Move image packing into separate file

Author: clareliguori

main.go

@@ -1,91 +1,14 @@
 package main
 
 import (
-	"context"
 	"fmt"
 	"os"
-	"path/filepath"
-
-	"github.com/containers/image/image"
-	"github.com/containers/image/pkg/blobinfocache"
-	"github.com/containers/image/transports/alltransports"
-	"github.com/containers/image/types"
-	"github.com/pkg/errors"
 )
 
 func main() {
-	err := ConvertImage("docker-daemon:lambda-php:latest")
+	err := RepackImage("docker-daemon:lambda-php:latest")
 	if err != nil {
 		fmt.Printf("Error: %+v", err)
 		os.Exit(1)
 	}
 }
-
-// Converts container image to Lambda layers
-func ConvertImage(name string) (retErr error) {
-	// Get image's layer data from image name
-	ref, err := alltransports.ParseImageName(name)
-	if err != nil {
-		return err
-	}
-
-	sys := &types.SystemContext{}
-
-	ctx := context.Background()
-
-	cache := blobinfocache.DefaultCache(sys)
-
-	rawSource, err := ref.NewImageSource(ctx, sys)
-	if err != nil {
-		return err
-	}
-
-	src, err := image.FromSource(ctx, sys, rawSource)
-	if err != nil {
-		if closeErr := rawSource.Close(); closeErr != nil {
-			return errors.Wrapf(err, " (close error: %v)", closeErr)
-		}
-
-		return err
-	}
-	defer func() {
-		if err := src.Close(); err != nil {
-			retErr = errors.Wrapf(retErr, " (close error: %v)", err)
-		}
-	}()
-
-	layerInfos := src.LayerInfos()
-
-	// Unpack and inspect each image layer, copy relevant files to new Lambda layer
-	dir, err := os.Getwd()
-	if err != nil {
-		return err
-	}
-	layerOutputDir := filepath.Join(dir, "image-output", name)
-	if err := os.MkdirAll(layerOutputDir, 0777); err != nil {
-		return err
-	}
-
-	lambdaLayerNum := 1
-
-	for _, layerInfo := range layerInfos {
-		lambdaLayerFilename := filepath.Join(layerOutputDir, fmt.Sprintf("layer-%d.zip", lambdaLayerNum))
-
-		layerStream, _, err := rawSource.GetBlob(ctx, layerInfo, cache)
-		if err != nil {
-			return err
-		}
-		defer layerStream.Close()
-
-		fileCreated, err := RepackLayer(lambdaLayerFilename, layerStream)
-		if err != nil {
-			return err
-		}
-
-		if fileCreated {
-			lambdaLayerNum++
-		}
-	}
-
-	return nil
-}

repack_image.go

@@ -0,0 +1,83 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/containers/image/image"
+	"github.com/containers/image/pkg/blobinfocache"
+	"github.com/containers/image/transports/alltransports"
+	"github.com/containers/image/types"
+	"github.com/pkg/errors"
+)
+
+// Converts container image to Lambda layers
+func RepackImage(imageName string) (retErr error) {
+	// Get image's layer data from image name
+	ref, err := alltransports.ParseImageName(imageName)
+	if err != nil {
+		return err
+	}
+
+	sys := &types.SystemContext{}
+
+	ctx := context.Background()
+
+	cache := blobinfocache.DefaultCache(sys)
+
+	rawSource, err := ref.NewImageSource(ctx, sys)
+	if err != nil {
+		return err
+	}
+
+	src, err := image.FromSource(ctx, sys, rawSource)
+	if err != nil {
+		if closeErr := rawSource.Close(); closeErr != nil {
+			return errors.Wrapf(err, " (close error: %v)", closeErr)
+		}
+
+		return err
+	}
+	defer func() {
+		if err := src.Close(); err != nil {
+			retErr = errors.Wrapf(retErr, " (close error: %v)", err)
+		}
+	}()
+
+	layerInfos := src.LayerInfos()
+
+	// Unpack and inspect each image layer, copy relevant files to new Lambda layer
+	dir, err := os.Getwd()
+	if err != nil {
+		return err
+	}
+	layerOutputDir := filepath.Join(dir, "image-output", imageName)
+	if err := os.MkdirAll(layerOutputDir, 0777); err != nil {
+		return err
+	}
+
+	lambdaLayerNum := 1
+
+	for _, layerInfo := range layerInfos {
+		lambdaLayerFilename := filepath.Join(layerOutputDir, fmt.Sprintf("layer-%d.zip", lambdaLayerNum))
+
+		layerStream, _, err := rawSource.GetBlob(ctx, layerInfo, cache)
+		if err != nil {
+			return err
+		}
+		defer layerStream.Close()
+
+		fileCreated, err := RepackLayer(lambdaLayerFilename, layerStream)
+		if err != nil {
+			return err
+		}
+
+		if fileCreated {
+			lambdaLayerNum++
+		}
+	}
+
+	return nil
+}