Implement DBFS filer (#139)

Adds a DBFS implementation of the `filer.Filer` interface.

The integration tests are reused between the workspace filesystem and
DBFS implementations to ensure identical behavior.

internal/filer_test.go

@@ -1,6 +1,7 @@
 package internal
 
 import (
+	"bytes"
 	"context"
 	"errors"
 	"fmt"
@@ -12,6 +13,7 @@ import (
 	"github.com/databricks/cli/libs/filer"
 	"github.com/databricks/databricks-sdk-go"
 	"github.com/databricks/databricks-sdk-go/apierr"
+	"github.com/databricks/databricks-sdk-go/service/files"
 	"github.com/databricks/databricks-sdk-go/service/workspace"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
@@ -28,12 +30,98 @@ func (f filerTest) assertContents(ctx context.Context, name string, contents str
 		return
 	}
 
-	body, err := io.ReadAll(reader)
+	var body bytes.Buffer
+	_, err = io.Copy(&body, reader)
 	if !assert.NoError(f, err) {
 		return
 	}
 
-	assert.Equal(f, contents, string(body))
+	assert.Equal(f, contents, body.String())
+}
+
+func runFilerReadWriteTest(t *testing.T, ctx context.Context, f filer.Filer) {
+	var err error
+
+	// Write should fail because the root path doesn't yet exist.
+	err = f.Write(ctx, "/foo/bar", strings.NewReader(`hello world`))
+	assert.True(t, errors.As(err, &filer.NoSuchDirectoryError{}))
+
+	// Read should fail because the root path doesn't yet exist.
+	_, err = f.Read(ctx, "/foo/bar")
+	assert.True(t, errors.As(err, &filer.FileDoesNotExistError{}))
+
+	// Write with CreateParentDirectories flag should succeed.
+	err = f.Write(ctx, "/foo/bar", strings.NewReader(`hello world`), filer.CreateParentDirectories)
+	assert.NoError(t, err)
+	filerTest{t, f}.assertContents(ctx, "/foo/bar", `hello world`)
+
+	// Write should fail because there is an existing file at the specified path.
+	err = f.Write(ctx, "/foo/bar", strings.NewReader(`hello universe`))
+	assert.True(t, errors.As(err, &filer.FileAlreadyExistsError{}))
+
+	// Write with OverwriteIfExists should succeed.
+	err = f.Write(ctx, "/foo/bar", strings.NewReader(`hello universe`), filer.OverwriteIfExists)
+	assert.NoError(t, err)
+	filerTest{t, f}.assertContents(ctx, "/foo/bar", `hello universe`)
+
+	// Delete should fail if the file doesn't exist.
+	err = f.Delete(ctx, "/doesnt_exist")
+	assert.True(t, errors.As(err, &filer.FileDoesNotExistError{}))
+
+	// Delete should succeed for file that does exist.
+	err = f.Delete(ctx, "/foo/bar")
+	assert.NoError(t, err)
+}
+
+func runFilerReadDirTest(t *testing.T, ctx context.Context, f filer.Filer) {
+	var err error
+
+	// We start with an empty directory.
+	entries, err := f.ReadDir(ctx, ".")
+	require.NoError(t, err)
+	assert.Len(t, entries, 0)
+
+	// Write a file.
+	err = f.Write(ctx, "/hello.txt", strings.NewReader(`hello world`))
+	require.NoError(t, err)
+
+	// Create a directory.
+	err = f.Mkdir(ctx, "/dir")
+	require.NoError(t, err)
+
+	// Write a file.
+	err = f.Write(ctx, "/dir/world.txt", strings.NewReader(`hello world`))
+	require.NoError(t, err)
+
+	// Create a nested directory (check that it creates intermediate directories).
+	err = f.Mkdir(ctx, "/dir/a/b/c")
+	require.NoError(t, err)
+
+	// Expect an error if the path doesn't exist.
+	_, err = f.ReadDir(ctx, "/dir/a/b/c/d/e")
+	assert.True(t, errors.As(err, &filer.NoSuchDirectoryError{}), err)
+
+	// Expect two entries in the root.
+	entries, err = f.ReadDir(ctx, ".")
+	require.NoError(t, err)
+	assert.Len(t, entries, 2)
+	assert.Equal(t, "dir", entries[0].Name)
+	assert.Equal(t, "hello.txt", entries[1].Name)
+	assert.Greater(t, entries[1].ModTime.Unix(), int64(0))
+
+	// Expect two entries in the directory.
+	entries, err = f.ReadDir(ctx, "/dir")
+	require.NoError(t, err)
+	assert.Len(t, entries, 2)
+	assert.Equal(t, "a", entries[0].Name)
+	assert.Equal(t, "world.txt", entries[1].Name)
+	assert.Greater(t, entries[1].ModTime.Unix(), int64(0))
+
+	// Expect a single entry in the nested path.
+	entries, err = f.ReadDir(ctx, "/dir/a/b")
+	require.NoError(t, err)
+	assert.Len(t, entries, 1)
+	assert.Equal(t, "c", entries[0].Name)
 }
 
