vendor/github.com/hashicorp/terraform/configs/configload/loader_snapshot.go

   1 package configload
   2
   3 import (
   4         "fmt"
   5         "io"
   6         "os"
   7         "path/filepath"
   8         "sort"
   9         "time"
  10
  11         version "github.com/hashicorp/go-version"
  12         "github.com/hashicorp/hcl2/hcl"
  13         "github.com/hashicorp/terraform/configs"
  14         "github.com/hashicorp/terraform/internal/modsdir"
  15         "github.com/spf13/afero"
  16 )
  17
  18 // LoadConfigWithSnapshot is a variant of LoadConfig that also simultaneously
  19 // creates an in-memory snapshot of the configuration files used, which can
  20 // be later used to create a loader that may read only from this snapshot.
  21 func (l *Loader) LoadConfigWithSnapshot(rootDir string) (*configs.Config, *Snapshot, hcl.Diagnostics) {
  22         rootMod, diags := l.parser.LoadConfigDir(rootDir)
  23         if rootMod == nil {
  24                 return nil, nil, diags
  25         }
  26
  27         snap := &Snapshot{
  28                 Modules: map[string]*SnapshotModule{},
  29         }
  30         walker := l.makeModuleWalkerSnapshot(snap)
  31         cfg, cDiags := configs.BuildConfig(rootMod, walker)
  32         diags = append(diags, cDiags...)
  33
  34         addDiags := l.addModuleToSnapshot(snap, "", rootDir, "", nil)
  35         diags = append(diags, addDiags...)
  36
  37         return cfg, snap, diags
  38 }
  39
  40 // NewLoaderFromSnapshot creates a Loader that reads files only from the
  41 // given snapshot.
  42 //
  43 // A snapshot-based loader cannot install modules, so calling InstallModules
  44 // on the return value will cause a panic.
  45 //
  46 // A snapshot-based loader also has access only to configuration files. Its
  47 // underlying parser does not have access to other files in the native
  48 // filesystem, such as values files. For those, either use a normal loader
  49 // (created by NewLoader) or use the configs.Parser API directly.
  50 func NewLoaderFromSnapshot(snap *Snapshot) *Loader {
  51         fs := snapshotFS{snap}
  52         parser := configs.NewParser(fs)
  53
  54         ret := &Loader{
  55                 parser: parser,
  56                 modules: moduleMgr{
  57                         FS:         afero.Afero{Fs: fs},
  58                         CanInstall: false,
  59                         manifest:   snap.moduleManifest(),
  60                 },
  61         }
  62
  63         return ret
  64 }
  65
  66 // Snapshot is an in-memory representation of the source files from a
  67 // configuration, which can be used as an alternative configurations source
  68 // for a loader with NewLoaderFromSnapshot.
  69 //
  70 // The primary purpose of a Snapshot is to build the configuration portion
  71 // of a plan file (see ../../plans/planfile) so that it can later be reloaded
  72 // and used to recover the exact configuration that the plan was built from.
  73 type Snapshot struct {
  74         // Modules is a map from opaque module keys (suitable for use as directory
  75         // names on all supported operating systems) to the snapshot information
  76         // about each module.
  77         Modules map[string]*SnapshotModule
  78 }
  79
  80 // NewEmptySnapshot constructs and returns a snapshot containing only an empty
  81 // root module. This is not useful for anything except placeholders in tests.
  82 func NewEmptySnapshot() *Snapshot {
  83         return &Snapshot{
  84                 Modules: map[string]*SnapshotModule{
  85                         "": &SnapshotModule{
  86                                 Files: map[string][]byte{},
  87                         },
  88                 },
  89         }
  90 }
  91
  92 // SnapshotModule represents a single module within a Snapshot.
  93 type SnapshotModule struct {
  94         // Dir is the path, relative to the root directory given when the
  95         // snapshot was created, where the module appears in the snapshot's
  96         // virtual filesystem.
  97         Dir string
  98
  99         // Files is a map from each configuration file filename for the
 100         // module to a raw byte representation of the source file contents.
 101         Files map[string][]byte
 102
 103         // SourceAddr is the source address given for this module in configuration.
 104         SourceAddr string `json:"Source"`
 105
 106         // Version is the version of the module that is installed, or nil if
 107         // the module is installed from a source that does not support versions.
 108         Version *version.Version `json:"-"`
 109 }
 110
 111 // moduleManifest constructs a module manifest based on the contents of
 112 // the receiving snapshot.
