make k8s the default builder

e2e/system/build_from_git_test.go

@@ -35,7 +35,6 @@ func (s *Suite) TestBuildFromGit() {
 			s.T().Logf("Error cleaning up knuu: %v", err)
 		}
 	})
-
 	s.Require().NoError(target.Build().Commit(ctx))
 
 	s.T().Logf("Starting instance")

e2e/system/file_test.go

@@ -83,6 +83,40 @@ func (s *Suite) TestDownloadFileFromRunningInstance() {
 
 	s.Assert().Equal(fileContent, string(gotContent))
 }
+func (s *Suite) TestDownloadFileFromBuilder() {
+	const namePrefix = "download-file-builder"
+	s.T().Parallel()
+	// Setup
+
+	target, err := s.Knuu.NewInstance(namePrefix + "-target")
+	s.Require().NoError(err)
+
+	ctx := context.Background()
+	s.Require().NoError(target.Build().SetImage(ctx, "alpine:latest"))
+
+	s.T().Cleanup(func() {
+		if err := target.Execution().Destroy(ctx); err != nil {
+			s.T().Logf("error destroying instance: %v", err)
+		}
+	})
+
+	// Test logic
+	const (
+		fileContent = "Hello World!"
+		filePath    = "/hello.txt"
+	)
+
+	s.Require().NoError(target.Storage().AddFileBytes([]byte(fileContent), filePath, "0:0"))
+
+	// The commit is required to make the changes persistent to the image
+	s.Require().NoError(target.Build().Commit(ctx))
+
+	// Now test if the file can be downloaded correctly from the built image
+	gotContent, err := target.Storage().GetFileBytes(ctx, filePath)
+	s.Require().NoError(err, "Error getting file bytes")
+
+	s.Assert().Equal(fileContent, string(gotContent))
+}
 
 func (s *Suite) TestMinio() {
 	const (

pkg/container/docker.go

@@ -2,20 +2,13 @@
 package container
 
 import (
-	"archive/tar"
-	"bytes"
 	"context"
 	"crypto/sha256"
 	"fmt"
-	"io"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"strings"
-	"time"
 
-	"github.com/docker/docker/api/types/container"
-	"github.com/docker/docker/client"
 	"github.com/sirupsen/logrus"
 
 	"github.com/celestiaorg/knuu/pkg/builder"
@@ -26,24 +19,18 @@ type BuilderFactory struct {
 	imageNameFrom          string
 	imageNameTo            string
 	imageBuilder           builder.Builder
-	cli                    *client.Client
 	dockerFileInstructions []string
 	buildContext           string
 }
 
 // NewBuilderFactory creates a new instance of BuilderFactory.
 func NewBuilderFactory(imageName, buildContext string, imageBuilder builder.Builder) (*BuilderFactory, error) {
-	cli, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
-	if err != nil {
-		return nil, ErrCreatingDockerClient.Wrap(err)
-	}
-	err = os.MkdirAll(buildContext, 0755)
-	if err != nil {
+	if err := os.MkdirAll(buildContext, 0755); err != nil {
 		return nil, ErrFailedToCreateContextDir.Wrap(err)
 	}
+
 	return &BuilderFactory{
 		imageNameFrom:          imageName,
-		cli:                    cli,
 		dockerFileInstructions: []string{"FROM " + imageName},
 		buildContext:           buildContext,
 		imageBuilder:           imageBuilder,
@@ -55,104 +42,24 @@ func (f *BuilderFactory) ImageNameFrom() string {
 	return f.imageNameFrom
 }
 
-// ExecuteCmdInBuilder runs the provided command in the context of the given builder.
-// It returns the command's output or any error encountered.
-func (f *BuilderFactory) ExecuteCmdInBuilder(command []string) (string, error) {
+// AddCmdToBuilder runs the provided command in the context of the given builder.
+func (f *BuilderFactory) AddCmdToBuilder(command []string) {
 	f.dockerFileInstructions = append(f.dockerFileInstructions, "RUN "+strings.Join(command, " "))
-	// FIXME: does not return expected output
-	return "", nil
 }
 
