feat: restart to apply update, privileged helper, rollback

internal/domain/update/updateRestart.go

@@ -0,0 +1,158 @@
+package update
+
+import (
+	"errors"
+	"regexp"
+	"time"
+)
+
+const (
+	StateRestarting = "restarting"
+	StateSucceeded  = "succeeded"
+
+	ErrorKindRolledBack = "rolled_back"
+	ErrorKindInstall    = "install"
+
+	RestartKindUpdate  = "update"
+	RestartKindRestart = "restart"
+
+	OutcomeRunning    = "running"
+	OutcomeSucceeded  = "succeeded"
+	OutcomeRolledBack = "rolled_back"
+	OutcomeFailed     = "failed"
+
+	RunningResultMaxAge = 5 * time.Minute
+)
+
+var (
+	ErrRestartPending      = errors.New("a restart is already pending or running")
+	ErrRestartKindMismatch = errors.New("the requested restart does not match the current state")
+	ErrNoRestartRequest    = errors.New("there is no restart request")
+	ErrSymlinkRefused      = errors.New("a symbolic link was found where a regular file is required")
+	ErrInvalidRestartTag   = errors.New("the restart request names an invalid version")
+	ErrHelperUnsupported   = errors.New("the privileged helper needs Linux")
+)
+
+var restartTagPattern = regexp.MustCompile(`^v[0-9]+(\.[0-9]+)*(-[0-9A-Za-z.]+)?$`)
+
+type RestartRequest struct {
+	Kind        string    `json:"kind"`
+	Tag         string    `json:"tag,omitempty"`
+	RequestedAt time.Time `json:"requested_at"`
+	RequestedBy uint32    `json:"requested_by"`
+}
+
+type Result struct {
+	Outcome     string     `json:"outcome"`
+	Kind        string     `json:"kind"`
+	Tag         string     `json:"tag"`
+	FromVersion string     `json:"from_version"`
+	StartedAt   time.Time  `json:"started_at"`
+	FinishedAt  *time.Time `json:"finished_at"`
+}
+
+type RunningInfo struct {
+	Version   string    `json:"version"`
+	Pid       int       `json:"pid"`
+	StartedAt time.Time `json:"started_at"`
+}
+
+type HelperStatus struct {
+	Version     int       `json:"version"`
+	Service     string    `json:"service"`
+	Binary      string    `json:"binary"`
+	DataDir     string    `json:"data_dir"`
+	InstalledAt time.Time `json:"installed_at"`
+}
+
+type FileInfo struct {
+	IsSymlink bool
+	IsDir     bool
+	IsRegular bool
+}
+
+type RestartRequestStore interface {
+	Write(request RestartRequest) error
+	Read() (RestartRequest, error)
+	Delete() error
+}
+
+type ResultStore interface {
+	Read() (Result, bool)
+	Write(result Result) error
+	Delete() error
+}
+
+type RunningInfoStore interface {
+	Write(info RunningInfo) error
+	Read() (RunningInfo, bool)
+}
+
+type HelperFilesystem interface {
+	Lstat(path string) (FileInfo, error)
+	ReadFile(path string) ([]byte, error)
+	CreateExclusive(path string, content []byte, mode uint32) error
+	Copy(source string, destination string, mode uint32) error
+	Rename(oldPath string, newPath string) error
+	Remove(path string) error
+	RemoveAll(path string) error
+	Chmod(path string, mode uint32) error
+	MakePrivateTempDir() (string, error)
+}
+
+type ServiceControl interface {
+	Restart() error
+	Status() (bool, error)
+}
+
+type HealthChecker interface {
+	Healthy() bool
+}
+
+type Clock interface {
+	Now() time.Time
+	Sleep(duration time.Duration)
+}
+
+func ValidateRestartTag(tag string, runningVersion string) error {
+	if !restartTagPattern.MatchString(tag) {
+		return ErrInvalidRestartTag
+	}
+	if _, err := ParseVersion(tag); err != nil || !IsNewer(runningVersion, tag) {
+		return ErrInvalidRestartTag
+	}
+	return nil
+}
+
+func (r Result) IsRunning() bool {
+	return r.Outcome == OutcomeRunning
+}
+
+func (r Result) IsKnown() bool {
+	switch r.Outcome {
+	case OutcomeRunning, OutcomeSucceeded, OutcomeRolledBack, OutcomeFailed:
+		return true
+	}
+	return false
+}
+
+func (i RunningInfo) IsNewerThan(previous RunningInfo, restartedAt time.Time) bool {
+	return i.Pid != previous.Pid || i.StartedAt.After(restartedAt)
+}
+
+const (
+	RestartWindow = 60 * time.Second
+	PollInterval  = time.Second
+)
+
+type SymlinkError struct {
+	Path string
+}
+
+func (e SymlinkError) Error() string {
+	return e.Path + " is a symbolic link"
+}
+
+func (e SymlinkError) Is(target error) bool {
+	return target == ErrSymlinkRefused
+}