 113 func (s *Snapshot) moduleManifest() modsdir.Manifest {
 114         ret := make(modsdir.Manifest)
 115
 116         for k, modSnap := range s.Modules {
 117                 ret[k] = modsdir.Record{
 118                         Key:        k,
 119                         Dir:        modSnap.Dir,
 120                         SourceAddr: modSnap.SourceAddr,
 121                         Version:    modSnap.Version,
 122                 }
 123         }
 124
 125         return ret
 126 }
 127
 128 // makeModuleWalkerSnapshot creates a configs.ModuleWalker that will exhibit
 129 // the same lookup behaviors as l.moduleWalkerLoad but will additionally write
 130 // source files from the referenced modules into the given snapshot.
 131 func (l *Loader) makeModuleWalkerSnapshot(snap *Snapshot) configs.ModuleWalker {
 132         return configs.ModuleWalkerFunc(
 133                 func(req *configs.ModuleRequest) (*configs.Module, *version.Version, hcl.Diagnostics) {
 134                         mod, v, diags := l.moduleWalkerLoad(req)
 135                         if diags.HasErrors() {
 136                                 return mod, v, diags
 137                         }
 138
 139                         key := l.modules.manifest.ModuleKey(req.Path)
 140                         record, exists := l.modules.manifest[key]
 141
 142                         if !exists {
 143                                 // Should never happen, since otherwise moduleWalkerLoader would've
 144                                 // returned an error and we would've returned already.
 145                                 panic(fmt.Sprintf("module %s is not present in manifest", key))
 146                         }
 147
 148                         addDiags := l.addModuleToSnapshot(snap, key, record.Dir, record.SourceAddr, record.Version)
 149                         diags = append(diags, addDiags...)
 150
 151                         return mod, v, diags
 152                 },
 153         )
 154 }
 155
 156 func (l *Loader) addModuleToSnapshot(snap *Snapshot, key string, dir string, sourceAddr string, v *version.Version) hcl.Diagnostics {
 157         var diags hcl.Diagnostics
 158
 159         primaryFiles, overrideFiles, moreDiags := l.parser.ConfigDirFiles(dir)
 160         if moreDiags.HasErrors() {
 161                 // Any diagnostics we get here should be already present
 162                 // in diags, so it's weird if we get here but we'll allow it
 163                 // and return a general error message in that case.
 164                 diags = append(diags, &hcl.Diagnostic{
 165                         Severity: hcl.DiagError,
 166                         Summary:  "Failed to read directory for module",
 167                         Detail:   fmt.Sprintf("The source directory %s could not be read", dir),
 168                 })
 169                 return diags
 170         }
 171
 172         snapMod := &SnapshotModule{
 173                 Dir:        dir,
 174                 Files:      map[string][]byte{},
 175                 SourceAddr: sourceAddr,
 176                 Version:    v,
 177         }
 178
 179         files := make([]string, 0, len(primaryFiles)+len(overrideFiles))
 180         files = append(files, primaryFiles...)
 181         files = append(files, overrideFiles...)
 182         sources := l.Sources() // should be populated with all the files we need by now
 183         for _, filePath := range files {
 184                 filename := filepath.Base(filePath)
 185                 src, exists := sources[filePath]
 186                 if !exists {
 187                         diags = append(diags, &hcl.Diagnostic{
 188                                 Severity: hcl.DiagError,
 189                                 Summary:  "Missing source file for snapshot",
 190                                 Detail:   fmt.Sprintf("The source code for file %s could not be found to produce a configuration snapshot.", filePath),
 191                         })
 192                         continue
 193                 }
 194                 snapMod.Files[filepath.Clean(filename)] = src
 195         }
 196
 197         snap.Modules[key] = snapMod
 198
 199         return diags
 200 }
 201
 202 // snapshotFS is an implementation of afero.Fs that reads from a snapshot.
 203 //
 204 // This is not intended as a general-purpose filesystem implementation. Instead,
 205 // it just supports the minimal functionality required to support the
 206 // configuration loader and parser as an implementation detail of creating
 207 // a loader from a snapshot.
 208 type snapshotFS struct {
 209         snap *Snapshot
 210 }
 211
 212 var _ afero.Fs = snapshotFS{}
 213
 214 func (fs snapshotFS) Create(name string) (afero.File, error) {
 215         return nil, fmt.Errorf("cannot create file inside configuration snapshot")
 216 }
 217
 218 func (fs snapshotFS) Mkdir(name string, perm os.FileMode) error {
 219         return fmt.Errorf("cannot create directory inside configuration snapshot")
 220 }
 221
 222 func (fs snapshotFS) MkdirAll(name string, perm os.FileMode) error {
 223         return fmt.Errorf("cannot create directories inside configuration snapshot")
 224 }
 225
 226 func (fs snapshotFS) Open(name string) (afero.File, error) {
 227
 228         // Our "filesystem" is sparsely populated only with the directories
 229         // mentioned by modules in our snapshot, so the high-level process
 230         // for opening a file is:
 231         // - Find the module snapshot corresponding to the containing directory
 232         // - Find the file within that snapshot
 233         // - Wrap the resulting byte slice in a snapshotFile to return
 234         //
 235         // The other possibility handled here is if the given name is for the
 236         // module directory itself, in which case we'll return a snapshotDir
 237         // instead.
