Deal with notebook remote filenames stripping .py (#90)

This PR introduces tracking of remote names and local names of files in snapshots to disambiguate between files which might have the same remote name and handle clean deleting of files whose remote name changes due (eg. python notebook getting converted to a python notebook)

cmd/sync/snapshot.go

@@ -1,12 +1,14 @@
 package sync
 
 import (
+	"bufio"
 	"context"
 	"encoding/json"
 	"fmt"
 	"io"
 	"os"
 	"path/filepath"
+	"regexp"
 	"strings"
 	"time"
 
@@ -38,6 +40,13 @@ type Snapshot struct {
 	// key: relative file path from project root
 	// value: last time the remote instance of this file was updated
 	LastUpdatedTimes map[string]time.Time `json:"last_modified_times"`
+	// This map maps local file names to their remote names
+	// eg. notebook named "foo.py" locally would be stored as "foo", thus this
+	// map will contain an entry "foo.py" -> "foo"
+	LocalToRemoteNames map[string]string `json:"local_to_remote_names"`
+	// Inverse of localToRemoteNames. Together the form a bijective mapping (ie
+	// there is a 1:1 unique mapping between local and remote name)
+	RemoteToLocalNames map[string]string `json:"remote_to_local_names"`
 }
 
 type diff struct {
@@ -87,9 +96,11 @@ func newSnapshot(ctx context.Context, remotePath string) (*Snapshot, error) {
 	}
 
 	return &Snapshot{
-		Host:             host,
-		RemotePath:       remotePath,
-		LastUpdatedTimes: make(map[string]time.Time),
+		Host:               host,
+		RemotePath:         remotePath,
+		LastUpdatedTimes:   make(map[string]time.Time),
+		LocalToRemoteNames: make(map[string]string),
+		RemoteToLocalNames: make(map[string]string),
 	}, nil
 }
 
@@ -161,9 +172,37 @@ func (d diff) String() string {
 	return strings.Join(changes, ", ")
 }
 
-func (s Snapshot) diff(all []git.File) (change diff) {
+func getNotebookDetails(path string) (isNotebook bool, typeOfNotebook string, err error) {
+	isNotebook = false
+	typeOfNotebook = ""
+
+	isPythonFile, err := regexp.Match(`\.py$`, []byte(path))
+	if err != nil {
+		return
+	}
+	if isPythonFile {
+		f, err := os.Open(path)
+		if err != nil {
+			return false, "", err
+		}
+		defer f.Close()
+		scanner := bufio.NewScanner(f)
+		ok := scanner.Scan()
+		if !ok {
+			return false, "", scanner.Err()
+		}
+		// A python file is a notebook if it starts with the following magic string
+		isNotebook = strings.Contains(scanner.Text(), "# Databricks notebook source")
+		return isNotebook, "PYTHON", nil
+	}
+	return false, "", nil
+}
+
+func (s Snapshot) diff(all []git.File) (change diff, err error) {
 	currentFilenames := map[string]bool{}
 	lastModifiedTimes := s.LastUpdatedTimes
+	remoteToLocalNames := s.RemoteToLocalNames
+	localToRemoteNames := s.LocalToRemoteNames
 	for _, f := range all {
 		// create set of current files to figure out if removals are needed
 		currentFilenames[f.Relative] = true
@@ -174,22 +213,52 @@ func (s Snapshot) diff(all []git.File) (change diff) {
 		if !seen || modified.After(lastSeenModified) {
 			change.put = append(change.put, f.Relative)
 			lastModifiedTimes[f.Relative] = modified
+
+			// Keep track of remote names of local files so we can delete them later
+			isNotebook, typeOfNotebook, err := getNotebookDetails(f.Absolute)
+			if err != nil {
+				return change, err
+			}
+			remoteName := f.Relative
+			if isNotebook && typeOfNotebook == "PYTHON" {
+				remoteName = strings.TrimSuffix(f.Relative, `.py`)
+			}
+
+			// If the remote handle of a file changes, we want to delete the old
+			// remote version of that file to avoid duplicates.
+			// This can happen if a python notebook is converted to a python
+			// script or vice versa
+			oldRemoteName, ok := localToRemoteNames[f.Relative]
+			if ok && oldRemoteName != remoteName {
+				change.delete = append(change.delete, oldRemoteName)
+				delete(remoteToLocalNames, oldRemoteName)
+			}
+			// We cannot allow two local files in the project to point to the same
+			// remote path
+			oldLocalName, ok := remoteToLocalNames[remoteName]
+			if ok && oldLocalName != f.Relative {
+				return change, fmt.Errorf("both %s and %s point to the same remote file location %s. Please remove one of them from your local project", oldLocalName, f.Relative, remoteName)
+			}
+			localToRemoteNames[f.Relative] = remoteName
+			remoteToLocalNames[remoteName] = f.Relative
 		}
 	}
-	// figure out files in the snapshot, but not on local filesystem
-	for relative := range lastModifiedTimes {
-		_, exists := currentFilenames[relative]
+	// figure out files in the snapshot.lastModifiedTimes, but not on local
+	// filesystem. These will be deleted
+	for localName := range lastModifiedTimes {
+		_, exists := currentFilenames[localName]
 		if exists {
 			continue
 		}
 		// add them to a delete batch
-		change.delete = append(change.delete, relative)
-		// remove the file from snapshot
-		delete(lastModifiedTimes, relative)
+		change.delete = append(change.delete, localToRemoteNames[localName])
 	}
 	// and remove them from the snapshot
-	for _, v := range change.delete {
-		delete(lastModifiedTimes, v)
+	for _, remoteName := range change.delete {
+		localName := remoteToLocalNames[remoteName]
+		delete(lastModifiedTimes, localName)
+		delete(remoteToLocalNames, remoteName)
+		delete(localToRemoteNames, localName)
 	}
 	return
 }

