Add support for .dockerignore file

cmd/executor/cmd/root.go

@@ -25,6 +25,7 @@ import (
 	"github.com/GoogleContainerTools/kaniko/pkg/buildcontext"
 	"github.com/GoogleContainerTools/kaniko/pkg/config"
 	"github.com/GoogleContainerTools/kaniko/pkg/constants"
+	"github.com/GoogleContainerTools/kaniko/pkg/dockerfile"
 	"github.com/GoogleContainerTools/kaniko/pkg/executor"
 	"github.com/GoogleContainerTools/kaniko/pkg/util"
 	"github.com/genuinetools/amicontained/container"
@@ -61,6 +62,9 @@ var RootCmd = &cobra.Command{
 		if err := resolveSourceContext(); err != nil {
 			return errors.Wrap(err, "error resolving source context")
 		}
+		if err := removeIgnoredFiles(); err != nil {
+			return errors.Wrap(err, "error removing .dockerignore files from build context")
+		}
 		return resolveDockerfilePath()
 	},
 	Run: func(cmd *cobra.Command, args []string) {
@@ -182,6 +186,44 @@ func resolveSourceContext() error {
 	return nil
 }
 
+func removeIgnoredFiles() error {
+	if !dockerfile.DockerignoreExists(opts) {
+		return nil
+	}
+	ignore, err := dockerfile.ParseDockerignore(opts)
+	if err != nil {
+		return err
+	}
+	logrus.Infof("Removing ignored files from build context: %s", ignore)
+	for r, i := range ignore {
+		ignore[r] = filepath.Clean(filepath.Join(opts.SrcContext, i))
+	}
+	// remove all files in .dockerignore
+	return filepath.Walk(opts.SrcContext, func(path string, fi os.FileInfo, _ error) error {
+		if ignoreFile(path, ignore) {
+			if err := os.RemoveAll(path); err != nil {
+				// don't return error, because this path could have been removed already
+				logrus.Debugf("error removing %s from buildcontext", path)
+			}
+		}
+		return nil
+	})
+}
+
+// ignoreFile returns true if the path matches any of the paths in ignore
+func ignoreFile(path string, ignore []string) bool {
+	for _, i := range ignore {
+		matched, err := filepath.Match(i, path)
+		if err != nil {
+			return false
+		}
+		if matched {
+			return true
+		}
+	}
+	return false
+}
+
 func exit(err error) {
 	fmt.Println(err)
 	os.Exit(1)

integration/dockerfiles/Dockerfile_test_ignore

@@ -0,0 +1,2 @@
+FROM scratch
+COPY . .

integration/images.go

@@ -37,6 +37,7 @@ const (
 	buildContextPath = "/workspace"
 	cacheDir         = "/workspace/cache"
 	baseImageToCache = "gcr.io/google-appengine/debian9@sha256:1d6a9a6d106bd795098f60f4abb7083626354fa6735e81743c7f8cfca11259f0"
+	testDirPath      = "context/test"
 )
 
 // Arguments to build Dockerfiles with, used for both docker and kaniko builds
@@ -54,6 +55,8 @@ var argsMap = map[string][]string{
 	"Dockerfile_test_multistage": {"file=/foo2"},
 }
 
+var filesToIgnore = []string{"context/test/*"}
+
 // Arguments to build Dockerfiles with when building with docker
 var additionalDockerFlagsMap = map[string][]string{
 	"Dockerfile_test_target": {"--target=second"},
@@ -158,11 +161,25 @@ func (d *DockerFileBuilder) BuildImage(imageRepo, gcsBucket, dockerfilesPath, do
 			"."},
 			additionalFlags...)...,
 	)
+	if err := setupTestDir(); err != nil {
+		return err
+	}
+	if err := generateDockerIgnore(); err != nil {
+		return err
+	}
+
 	_, err := RunCommandWithoutTest(dockerCmd)
 	if err != nil {
 		return fmt.Errorf("Failed to build image %s with docker command \"%s\": %s", dockerImage, dockerCmd.Args, err)
 	}
 
+	if err := setupTestDir(); err != nil {
+		return err
+	}
+	if err := generateDockerIgnore(); err != nil {
+		return err
+	}
+
 	contextFlag := "-c"
 	contextPath := buildContextPath
 	for _, d := range bucketContextTests {
@@ -252,3 +269,28 @@ func (d *DockerFileBuilder) buildCachedImages(imageRepo, cacheRepo, dockerfilesP
 	}
 	return nil
 }
+
+func setupTestDir() error {
+	if err := os.MkdirAll(testDirPath, 0750); err != nil {
+		return err
+	}
+	p := filepath.Join(testDirPath, "foo")
+	f, err := os.Create(p)
+	if err != nil {
+		return err
+	}
+	return f.Close()
+}
+
+func generateDockerIgnore() error {
+	f, err := os.Create(".dockerignore")
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+	contents := strings.Join(filesToIgnore, "\n")
+	if _, err := f.Write([]byte(contents)); err != nil {
+		return err
+	}
+	return nil
+}

pkg/dockerfile/dockerfile.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"fmt"
 	"io/ioutil"
+	"path/filepath"
 	"strconv"
 	"strings"
 
@@ -168,3 +169,23 @@ func saveStage(index int, stages []instructions.Stage) bool {
 	}
 	return false
 }
+
+// DockerignoreExists returns true if .dockerignore exists in the source context
+func DockerignoreExists(opts *config.KanikoOptions) bool {
+	path := filepath.Join(opts.SrcContext, ".dockerignore")
+	return util.FilepathExists(path)
+}
+
+// ParseDockerignore returns a list of all paths in .dockerignore
+func ParseDockerignore(opts *config.KanikoOptions) ([]string, error) {
+	path := filepath.Join(opts.SrcContext, ".dockerignore")
+	contents, err := ioutil.ReadFile(path)
+	if err != nil {
+		return nil, errors.Wrap(err, "parsing .dockerignore")
+	}
+	return strings.FieldsFunc(string(contents), split), nil
+}
+
+func split(r rune) bool {
+	return r == '\n' || r == ' '
+}