 func temporaryWorkspaceDir(t *testing.T, w *databricks.WorkspaceClient) string {
@@ -41,7 +129,7 @@ func temporaryWorkspaceDir(t *testing.T, w *databricks.WorkspaceClient) string {
 	me, err := w.CurrentUser.Me(ctx)
 	require.NoError(t, err)
 
-	path := fmt.Sprintf("/Users/%s/%s", me.UserName, RandomName("wsfs-files-"))
+	path := fmt.Sprintf("/Users/%s/%s", me.UserName, RandomName("integration-test-filer-wsfs-"))
 
 	// Ensure directory exists, but doesn't exist YET!
 	// Otherwise we could inadvertently remove a directory that already exists on cleanup.
@@ -59,7 +147,7 @@ func temporaryWorkspaceDir(t *testing.T, w *databricks.WorkspaceClient) string {
 		if err == nil || apierr.IsMissing(err) {
 			return
 		}
-		t.Logf("unable to remove temporary workspace path %s: %#v", path, err)
+		t.Logf("unable to remove temporary workspace directory %s: %#v", path, err)
 	})
 
 	return path
@@ -85,90 +173,57 @@ func setupWorkspaceFilesTest(t *testing.T) (context.Context, filer.Filer) {
 }
 
 func TestAccFilerWorkspaceFilesReadWrite(t *testing.T) {
-	var err error
-
 	ctx, f := setupWorkspaceFilesTest(t)
-
+	runFilerReadWriteTest(t, ctx, f)
-	// Write should fail because the root path doesn't yet exist.
-	err = f.Write(ctx, "/foo/bar", strings.NewReader(`hello world`))
-	assert.True(t, errors.As(err, &filer.NoSuchDirectoryError{}))
-
-	// Read should fail because the root path doesn't yet exist.
-	_, err = f.Read(ctx, "/foo/bar")
-	assert.True(t, apierr.IsMissing(err))
-
-	// Write with CreateParentDirectories flag should succeed.
-	err = f.Write(ctx, "/foo/bar", strings.NewReader(`hello world`), filer.CreateParentDirectories)
-	assert.NoError(t, err)
-	filerTest{t, f}.assertContents(ctx, "/foo/bar", `hello world`)
-
-	// Write should fail because there is an existing file at the specified path.
-	err = f.Write(ctx, "/foo/bar", strings.NewReader(`hello universe`))
-	assert.True(t, errors.As(err, &filer.FileAlreadyExistsError{}))
-
-	// Write with OverwriteIfExists should succeed.
-	err = f.Write(ctx, "/foo/bar", strings.NewReader(`hello universe`), filer.OverwriteIfExists)
-	assert.NoError(t, err)
-	filerTest{t, f}.assertContents(ctx, "/foo/bar", `hello universe`)
-
-	// Delete should fail if the file doesn't exist.
-	err = f.Delete(ctx, "/doesnt_exist")
-	assert.True(t, apierr.IsMissing(err))
-
-	// Delete should succeed for file that does exist.
-	err = f.Delete(ctx, "/foo/bar")
-	assert.NoError(t, err)
 }
 