 // AddToBuilder adds a file from the source path to the destination path in the image, with the specified ownership.
-func (f *BuilderFactory) AddToBuilder(srcPath, destPath, chown string) error {
+func (f *BuilderFactory) AddToBuilder(srcPath, destPath, chown string) {
 	f.dockerFileInstructions = append(f.dockerFileInstructions, "ADD --chown="+chown+" "+srcPath+" "+destPath)
-	return nil
-}
-
-// ReadFileFromBuilder reads a file from the given builder's mount point.
-// It returns the file's content or any error encountered.
-func (f *BuilderFactory) ReadFileFromBuilder(filePath string) ([]byte, error) {
-	if f.imageNameTo == "" {
-		return nil, ErrNoImageNameProvided
-	}
-	containerConfig := &container.Config{
-		Image: f.imageNameTo,
-		Cmd:   []string{"tail", "-f", "/dev/null"}, // This keeps the container running
-	}
-	resp, err := f.cli.ContainerCreate(
-		context.Background(),
-		containerConfig,
-		nil,
-		nil,
-		nil,
-		"",
-	)
-	if err != nil {
-		return nil, ErrFailedToCreateContainer.Wrap(err)
-	}
-
-	defer func() {
-		// Stop the container
-		timeout := int(time.Duration(10) * time.Second)
-		stopOptions := container.StopOptions{
-			Timeout: &timeout,
-		}
-
-		if err := f.cli.ContainerStop(context.Background(), resp.ID, stopOptions); err != nil {
-			logrus.Warn(ErrFailedToStopContainer.Wrap(err))
-		}
-
-		// Remove the container
-		if err := f.cli.ContainerRemove(context.Background(), resp.ID, container.RemoveOptions{}); err != nil {
-			logrus.Warn(ErrFailedToRemoveContainer.Wrap(err))
-		}
-	}()
-
-	if err := f.cli.ContainerStart(context.Background(), resp.ID, container.StartOptions{}); err != nil {
-		return nil, ErrFailedToStartContainer.Wrap(err)
-	}
-
-	// Now you can copy the file
-	reader, _, err := f.cli.CopyFromContainer(context.Background(), resp.ID, filePath)
-	if err != nil {
-		return nil, ErrFailedToCopyFileFromContainer.Wrap(err)
-	}
-	defer reader.Close()
-
-	tarReader := tar.NewReader(reader)
-
-	for {
-		header, err := tarReader.Next()
-
-		if err == io.EOF {
-			break // End of archive
-		}
-		if err != nil {
-			return nil, ErrFailedToReadFromTar.Wrap(err)
-		}
-
-		if header.Typeflag == tar.TypeReg { // if it's a file then extract it
-			data, err := io.ReadAll(tarReader)
-			if err != nil {
-				return nil, ErrFailedToReadFileFromTar.Wrap(err)
-			}
-			return data, nil
-		}
-	}
-
-	return nil, ErrFileNotFoundInTar
 }
 
 // SetEnvVar sets the value of an environment variable in the builder.
-func (f *BuilderFactory) SetEnvVar(name, value string) error {
+func (f *BuilderFactory) SetEnvVar(name, value string) {
 	f.dockerFileInstructions = append(f.dockerFileInstructions, "ENV "+name+"="+value)
-	return nil
 }
 
 // SetUser sets the user in the builder.
-func (f *BuilderFactory) SetUser(user string) error {
+func (f *BuilderFactory) SetUser(user string) {
 	f.dockerFileInstructions = append(f.dockerFileInstructions, "USER "+user)
-	return nil
 }
 
 // Changed returns true if the builder has been modified, false otherwise.
@@ -178,6 +85,7 @@ func (f *BuilderFactory) PushBuilderImage(ctx context.Context, imageName string)
 			return ErrFailedToCreateContextDir.Wrap(err)
 		}
 	}
+
 	dockerFile := strings.Join(f.dockerFileInstructions, "\n")
 	err := os.WriteFile(dockerFilePath, []byte(dockerFile), 0644)
 	if err != nil {
@@ -240,17 +148,6 @@ func (f *BuilderFactory) BuildImageFromGitRepo(ctx context.Context, gitCtx build
 	return err
 }
 
-func runCommand(cmd *exec.Cmd) error { // nolint: unused
-	var stdout, stderr bytes.Buffer
-	cmd.Stdout = &stdout
-	cmd.Stderr = &stderr
-	err := cmd.Run()
-	if err != nil {
-		return fmt.Errorf("command failed: %w\nstdout: %s\nstderr: %s", err, stdout.String(), stderr.String())
-	}
-	return nil
-}
-
 // GenerateImageHash creates a hash value based on the contents of the Dockerfile instructions and all files in the build context.
 func (f *BuilderFactory) GenerateImageHash() (string, error) {
 	hasher := sha256.New()

pkg/instance/build.go

@@ -108,10 +108,7 @@ func (b *build) ExecuteCommand(command ...string) error {
 		return ErrAddingCommandNotAllowed.WithParams(b.instance.state.String())
 	}
 
