Moved filename flag to diff, rewrote DiffFile

Author: Priya Wadhwa

cmd/analyze.go

@@ -36,9 +36,6 @@ var analyzeCmd = &cobra.Command{
 		if err := validateArgs(args, checkAnalyzeArgNum); err != nil {
 			return err
 		}
-		if err := checkAnalyzeFilenameFlag(); err != nil {
-			return err
-		}
 		if err := checkIfValidAnalyzer(types); err != nil {
 			return err
 		}
@@ -59,13 +56,6 @@ func checkAnalyzeArgNum(args []string) error {
 	return nil
 }
 
-func checkAnalyzeFilenameFlag() error {
-	if filename != "" {
-		return errors.New("please remove --filename flag, incompatible with analyze")
-	}
-	return nil
-}
-
 func analyzeImage(imageName string, analyzerArgs []string) error {
 	analyzeTypes, err := differs.GetAnalyzers(analyzerArgs)
 	if err != nil {

cmd/diff.go

@@ -29,6 +29,8 @@ import (
 	"sync"
 )
 
+var filename string
+
 var diffCmd = &cobra.Command{
 	Use:   "diff",
 	Short: "Compare two images: [image1] [image2]",
@@ -106,7 +108,7 @@ func diffImages(image1Arg, image2Arg string, diffArgs []string, typesFlagSet boo
 
 	if filename != "" {
 		fmt.Fprintln(os.Stderr, "Computing filename diffs")
-		err := diffFile(imageMap, image1Arg, image2Arg)
+		err := diffFile(imageMap[image1Arg], imageMap[image2Arg])
 		if err != nil {
 			return err
 		}
@@ -130,21 +132,17 @@ func diffImages(image1Arg, image2Arg string, diffArgs []string, typesFlagSet boo
 	return nil
 }
 
-func diffFile(imageMap map[string]*pkgutil.Image, image1Arg, image2Arg string) error {
-
-	image1FilePath := imageMap[image1Arg].FSPath + filename
-	image2FilePath := imageMap[image2Arg].FSPath + filename
-
-	diff, err := util.DiffFile(image1FilePath, image2FilePath, image1Arg, image2Arg)
+func diffFile(image1, image2 *pkgutil.Image) error {
+	diff, err := util.DiffFile(image1, image2, filename)
 	if err != nil {
 		return err
 	}
-	diff.Filename = filename
 	util.TemplateOutput(diff, "FileNameDiff")
 	return nil
 }
 
 func init() {
+	diffCmd.Flags().StringVarP(&filename, "filename", "f", "", "Set this flag to the path of a file in both containers to view the diff of the file")
 	RootCmd.AddCommand(diffCmd)
 	addSharedFlags(diffCmd)
 }

cmd/root.go

@@ -36,7 +36,6 @@ import (
 var json bool
 var save bool
 var types string
-var filename string
 
 var LogLevel string
 
@@ -157,5 +156,4 @@ func addSharedFlags(cmd *cobra.Command) {
 	cmd.Flags().StringVarP(&types, "types", "t", "apt", "This flag sets the list of analyzer types to use.  It expects a comma separated list of supported analyzers.")
 	cmd.Flags().BoolVarP(&save, "save", "s", false, "Set this flag to save rather than remove the final image filesystems on exit.")
 	cmd.Flags().BoolVarP(&util.SortSize, "order", "o", false, "Set this flag to sort any file/package results by descending size. Otherwise, they will be sorted by name.")
-	cmd.Flags().StringVarP(&filename, "filename", "f", "", "View the diff of a file in both containers (can only be used with container-diff diff)")
 }

pkg/util/fs_utils.go

@@ -18,7 +18,6 @@ package util
 
 import (
 	"bytes"
-	"errors"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -55,21 +54,22 @@ func GetSize(path string) int64 {
 }
 
 //GetFileContents returns the contents of a file at the specified path
-func GetFileContents(path string) ([]string, error) {
-	stat, err := os.Stat(path)
-	if err != nil {
-		return nil, err
+func GetFileContents(path string) (*string, error) {
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		return nil, nil
 	}
 