 238         //
 239         // This function doesn't try to be incredibly robust in supporting
 240         // different permutations of paths, etc because in practice we only
 241         // need to support the path forms that our own loader and parser will
 242         // generate.
 243
 244         dir := filepath.Dir(name)
 245         fn := filepath.Base(name)
 246         directDir := filepath.Clean(name)
 247
 248         // First we'll check to see if this is an exact path for a module directory.
 249         // We need to do this first (rather than as part of the next loop below)
 250         // because a module in a child directory of another module can otherwise
 251         // appear to be a file in that parent directory.
 252         for _, candidate := range fs.snap.Modules {
 253                 modDir := filepath.Clean(candidate.Dir)
 254                 if modDir == directDir {
 255                         // We've matched the module directory itself
 256                         filenames := make([]string, 0, len(candidate.Files))
 257                         for n := range candidate.Files {
 258                                 filenames = append(filenames, n)
 259                         }
 260                         sort.Strings(filenames)
 261                         return snapshotDir{
 262                                 filenames: filenames,
 263                         }, nil
 264                 }
 265         }
 266
 267         // If we get here then the given path isn't a module directory exactly, so
 268         // we'll treat it as a file path and try to find a module directory it
 269         // could be located in.
 270         var modSnap *SnapshotModule
 271         for _, candidate := range fs.snap.Modules {
 272                 modDir := filepath.Clean(candidate.Dir)
 273                 if modDir == dir {
 274                         modSnap = candidate
 275                         break
 276                 }
 277         }
 278         if modSnap == nil {
 279                 return nil, os.ErrNotExist
 280         }
 281
 282         src, exists := modSnap.Files[fn]
 283         if !exists {
 284                 return nil, os.ErrNotExist
 285         }
 286
 287         return &snapshotFile{
 288                 src: src,
 289         }, nil
 290 }
 291
 292 func (fs snapshotFS) OpenFile(name string, flag int, perm os.FileMode) (afero.File, error) {
 293         return fs.Open(name)
 294 }
 295
 296 func (fs snapshotFS) Remove(name string) error {
 297         return fmt.Errorf("cannot remove file inside configuration snapshot")
 298 }
 299
 300 func (fs snapshotFS) RemoveAll(path string) error {
 301         return fmt.Errorf("cannot remove files inside configuration snapshot")
 302 }
 303
 304 func (fs snapshotFS) Rename(old, new string) error {
 305         return fmt.Errorf("cannot rename file inside configuration snapshot")
 306 }
 307
 308 func (fs snapshotFS) Stat(name string) (os.FileInfo, error) {
 309         f, err := fs.Open(name)
 310         if err != nil {
 311                 return nil, err
 312         }
 313         _, isDir := f.(snapshotDir)
 314         return snapshotFileInfo{
 315                 name:  filepath.Base(name),
 316                 isDir: isDir,
 317         }, nil
 318 }
 319
 320 func (fs snapshotFS) Name() string {
 321         return "ConfigSnapshotFS"
 322 }
 323
 324 func (fs snapshotFS) Chmod(name string, mode os.FileMode) error {
 325         return fmt.Errorf("cannot set file mode inside configuration snapshot")
 326 }
 327
 328 func (fs snapshotFS) Chtimes(name string, atime, mtime time.Time) error {
 329         return fmt.Errorf("cannot set file times inside configuration snapshot")
 330 }
 331
 332 type snapshotFile struct {
 333         snapshotFileStub
 334         src []byte
 335         at  int64
 336 }
 337
 338 var _ afero.File = (*snapshotFile)(nil)
 339
 340 func (f *snapshotFile) Read(p []byte) (n int, err error) {
 341         if len(p) > 0 && f.at == int64(len(f.src)) {
 342                 return 0, io.EOF
 343         }
 344         if f.at > int64(len(f.src)) {
 345                 return 0, io.ErrUnexpectedEOF
 346         }
 347         if int64(len(f.src))-f.at >= int64(len(p)) {
 348                 n = len(p)
 349         } else {
 350                 n = int(int64(len(f.src)) - f.at)
 351         }
 352         copy(p, f.src[f.at:f.at+int64(n)])
 353         f.at += int64(n)
 354         return
