| 1 | package provision |
| 2 | |
| 3 | import ( |
| 4 | "context" |
| 5 | "errors" |
| 6 | "fmt" |
| 7 | "io" |
| 8 | "maps" |
| 9 | "os" |
| 10 | "slices" |
| 11 | "strings" |
| 12 | "sync" |
| 13 | |
| 14 | "github.com/carlosframework/platform/internal/domains" |
| 15 | "github.com/carlosframework/platform/internal/release" |
| 16 | ) |
| 17 | |
| 18 | // ViewSnapshot is one immutable publication of a RecordView. Epoch increases |
| 19 | // with every publication. Complete is false while any scope has a failed or |
| 20 | // outstanding re-read, after a walk that could not list an account's apps, |
| 21 | // or when the record walk over the snapshot would itself be partial (an |
| 22 | // account manifest that will not read cleanly, an app listing that failed). |
| 23 | // It is never read and changed at once: a Refresh builds a new one. |
| 24 | type ViewSnapshot struct { |
| 25 | Epoch uint64 |
| 26 | Complete bool |
| 27 | |
| 28 | accounts map[string]*acctEntry // sqid -> accounts/<sqid>/ |
| 29 | strays []string // keys under accounts/ outside every account scope, from the last walk |
| 30 | apps map[string]map[string]*appEntry // acct -> app -> apps/<acct>/<app>/ |
| 31 | dirErrs map[string]error // acct -> why the last walk could not list apps/<acct>/ |
| 32 | walkErr error // the last walk failed at the top: accounts/ and apps/ answer it |
| 33 | } |
| 34 | |
| 35 | // acctEntry is one account scope: its complete key listing and account.json, |
| 36 | // or the listing failure (which the manifest then carries too, so a reader |
| 37 | // asking for the manifest learns the read failed rather than that it is |
| 38 | // absent). |
| 39 | type acctEntry struct { |
| 40 | keys []release.KeyETag |
| 41 | listErr error |
| 42 | manifest object |
| 43 | } |
| 44 | |
| 45 | // appEntry is one app scope: both record listings (or why each failed), and |
| 46 | // objs, every listed record body plus the two manifests and the trash marker. |
| 47 | type appEntry struct { |
| 48 | inst, side []release.KeyETag |
| 49 | instErr, sideErr error |
| 50 | objs map[string]object |
| 51 | } |
| 52 | |
| 53 | // object is one cached read: a body and its ETag, a not-found error wrapping |
| 54 | // os.ErrNotExist, or the read error itself. |
| 55 | type object struct { |
| 56 | body []byte |
| 57 | etag string |
| 58 | err error |
| 59 | } |
| 60 | |
| 61 | func absent(key string) object { |
| 62 | return object{err: fmt.Errorf("provision: record view: %s: %w", key, os.ErrNotExist)} |
| 63 | } |
| 64 | |
| 65 | // failed reports a read that did not answer: anything but a body or absence. |
| 66 | func (o object) failed() bool { return o.err != nil && !errors.Is(o.err, os.ErrNotExist) } |
| 67 | |
| 68 | // result is the object as Get returns it, with a body the caller may keep. |
| 69 | func (o object) result() ([]byte, string, error) { |
| 70 | if o.err != nil { |
| 71 | return nil, "", o.err |
| 72 | } |
| 73 | return slices.Clone(o.body), o.etag, nil |
| 74 | } |
| 75 | |
| 76 | func accountManifestKey(a string) string { return "accounts/" + a + "/account.json" } |
| 77 | |
| 78 | func (e *acctEntry) empty() bool { |
| 79 | return e == nil || (len(e.keys) == 0 && e.listErr == nil) |
| 80 | } |
| 81 | |
| 82 | // empty reports an app with no record-family state at all: nothing listed, |
| 83 | // nothing failed, and all three per-app objects absent. A purged app is |
| 84 | // dropped from the view, and from ListDirs over it. |
| 85 | func (e *appEntry) empty() bool { |