-	if stat.IsDir() {
-		return nil, errors.New("--filename is a directory, not a file")
-	}
 	contents, err := ioutil.ReadFile(path)
-
 	if err != nil {
 		return nil, err
 	}
-	return []string{string(contents)}, nil
+
+	strContents := string(contents)
+	//If file is empty, return nil
+	if strContents == "" {
+		return nil, nil
+	}
+	return &strContents, nil
 }
 
 func getDirectorySize(path string) (int64, error) {

util/diff_utils.go

@@ -35,8 +35,9 @@ type DirDiff struct {
 }
 
 type FileNameDiff struct {
-	Filename string
-	Diff     string
+	Filename    string
+	Description string
+	Diff        string
 }
 
 type EntryDiff struct {
@@ -123,34 +124,62 @@ func DiffDirectory(d1, d2 pkgutil.Directory) (DirDiff, bool) {
 	return DirDiff{addedEntries, deletedEntries, modifiedEntries}, same
 }
 
-//DiffFile diffs within a file
-func DiffFile(path1, path2, image1, image2 string) (FileNameDiff, error) {
+func DiffFile(image1, image2 *pkgutil.Image, filename string) (*FileNameDiff, error) {
+	//Join paths
+	image1FilePath := filepath.Join(image1.FSPath, filename)
+	image2FilePath := filepath.Join(image2.FSPath, filename)
 
-	var result FileNameDiff
-
-	image1Contents, err := pkgutil.GetFileContents(path1)
+	//Get contents of files
+	image1FileContents, err := pkgutil.GetFileContents(image1FilePath)
 	if err != nil {
-		return result, err
+		return nil, err
 	}
-	image2Contents, err := pkgutil.GetFileContents(path2)
 
+	image2FileContents, err := pkgutil.GetFileContents(image2FilePath)
 	if err != nil {
-		return result, err
+		return nil, err
+	}
+
+	description := ""
+	//Check if file contents are empty or if they are the same
+	if image1FileContents == nil && image2FileContents == nil {
+		description := "Both files are empty"
+		return &FileNameDiff{filename, description, ""}, nil
+	}
+
+	if image1FileContents == nil {
+		description := fmt.Sprintf("%s contains an empty file, the contents of %s are:", image1.Source, image2.Source)
+		return &FileNameDiff{filename, description, *image2FileContents}, nil
 	}
 
+	if image2FileContents == nil {
+		description := fmt.Sprintf("%s contains an empty file, the contents of %s are:", image2.Source, image1.Source)
+		return &FileNameDiff{filename, description, *image1FileContents}, nil
+	}
+
+	if *image1FileContents == *image2FileContents {
+		description := "Both files are the same, the contents are:"
+		return &FileNameDiff{filename, description, *image1FileContents}, nil
+	}
+
+	//Carry on with diffing, make string array for difflib requirements
+	image1Contents := []string{string(*image1FileContents)}
+	image2Contents := []string{string(*image2FileContents)}
+
+	//Run diff
 	diff := difflib.UnifiedDiff{
 		A:        image1Contents,
 		B:        image2Contents,
-		FromFile: image1,
-		ToFile:   image2,
+		FromFile: image1.Source,
+		ToFile:   image2.Source,
 	}
 
 	text, err := difflib.GetUnifiedDiffString(diff)
 
 	if err != nil {
-		return result, err
+		return nil, err
 	}
-	return FileNameDiff{Diff: text}, nil
+	return &FileNameDiff{filename, description, text}, nil
 }
 
 // Checks for content differences between files of the same name from different directories

util/template_utils.go

@@ -67,6 +67,7 @@ Docker history lines found only in {{.Image2}}:{{if not .Diff.Dels}} None{{else}
 `
 const FilenameDiffOutput = `
 -----Diff of {{.Filename}}-----
+{{.Description}}
 
 {{.Diff}}
 `