-	_, err := b.builderFactory.ExecuteCmdInBuilder(command)
-	if err != nil {
-		return ErrExecutingCommandInInstance.WithParams(command, b.instance.name).Wrap(err)
-	}
+	b.builderFactory.AddCmdToBuilder(command)
 	return nil
 }
 
@@ -122,9 +119,7 @@ func (b *build) SetUser(user string) error {
 		return ErrSettingUserNotAllowed.WithParams(b.instance.state.String())
 	}
 
-	if err := b.builderFactory.SetUser(user); err != nil {
-		return ErrSettingUser.WithParams(user, b.instance.name).Wrap(err)
-	}
+	b.builderFactory.SetUser(user)
 	b.instance.Logger.Debugf("Set user '%s' for instance '%s'", user, b.instance.name)
 	return nil
 }
@@ -196,14 +191,10 @@ func (b *build) getBuildDir() string {
 }
 
 // addFileToBuilder adds a file to the builder
-func (b *build) addFileToBuilder(src, dest, chown string) error {
-	_ = src
+func (b *build) addFileToBuilder(src, dest, chown string) {
 	// dest is the same as src here, as we copy the file to the build dir with the subfolder structure of dest
-	err := b.builderFactory.AddToBuilder(dest, dest, chown)
-	if err != nil {
-		return ErrAddingFileToInstance.WithParams(dest, b.instance.name).Wrap(err)
-	}
-	return nil
+	_ = src
+	b.builderFactory.AddToBuilder(dest, dest, chown)
 }
 
 // SetEnvironmentVariable sets the given environment variable in the instance
@@ -214,7 +205,8 @@ func (b *build) SetEnvironmentVariable(key, value string) error {
 	}
 	b.instance.Logger.Debugf("Setting environment variable '%s' in instance '%s'", key, b.instance.name)
 	if b.instance.state == StatePreparing {
-		return b.builderFactory.SetEnvVar(key, value)
+		b.builderFactory.SetEnvVar(key, value)
+		return nil
 	}
 
 	b.env[key] = value

pkg/instance/storage.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 
 	"github.com/celestiaorg/knuu/pkg/k8s"
+	"github.com/celestiaorg/knuu/pkg/names"
 
 	"k8s.io/apimachinery/pkg/api/resource"
 )
@@ -46,7 +47,8 @@ func (s *storage) AddFile(src string, dest string, chown string) error {
 
 	switch s.instance.state {
 	case StatePreparing:
-		return s.instance.build.addFileToBuilder(src, dest, chown)
+		s.instance.build.addFileToBuilder(src, dest, chown)
+		return nil
 	case StateCommitted:
 		return s.addFileToInstance(dstPath, dest, chown)
 	}
@@ -163,7 +165,7 @@ func (s *storage) GetFileBytes(ctx context.Context, file string) ([]byte, error)
 	}
 
 	if s.instance.state != StateStarted {
-		bytes, err := s.instance.build.builderFactory.ReadFileFromBuilder(file)
+		bytes, err := s.readFileFromImage(ctx, file)
 		if err != nil {
 			return nil, ErrGettingFile.WithParams(file, s.instance.name).Wrap(err)
 		}
@@ -345,6 +347,48 @@ func (s *storage) destroyFiles(ctx context.Context) error {
 	return nil
 }
 
+func (s *storage) readFileFromImage(ctx context.Context, filePath string) ([]byte, error) {
+	// Another way to implement this is to download all the layers of the image and then
+	// extract the file from them, but it seems hacky and will run on the user's machine.
+	// Therefore, we will use the tmp instance to get the file from the image
+
+	tmpName, err := names.NewRandomK8("tmp-dl")
+	if err != nil {
+		return nil, err
+	}
+
+	ti, err := New(tmpName, s.instance.SystemDependencies)
+	if err != nil {
+		return nil, err
+	}
+	if err := ti.build.SetImage(ctx, s.instance.build.ImageName()); err != nil {
+		return nil, err
+	}
+
+	if err := ti.build.SetStartCommand("sleep", "infinity"); err != nil {
+		return nil, err
+	}
+
+	if err := ti.build.Commit(ctx); err != nil {
+		return nil, err
+	}
+
+	if err := ti.execution.Start(ctx); err != nil {
+		return nil, err
+	}
+	defer func() {
+		if err := ti.execution.Destroy(ctx); err != nil {
+			ti.Logger.Errorf("failed to destroy tmp instance %s: %v", ti.k8sName, err)
+		}
+	}()
+
+	output, err := ti.execution.ExecuteCommand(ctx, "cat", filePath)
+	if err != nil {
+		return nil, err
+	}
+	return []byte(output), nil
+}
+
 func (s *storage) clone() *storage {
 	if s == nil {
 		return nil