Merge 42ebf52 into c2c1884

README.md

@@ -67,3 +67,5 @@ type IP struct {
 
 To skip the tag for the generated XXX_* fields, use
 `-XXX_skip=yaml,xml` flag.
+
+To enable verbose logging, use `-verbose`

file.go

@@ -6,7 +6,6 @@ import (
 	"go/parser"
 	"go/token"
 	"io/ioutil"
-	"log"
 	"os"
 	"regexp"
 	"strings"
@@ -26,7 +25,7 @@ type textArea struct {
 }
 
 func parseFile(inputPath string, xxxSkip []string) (areas []textArea, err error) {
-	log.Printf("parsing file %q for inject tag comments", inputPath)
+	logf("parsing file %q for inject tag comments", inputPath)
 	fset := token.NewFileSet()
 	f, err := parser.ParseFile(fset, inputPath, nil, parser.ParseComments)
 	if err != nil {
@@ -103,7 +102,7 @@ func parseFile(inputPath string, xxxSkip []string) (areas []textArea, err error)
 			}
 		}
 	}
-	log.Printf("parsed file %q, number of fields to inject custom tags: %d", inputPath, len(areas))
+	logf("parsed file %q, number of fields to inject custom tags: %d", inputPath, len(areas))
 	return
 }
 
@@ -125,15 +124,15 @@ func writeFile(inputPath string, areas []textArea) (err error) {
 	// inject custom tags from tail of file first to preserve order
 	for i := range areas {
 		area := areas[len(areas)-i-1]
-		log.Printf("inject custom tag %q to expression %q", area.InjectTag, string(contents[area.Start-1:area.End-1]))
+		logf("inject custom tag %q to expression %q", area.InjectTag, string(contents[area.Start-1:area.End-1]))
 		contents = injectTag(contents, area)
 	}
 	if err = ioutil.WriteFile(inputPath, contents, 0644); err != nil {
 		return
 	}
 
 	if len(areas) > 0 {
-		log.Printf("file %q is injected with custom tags", inputPath)
+		logf("file %q is injected with custom tags", inputPath)
 	}
 	return
 }

main.go

@@ -11,6 +11,7 @@ func main() {
 	var xxxTags string
 	flag.StringVar(&inputFile, "input", "", "path to input file")
 	flag.StringVar(&xxxTags, "XXX_skip", "", "skip tags to inject on XXX fields")
+	flag.BoolVar(&verbose, "verbose", false, "verbose logging")
 
 	flag.Parse()
 

main_test.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"bytes"
 	"io/ioutil"
+	"log"
 	"os"
 	"strings"
 	"testing"
@@ -160,3 +162,18 @@ func TestContinueParsingWhenSkippingFields(t *testing.T) {
 		}
 	}
 }
+
+func TestVerbose(t *testing.T) {
+	b := new(bytes.Buffer)
+	log.SetOutput(b)
+	verbose = false
+	logf("test")
+	if len(b.Bytes()) > 0 {
+		t.Errorf("verbose should be off")
+	}
+	verbose = true
+	logf("test")
+	if len(b.Bytes()) == 0 {
+		t.Errorf("verbose should be on")
+	}
+}

verbose.go

@@ -0,0 +1,14 @@
+package main
+
+import (
+	"log"
+)
+
+var verbose = false
+
+func logf(format string, v ...interface{}) {
+	if !verbose {
+		return
+	}
+	log.Printf(format, v...)
+}