feat: add deployment foundation and cross-device handoff

internal/planner/intent.go

@@ -0,0 +1,56 @@
+// Package planner builds offline previews. It does not inspect or change a host.
+package planner
+
+import (
+	"errors"
+	"net"
+	"regexp"
+	"strings"
+)
+
+const ProtocolVersion = 1
+
+var (
+	idPattern     = regexp.MustCompile(`^[a-z][a-z0-9-]{0,47}$`)
+	digestPattern = regexp.MustCompile(`^sha256:[a-f0-9]{64}$`)
+	labelPattern  = regexp.MustCompile(`^[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?$`)
+)
+
+// Intent contains no secrets. ObservedStateDigest is caller-supplied in offline
+// mode; a future executor must obtain it independently from the target host.
+type Intent struct {
+	ProtocolVersion     int    `json:"protocolVersion"`
+	HostID              string `json:"hostId"`
+	InstanceID          string `json:"instanceId"`
+	AppID               string `json:"appId"`
+	PackageDigest       string `json:"packageDigest"`
+	ImageDigest         string `json:"imageDigest"`
+	Domain              string `json:"domain"`
+	ObservedStateDigest string `json:"observedStateDigest"`
+}
+
+func (i Intent) Validate() error {
+	if i.ProtocolVersion != ProtocolVersion {
+		return errors.New("unsupported protocol version")
+	}
+	for _, id := range []string{i.HostID, i.InstanceID, i.AppID} {
+		if !idPattern.MatchString(id) {
+			return errors.New("invalid resource identifier")
+		}
+	}
+	for _, digest := range []string{i.PackageDigest, i.ImageDigest, i.ObservedStateDigest} {
+		if !digestPattern.MatchString(digest) {
+			return errors.New("expected a SHA-256 digest")
+		}
+	}
+	labels := strings.Split(i.Domain, ".")
+	if len(i.Domain) > 253 || len(labels) < 2 || net.ParseIP(i.Domain) != nil {
+		return errors.New("expected an ASCII DNS hostname")
+	}
+	for _, label := range labels {
+		if !labelPattern.MatchString(label) {
+			return errors.New("invalid DNS hostname label")
+		}
+	}
+	return nil
+}