| 86 | if e == nil { |
| 87 | return true |
| 88 | } |
| 89 | if len(e.inst) > 0 || len(e.side) > 0 || e.instErr != nil || e.sideErr != nil { |
| 90 | return false |
| 91 | } |
| 92 | for _, o := range e.objs { |
| 93 | if !errors.Is(o.err, os.ErrNotExist) { |
| 94 | return false |
| 95 | } |
| 96 | } |
| 97 | return true |
| 98 | } |
| 99 | |
| 100 | // object is the cached read of key, or nil when the entry holds none. |
| 101 | func (e *appEntry) object(key string) *object { |
| 102 | if e == nil { |
| 103 | return nil |
| 104 | } |
| 105 | o, ok := e.objs[key] |
| 106 | if !ok { |
| 107 | return nil |
| 108 | } |
| 109 | return &o |
| 110 | } |
| 111 | |
| 112 | func (sn *ViewSnapshot) app(a, b string) *appEntry { |
| 113 | if sn == nil { |
| 114 | return nil |
| 115 | } |
| 116 | return sn.apps[a][b] |
| 117 | } |
| 118 | |
| 119 | // clone copies the maps a Refresh changes; entries are shared, never mutated. |
| 120 | func (sn *ViewSnapshot) clone() *ViewSnapshot { |
| 121 | out := &ViewSnapshot{ |
| 122 | accounts: maps.Clone(sn.accounts), |
| 123 | strays: sn.strays, |
| 124 | apps: make(map[string]map[string]*appEntry, len(sn.apps)), |
| 125 | dirErrs: sn.dirErrs, |
| 126 | walkErr: sn.walkErr, |
| 127 | } |
| 128 | for a, inner := range sn.apps { |
| 129 | out.apps[a] = maps.Clone(inner) |
| 130 | } |
| 131 | return out |
| 132 | } |
| 133 | |
| 134 | func (sn *ViewSnapshot) setAccount(a string, e *acctEntry) { |
| 135 | if e.empty() { |
| 136 | delete(sn.accounts, a) |
| 137 | return |
| 138 | } |
| 139 | sn.accounts[a] = e |
| 140 | } |
| 141 | |
| 142 | func (sn *ViewSnapshot) setApp(a, b string, e *appEntry) { |
| 143 | if e.empty() { |
| 144 | delete(sn.apps[a], b) |
| 145 | if len(sn.apps[a]) == 0 { |
| 146 | delete(sn.apps, a) |
| 147 | } |
| 148 | return |
| 149 | } |
| 150 | if sn.apps[a] == nil { |
| 151 | sn.apps[a] = map[string]*appEntry{} |
| 152 | } |
| 153 | sn.apps[a][b] = e |
| 154 | } |
| 155 | |
| 156 | // appKey splits apps/<a>/<b>/<rest> with all three parts non-empty. |
| 157 | func appKey(key string) (a, b, rest string, ok bool) { |
| 158 | parts := strings.SplitN(key, "/", 4) |
| 159 | if len(parts) < 4 || parts[0] != "apps" || parts[1] == "" || parts[2] == "" || parts[3] == "" { |
| 160 | return "", "", "", false |
| 161 | } |
| 162 | return parts[1], parts[2], parts[3], true |
| 163 | } |
| 164 | |
| 165 | // lookup answers Get of a key in a cached family; handled is false for every |
| 166 | // other key. A key the view does not hold is absent: its family's listing is |
| 167 | // complete. A record under a listing that failed answers that failure, and |
| 168 | // so does any key of an app the view never read because the walk could not |
| 169 | // list its account's apps. |
| 170 | func (sn *ViewSnapshot) lookup(key string) (o object, handled bool) { |
| 171 | if sn == nil { |
| 172 | return object{}, false |
| 173 | } |
| 174 | if a, ok := domains.AccountManifestSqid(key); ok { |
| 175 | e := sn.accounts[a] |
| 176 | if e == nil { |
| 177 | return absent(key), true |
| 178 | } |
| 179 | return e.manifest, true |
| 180 | } |
| 181 | a, b, rest, ok := appKey(key) |
| 182 | if !ok { |
| 183 | return object{}, false |
| 184 | } |
| 185 | var listErr error |
| 186 | switch { |
| 187 | case rest == "instances.json" || rest == "sidecars.json" || rest == "deleted.json": |
| 188 | case strings.HasPrefix(rest, "instances/") && rest != "instances/": |
| 189 | listErr = sn.app(a, b).listErr(true) |
