
 		options = new(ScriptStageOptions)
 	case "org.osbuild.sysconfig":

internal/osbuild2/stage_test.go

@@ -329,6 +329,34 @@ func TestStage_UnmarshalJSON(t *testing.T) {
 				data: []byte(`{"type":"org.osbuild.systemd","options":{"enabled_services":["foo.service"]}}`),
 			},
 		},
+		{
+			name: "systemd-logind",
+			fields: fields{
+				Type:    "org.osbuild.systemd-logind",
+				Options: &SystemdLogindStageOptions{},
+			},
+			args: args{
+				data: []byte(`{"type":"org.osbuild.systemd-logind","options":{}}`),
+			},
+		},
+		{
+			name: "systemd-logind-data",
+			fields: fields{
+				Type: "org.osbuild.systemd-logind",
+				Options: &SystemdLogindStageOptions{
+					ConfigDropins: map[string]SystemdLogindConfigDropin{
+						"10-ec2-getty-fix.conf": {
+							Login: SystemdLogindConfigLoginSection{
+								NAutoVT: common.IntToPtr(0),
+							},
+						},
+					},
+				},
+			},
+			args: args{
+				data: []byte(`{"type":"org.osbuild.systemd-logind","options":{"configuration_dropins":{"10-ec2-getty-fix.conf":{"Login":{"NAutoVT":0}}}}}`),
+			},
+		},
 		{
 			name: "timezone",
 			fields: fields{

internal/osbuild2/systemd_logind_stage.go

@@ -0,0 +1,46 @@
+package osbuild2
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+type SystemdLogindStageOptions struct {
+	ConfigDropins map[string]SystemdLogindConfigDropin `json:"configuration_dropins,omitempty"`
+}
+
+func (SystemdLogindStageOptions) isStageOptions() {}
+
+func NewSystemdLogindStage(options *SystemdLogindStageOptions) *Stage {
+	return &Stage{
+		Type:    "org.osbuild.systemd-logind",
+		Options: options,
+	}
+}
+
+// Drop-in configuration for systemd-logind
+type SystemdLogindConfigDropin struct {
+	Login SystemdLogindConfigLoginSection `json:"Login"`
+}
+
+// 'Login' configuration section - at least one option must be specified
+type SystemdLogindConfigLoginSection struct {
+	// Configures how many virtual terminals (VTs) to allocate by default
+	// The option is optional, but zero is a valid value
+	NAutoVT *int `json:"NAutoVT,omitempty"`
+}
+
+// Unexported struct for use in SystemdLogindConfigLoginSection's MarshalJSON() to prevent recursion
+type systemdLogindConfigLoginSection struct {
+	// Configures how many virtual terminals (VTs) to allocate by default
+	// The option is optional, but zero is a valid value
+	NAutoVT *int `json:"NAutoVT,omitempty"`
+}
+
+func (s SystemdLogindConfigLoginSection) MarshalJSON() ([]byte, error) {
+	if s.NAutoVT == nil {
+		return nil, fmt.Errorf("at least one 'Login' section option must be specified")
+	}
+	loginSection := systemdLogindConfigLoginSection(s)
+	return json.Marshal(loginSection)
+}

internal/osbuild2/systemd_logind_stage_test.go

@@ -0,0 +1,41 @@
+package osbuild2
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewSystemdLogindStage(t *testing.T) {
+	expectedStage := &Stage{
+		Type:    "org.osbuild.systemd-logind",
+		Options: &SystemdLogindStageOptions{},
+	}
+	actualStage := NewSystemdLogindStage(&SystemdLogindStageOptions{})
+	assert.Equal(t, expectedStage, actualStage)
+}
+
+func TestSystemdLogindStage_MarshalJSON_Invalid(t *testing.T) {
+	tests := []struct {
+		name    string
+		options SystemdLogindStageOptions
+	}{
+		{
+			name: "no-section-options",
+			options: SystemdLogindStageOptions{
+				ConfigDropins: map[string]SystemdLogindConfigDropin{
+					"10-ec2-getty-fix.conf": {
+						Login: SystemdLogindConfigLoginSection{},
+					},
+				},
+			},
+		},
+	}
+	for idx, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			gotBytes, err := json.Marshal(tt.options)
+			assert.NotNilf(t, err, "json.Marshal() didn't return an error, but: %s [idx: %d]", string(gotBytes), idx)
+		})
+	}
+}