stage/systemd-unit-create:add systemd-unit-create stage

Create systemd unit using the system-unit-create stage
This new stage adds the ability to create a systemd service unit file.
It provides customization to choose the unit-type and unit-path, defaults to '/usr/lib/systemd/system/'
Filename is validated using the same rules as specified by systemd.unit(5) and they must contain the
'.service' suffix (other types of unit files are not supported). config accepts sections: `Unit`,
`Service`, `Install` and each section accepts list of options that is in accordance to systemd.service
documentation. Relavent testing is also added.

Signed-off-by: Sayan Paul <[email protected]>

pkg/osbuild/systemd_unit_create_stage.go

@@ -0,0 +1,61 @@
+package osbuild
+
+type serviceType string
+type unitPath string
+
+const (
+	Simple              serviceType = "simple"
+	Exec                serviceType = "exec"
+	Forking             serviceType = "forking"
+	Oneshot             serviceType = "oneshot"
+	Dbus                serviceType = "dbus"
+	Notify              serviceType = "notify"
+	NotifyReloadservice serviceType = "notify-reload"
+	Idle                serviceType = "idle"
+	Etc                 unitPath    = "etc"
+	Usr                 unitPath    = "usr"
+)
+
+type Unit struct {
+	Description              string   `json:"Description,omitempty"`
+	DefaultDependencies      bool     `json:"DefaultDependencies,omitempty"`
+	ConditionPathExists      []string `json:"ConditionPathExists,omitempty"`
+	ConditionPathIsDirectory []string `json:"ConditionPathIsDirectory,omitempty"`
+	Requires                 []string `json:"Requires,omitempty"`
+	Wants                    []string `json:"Wants,omitempty"`
+}
+
+type Service struct {
+	Type            serviceType `json:"Type,omitempty"`
+	RemainAfterExit bool        `json:"RemainAfterExit,omitempty"`
+	ExecStartPre    []string    `json:"ExecStartPre,omitempty"`
+	ExecStopPost    []string    `json:"ExecStopPost,omitempty"`
+	ExecStart       []string    `json:"ExecStart,omitempty"`
+}
+
+type Install struct {
+	RequiredBy []string `json:"RequiredBy,omitempty"`
+	WantedBy   []string `json:"WantedBy,omitempty"`
+}
+
+type SystemdServiceUnit struct {
+	Unit    *Unit    `json:"Unit"`
+	Service *Service `json:"Service"`
+	Install *Install `json:"Install"`
+}
+
+type SystemdUnitCreateStageOptions struct {
+	Filename string             `json:"filename"`
+	UnitType unitType           `json:"unit-type,omitempty"` // unitType defined in ./systemd_unit_stage.go
+	UnitPath unitPath           `json:"unit-path,omitempty"`
+	Config   SystemdServiceUnit `json:"config"`
+}
+
+func (SystemdUnitCreateStageOptions) isStageOptions() {}
+
+func NewSystemdUnitCreateStageOptions(options *SystemdUnitCreateStageOptions) *Stage {
+	return &Stage{
+		Type:    "org.osbuild.systemd.unit.create",
+		Options: options,
+	}
+}

pkg/osbuild/systemd_unit_create_stage_test.go

@@ -0,0 +1,70 @@
+package osbuild
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func createSystemdUnit() SystemdServiceUnit {
+
+	var unit = Unit{
+		Description:              "Create directory and files",
+		ConditionPathExists:      []string{"!/etc/myfile"},
+		ConditionPathIsDirectory: []string{"!/etc/mydir"},
+		Requires:                 []string{"dbus.service", "libvirtd.service"},
+		Wants:                    []string{"local-fs.target"},
+	}
+	var service = Service{
+		Type:            Oneshot,
+		RemainAfterExit: true,
+		ExecStartPre:    []string{"echo creating_files"},
+		ExecStopPost:    []string{"echo done_creating_files"},
+		ExecStart:       []string{"mkdir -p /etc/mydir", "touch /etc/myfiles"},
+	}
+
+	var install = Install{
+		RequiredBy: []string{"multi-user.target", "boot-complete.target"},
+		WantedBy:   []string{"sshd.service"},
+	}
+
+	var systemdUnit = SystemdServiceUnit{
+		Unit:    &unit,
+		Service: &service,
+		Install: &install,
+	}
+
+	return systemdUnit
+}
+
+func TestNewSystemdUnitCreateStage(t *testing.T) {
+	systemdServiceConfig := createSystemdUnit()
+	var options = SystemdUnitCreateStageOptions{
+		Filename: "create-dir-files",
+		Config:   systemdServiceConfig,
+	}
+	expectedStage := &Stage{
+		Type:    "org.osbuild.systemd.unit.create",
+		Options: &options,
+	}
+
+	actualStage := NewSystemdUnitCreateStageOptions(&options)
+	assert.Equal(t, expectedStage, actualStage)
+}
+
+func TestNewSystemdUnitCreateStageInEtc(t *testing.T) {
+	systemdServiceConfig := createSystemdUnit()
+	var options = SystemdUnitCreateStageOptions{
+		Filename: "create-dir-files",
+		Config:   systemdServiceConfig,
+		UnitPath: Etc,
+		UnitType: Global,
+	}
+	expectedStage := &Stage{
+		Type:    "org.osbuild.systemd.unit.create",
+		Options: &options,
+	}
+
+	actualStage := NewSystemdUnitCreateStageOptions(&options)
+	assert.Equal(t, expectedStage, actualStage)
+}