| 190 | case strings.HasPrefix(rest, "sidecars/") && rest != "sidecars/": |
| 191 | listErr = sn.app(a, b).listErr(false) |
| 192 | default: |
| 193 | return object{}, false |
| 194 | } |
| 195 | if listErr != nil { |
| 196 | return object{err: listErr}, true |
| 197 | } |
| 198 | if err := sn.dirErrs[a]; err != nil && sn.app(a, b) == nil { |
| 199 | // The last walk could not list this account's apps, and no refresh |
| 200 | // has read this one since: the view does not know, so it must not |
| 201 | // answer absent. |
| 202 | return object{err: err}, true |
| 203 | } |
| 204 | if p := sn.app(a, b).object(key); p != nil { |
| 205 | return *p, true |
| 206 | } |
| 207 | return absent(key), true |
| 208 | } |
| 209 | |
| 210 | func (e *appEntry) listErr(inst bool) error { |
| 211 | switch { |
| 212 | case e == nil: |
| 213 | return nil |
| 214 | case inst: |
| 215 | return e.instErr |
| 216 | } |
| 217 | return e.sideErr |
| 218 | } |
| 219 | |
| 220 | // list answers List of a cached family, sorted as the stores list. |
| 221 | func (sn *ViewSnapshot) list(prefix string) (keys []string, handled bool, err error) { |
| 222 | if prefix == "accounts/" { |
| 223 | if sn.walkErr != nil { |
| 224 | return nil, true, sn.walkErr |
| 225 | } |
| 226 | out := slices.Clone(sn.strays) |
| 227 | for a, e := range sn.accounts { |
| 228 | if e.listErr != nil { |
| 229 | // Unknown keys; the manifest is listed so a reader asks for it |
| 230 | // and learns the read failed (knownAccounts' readFailed). |
| 231 | out = append(out, accountManifestKey(a)) |
| 232 | continue |
| 233 | } |
| 234 | out = append(out, keysOf(e.keys)...) |
| 235 | } |
| 236 | slices.Sort(out) |
| 237 | return out, true, nil |
| 238 | } |
| 239 | if a, ok := strings.CutPrefix(prefix, "accounts/"); ok { |
| 240 | a, ok = strings.CutSuffix(a, "/") |
| 241 | if !ok || a == "" || strings.Contains(a, "/") { |
| 242 | return nil, false, nil |
| 243 | } |
| 244 | e := sn.accounts[a] |
| 245 | if e == nil { |
| 246 | return nil, true, nil |
| 247 | } |
| 248 | return keysOf(e.keys), true, e.listErr |
| 249 | } |
| 250 | a, b, rest, ok := appKey(prefix) |
| 251 | if !ok || (rest != "instances/" && rest != "sidecars/") { |
| 252 | return nil, false, nil |
| 253 | } |
| 254 | e := sn.app(a, b) |
| 255 | if e == nil { |
| 256 | return nil, true, sn.dirErrs[a] // unknown, not empty, when the walk could not list the account's apps |
| 257 | } |
| 258 | if rest == "instances/" { |
| 259 | return keysOf(e.inst), true, e.instErr |
| 260 | } |
| 261 | return keysOf(e.side), true, e.sideErr |
| 262 | } |
| 263 | |
| 264 | // listDirs answers ListDirs("apps/") and ListDirs("apps/<a>/"): accounts and |
| 265 | // apps holding record-family state, as full prefixes, sorted. An account whose |
| 266 | // apps the last walk could not list is listed, and listing it fails, as it did. |
| 267 | func (sn *ViewSnapshot) listDirs(prefix string) (dirs []string, handled bool, err error) { |
| 268 | if prefix == "apps/" { |
| 269 | if sn.walkErr != nil { |
| 270 | return nil, true, sn.walkErr |
| 271 | } |
| 272 | var out []string |
| 273 | for a := range sn.apps { |
| 274 | out = append(out, "apps/"+a+"/") |
| 275 | } |
| 276 | for a := range sn.dirErrs { |
| 277 | if sn.apps[a] == nil { |
| 278 | out = append(out, "apps/"+a+"/") |
| 279 | } |
| 280 | } |
| 281 | slices.Sort(out) |
| 282 | return out, true, nil |
| 283 | } |
| 284 | a, ok := strings.CutPrefix(prefix, "apps/") |
| 285 | if !ok { |
| 286 | return nil, false, nil |
| 287 | } |