 func TestAccFilerWorkspaceFilesReadDir(t *testing.T) {
-	var err error
-
 	ctx, f := setupWorkspaceFilesTest(t)
-
+	runFilerReadDirTest(t, ctx, f)
-	// We start with an empty directory.
+}
-	entries, err := f.ReadDir(ctx, ".")
+
-	require.NoError(t, err)
+func temporaryDbfsDir(t *testing.T, w *databricks.WorkspaceClient) string {
-	assert.Len(t, entries, 0)
+	ctx := context.Background()
-
+	path := fmt.Sprintf("/tmp/%s", RandomName("integration-test-filer-dbfs-"))
-	// Write a file.
+
-	err = f.Write(ctx, "/hello.txt", strings.NewReader(`hello world`))
+	// This call fails if the path already exists.
-	require.NoError(t, err)
+	t.Logf("mkdir dbfs:%s", path)
-
+	err := w.Dbfs.MkdirsByPath(ctx, path)
-	// Create a directory.
+	require.NoError(t, err)
-	err = f.Mkdir(ctx, "/dir")
+
-	require.NoError(t, err)
+	// Remove test directory on test completion.
-
+	t.Cleanup(func() {
-	// Write a file.
+		t.Logf("rm -rf dbfs:%s", path)
-	err = f.Write(ctx, "/dir/world.txt", strings.NewReader(`hello world`))
+		err := w.Dbfs.Delete(ctx, files.Delete{
-	require.NoError(t, err)
+			Path:      path,
-
+			Recursive: true,
-	// Create a nested directory (check that it creates intermediate directories).
+		})
-	err = f.Mkdir(ctx, "/dir/a/b/c")
+		if err == nil || apierr.IsMissing(err) {
-	require.NoError(t, err)
+			return
-
+		}
-	// Expect an error if the path doesn't exist.
+		t.Logf("unable to remove temporary dbfs directory %s: %#v", path, err)
-	_, err = f.ReadDir(ctx, "/dir/a/b/c/d/e")
+	})
-	assert.True(t, errors.As(err, &filer.NoSuchDirectoryError{}))
+
-
+	return path
-	// Expect two entries in the root.
+}
-	entries, err = f.ReadDir(ctx, ".")
+
-	require.NoError(t, err)
+func setupFilerDbfsTest(t *testing.T) (context.Context, filer.Filer) {
-	assert.Len(t, entries, 2)
+	t.Log(GetEnvOrSkipTest(t, "CLOUD_ENV"))
-	assert.Equal(t, "dir", entries[0].Name)
+
-	assert.Equal(t, "hello.txt", entries[1].Name)
+	ctx := context.Background()
-	assert.Greater(t, entries[1].ModTime.Unix(), int64(0))
+	w := databricks.Must(databricks.NewWorkspaceClient())
-
+	tmpdir := temporaryDbfsDir(t, w)
-	// Expect two entries in the directory.
+	f, err := filer.NewDbfsClient(w, tmpdir)
-	entries, err = f.ReadDir(ctx, "/dir")
+	require.NoError(t, err)
-	require.NoError(t, err)
+	return ctx, f
-	assert.Len(t, entries, 2)
+}
-	assert.Equal(t, "a", entries[0].Name)
+
-	assert.Equal(t, "world.txt", entries[1].Name)
+func TestAccFilerDbfsReadWrite(t *testing.T) {
-	assert.Greater(t, entries[1].ModTime.Unix(), int64(0))
+	ctx, f := setupFilerDbfsTest(t)
-
+	runFilerReadWriteTest(t, ctx, f)
-	// Expect a single entry in the nested path.
+}
-	entries, err = f.ReadDir(ctx, "/dir/a/b")
+
-	require.NoError(t, err)
+func TestAccFilerDbfsReadDir(t *testing.T) {
-	assert.Len(t, entries, 1)
+	ctx, f := setupFilerDbfsTest(t)
-	assert.Equal(t, "c", entries[0].Name)
+	runFilerReadDirTest(t, ctx, f)
 }

