package template import ( "bufio" "bytes" "encoding/json" "fmt" "io" "io/ioutil" "os" "path/filepath" "sort" "strings" "github.com/hashicorp/go-multierror" "github.com/mitchellh/mapstructure" ) // rawTemplate is the direct JSON document format of the template file. // This is what is decoded directly from the file, and then it is turned // into a Template object thereafter. type rawTemplate struct { MinVersion string `mapstructure:"min_packer_version"` Description string Builders []map[string]interface{} Push map[string]interface{} PostProcessors []interface{} `mapstructure:"post-processors"` Provisioners []map[string]interface{} Variables map[string]interface{} RawContents []byte } // Template returns the actual Template object built from this raw // structure. func (r *rawTemplate) Template() (*Template, error) { var result Template var errs error // Copy some literals result.Description = r.Description result.MinVersion = r.MinVersion result.RawContents = r.RawContents // Gather the variables if len(r.Variables) > 0 { result.Variables = make(map[string]*Variable, len(r.Variables)) } for k, rawV := range r.Variables { var v Variable // Variable is required if the value is exactly nil v.Required = rawV == nil // Weak decode the default if we have one if err := r.decoder(&v.Default, nil).Decode(rawV); err != nil { errs = multierror.Append(errs, fmt.Errorf( "variable %s: %s", k, err)) continue } result.Variables[k] = &v } // Let's start by gathering all the builders if len(r.Builders) > 0 { result.Builders = make(map[string]*Builder, len(r.Builders)) } for i, rawB := range r.Builders { var b Builder if err := mapstructure.WeakDecode(rawB, &b); err != nil { errs = multierror.Append(errs, fmt.Errorf( "builder %d: %s", i+1, err)) continue } // Set the raw configuration and delete any special keys b.Config = rawB delete(b.Config, "name") delete(b.Config, "type") if len(b.Config) == 0 { b.Config = nil } // If there is no type set, it is an error if b.Type == "" { errs = multierror.Append(errs, fmt.Errorf( "builder %d: missing 'type'", i+1)) continue } // The name defaults to the type if it isn't set if b.Name == "" { b.Name = b.Type } // If this builder already exists, it is an error if _, ok := result.Builders[b.Name]; ok { errs = multierror.Append(errs, fmt.Errorf( "builder %d: builder with name '%s' already exists", i+1, b.Name)) continue } // Append the builders result.Builders[b.Name] = &b } // Gather all the post-processors if len(r.PostProcessors) > 0 { result.PostProcessors = make([][]*PostProcessor, 0, len(r.PostProcessors)) } for i, v := range r.PostProcessors { // Parse the configurations. We need to do this because post-processors // can take three different formats. configs, err := r.parsePostProcessor(i, v) if err != nil { errs = multierror.Append(errs, err) continue } // Parse the PostProcessors out of the configs pps := make([]*PostProcessor, 0, len(configs)) for j, c := range configs { var pp PostProcessor if err := r.decoder(&pp, nil).Decode(c); err != nil { errs = multierror.Append(errs, fmt.Errorf( "post-processor %d.%d: %s", i+1, j+1, err)) continue } // Type is required if pp.Type == "" { errs = multierror.Append(errs, fmt.Errorf( "post-processor %d.%d: type is required", i+1, j+1)) continue } // Set the configuration delete(c, "except") delete(c, "only") delete(c, "keep_input_artifact") delete(c, "type") if len(c) > 0 { pp.Config = c } pps = append(pps, &pp) } result.PostProcessors = append(result.PostProcessors, pps) } // Gather all the provisioners if len(r.Provisioners) > 0 { result.Provisioners = make([]*Provisioner, 0, len(r.Provisioners)) } for i, v := range r.Provisioners { var p Provisioner if err := r.decoder(&p, nil).Decode(v); err != nil { errs = multierror.Append(errs, fmt.Errorf( "provisioner %d: %s", i+1, err)) continue } // Type is required before any richer validation if p.Type == "" { errs = multierror.Append(errs, fmt.Errorf( "provisioner %d: missing 'type'", i+1)) continue } // Copy the configuration delete(v, "except") delete(v, "only") delete(v, "override") delete(v, "pause_before") delete(v, "type") if len(v) > 0 { p.Config = v } // TODO: stuff result.Provisioners = append(result.Provisioners, &p) } // Push if len(r.Push) > 0 { var p Push if err := r.decoder(&p, nil).Decode(r.Push); err != nil { errs = multierror.Append(errs, fmt.Errorf( "push: %s", err)) } result.Push = p } // If we have errors, return those with a nil result if errs != nil { return nil, errs } return &result, nil } func (r *rawTemplate) decoder( result interface{}, md *mapstructure.Metadata) *mapstructure.Decoder { d, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{ DecodeHook: mapstructure.StringToTimeDurationHookFunc(), Metadata: md, Result: result, }) if err != nil { // This really shouldn't happen since we have firm control over // all the arguments and they're all unit tested. So we use a // panic here to note this would definitely be a bug. panic(err) } return d } func (r *rawTemplate) parsePostProcessor( i int, raw interface{}) ([]map[string]interface{}, error) { switch v := raw.