| 288 | a, ok = strings.CutSuffix(a, "/") |
| 289 | if !ok || a == "" || strings.Contains(a, "/") { |
| 290 | return nil, false, nil |
| 291 | } |
| 292 | if err := sn.dirErrs[a]; err != nil { |
| 293 | return nil, true, err |
| 294 | } |
| 295 | var out []string |
| 296 | for b := range sn.apps[a] { |
| 297 | out = append(out, prefix+b+"/") |
| 298 | } |
| 299 | slices.Sort(out) |
| 300 | return out, true, nil |
| 301 | } |
| 302 | |
| 303 | // Store is the snapshot as a release.Store over live: the cached families are |
| 304 | // answered from the snapshot, everything else from live. Every write goes to |
| 305 | // live, and from then on that key, and every listing it falls under, is read |
| 306 | // from live for the rest of this store's life, so a caller reads its own |
| 307 | // writes and a CAS retry re-reads the bucket. Each call returns a fresh store; |
| 308 | // the snapshot itself never changes. |
| 309 | func (sn *ViewSnapshot) Store(live release.Store) release.Store { |
| 310 | return &snapStore{sn: sn, live: live} |
| 311 | } |
| 312 | |
| 313 | // freshStore is the store a reader that must see the bucket as it is now |
| 314 | // reads through: live under a snapshot store, s itself otherwise. A guard |
| 315 | // that re-reads a record to check that nothing moved since the listing |
| 316 | // (holdExisting) would only read the listing's own snapshot back. |
| 317 | func freshStore(s release.Store) release.Store { |
| 318 | if ss, ok := s.(*snapStore); ok { |
| 319 | return ss.live |
| 320 | } |
| 321 | return s |
| 322 | } |
| 323 | |
| 324 | // onSnapshot reports whether s is a record view snapshot store. A snapshot's |
| 325 | // absence is not the bucket's decision: a record written without its bump (a |
| 326 | // failed bump, an old binary, a direct-bucket writer) is missing from a |
| 327 | // Complete snapshot until the backstop rebuild. So Reconcile and |
| 328 | // ReconcileSidecars over a snapshot decide any removal from the bucket's own |
| 329 | // walk (scanRecords, scanSidecars over freshStore), and over any other store |
| 330 | // from the walk they already made. |
| 331 | func onSnapshot(s release.Store) bool { |
| 332 | _, ok := s.(*snapStore) |
| 333 | return ok |
| 334 | } |
| 335 | |
| 336 | // walkErrSuffix renders the error of a bucket walk that could not be read |
| 337 | // cleanly for a log line: nothing when the walk returned but read partially |
| 338 | // (its own lines name what failed). |
| 339 | func walkErrSuffix(err error) string { |
| 340 | if err == nil { |
| 341 | return "" |
| 342 | } |
| 343 | return ": " + err.Error() |
| 344 | } |
| 345 | |
| 346 | type snapStore struct { |
| 347 | sn *ViewSnapshot |
| 348 | live release.Store |
| 349 | |
| 350 | mu sync.Mutex |
| 351 | wrote []string |
| 352 | } |
| 353 | |
| 354 | var ( |
| 355 | _ release.Store = (*snapStore)(nil) |
| 356 | _ release.BucketListDirs = (*snapStore)(nil) |
| 357 | _ release.Opener = (*snapStore)(nil) |
| 358 | _ release.PutStreamer = (*snapStore)(nil) |
| 359 | _ release.ConditionalDeleter = (*snapStore)(nil) |
| 360 | _ release.ModLister = (*snapStore)(nil) |
| 361 | _ release.SizeLister = (*snapStore)(nil) |
| 362 | _ release.PageLister = (*snapStore)(nil) |
| 363 | _ release.ConditionalGetter = (*snapStore)(nil) |
| 364 | _ release.ETagLister = (*snapStore)(nil) |
| 365 | _ release.AppMutationRunner = (*snapStore)(nil) |
| 366 | ) |
| 367 | |
| 368 | func (s *snapStore) mark(key string) { |
| 369 | s.mu.Lock() |
