Use regexp to extract tags from file names

cmd/name_to_tag.go

@@ -0,0 +1,87 @@
+package cmd
+
+import (
+	"context"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	"github.com/corvus-ch/bilocation/tag"
+	"golang.org/x/sync/errgroup"
+	"gopkg.in/alecthomas/kingpin.v2"
+)
+
+var test bool
+
+// NameToTag registers the name to tag sub command to the application.
+func NameToTag(app *kingpin.Application, cfg *config) {
+	c := app.Command("ntt", "tags files based on their names")
+	c.Action(func(_ *kingpin.ParseContext) error {
+		log := cfg.Log()
+		for path := range findFiles(cfg) {
+			tags, err := tag.NewTagSet([]byte{})
+			if err != nil {
+				return err
+			}
+			for _, rule := range cfg.Tags() {
+				parts := strings.SplitN(rule, "=", 2)
+				re, err := regexp.Compile(parts[1])
+				if err != nil {
+					return err
+				}
+				matches := re.FindStringSubmatch(path)
+				if len(matches) < 1 {
+					continue
+				}
+				tags.Add(matches[1], parts[0])
+			}
+			if test {
+				log.Infof("%s %v", path, tags)
+			} else if tags.Size() > 0 {
+				if err := tag.Write(path, tags); err != nil {
+					return err
+				}
+			}
+		}
+		return nil
+	})
+
+	c.Flag("path", "path to the directory containing the files to be tagged").
+		Short('C').
+		Default(".").
+		ExistingDirVar(&cfg.root)
+	c.Flag("dry-run", "print the result and does not touch the files").
+		Short('n').
+		BoolVar(&test)
+	c.Arg("rule", "a list of tag names and their regexp").
+		Required().
+		StringsVar(&cfg.tags)
+}
+
+func findFiles(cfg *config) chan string {
+	g, ctx := errgroup.WithContext(context.Background())
+	ch := make(chan string, 100)
+	g.Go(func() error {
+		defer close(ch)
+
+		return filepath.Walk(cfg.Root(), func(path string, info os.FileInfo, err error) error {
+			if err != nil {
+				return err
+			}
+			if !info.Mode().IsRegular() {
+				return nil
+			}
+
+			select {
+			case ch <- path:
+			case <-ctx.Done():
+				return ctx.Err()
+			}
+			return nil
+		})
+
+	})
+
+	return ch
+}

main.go

@@ -31,6 +31,7 @@ func App(log logr.Logger) *kingpin.Application {
 	cmd.Inspect(app, cfg)
 	cmd.Search(app, cfg)
 	cmd.Summary(app, cfg)
+	cmd.NameToTag(app, cfg)
 
 	return app
 }

tag/set.go

@@ -1,6 +1,9 @@
 package tag
 
 import (
+	"fmt"
+	"strings"
+
 	"github.com/corvus-ch/bilocation/tag/internal"
 	"github.com/golang/protobuf/proto"
 )
@@ -104,3 +107,14 @@ func (s Set) Bytes() ([]byte, error) {
 	}
 	return proto.Marshal(set)
 }
+
+func (s Set) String() string {
+	var pairs []string
+	for value, keys := range s {
+		for key := range keys {
+			pairs = append(pairs, fmt.Sprintf("%s='%s'", key, value))
+		}
+	}
+
+	return strings.Join(pairs, " ")
+}