(type) { case string: return []map[string]interface{}{ {"type": v}, }, nil case map[string]interface{}: return []map[string]interface{}{v}, nil case []interface{}: var err error result := make([]map[string]interface{}, len(v)) for j, innerRaw := range v { switch innerV := innerRaw.(type) { case string: result[j] = map[string]interface{}{"type": innerV} case map[string]interface{}: result[j] = innerV case []interface{}: err = multierror.Append(err, fmt.Errorf( "post-processor %d.%d: sequence not allowed to be nested in a sequence", i+1, j+1)) default: err = multierror.Append(err, fmt.Errorf( "post-processor %d.%d: unknown format", i+1, j+1)) } } if err != nil { return nil, err } return result, nil default: return nil, fmt.Errorf("post-processor %d: bad format", i+1) } } // Parse takes the given io.Reader and parses a Template object out of it. func Parse(r io.Reader) (*Template, error) { // Create a buffer to copy what we read var buf bytes.Buffer if _, err := buf.ReadFrom(r); err != nil { return nil, err } // First, decode the object into an interface{}. We do this instead of // the rawTemplate directly because we'd rather use mapstructure to // decode since it has richer errors. var raw interface{} if err := json.Unmarshal(buf.Bytes(), &raw); err != nil { return nil, err } // Create our decoder var md mapstructure.Metadata var rawTpl rawTemplate rawTpl.RawContents = buf.Bytes() decoder, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{ Metadata: &md, Result: &rawTpl, }) if err != nil { return nil, err } // Do the actual decode into our structure if err := decoder.Decode(raw); err != nil { return nil, err } // Build an error if there are unused root level keys if len(md.Unused) > 0 { sort.Strings(md.Unused) for _, unused := range md.Unused { // Ignore keys starting with '_' as comments if unused[0] == '_' { continue } err = multierror.Append(err, fmt.Errorf( "Unknown root level key in template: '%s'", unused)) } } if err != nil { return nil, err } // Return the template parsed from the raw structure return rawTpl.Template() } // ParseFile is the same as Parse but is a helper to automatically open // a file for parsing. func ParseFile(path string) (*Template, error) { var f *os.File var err error if path == "-" { // Create a temp file for stdin in case of errors f, err = ioutil.TempFile(os.TempDir(), "packer") if err != nil { return nil, err } defer os.Remove(f.Name()) defer f.Close() io.Copy(f, os.Stdin) f.Seek(0, os.SEEK_SET) } else { f, err = os.Open(path) if err != nil { return nil, err } defer f.Close() } tpl, err := Parse(f) if err != nil { syntaxErr, ok := err.(*json.SyntaxError) if !ok { return nil, err } // Rewind the file and get a better error f.Seek(0, os.SEEK_SET) // Grab the error location, and return a string to point to offending syntax error line, col, highlight := highlightPosition(f, syntaxErr.Offset) err = fmt.Errorf("Error parsing JSON: %s\nAt line %d, column %d (offset %d):\n%s", err, line, col, syntaxErr.Offset, highlight) return nil, err } if !filepath.IsAbs(path) { path, err = filepath.Abs(path) if err != nil { return nil, err } } tpl.Path = path return tpl, nil } // Takes a file and the location in bytes of a parse error // from json.SyntaxError.Offset and returns the line, column, // and pretty-printed context around the error with an arrow indicating the exact // position of the syntax error. func highlightPosition(f *os.File, pos int64) (line, col int, highlight string) { // Modified version of the function in Camlistore by Brad Fitzpatrick // https://github.com/camlistore/camlistore/blob/4b5403dd5310cf6e1ae8feb8533fd59262701ebc/vendor/go4.org/errorutil/highlight.go line = 1 // New io.Reader for file br := bufio.NewReader(f) // Initialize lines lastLine := "" thisLine := new(bytes.Buffer) // Loop through template to find line, column for n := int64(0); n < pos; n++ { // read byte from io.Reader b, err := br.ReadByte() if err != nil { break } // If end of line, save line as previous line in case next line is offender if b == '\n' { lastLine = thisLine.String() thisLine.Reset() line++ col = 1 } else { // Write current line, until line is safe, or error point is encountered col++ thisLine.WriteByte(b) } } // Populate highlight string to place a '^' char at offending column if line > 1 { highlight += fmt.Sprintf("%5d: %s\n", line-1, lastLine) } highlight += fmt.Sprintf("%5d: %s\n", line, thisLine.String()) highlight += fmt.Sprintf("%s^\n", strings.Repeat(" ", col+5)) return }