package configload import ( "fmt" "io" "os" "path/filepath" "sort" "time" version "github.com/hashicorp/go-version" "github.com/hashicorp/hcl/v2" "github.com/hashicorp/terraform/internal/configs" "github.com/hashicorp/terraform/internal/modsdir" "github.com/spf13/afero" ) // LoadConfigWithSnapshot is a variant of LoadConfig that also simultaneously // creates an in-memory snapshot of the configuration files used, which can // be later used to create a loader that may read only from this snapshot. func (l *Loader) LoadConfigWithSnapshot(rootDir string) (*configs.Config, *Snapshot, hcl.Diagnostics) { rootMod, diags := l.parser.LoadConfigDir(rootDir) if rootMod == nil { return nil, nil, diags } snap := &Snapshot{ Modules: map[string]*SnapshotModule{}, } walker := l.makeModuleWalkerSnapshot(snap) cfg, cDiags := configs.BuildConfig(rootMod, walker) diags = append(diags, cDiags...) addDiags := l.addModuleToSnapshot(snap, "", rootDir, "", nil) diags = append(diags, addDiags...) return cfg, snap, diags } // NewLoaderFromSnapshot creates a Loader that reads files only from the // given snapshot. // // A snapshot-based loader cannot install modules, so calling InstallModules // on the return value will cause a panic. // // A snapshot-based loader also has access only to configuration files. Its // underlying parser does not have access to other files in the native // filesystem, such as values files. For those, either use a normal loader // (created by NewLoader) or use the configs.Parser API directly. func NewLoaderFromSnapshot(snap *Snapshot) *Loader { fs := snapshotFS{snap} parser := configs.NewParser(fs) ret := &Loader{ parser: parser, modules: moduleMgr{ FS: afero.Afero{Fs: fs}, CanInstall: false, manifest: snap.moduleManifest(), }, } return ret } // Snapshot is an in-memory representation of the source files from a // configuration, which can be used as an alternative configurations source // for a loader with NewLoaderFromSnapshot. // // The primary purpose of a Snapshot is to build the configuration portion // of a plan file (see ../../plans/planfile) so that it can later be reloaded // and used to recover the exact configuration that the plan was built from. type Snapshot struct { // Modules is a map from opaque module keys (suitable for use as directory // names on all supported operating systems) to the snapshot information // about each module. Modules map[string]*SnapshotModule } // NewEmptySnapshot constructs and returns a snapshot containing only an empty // root module. This is not useful for anything except placeholders in tests. func NewEmptySnapshot() *Snapshot { return &Snapshot{ Modules: map[string]*SnapshotModule{ "": &SnapshotModule{ Files: map[string][]byte{}, }, }, } } // SnapshotModule represents a single module within a Snapshot. type SnapshotModule struct { // Dir is the path, relative to the root directory given when the // snapshot was created, where the module appears in the snapshot's // virtual filesystem. Dir string // Files is a map from each configuration file filename for the // module to a raw byte representation of the source file contents. Files map[string][]byte // SourceAddr is the source address given for this module in configuration. SourceAddr string `json:"Source"` // Version is the version of the module that is installed, or nil if // the module is installed from a source that does not support versions. Version *version.Version `json:"-"` } // moduleManifest constructs a module manifest based on the contents of // the receiving snapshot. func (s *Snapshot) moduleManifest() modsdir.Manifest { ret := make(modsdir.Manifest) for k, modSnap := range s.Modules { ret[k] = modsdir.Record{ Key: k, Dir: modSnap.Dir, SourceAddr: modSnap.SourceAddr, Version: modSnap.Version, } } return ret } // makeModuleWalkerSnapshot creates a configs.ModuleWalker that will exhibit // the same lookup behaviors as l.moduleWalkerLoad but will additionally write // source files from the referenced modules into the given snapshot. func (l *Loader) makeModuleWalkerSnapshot(snap *Snapshot) configs.ModuleWalker { return configs.ModuleWalkerFunc( func(req *configs.ModuleRequest) (*configs.Module, *version.Version, hcl.Diagnostics) { mod, v, diags := l.moduleWalkerLoad(req) if diags.HasErrors() { return mod, v, diags } key := l.modules.manifest.ModuleKey(req.Path) record, exists := l.modules.manifest[key] if !exists { // Should never happen, since otherwise moduleWalkerLoader would've // returned an error and we