github.com/pulumi/terraform@v1.4.0/pkg/configs/parser.go (about) 1 package configs 2 3 import ( 4 "fmt" 5 "strings" 6 7 "github.com/hashicorp/hcl/v2" 8 "github.com/hashicorp/hcl/v2/hclparse" 9 "github.com/spf13/afero" 10 ) 11 12 // Parser is the main interface to read configuration files and other related 13 // files from disk. 14 // 15 // It retains a cache of all files that are loaded so that they can be used 16 // to create source code snippets in diagnostics, etc. 17 type Parser struct { 18 fs afero.Afero 19 p *hclparse.Parser 20 21 // allowExperiments controls whether we will allow modules to opt in to 22 // experimental language features. In main code this will be set only 23 // for alpha releases and some development builds. Test code must decide 24 // for itself whether to enable it so that tests can cover both the 25 // allowed and not-allowed situations. 26 allowExperiments bool 27 } 28 29 // NewParser creates and returns a new Parser that reads files from the given 30 // filesystem. If a nil filesystem is passed then the system's "real" filesystem 31 // will be used, via afero.OsFs. 32 func NewParser(fs afero.Fs) *Parser { 33 if fs == nil { 34 fs = afero.OsFs{} 35 } 36 37 return &Parser{ 38 fs: afero.Afero{Fs: fs}, 39 p: hclparse.NewParser(), 40 } 41 } 42 43 // LoadHCLFile is a low-level method that reads the file at the given path, 44 // parses it, and returns the hcl.Body representing its root. In many cases 45 // it is better to use one of the other Load*File methods on this type, 46 // which additionally decode the root body in some way and return a higher-level 47 // construct. 48 // 49 // If the file cannot be read at all -- e.g. because it does not exist -- then 50 // this method will return a nil body and error diagnostics. In this case 51 // callers may wish to ignore the provided error diagnostics and produce 52 // a more context-sensitive error instead. 53 // 54 // The file will be parsed using the HCL native syntax unless the filename 55 // ends with ".json", in which case the HCL JSON syntax will be used. 56 func (p *Parser) LoadHCLFile(path string) (hcl.Body, hcl.Diagnostics) { 57 src, err := p.fs.ReadFile(path) 58 59 if err != nil { 60 return nil, hcl.Diagnostics{ 61 { 62 Severity: hcl.DiagError, 63 Summary: "Failed to read file", 64 Detail: fmt.Sprintf("The file %q could not be read.", path), 65 }, 66 } 67 } 68 69 var file *hcl.File 70 var diags hcl.Diagnostics 71 switch { 72 case strings.HasSuffix(path, ".json"): 73 file, diags = p.p.ParseJSON(src, path) 74 default: 75 file, diags = p.p.ParseHCL(src, path) 76 } 77 78 // If the returned file or body is nil, then we'll return a non-nil empty 79 // body so we'll meet our contract that nil means an error reading the file. 80 if file == nil || file.Body == nil { 81 return hcl.EmptyBody(), diags 82 } 83 84 return file.Body, diags 85 } 86 87 // Sources returns a map of the cached source buffers for all files that 88 // have been loaded through this parser, with source filenames (as requested 89 // when each file was opened) as the keys. 90 func (p *Parser) Sources() map[string][]byte { 91 return p.p.Sources() 92 } 93 94 // ForceFileSource artificially adds source code to the cache of file sources, 95 // as if it had been loaded from the given filename. 96 // 97 // This should be used only in special situations where configuration is loaded 98 // some other way. Most callers should load configuration via methods of 99 // Parser, which will update the sources cache automatically. 100 func (p *Parser) ForceFileSource(filename string, src []byte) { 101 // We'll make a synthetic hcl.File here just so we can reuse the 102 // existing cache. 103 p.p.AddFile(filename, &hcl.File{ 104 Body: hcl.EmptyBody(), 105 Bytes: src, 106 }) 107 } 108 109 // AllowLanguageExperiments specifies whether subsequent LoadConfigFile (and 110 // similar) calls will allow opting in to experimental language features. 111 // 112 // If this method is never called for a particular parser, the default behavior 113 // is to disallow language experiments. 114 // 115 // Main code should set this only for alpha or development builds. Test code 116 // is responsible for deciding for itself whether and how to call this 117 // method. 118 func (p *Parser) AllowLanguageExperiments(allowed bool) { 119 p.allowExperiments = allowed 120 }