osbuild2: add support for org.osbuild.cloud-init stage

Add support for the `org.osbuild.cloud-init` osbuild stage [1],
which allows one to configure cloud-init by creating
configuration files under `/etc/cloud/cloud.cfg.d/`.

Add unit test cases for the newly added stage.

[1] https://github.com/osbuild/osbuild/pull/689

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

internal/osbuild2/cloud_init_stage.go

@@ -0,0 +1,73 @@
+package osbuild2
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+type CloudInitStageOptions struct {
+	ConfigFiles map[string]CloudInitConfigFile `json:"configuration_files,omitempty"`
+}
+
+func (CloudInitStageOptions) isStageOptions() {}
+
+func NewCloudInitStage(options *CloudInitStageOptions) *Stage {
+	return &Stage{
+		Type:    "org.osbuild.cloud-init",
+		Options: options,
+	}
+}
+
+// Represents a cloud-init configuration file
+type CloudInitConfigFile struct {
+	SystemInfo *CloudInitConfigSystemInfo `json:"system_info,omitempty"`
+}
+
+// Unexported struct for use in CloudInitConfigFile's MarshalJSON() to prevent recursion
+type cloudInitConfigFile struct {
+	SystemInfo *CloudInitConfigSystemInfo `json:"system_info,omitempty"`
+}
+
+func (c CloudInitConfigFile) MarshalJSON() ([]byte, error) {
+	if c.SystemInfo == nil {
+		return nil, fmt.Errorf("at least one cloud-init configuration option must be specified")
+	}
+	configFile := cloudInitConfigFile(c)
+	return json.Marshal(configFile)
+}
+
+// Represents the 'system_info' configuration section
+type CloudInitConfigSystemInfo struct {
+	DefaultUser *CloudInitConfigDefaultUser `json:"default_user,omitempty"`
+}
+
+// Unexported struct for use in CloudInitConfigSystemInfo's MarshalJSON() to prevent recursion
+type cloudInitConfigSystemInfo struct {
+	DefaultUser *CloudInitConfigDefaultUser `json:"default_user,omitempty"`
+}
+
+func (si CloudInitConfigSystemInfo) MarshalJSON() ([]byte, error) {
+	if si.DefaultUser == nil {
+		return nil, fmt.Errorf("at least one configuration option must be specified for 'system_info' section")
+	}
+	systemInfo := cloudInitConfigSystemInfo(si)
+	return json.Marshal(systemInfo)
+}
+
+// Configuration of the 'default' user created by cloud-init.
+type CloudInitConfigDefaultUser struct {
+	Name string `json:"name,omitempty"`
+}
+
+// Unexported struct for use in CloudInitConfigDefaultUser's MarshalJSON() to prevent recursion
+type cloudInitConfigDefaultUser struct {
+	Name string `json:"name,omitempty"`
+}
+
+func (du CloudInitConfigDefaultUser) MarshalJSON() ([]byte, error) {
+	if du.Name == "" {
+		return nil, fmt.Errorf("at least one configuration option must be specified for 'default_user' section")
+	}
+	defaultUser := cloudInitConfigDefaultUser(du)
+	return json.Marshal(defaultUser)
+}

internal/osbuild2/cloud_init_stage_test.go

@@ -0,0 +1,61 @@
+package osbuild2
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewCloudInitStage(t *testing.T) {
+	expectedStage := &Stage{
+		Type:    "org.osbuild.cloud-init",
+		Options: &CloudInitStageOptions{},
+	}
+	actualStage := NewCloudInitStage(&CloudInitStageOptions{})
+	assert.Equal(t, expectedStage, actualStage)
+}
+
+func TestCloudInitStage_MarshalJSON_Invalid(t *testing.T) {
+	tests := []struct {
+		name    string
+		options CloudInitStageOptions
+	}{
+		{
+			name: "no-config-file-section",
+			options: CloudInitStageOptions{
+				ConfigFiles: map[string]CloudInitConfigFile{
+					"00-default_user.cfg": {},
+				},
+			},
+		},
+		{
+			name: "no-system-info-section-option",
+			options: CloudInitStageOptions{
+				ConfigFiles: map[string]CloudInitConfigFile{
+					"00-default_user.cfg": {
+						SystemInfo: &CloudInitConfigSystemInfo{},
+					},
+				},
+			},
+		},
+		{
+			name: "no-default-user-section-option",
+			options: CloudInitStageOptions{
+				ConfigFiles: map[string]CloudInitConfigFile{
+					"00-default_user.cfg": {
+						SystemInfo: &CloudInitConfigSystemInfo{
+							DefaultUser: &CloudInitConfigDefaultUser{},
+						},
+					},
+				},
+			},
+		},
+	}
+	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)
+		})
+	}
+}

internal/osbuild2/stage.go

@@ -85,6 +85,8 @@ func (stage *Stage) UnmarshalJSON(data []byte) error {
 		options = new(GroupsStageOptions)
 	case "org.osbuild.timezone":
 		options = new(TimezoneStageOptions)
+	case "org.osbuild.cloud-init":
+		options = new(CloudInitStageOptions)
 	case "org.osbuild.chrony":
 		options = new(ChronyStageOptions)
 	case "org.osbuild.dracut":

internal/osbuild2/stage_test.go

@@ -52,6 +52,36 @@ func TestStage_UnmarshalJSON(t *testing.T) {
 			},
 			wantErr: true,
 		},
+		{
+			name: "cloud-init",
+			fields: fields{
+				Type:    "org.osbuild.cloud-init",
+				Options: &CloudInitStageOptions{},
+			},
+			args: args{
+				data: []byte(`{"type":"org.osbuild.cloud-init","options":{}}`),
+			},
+		},
+		{
+			name: "cloud-init-data",
+			fields: fields{
+				Type: "org.osbuild.cloud-init",
+				Options: &CloudInitStageOptions{
+					ConfigFiles: map[string]CloudInitConfigFile{
+						"00-default_user.cfg": {
+							SystemInfo: &CloudInitConfigSystemInfo{
+								DefaultUser: &CloudInitConfigDefaultUser{
+									Name: "ec2-user",
+								},
+							},
+						},
+					},
+				},
+			},
+			args: args{
+				data: []byte(`{"type":"org.osbuild.cloud-init","options":{"configuration_files":{"00-default_user.cfg":{"system_info":{"default_user":{"name":"ec2-user"}}}}}}`),
+			},
+		},
 		{
 			name: "chrony",
 			fields: fields{