would've returned already. panic(fmt.Sprintf("module %s is not present in manifest", key)) } addDiags := l.addModuleToSnapshot(snap, key, record.Dir, record.SourceAddr, record.Version) diags = append(diags, addDiags...) return mod, v, diags }, ) } func (l *Loader) addModuleToSnapshot(snap *Snapshot, key string, dir string, sourceAddr string, v *version.Version) hcl.Diagnostics { var diags hcl.Diagnostics primaryFiles, overrideFiles, moreDiags := l.parser.ConfigDirFiles(dir) if moreDiags.HasErrors() { // Any diagnostics we get here should be already present // in diags, so it's weird if we get here but we'll allow it // and return a general error message in that case. diags = append(diags, &hcl.Diagnostic{ Severity: hcl.DiagError, Summary: "Failed to read directory for module", Detail: fmt.Sprintf("The source directory %s could not be read", dir), }) return diags } snapMod := &SnapshotModule{ Dir: dir, Files: map[string][]byte{}, SourceAddr: sourceAddr, Version: v, } files := make([]string, 0, len(primaryFiles)+len(overrideFiles)) files = append(files, primaryFiles...) files = append(files, overrideFiles...) sources := l.Sources() // should be populated with all the files we need by now for _, filePath := range files { filename := filepath.Base(filePath) src, exists := sources[filePath] if !exists { diags = append(diags, &hcl.Diagnostic{ Severity: hcl.DiagError, Summary: "Missing source file for snapshot", Detail: fmt.Sprintf("The source code for file %s could not be found to produce a configuration snapshot.", filePath), }) continue } snapMod.Files[filepath.Clean(filename)] = src } snap.Modules[key] = snapMod return diags } // snapshotFS is an implementation of afero.Fs that reads from a snapshot. // // This is not intended as a general-purpose filesystem implementation. Instead, // it just supports the minimal functionality required to support the // configuration loader and parser as an implementation detail of creating // a loader from a snapshot. type snapshotFS struct { snap *Snapshot } var _ afero.Fs = snapshotFS{} func (fs snapshotFS) Create(name string) (afero.File, error) { return nil, fmt.Errorf("cannot create file inside configuration snapshot") } func (fs snapshotFS) Mkdir(name string, perm os.FileMode) error { return fmt.Errorf("cannot create directory inside configuration snapshot") } func (fs snapshotFS) MkdirAll(name string, perm os.FileMode) error { return fmt.Errorf("cannot create directories inside configuration snapshot") } func (fs snapshotFS) Open(name string) (afero.File, error) { // Our "filesystem" is sparsely populated only with the directories // mentioned by modules in our snapshot, so the high-level process // for opening a file is: // - Find the module snapshot corresponding to the containing directory // - Find the file within that snapshot // - Wrap the resulting byte slice in a snapshotFile to return // // The other possibility handled here is if the given name is for the // module directory itself, in which case we'll return a snapshotDir // instead. // // This function doesn't try to be incredibly robust in supporting // different permutations of paths, etc because in practice we only // need to support the path forms that our own loader and parser will // generate. dir := filepath.Dir(name) fn := filepath.Base(name) directDir := filepath.Clean(name) // First we'll check to see if this is an exact path for a module directory. // We need to do this first (rather than as part of the next loop below) // because a module in a child directory of another module can otherwise // appear to be a file in that parent directory. for _, candidate := range fs.snap.Modules { modDir := filepath.Clean(candidate.Dir) if modDir == directDir { // We've matched the module directory itself filenames := make([]string, 0, len(candidate.Files)) for n := range candidate.Files { filenames = append(filenames, n) } sort.Strings(filenames) return &snapshotDir{ filenames: filenames, }, nil } } // If we get here then the given path isn't a module directory exactly, so // we'll treat it as a file path and try to find a module directory it // could be located in. var modSnap *SnapshotModule for _, candidate := range fs.snap.Modules { modDir := filepath.Clean(candidate.Dir) if modDir == dir { modSnap = candidate break } } if modSnap == nil { return nil, os.ErrNotExist } src, exists := modSnap.Files[fn] if !exists { return nil, os.ErrNotExist } return &snapshotFile{ src: src, }, nil } func (fs snapshotFS) OpenFile(name string, flag int, perm os.FileMode) (afero.File, error) { return fs.Open(name) } func (fs snapshotFS) Remove(name string) error { return fmt.Errorf("cannot remove file inside configuration snapshot") } func (fs snapshotFS) RemoveAll(path string) error { return fmt.Errorf("cannot remove files inside configuration snapshot") } func (fs snapshotFS) Rename(old, new string) error { return fmt.Errorf("cannot rename file inside configuration snapshot") } func (fs snapshotFS) Stat(name string) (os.FileInfo, error) { f, err := fs.Open(name) if err != nil { return nil, err } _, isDir := f.