libs/filer/dbfs_client.go

@@ -0,0 +1,199 @@
+package filer
+
+import (
+	"context"
+	"errors"
+	"io"
+	"net/http"
+	"path"
+	"sort"
+	"time"
+
+	"github.com/databricks/databricks-sdk-go"
+	"github.com/databricks/databricks-sdk-go/apierr"
+	"github.com/databricks/databricks-sdk-go/service/files"
+	"golang.org/x/exp/slices"
+)
+
+// DbfsClient implements the [Filer] interface for the DBFS backend.
+type DbfsClient struct {
+	workspaceClient *databricks.WorkspaceClient
+
+	// File operations will be relative to this path.
+	root RootPath
+}
+
+func NewDbfsClient(w *databricks.WorkspaceClient, root string) (Filer, error) {
+	return &DbfsClient{
+		workspaceClient: w,
+
+		root: NewRootPath(root),
+	}, nil
+}
+
+func (w *DbfsClient) Write(ctx context.Context, name string, reader io.Reader, mode ...WriteMode) error {
+	absPath, err := w.root.Join(name)
+	if err != nil {
+		return err
+	}
+
+	fileMode := files.FileModeWrite
+	if slices.Contains(mode, OverwriteIfExists) {
+		fileMode |= files.FileModeOverwrite
+	}
+
+	// Issue info call before write because it automatically creates parent directories.
+	//
+	// For discussion: we could decide this is actually convenient, remove the call below,
+	// and apply the same semantics for the WSFS filer.
+	//
+	if !slices.Contains(mode, CreateParentDirectories) {
+		_, err = w.workspaceClient.Dbfs.GetStatusByPath(ctx, path.Dir(absPath))
+		if err != nil {
+			var aerr *apierr.APIError
+			if !errors.As(err, &aerr) {
+				return err
+			}
+
+			// This API returns a 404 if the file doesn't exist.
+			if aerr.StatusCode == http.StatusNotFound {
+				if aerr.ErrorCode == "RESOURCE_DOES_NOT_EXIST" {
+					return NoSuchDirectoryError{path.Dir(absPath)}
+				}
+			}
+
+			return err
+		}
+	}
+
+	handle, err := w.workspaceClient.Dbfs.Open(ctx, absPath, fileMode)
+	if err != nil {
+		var aerr *apierr.APIError
+		if !errors.As(err, &aerr) {
+			return err
+		}
+
+		// This API returns a 400 if the file already exists.
+		if aerr.StatusCode == http.StatusBadRequest {
+			if aerr.ErrorCode == "RESOURCE_ALREADY_EXISTS" {
+				return FileAlreadyExistsError{absPath}
+			}
+		}
+
+		return err
+	}
+
+	_, err = io.Copy(handle, reader)
+	cerr := handle.Close()
+	if err == nil {
+		err = cerr
+	}
+
+	return err
+}
+
+func (w *DbfsClient) Read(ctx context.Context, name string) (io.Reader, error) {
+	absPath, err := w.root.Join(name)
+	if err != nil {
+		return nil, err
+	}
+
+	handle, err := w.workspaceClient.Dbfs.Open(ctx, absPath, files.FileModeRead)
+	if err != nil {
+		var aerr *apierr.APIError
+		if !errors.As(err, &aerr) {
+			return nil, err
+		}
+
+		// This API returns a 404 if the file doesn't exist.
+		if aerr.StatusCode == http.StatusNotFound {
+			if aerr.ErrorCode == "RESOURCE_DOES_NOT_EXIST" {
+				return nil, FileDoesNotExistError{absPath}
+			}
+		}
+
+		return nil, err
+	}
+
+	return handle, nil
+}
+
+func (w *DbfsClient) Delete(ctx context.Context, name string) error {
+	absPath, err := w.root.Join(name)
+	if err != nil {
+		return err
+	}
+
+	// Issue info call before delete because delete succeeds if the specified path doesn't exist.
+	//
+	// For discussion: we could decide this is actually convenient, remove the call below,
+	// and apply the same semantics for the WSFS filer.
+	//
+	_, err = w.workspaceClient.Dbfs.GetStatusByPath(ctx, absPath)
+	if err != nil {
+		var aerr *apierr.APIError
+		if !errors.As(err, &aerr) {
+			return err
+		}
+
+		// This API returns a 404 if the file doesn't exist.
+		if aerr.StatusCode == http.StatusNotFound {
+			if aerr.ErrorCode == "RESOURCE_DOES_NOT_EXIST" {
+				return FileDoesNotExistError{absPath}
+			}
+		}
+
+		return err
+	}
+
+	return w.workspaceClient.Dbfs.Delete(ctx, files.Delete{
+		Path:      absPath,
+		Recursive: false,
+	})
+}
+
+func (w *DbfsClient) ReadDir(ctx context.Context, name string) ([]FileInfo, error) {
+	absPath, err := w.root.Join(name)
+	if err != nil {
+		return nil, err
+	}
+
+	res, err := w.workspaceClient.Dbfs.ListByPath(ctx, absPath)
+	if err != nil {
+		var aerr *apierr.APIError
+		if !errors.As(err, &aerr) {
+			return nil, err
+		}
+
+		// This API returns a 404 if the file doesn't exist.
+		if aerr.StatusCode == http.StatusNotFound {
+			if aerr.ErrorCode == "RESOURCE_DOES_NOT_EXIST" {
+				return nil, NoSuchDirectoryError{absPath}
+			}
+		}
+
+		return nil, err
+	}
+
+	info := make([]FileInfo, len(res.Files))
+	for i, v := range res.Files {
+		info[i] = FileInfo{
+			Name:    path.Base(v.Path),
+			Size:    v.FileSize,
+			ModTime: time.UnixMilli(v.ModificationTime),
+		}
+	}
+
+	// Sort by name for parity with os.ReadDir.
+	sort.Slice(info, func(i, j int) bool { return info[i].Name < info[j].Name })
+	return info, nil
+}
+
+func (w *DbfsClient) Mkdir(ctx context.Context, name string) error {
+	dirPath, err := w.root.Join(name)
+	if err != nil {
+		return err
+	}
+
+	return w.workspaceClient.Dbfs.MkdirsByPath(ctx, dirPath)
+}