 355 }
 356
 357 func (f *snapshotFile) ReadAt(p []byte, off int64) (n int, err error) {
 358         f.at = off
 359         return f.Read(p)
 360 }
 361
 362 func (f *snapshotFile) Seek(offset int64, whence int) (int64, error) {
 363         switch whence {
 364         case 0:
 365                 f.at = offset
 366         case 1:
 367                 f.at += offset
 368         case 2:
 369                 f.at = int64(len(f.src)) + offset
 370         }
 371         return f.at, nil
 372 }
 373
 374 type snapshotDir struct {
 375         snapshotFileStub
 376         filenames []string
 377         at        int
 378 }
 379
 380 var _ afero.File = snapshotDir{}
 381
 382 func (f snapshotDir) Readdir(count int) ([]os.FileInfo, error) {
 383         names, err := f.Readdirnames(count)
 384         if err != nil {
 385                 return nil, err
 386         }
 387         ret := make([]os.FileInfo, len(names))
 388         for i, name := range names {
 389                 ret[i] = snapshotFileInfo{
 390                         name:  name,
 391                         isDir: false,
 392                 }
 393         }
 394         return ret, nil
 395 }
 396
 397 func (f snapshotDir) Readdirnames(count int) ([]string, error) {
 398         var outLen int
 399         names := f.filenames[f.at:]
 400         if count > 0 {
 401                 if len(names) < count {
 402                         outLen = len(names)
 403                 } else {
 404                         outLen = count
 405                 }
 406                 if len(names) == 0 {
 407                         return nil, io.EOF
 408                 }
 409         } else {
 410                 outLen = len(names)
 411         }
 412         f.at += outLen
 413
 414         return names[:outLen], nil
 415 }
 416
 417 // snapshotFileInfo is a minimal implementation of os.FileInfo to support our
 418 // virtual filesystem from snapshots.
 419 type snapshotFileInfo struct {
 420         name  string
 421         isDir bool
 422 }
 423
 424 var _ os.FileInfo = snapshotFileInfo{}
 425
 426 func (fi snapshotFileInfo) Name() string {
 427         return fi.name
 428 }
 429
 430 func (fi snapshotFileInfo) Size() int64 {
 431         // In practice, our parser and loader never call Size
 432         return -1
 433 }
 434
 435 func (fi snapshotFileInfo) Mode() os.FileMode {
 436         return os.ModePerm
 437 }
 438
 439 func (fi snapshotFileInfo) ModTime() time.Time {
 440         return time.Now()
 441 }
 442
 443 func (fi snapshotFileInfo) IsDir() bool {
 444         return fi.isDir
 445 }
 446
 447 func (fi snapshotFileInfo) Sys() interface{} {
 448         return nil
 449 }
 450
 451 type snapshotFileStub struct{}
 452
 453 func (f snapshotFileStub) Close() error {
 454         return nil
 455 }
 456
 457 func (f snapshotFileStub) Read(p []byte) (n int, err error) {
 458         return 0, fmt.Errorf("cannot read")
 459 }
 460
 461 func (f snapshotFileStub) ReadAt(p []byte, off int64) (n int, err error) {
 462         return 0, fmt.Errorf("cannot read")
 463 }
 464
 465 func (f snapshotFileStub) Seek(offset int64, whence int) (int64, error) {
 466         return 0, fmt.Errorf("cannot seek")
 467 }
 468
 469 func (f snapshotFileStub) Write(p []byte) (n int, err error) {
 470         return f.WriteAt(p, 0)
 471 }
 472
 473 func (f snapshotFileStub) WriteAt(p []byte, off int64) (n int, err error) {
 474         return 0, fmt.Errorf("cannot write to file in snapshot")
 475 }
 476
 477 func (f snapshotFileStub) WriteString(s string) (n int, err error) {
 478         return 0, fmt.Errorf("cannot write to file in snapshot")
 479 }
 480
 481 func (f snapshotFileStub) Name() string {
 482         // in practice, the loader and parser never use this
 483         return "<unimplemented>"
 484 }
 485
 486 func (f snapshotFileStub) Readdir(count int) ([]os.FileInfo, error) {
 487         return nil, fmt.Errorf("cannot use Readdir on a file")
 488 }
 489
 490 func (f snapshotFileStub) Readdirnames(count int) ([]string, error) {
 491         return nil, fmt.Errorf("cannot use Readdir on a file")
 492 }
 493
 494 func (f snapshotFileStub) Stat() (os.FileInfo, error) {
 495         return nil, fmt.Errorf("cannot stat")
 496 }
 497
 498 func (f snapshotFileStub) Sync() error {
 499         return nil
 500 }
 501
 502 func (f snapshotFileStub) Truncate(size int64) error {
 503         return fmt.Errorf("cannot write to file in snapshot")
 504 }