(*snapshotDir) return snapshotFileInfo{ name: filepath.Base(name), isDir: isDir, }, nil } func (fs snapshotFS) Name() string { return "ConfigSnapshotFS" } func (fs snapshotFS) Chmod(name string, mode os.FileMode) error { return fmt.Errorf("cannot set file mode inside configuration snapshot") } func (fs snapshotFS) Chtimes(name string, atime, mtime time.Time) error { return fmt.Errorf("cannot set file times inside configuration snapshot") } type snapshotFile struct { snapshotFileStub src []byte at int64 } var _ afero.File = (*snapshotFile)(nil) func (f *snapshotFile) Read(p []byte) (n int, err error) { if len(p) > 0 && f.at == int64(len(f.src)) { return 0, io.EOF } if f.at > int64(len(f.src)) { return 0, io.ErrUnexpectedEOF } if int64(len(f.src))-f.at >= int64(len(p)) { n = len(p) } else { n = int(int64(len(f.src)) - f.at) } copy(p, f.src[f.at:f.at+int64(n)]) f.at += int64(n) return } func (f *snapshotFile) ReadAt(p []byte, off int64) (n int, err error) { f.at = off return f.Read(p) } func (f *snapshotFile) Seek(offset int64, whence int) (int64, error) { switch whence { case 0: f.at = offset case 1: f.at += offset case 2: f.at = int64(len(f.src)) + offset } return f.at, nil } type snapshotDir struct { snapshotFileStub filenames []string at int } var _ afero.File = (*snapshotDir)(nil) func (f *snapshotDir) Readdir(count int) ([]os.FileInfo, error) { names, err := f.Readdirnames(count) if err != nil { return nil, err } ret := make([]os.FileInfo, len(names)) for i, name := range names { ret[i] = snapshotFileInfo{ name: name, isDir: false, } } return ret, nil } func (f *snapshotDir) Readdirnames(count int) ([]string, error) { var outLen int names := f.filenames[f.at:] if count > 0 { if len(names) < count { outLen = len(names) } else { outLen = count } if len(names) == 0 { return nil, io.EOF } } else { outLen = len(names) } f.at += outLen return names[:outLen], nil } // snapshotFileInfo is a minimal implementation of os.FileInfo to support our // virtual filesystem from snapshots. type snapshotFileInfo struct { name string isDir bool } var _ os.FileInfo = snapshotFileInfo{} func (fi snapshotFileInfo) Name() string { return fi.name } func (fi snapshotFileInfo) Size() int64 { // In practice, our parser and loader never call Size return -1 } func (fi snapshotFileInfo) Mode() os.FileMode { return os.ModePerm } func (fi snapshotFileInfo) ModTime() time.Time { return time.Now() } func (fi snapshotFileInfo) IsDir() bool { return fi.isDir } func (fi snapshotFileInfo) Sys() interface{} { return nil } type snapshotFileStub struct{} func (f snapshotFileStub) Close() error { return nil } func (f snapshotFileStub) Read(p []byte) (n int, err error) { return 0, fmt.Errorf("cannot read") } func (f snapshotFileStub) ReadAt(p []byte, off int64) (n int, err error) { return 0, fmt.Errorf("cannot read") } func (f snapshotFileStub) Seek(offset int64, whence int) (int64, error) { return 0, fmt.Errorf("cannot seek") } func (f snapshotFileStub) Write(p []byte) (n int, err error) { return f.WriteAt(p, 0) } func (f snapshotFileStub) WriteAt(p []byte, off int64) (n int, err error) { return 0, fmt.Errorf("cannot write to file in snapshot") } func (f snapshotFileStub) WriteString(s string) (n int, err error) { return 0, fmt.Errorf("cannot write to file in snapshot") } func (f snapshotFileStub) Name() string { // in practice, the loader and parser never use this return "" } func (f snapshotFileStub) Readdir(count int) ([]os.FileInfo, error) { return nil, fmt.Errorf("cannot use Readdir on a file") } func (f snapshotFileStub) Readdirnames(count int) ([]string, error) { return nil, fmt.Errorf("cannot use Readdir on a file") } func (f snapshotFileStub) Stat() (os.FileInfo, error) { return nil, fmt.Errorf("cannot stat") } func (f snapshotFileStub) Sync() error { return nil } func (f snapshotFileStub) Truncate(size int64) error { return fmt.Errorf("cannot write to file in snapshot") }