cmd/sync/snapshot_test.go

@@ -10,57 +10,220 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+type testFile struct {
+	mtime time.Time
+	fd    *os.File
+	path  string
+}
+
+func createFile(t *testing.T, path string) *testFile {
+	f, err := os.Create(path)
+	assert.NoError(t, err)
+
+	fileInfo, err := os.Stat(path)
+	assert.NoError(t, err)
+
+	return &testFile{
+		path:  path,
+		fd:    f,
+		mtime: fileInfo.ModTime(),
+	}
+}
+
+func (f *testFile) close(t *testing.T) {
+	err := f.fd.Close()
+	assert.NoError(t, err)
+}
+
+func (f *testFile) overwrite(t *testing.T, s string) {
+	err := os.Truncate(f.path, 0)
+	assert.NoError(t, err)
+
+	_, err = f.fd.Seek(0, 0)
+	assert.NoError(t, err)
+
+	_, err = f.fd.WriteString(s)
+	assert.NoError(t, err)
+
+	// We manually update mtime after write because github actions file
+	// system does not :')
+	err = os.Chtimes(f.path, f.mtime.Add(time.Minute), f.mtime.Add(time.Minute))
+	assert.NoError(t, err)
+	f.mtime = f.mtime.Add(time.Minute)
+}
+
+func (f *testFile) remove(t *testing.T) {
+	err := os.Remove(f.path)
+	assert.NoError(t, err)
+}
+
+func assertKeysOfMap(t *testing.T, m map[string]time.Time, expectedKeys []string) {
+	keys := make([]string, len(m))
+	i := 0
+	for k := range m {
+		keys[i] = k
+		i++
+	}
+	assert.ElementsMatch(t, expectedKeys, keys)
+}
+
 func TestDiff(t *testing.T) {
 	// Create temp project dir
 	projectDir := t.TempDir()
-
-	f1, err := os.Create(filepath.Join(projectDir, "hello.txt"))
-	assert.NoError(t, err)
-	defer f1.Close()
-	worldFilePath := filepath.Join(projectDir, "world.txt")
-	f2, err := os.Create(worldFilePath)
-	assert.NoError(t, err)
-	defer f2.Close()
-
 	fileSet := git.NewFileSet(projectDir)
+	state := Snapshot{
+		LastUpdatedTimes:   make(map[string]time.Time),
+		LocalToRemoteNames: make(map[string]string),
+		RemoteToLocalNames: make(map[string]string),
+	}
+
+	f1 := createFile(t, filepath.Join(projectDir, "hello.txt"))
+	defer f1.close(t)
+	worldFilePath := filepath.Join(projectDir, "world.txt")
+	f2 := createFile(t, worldFilePath)
+	defer f2.close(t)
+
+	// New files are put
 	files, err := fileSet.All()
 	assert.NoError(t, err)
-	state := Snapshot{
-		LastUpdatedTimes: make(map[string]time.Time),
-	}
-	change := state.diff(files)
-
-	// New files are added to put
+	change, err := state.diff(files)
+	assert.NoError(t, err)
 	assert.Len(t, change.delete, 0)
 	assert.Len(t, change.put, 2)
 	assert.Contains(t, change.put, "hello.txt")
 	assert.Contains(t, change.put, "world.txt")
+	assertKeysOfMap(t, state.LastUpdatedTimes, []string{"hello.txt", "world.txt"})
+	assert.Equal(t, map[string]string{"hello.txt": "hello.txt", "world.txt": "world.txt"}, state.LocalToRemoteNames)
+	assert.Equal(t, map[string]string{"hello.txt": "hello.txt", "world.txt": "world.txt"}, state.RemoteToLocalNames)
 
