feat: add resilient updates and access controls

internal/updateprotocol/protocol.go

@@ -0,0 +1,40 @@
+package updateprotocol
+
+import (
+	"regexp"
+	"time"
+)
+
+var releaseVersionPattern = regexp.MustCompile(`^v(?:0|[1-9][0-9]*)\.(?:0|[1-9][0-9]*)\.(?:0|[1-9][0-9]*)$`)
+
+const (
+	PhaseIdle       = "idle"
+	PhaseQueued     = "queued"
+	PhasePulling    = "pulling"
+	PhaseRestarting = "restarting"
+	PhaseVerifying  = "verifying"
+	PhaseComplete   = "complete"
+	PhaseFailed     = "failed"
+)
+
+type Request struct {
+	Version          string `json:"version"`
+	RegistryUsername string `json:"registry_username"`
+	RegistryToken    string `json:"registry_token"`
+}
+
+type Status struct {
+	Phase         string    `json:"phase"`
+	TargetVersion string    `json:"target_version,omitempty"`
+	Message       string    `json:"message,omitempty"`
+	StartedAt     time.Time `json:"started_at,omitempty"`
+	UpdatedAt     time.Time `json:"updated_at,omitempty"`
+}
+
+func (s Status) Busy() bool {
+	return s.Phase == PhaseQueued || s.Phase == PhasePulling || s.Phase == PhaseRestarting || s.Phase == PhaseVerifying
+}
+
+func ValidVersion(version string) bool {
+	return len(version) <= 64 && releaseVersionPattern.MatchString(version)
+}