Add Markdown output format

main.go

@@ -36,13 +36,16 @@ func realMain() int {
 	termOut := &TermOutput{Out: os.Stdout}
 
 	var flagLicense bool
+	var flagOutMD string
 	var flagOutXLSX string
 	flags := flag.NewFlagSet(os.Args[0], flag.ExitOnError)
 	flags.BoolVar(&flagLicense, "license", true,
 		"look up and verify license. If false, dependencies are\n"+
 			"printed without licenses.")
 	flags.BoolVar(&termOut.Plain, "plain", false, "plain terminal output, no colors or live updates")
 	flags.BoolVar(&termOut.Verbose, "verbose", false, "additional logging to terminal, requires -plain")
+	flags.StringVar(&flagOutMD, "out-md", "",
+		"save report in Markdown format to the given path")
 	flags.StringVar(&flagOutXLSX, "out-xlsx", "",
 		"save report in Excel XLSX format to the given path")
 	flags.Parse(os.Args[1:])
@@ -116,6 +119,12 @@ func realMain() int {
 
 	// Setup the outputs
 	out := &MultiOutput{Outputs: []Output{termOut}}
+	if flagOutMD != "" {
+		out.Outputs = append(out.Outputs, &MDOutput{
+			Path:   flagOutMD,
+			Config: &cfg,
+		})
+	}
 	if flagOutXLSX != "" {
 		out.Outputs = append(out.Outputs, &XLSXOutput{
 			Path:   flagOutXLSX,

output_md.go

@@ -0,0 +1,111 @@
+package main
+
+import (
+	"os"
+	"sort"
+	"strings"
+	"sync"
+
+	"github.com/mitchellh/golicense/config"
+	"github.com/mitchellh/golicense/license"
+	"github.com/mitchellh/golicense/module"
+)
+
+// MDOutput writes the results of license lookups to an MD file.
+type MDOutput struct {
+	// Path is the path to the file to write. This will be overwritten if
+	// it exists.
+	Path string
+
+	// Config is the configuration (if any). This will be used to check
+	// if a license is allowed or not.
+	Config *config.Config
+
+	modules map[*module.Module]interface{}
+	lock    sync.Mutex
+}
+
+// Start implements Output
+func (o *MDOutput) Start(m *module.Module) {}
+
+// Update implements Output
+func (o *MDOutput) Update(m *module.Module, t license.StatusType, msg string) {}
+
+// Finish implements Output
+func (o *MDOutput) Finish(m *module.Module, l *license.License, err error) {
+	o.lock.Lock()
+	defer o.lock.Unlock()
+
+	if o.modules == nil {
+		o.modules = make(map[*module.Module]interface{})
+	}
+
+	o.modules[m] = l
+	if err != nil {
+		o.modules[m] = err
+	}
+}
+
+// Close implements Output
+func (o *MDOutput) Close() error {
+	o.lock.Lock()
+	defer o.lock.Unlock()
+
+	f, err := os.Create(o.Path)
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	// Headers
+	_, err = f.WriteString("# Licenses\n\n|Dependency|Version|SPDX ID|License|Allowed|\n|----------|-------|-------|-------|-------|\n")
+	if err != nil {
+		return err
+	}
+
+	// Sort the modules by name
+	keys := make([]string, 0, len(o.modules))
+	index := map[string]*module.Module{}
+	for m := range o.modules {
+		keys = append(keys, m.Path)
+		index[m.Path] = m
+	}
+	sort.Strings(keys)
+
+	// Go through each module and output it into the spreadsheet
+	for _, k := range keys {
+		m := index[k]
+
+		SPDX := ""
+		License := "no"
+		Allowed := "unknown"
+
+		raw := o.modules[m]
+		if raw == nil {
+		} else if err, ok := raw.(error); ok {
+			// If the value is an error, then note the error
+			License = strings.ReplaceAll(err.Error(), "\n", "<br/>")
+			Allowed = "no"
+		} else if lic, ok := raw.(*license.License); ok {
+			// If the value is a license, then mark the license
+			if lic != nil {
+				SPDX = lic.SPDX
+			}
+			License = strings.ReplaceAll(strings.ReplaceAll(lic.String(), ">", "*"), "<", "*")
+			if o.Config != nil {
+				switch o.Config.Allowed(lic) {
+				case config.StateAllowed:
+					Allowed = "yes"
+				case config.StateDenied:
+					Allowed = "no"
+				}
+			}
+		}
+		_, err = f.WriteString("|[" + m.Path + "](https://" + m.Path + ")|" + m.Version + "|" + SPDX + "|" + License + "|" + Allowed + "|\n")
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}