add template output support

README.md

@@ -124,6 +124,27 @@ screenshot is shown below:
 
 ![Excel Report](https://user-images.githubusercontent.com/1299/48667086-84893500-ea83-11e8-925c-7929ed441b1b.png)
 
+### Custom Template output
+
+It is possible to provide a template to get a custom report. For the template
+the [Go text/template](https://golang.org/pkg/text/template/) is used.
+
+```
+$ golicense -in-template report.tmpl -out-template=report.md ./my-program
+```
+
+The in-template paramter specifies the template file to use and the out-template
+as the filename to write the result.
+
+A simple example of a template content.
+
+```
+|Dependency | Version | SPDX| License | Allowed |
+|-----------|---------|-----|---------|---------|
+{{range . }}| {{.Dependency}} | {{.Version}} | {{.Spdx}} | {{.License}} | {{.Allowed}} |
+{{end}}
+```
+
 ## Limitations
 
 There are a number of limitations to `golicense` currently. These are fixable

main.go

@@ -37,6 +37,9 @@ func realMain() int {
 
 	var flagLicense bool
 	var flagOutXLSX string
+	var flagOutTemplate string
+	var flagInTemplate string
+
 	flags := flag.NewFlagSet(os.Args[0], flag.ExitOnError)
 	flags.BoolVar(&flagLicense, "license", true,
 		"look up and verify license. If false, dependencies are\n"+
@@ -45,6 +48,10 @@ func realMain() int {
 	flags.BoolVar(&termOut.Verbose, "verbose", false, "additional logging to terminal, requires -plain")
 	flags.StringVar(&flagOutXLSX, "out-xlsx", "",
 		"save report in Excel XLSX format to the given path")
+	flags.StringVar(&flagOutTemplate, "out-template", "",
+		"save report with in-template in the given path")
+	flags.StringVar(&flagInTemplate, "in-template", "",
+		"save report the given template")
 	flags.Parse(os.Args[1:])
 	args := flags.Args()
 	if len(args) == 0 {
@@ -59,6 +66,13 @@ func realMain() int {
 		return 1
 	}
 
+	if flagOutTemplate != "" && flagInTemplate =="" {
+		fmt.Fprintf(os.Stderr, color.RedString(
+			"❗️ Path to template file for template output expected.\n\n"))
+		printHelp(flags)
+		return 1
+	}
+
 	// Determine the exe path and parse the configuration if given.
 	var cfg config.Config
 	exePath := args[0]
@@ -117,6 +131,19 @@ func realMain() int {
 		})
 	}
 
+	if flagOutTemplate != "" {
+		if _, err := os.Stat(flagInTemplate); os.IsNotExist(err) {
+			fmt.Fprintf(os.Stderr, color.RedString(fmt.Sprintf(
+				"❗️ Error Teamplte file does not exist: %s\n", flagInTemplate)))
+			return 1
+		}
+		out.Outputs = append(out.Outputs, &TemplateOutput {
+			Path:	flagOutTemplate,
+			Template: flagInTemplate,
+			Config: &cfg,
+		})
+	}
+
 	// Setup a context. We don't connect this to an interrupt signal or
 	// anything since we just exit immediately on interrupt. No cleanup
 	// necessary.

output_template.go

@@ -0,0 +1,121 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"sort"
+	"sync"
+	"text/template"
+
+	"github.com/mitchellh/golicense/config"
+	"github.com/mitchellh/golicense/license"
+	"github.com/mitchellh/golicense/module"
+)
+
+// TemplateOutput writes the results of license lookups to a tempalte file.
+type TemplateOutput struct {
+	// Path is the path to the file to write. This will be overwritten if
+	// it exists.
+	Path string
+
+	// The template file to use for rendering.
+	Template 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 *TemplateOutput) Start(m *module.Module) {}
+
+// Update implements Output
+func (o *TemplateOutput) Update(m *module.Module, t license.StatusType, msg string) {}
+
+// Finish implements Output
+func (o *TemplateOutput) 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
+	}
+}
+
+type libraryEntry struct {
+	Dependency string
+	Version    string
+	Spdx       string
+	License    string
+	Allowed    string
+}
+
+// Close implements Output
+func (o *TemplateOutput) Close() error {
+	o.lock.Lock()
+	defer o.lock.Unlock()
+
+	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)
+
+	entries := []*libraryEntry{}
+
+	// Go through each module and output it into the spreadsheet
+	for _, k := range keys {
+		m := index[k]
+		entry := libraryEntry{
+			Dependency: m.Path,
+			Version:    m.Version,
+			Spdx:       "",
+			License:    "",
+			Allowed:    "unknown",
+		}
+
+		raw := o.modules[m]
+		if raw == nil {
+			entry.License = "no"
+			continue
+		}
+
+		if err, ok := raw.(error); ok {
+			entry.License = fmt.Sprintf("ERROR: %s", err)
+			continue
+		}
+
+		if lic, ok := raw.(*license.License); ok {
+			if lic != nil {
+				entry.Spdx = lic.SPDX
+			}
+			entry.License = fmt.Sprintf(lic.String())
+
+			if o.Config != nil {
+				switch o.Config.Allowed(lic) {
+				case config.StateAllowed:
+					entry.Allowed = "yes"
+				case config.StateDenied:
+					entry.Allowed = "no"
+				}
+			}
+		}
+		entries = append(entries, &entry)
+	}
+
+	t := template.Must(template.ParseFiles(o.Template))
+	writer, _ := os.Create(o.Path)
+	t.Execute(writer, entries)
+
+	return nil
+}