feat: read from stdin, write to stdout (#1831)

cmd/swag/main.go

@@ -18,6 +18,7 @@
 	searchDirFlag            = "dir"
 	excludeFlag              = "exclude"
 	generalInfoFlag          = "generalInfo"
+	pipeFlag                 = "pipe"
 	propertyStrategyFlag     = "propertyStrategy"
 	outputFlag               = "output"
 	outputTypesFlag          = "outputTypes"
@@ -195,11 +196,17 @@
 	if ctx.IsSet(templateDelimsFlag) {
 		delims := strings.Split(ctx.String(templateDelimsFlag), ",")
 		if len(delims) != 2 {
-			return fmt.Errorf("exactly two template delimiters must be provided, comma separated")
+			return fmt.Errorf(
+				"exactly two template delimiters must be provided, comma separated",
+			)
 		} else if delims[0] == delims[1] {
 			return fmt.Errorf("template delimiters must be different")
 		}
-		leftDelim, rightDelim = strings.TrimSpace(delims[0]), strings.TrimSpace(delims[1])
+		leftDelim, rightDelim = strings.TrimSpace(
+			delims[0],
+		), strings.TrimSpace(
+			delims[1],
+		)
 	}
 
 	outputTypes := strings.Split(ctx.String(outputTypesFlag), ",")
@@ -211,9 +218,14 @@
 		logger = log.New(io.Discard, "", log.LstdFlags)
 	}
 
-	collectionFormat := swag.TransToValidCollectionFormat(ctx.String(collectionFormatFlag))
+	collectionFormat := swag.TransToValidCollectionFormat(
+		ctx.String(collectionFormatFlag),
+	)
 	if collectionFormat == "" {
-		return fmt.Errorf("not supported %s collectionFormat", ctx.String(collectionFormat))
+		return fmt.Errorf(
+			"not supported %s collectionFormat",
+			ctx.String(collectionFormat),
+		)
 	}
 
 	var pdv = ctx.Int(parseDependencyLevelFlag)
@@ -269,6 +281,11 @@
 			Aliases: []string{"f"},
 			Usage:   "format swag comments",
 			Action: func(c *cli.Context) error {
+
+				if c.Bool(pipeFlag) {
+					return format.New().Run(os.Stdin, os.Stdout)
+				}
+
 				searchDir := c.String(searchDirFlag)
 				excludeDir := c.String(excludeFlag)
 				mainFile := c.String(generalInfoFlag)
@@ -296,6 +313,12 @@
 					Value:   "main.go",
 					Usage:   "Go file path in which 'swagger general API Info' is written",
 				},
+				&cli.BoolFlag{
+					Name:    "pipe",
+					Aliases: []string{"p"},
+					Value:   false,
+					Usage:   "Read from stdin, write to stdout.",
+				},
 			},
 		},
 	}

format/format.go

@@ -3,6 +3,7 @@
 import (
 	"bytes"
 	"fmt"
+	"io"
 	"os"
 	"path/filepath"
 	"strings"
@@ -81,7 +82,8 @@
 
 func (f *Format) excludeDir(path string) bool {
 	return f.exclude[path] ||
-		filepath.Base(path)[0] == '.' && len(filepath.Base(path)) > 1 // exclude hidden folders
+		filepath.Base(path)[0] == '.' &&
+			len(filepath.Base(path)) > 1 // exclude hidden folders
 }
 
 func (f *Format) excludeFile(path string) bool {
@@ -127,3 +129,20 @@
 	}
 	return os.Rename(f.Name(), path)
 }
+
+// Run the format on src and write the result to dst.
+func (f *Format) Run(src io.Reader, dst io.Writer) error {
+	contents, err := io.ReadAll(src)
+	if err != nil {
+		return err
+	}
+	result, err := f.formatter.Format("", contents)
+	if err != nil {
+		return err
+	}
+	r := bytes.NewReader(result)
+	if _, err := io.Copy(dst, r); err != nil {
+		return err
+	}
+	return nil
+}