libs/filer/filer.go

@@ -38,6 +38,14 @@ func (err FileAlreadyExistsError) Error() string {
 	return fmt.Sprintf("file already exists: %s", err.path)
 }
 
+type FileDoesNotExistError struct {
+	path string
+}
+
+func (err FileDoesNotExistError) Error() string {
+	return fmt.Sprintf("file does not exist: %s", err.path)
+}
+
 type NoSuchDirectoryError struct {
 	path string
 }

libs/filer/workspace_files_client.go

@@ -68,7 +68,12 @@ func (w *WorkspaceFilesClient) Write(ctx context.Context, name string, reader io
 
 	err = w.apiClient.Do(ctx, http.MethodPost, urlPath, body, nil)
 
-	// If we got an API error we deal with it below.
+	// Return early on success.
+	if err == nil {
+		return nil
+	}
+
+	// Special handling of this error only if it is an API error.
 	var aerr *apierr.APIError
 	if !errors.As(err, &aerr) {
 		return err
@@ -112,11 +117,23 @@ func (w *WorkspaceFilesClient) Read(ctx context.Context, name string) (io.Reader
 
 	var res []byte
 	err = w.apiClient.Do(ctx, http.MethodGet, urlPath, nil, &res)
-	if err != nil {
+
+	// Return early on success.
+	if err == nil {
+		return bytes.NewReader(res), nil
+	}
+
+	// Special handling of this error only if it is an API error.
+	var aerr *apierr.APIError
+	if !errors.As(err, &aerr) {
 		return nil, err
 	}
 
-	return bytes.NewReader(res), nil
+	if aerr.StatusCode == http.StatusNotFound {
+		return nil, FileDoesNotExistError{absPath}
+	}
+
+	return nil, err
 }
 
 func (w *WorkspaceFilesClient) Delete(ctx context.Context, name string) error {
@@ -125,10 +142,27 @@ func (w *WorkspaceFilesClient) Delete(ctx context.Context, name string) error {
 		return err
 	}
 
-	return w.workspaceClient.Workspace.Delete(ctx, workspace.Delete{
+	err = w.workspaceClient.Workspace.Delete(ctx, workspace.Delete{
 		Path:      absPath,
 		Recursive: false,
 	})
+
+	// Return early on success.
+	if err == nil {
+		return nil
+	}
+
+	// Special handling of this error only if it is an API error.
+	var aerr *apierr.APIError
+	if !errors.As(err, &aerr) {
+		return err
+	}
+
+	if aerr.StatusCode == http.StatusNotFound {
+		return FileDoesNotExistError{absPath}
+	}
+
+	return err
 }
 
 func (w *WorkspaceFilesClient) ReadDir(ctx context.Context, name string) ([]FileInfo, error) {