| 1 | // Package seeds is the shared vocabulary of instances that start from a |
| 2 | // database (#260 --from, #261 import): seed ids, the snapshot's bucket keys, |
| 3 | // the states a record's seed moves through, the verify token, and the |
| 4 | // registry column the box reads. It holds no I/O. Spec: |
| 5 | // docs/superpowers/specs/2026-10-08-seeded-instances-design.md. |
| 6 | // |
| 7 | // It must never import internal/moves (the moves copy gate inventories every |
| 8 | // changed file that does). |
| 9 | package seeds |
| 10 | |
| 11 | import ( |
| 12 | "crypto/rand" |
| 13 | "encoding/base32" |
| 14 | "errors" |
| 15 | "fmt" |
| 16 | "io" |
| 17 | "regexp" |
| 18 | "strings" |
| 19 | |
| 20 | "github.com/carlosframework/platform/internal/controlname" |
| 21 | ) |
| 22 | |
| 23 | // The two kinds of seed (spec §3.2). |
| 24 | const ( |
| 25 | KindReplica = "replica" // --from: a sibling's replica |
| 26 | KindImport = "import" // an uploaded snapshot |
| 27 | ) |
| 28 | |
| 29 | // The states of spec §3.2. |
| 30 | const ( |
| 31 | StateReserving = "reserving" |
| 32 | StateAwaitingUpload = "awaiting-upload" |
| 33 | StateUploaded = "uploaded" |
| 34 | StateReady = "ready" |
| 35 | StateSwapped = "swapped" |
| 36 | StatePlaced = "placed" |
| 37 | StateCommitted = "committed" |
| 38 | StateRefused = "refused" |
| 39 | StateAborted = "aborted" |
| 40 | StateRolledBack = "rolled-back" |
| 41 | ) |
| 42 | |
| 43 | // MaxBytes is the largest database either door accepts (spec §4 step 5, |
| 44 | // §5.1): 4 GiB, under S3's 5 GB single-PUT limit. |
| 45 | const MaxBytes int64 = 4 << 30 |
| 46 | |
| 47 | // Prefix is the snapshots' prefix in a region's data bucket, beside |
| 48 | // instances/ and moves/ (spec §3.1). |
| 49 | const Prefix = "seeds/" |
| 50 | |
| 51 | const snapshotName = "snapshot.db" |
| 52 | |
| 53 | // invalidHost stands in for a host or id that failed validation. It is not a |
| 54 | // host shape (the "!"), so no real seed lives under it: a read of such a key |
| 55 | // finds nothing and a delete of its prefix removes nothing. |
| 56 | const invalidHost = "!invalid" |
| 57 | |
| 58 | // ErrBadHost and ErrBadID are what Check returns. A door that takes a host |
| 59 | // or id from a request or a record calls Check first and refuses with them. |
| 60 | var ( |
| 61 | ErrBadHost = errors.New("seeds: not a host") |
| 62 | ErrBadID = errors.New("seeds: not a seed id") |
| 63 | ) |
| 64 | |
| 65 | var idShape = regexp.MustCompile(`^sd_[a-z2-7]{26}$`) |
| 66 | |
| 67 | var lowerBase32 = base32.NewEncoding("abcdefghijklmnopqrstuvwxyz234567").WithPadding(base32.NoPadding) |
| 68 | |
| 69 | // randReader is crypto/rand's reader, a variable so a test can fail it. |
| 70 | var randReader io.Reader = rand.Reader |
| 71 | |
| 72 | // NewID mints a seed id: "sd_" and 128 random bits in lowercase base32. An |
| 73 | // id is never reused (spec §3.2): every cleanup is scoped to one. Ids come |
| 74 | // only from crypto/rand. |
| 75 | func NewID() (string, error) { |
| 76 | var b [16]byte |
| 77 | if _, err := io.ReadFull(randReader, b[:]); err != nil { |
| 78 | return "", fmt.Errorf("seeds: mint an id: %w", err) |
| 79 | } |
| 80 | return "sd_" + lowerBase32.EncodeToString(b[:]), nil |
| 81 | } |
| 82 | |
| 83 | // ValidID reports whether id has NewID's shape. Every id that passes is 29 |
| 84 | // bytes of [a-z2-7_] and so is one clean path element: no slash, backslash |
| 85 | // or dot. |
| 86 | func ValidID(id string) bool { return idShape.MatchString(id) } |
| 87 | |
| 88 | // Check reports ErrBadHost if host is not a host shape (lowercase DNS labels, |
| 89 | // so one clean path element with no slash or "..") and ErrBadID if id is not |
| 90 | // a seed id. |
| 91 | func Check(host, id string) error { |
| 92 | if !controlname.ValidHostShape(host) { |
| 93 | return ErrBadHost |
| 94 | } |
| 95 | if !ValidID(id) { |
| 96 | return ErrBadID |
| 97 | } |
| 98 | return nil |
| 99 | } |
| 100 | |
| 101 | // HostPrefix is every seed of host: seeds/<host>/. A host that is not a host |
| 102 | // shape yields seeds/!invalid/, which names nothing. |
| 103 | func HostPrefix(host string) string { |
| 104 | if !controlname.ValidHostShape(host) { |
| 105 | host = invalidHost |
| 106 | } |
| 107 | return Prefix + host + "/" |
| 108 | } |
| 109 | |
| 110 | // SnapshotPrefix is one seed's prefix: seeds/<host>/<id>/. Every delete of |
| 111 | // a snapshot names it (codex R4-1). A host or id that fails Check yields |
| 112 | // seeds/!invalid/invalid/, so no key built here leaves seeds/<host>/<id>/ and |
| 113 | // no prefix built here covers more than one seed. |
| 114 | func SnapshotPrefix(host, id string) string { |
| 115 | if Check(host, id) != nil { |
| 116 | return HostPrefix("") + "invalid/" |
| 117 | } |
| 118 | return HostPrefix(host) + id + "/" |
| 119 | } |
| 120 | |
| 121 | // SnapshotKey is one seed's snapshot: seeds/<host>/<id>/snapshot.db. |
| 122 | func SnapshotKey(host, id string) string { return SnapshotPrefix(host, id) + snapshotName } |
| 123 | |
| 124 | // ParseSnapshotKey is SnapshotKey's inverse. Anything else under seeds/ is |
| 125 | // not a snapshot and does not parse. |
| 126 | func ParseSnapshotKey(key string) (host, id string, ok bool) { |
| 127 | rest, found := strings.CutPrefix(key, Prefix) |
| 128 | if !found { |
| 129 | return "", "", false |
| 130 | } |
| 131 | parts := strings.Split(rest, "/") |
| 132 | if len(parts) != 3 || parts[2] != snapshotName || Check(parts[0], parts[1]) != nil { |
| 133 | return "", "", false |
| 134 | } |
| 135 | return parts[0], parts[1], true |
| 136 | } |
| 137 | |
amadan