| 370 | s.wrote = append(s.wrote, key) |
| 371 | s.mu.Unlock() |
| 372 | } |
| 373 | |
| 374 | // wroteUnder reports a write through this store to a key under prefix (or, |
| 375 | // with exact, to key itself). |
| 376 | func (s *snapStore) wroteUnder(prefix string, exact bool) bool { |
| 377 | s.mu.Lock() |
| 378 | defer s.mu.Unlock() |
| 379 | for _, k := range s.wrote { |
| 380 | if k == prefix || (!exact && strings.HasPrefix(k, prefix)) { |
| 381 | return true |
| 382 | } |
| 383 | } |
| 384 | return false |
| 385 | } |
| 386 | |
| 387 | // BucketShapedListDirs: the snapshot answers ListDirs("apps/") and |
| 388 | // ListDirs("apps/<a>/") in the bucket's shape whatever live's shape is (after |
| 389 | // a write it asks live only when live is bucket-shaped too), so the record |
| 390 | // walk lists per app instead of the whole of apps/. |
| 391 | func (s *snapStore) BucketShapedListDirs() bool { return true } |
| 392 | |
| 393 | func (s *snapStore) Get(ctx context.Context, key string) ([]byte, string, error) { |
| 394 | if !s.wroteUnder(key, true) { |
| 395 | if o, ok := s.sn.lookup(key); ok { |
| 396 | return o.result() |
| 397 | } |
| 398 | } |
| 399 | return s.live.Get(ctx, key) |
| 400 | } |
| 401 | |
| 402 | func (s *snapStore) List(ctx context.Context, prefix string) ([]string, error) { |
| 403 | if !s.wroteUnder(prefix, false) { |
| 404 | if keys, ok, err := s.sn.list(prefix); ok { |
| 405 | return keys, err |
| 406 | } |
| 407 | } |
| 408 | return s.live.List(ctx, prefix) |
| 409 | } |
| 410 | |
| 411 | func (s *snapStore) ListDirs(ctx context.Context, prefix string) ([]string, error) { |
| 412 | norm := prefix |
| 413 | if norm != "" && !strings.HasSuffix(norm, "/") { |
| 414 | norm += "/" |
| 415 | } |
| 416 | dirs, ok, err := s.sn.listDirs(norm) |
| 417 | if !ok { |
| 418 | return s.live.ListDirs(ctx, prefix) |
| 419 | } |
| 420 | if err != nil || !s.wroteUnder(norm, false) { |
| 421 | return dirs, err |
| 422 | } |
| 423 | // A write under prefix: live knows the directories it made, but only a |
| 424 | // bucket-shaped live answers in the shape this store promises. The fleet |
| 425 | // door's ListDirs("apps/") is its account's apps, and walking that as |
| 426 | // accounts found no records at all (listAppSubtree). Otherwise the |
| 427 | // snapshot's directories plus those the writes imply. |
| 428 | if release.HasBucketListDirs(s.live) { |
| 429 | return s.live.ListDirs(ctx, prefix) |
| 430 | } |
| 431 | s.mu.Lock() |
| 432 | for _, k := range s.wrote { |
| 433 | rest, ok := strings.CutPrefix(k, norm) |
| 434 | if !ok { |
| 435 | continue |
| 436 | } |
| 437 | if child, _, ok := strings.Cut(rest, "/"); ok && child != "" { |
| 438 | if d := norm + child + "/"; !slices.Contains(dirs, d) { |
| 439 | dirs = append(dirs, d) |
| 440 | } |
| 441 | } |
| 442 | } |
| 443 | s.mu.Unlock() |
| 444 | slices.Sort(dirs) |
| 445 | return dirs, nil |
| 446 | } |
| 447 | |
| 448 | func (s *snapStore) Put(ctx context.Context, key string, body []byte, ifMatch string) (string, error) { |
| 449 | s.mark(key) |
| 450 | return s.live.Put(ctx, key, body, ifMatch) |
| 451 | } |
| 452 | |
| 453 | func (s *snapStore) PutFrom(ctx context.Context, key string, body io.ReadSeeker, size int64, ifMatch string) (string, error) { |
| 454 | s.mark(key) |
| 455 | return release.PutObjectFrom(ctx, s.live, key, body, size, ifMatch) |
| 456 | } |
| 457 | |
| 458 | func (s *snapStore) Delete(ctx context.Context, key string) error { |
| 459 | s.mark(key) |
| 460 | return s.live.Delete(ctx, key) |
| 461 | } |
| 462 | |
| 463 | func (s *snapStore) DeleteIfMatch(ctx context.Context, key, etag string) error { |
| 464 | s.mark(key) |
| 465 | return release.DeleteIfMatch(ctx, s.live, key, etag) |
| 466 | } |
| 467 | |
| 468 | // The remaining extensions are not cached families: forwarded to live, and |
| 469 | // errors.ErrUnsupported when live lacks one. |
| 470 | |
| 471 | func (s *snapStore) Open(ctx context.Context, key string) (io.ReadCloser, string, error) { |
| 472 | return release.OpenObject(ctx, s.live, key) |
| 473 | } |
| 474 | |
| 475 | func (s *snapStore) GetIfChanged(ctx context.Context, key, etag string) ([]byte, string, bool, error) { |
| 476 | if g, ok := s.live.(release.ConditionalGetter); ok { |
| 477 | return g.GetIfChanged(ctx, key, etag) |
| 478 | } |
| 479 | return nil, "", false, errors.ErrUnsupported |
| 480 | } |
| 481 | |
| 482 | func (s *snapStore) ListETags(ctx context.Context, prefix string) ([]release.KeyETag, error) { |
| 483 | if l, ok := s.live.(release.ETagLister); ok { |
| 484 | return l.ListETags(ctx, prefix) |
| 485 | } |
| 486 | return nil, errors.ErrUnsupported |
| 487 | } |
| 488 | |
| 489 | func (s *snapStore) ListMod(ctx context.Context, prefix string) ([]release.KeyMod, error) { |
| 490 | if l, ok := s.live.(release.ModLister); ok { |
| 491 | return l.ListMod(ctx, prefix) |
| 492 | } |
| 493 | return nil, errors.ErrUnsupported |
| 494 | } |
| 495 | |
| 496 | func (s *snapStore) ListSizes(ctx context.Context, prefix string) ([]release.KeySize, error) { |
| 497 | if l, ok := s.live.(release.SizeLister); ok { |
| 498 | return l.ListSizes(ctx, prefix) |
| 499 | } |
| 500 | return nil, errors.ErrUnsupported |
| 501 | } |
| 502 | |
| 503 | func (s *snapStore) ListPage(ctx context.Context, prefix, startAfter string, limit int) ([]string, error) { |
| 504 | if l, ok := s.live.(release.PageLister); ok { |
| 505 | return l.ListPage(ctx, prefix, startAfter, limit) |
| 506 | } |
| 507 | return nil, errors.ErrUnsupported |
| 508 | } |
| 509 | |
| 510 | // RunAppMutation keeps live's claim boundary for writes made through the |
| 511 | // snapshot store; a live store without one runs f directly, as |
| 512 | // release.WithAppMutation would. |
| 513 | func (s *snapStore) RunAppMutation(ctx context.Context, acct, app, action string, f func(context.Context) error) error { |
| 514 | if r, ok := s.live.(release.AppMutationRunner); ok { |
| 515 | return r.RunAppMutation(ctx, acct, app, action, f) |
| 516 | } |
| 517 | return f(ctx) |
| 518 | } |
| 519 | |
| 520 | // uncachedStore refuses everything. walkComplete runs the record walk over a |
| 521 | // snapshot store backed by it, so a read the cache does not answer shows up |
| 522 | // as a failure instead of a bucket request. |
| 523 | type uncachedStore struct{} |
| 524 | |
| 525 | var errUncached = errors.New("provision: record view: not in the snapshot") |
| 526 | |
| 527 | func (uncachedStore) Get(context.Context, string) ([]byte, string, error) { |
| 528 | return nil, "", errUncached |
| 529 | } |
| 530 | func (uncachedStore) Put(context.Context, string, []byte, string) (string, error) { |
| 531 | return "", errUncached |
| 532 | } |
| 533 | func (uncachedStore) List(context.Context, string) ([]string, error) { return nil, errUncached } |
| 534 | func (uncachedStore) ListDirs(context.Context, string) ([]string, error) { return nil, errUncached } |
| 535 | func (uncachedStore) Delete(context.Context, string) error { return errUncached } |
| 536 | |
amadan