-	// Edited files are added to put.
-	// File system in the github actions env does not update
-	// mtime on writes to a file. So we are manually editting it
-	// instead of writing to world.txt
-	worldFileInfo, err := os.Stat(worldFilePath)
-	assert.NoError(t, err)
-	os.Chtimes(worldFilePath,
-		worldFileInfo.ModTime().Add(time.Nanosecond),
-		worldFileInfo.ModTime().Add(time.Nanosecond))
-
+	// world.txt is editted
+	f2.overwrite(t, "bunnies are cute.")
 	assert.NoError(t, err)
 	files, err = fileSet.All()
 	assert.NoError(t, err)
-	change = state.diff(files)
+	change, err = state.diff(files)
+	assert.NoError(t, err)
+
 	assert.Len(t, change.delete, 0)
 	assert.Len(t, change.put, 1)
 	assert.Contains(t, change.put, "world.txt")
+	assertKeysOfMap(t, state.LastUpdatedTimes, []string{"hello.txt", "world.txt"})
+	assert.Equal(t, map[string]string{"hello.txt": "hello.txt", "world.txt": "world.txt"}, state.LocalToRemoteNames)
+	assert.Equal(t, map[string]string{"hello.txt": "hello.txt", "world.txt": "world.txt"}, state.RemoteToLocalNames)
 
-	// Removed files are added to delete
-	err = os.Remove(filepath.Join(projectDir, "hello.txt"))
+	// hello.txt is deleted
+	f1.remove(t)
 	assert.NoError(t, err)
 	files, err = fileSet.All()
 	assert.NoError(t, err)
-	change = state.diff(files)
+	change, err = state.diff(files)
+	assert.NoError(t, err)
 	assert.Len(t, change.delete, 1)
 	assert.Len(t, change.put, 0)
 	assert.Contains(t, change.delete, "hello.txt")
+	assertKeysOfMap(t, state.LastUpdatedTimes, []string{"world.txt"})
+	assert.Equal(t, map[string]string{"world.txt": "world.txt"}, state.LocalToRemoteNames)
+	assert.Equal(t, map[string]string{"world.txt": "world.txt"}, state.RemoteToLocalNames)
+}
+
+func TestPythonNotebookDiff(t *testing.T) {
+	// Create temp project dir
+	projectDir := t.TempDir()
+	fileSet := git.NewFileSet(projectDir)
+	state := Snapshot{
+		LastUpdatedTimes:   make(map[string]time.Time),
+		LocalToRemoteNames: make(map[string]string),
+		RemoteToLocalNames: make(map[string]string),
+	}
+
+	foo := createFile(t, filepath.Join(projectDir, "foo.py"))
+	defer foo.close(t)
+
+	// Case 1: notebook foo.py is uploaded
+	files, err := fileSet.All()
+	assert.NoError(t, err)
+	foo.overwrite(t, "# Databricks notebook source\nprint(\"abc\")")
+	change, err := state.diff(files)
+	assert.NoError(t, err)
+	assert.Len(t, change.delete, 0)
+	assert.Len(t, change.put, 1)
+	assert.Contains(t, change.put, "foo.py")
+	assertKeysOfMap(t, state.LastUpdatedTimes, []string{"foo.py"})
+	assert.Equal(t, map[string]string{"foo.py": "foo"}, state.LocalToRemoteNames)
+	assert.Equal(t, map[string]string{"foo": "foo.py"}, state.RemoteToLocalNames)
+
+	// Case 2: notebook foo.py is converted to python script by removing
+	// magic keyword
+	foo.overwrite(t, "print(\"abc\")")
+	files, err = fileSet.All()
+	assert.NoError(t, err)
+	change, err = state.diff(files)
+	assert.NoError(t, err)
+	assert.Len(t, change.delete, 1)
+	assert.Len(t, change.put, 1)
+	assert.Contains(t, change.put, "foo.py")
+	assert.Contains(t, change.delete, "foo")
+	assertKeysOfMap(t, state.LastUpdatedTimes, []string{"foo.py"})
+	assert.Equal(t, map[string]string{"foo.py": "foo.py"}, state.LocalToRemoteNames)
+	assert.Equal(t, map[string]string{"foo.py": "foo.py"}, state.RemoteToLocalNames)
+
+	// Case 3: Python script foo.py is converted to a databricks notebook
+	foo.overwrite(t, "# Databricks notebook source\nprint(\"def\")")
+	files, err = fileSet.All()
+	assert.NoError(t, err)
+	change, err = state.diff(files)
+	assert.NoError(t, err)
+	assert.Len(t, change.delete, 1)
+	assert.Len(t, change.put, 1)
+	assert.Contains(t, change.put, "foo.py")
+	assert.Contains(t, change.delete, "foo.py")
+	assertKeysOfMap(t, state.LastUpdatedTimes, []string{"foo.py"})
+	assert.Equal(t, map[string]string{"foo.py": "foo"}, state.LocalToRemoteNames)
+	assert.Equal(t, map[string]string{"foo": "foo.py"}, state.RemoteToLocalNames)
+
+	// Case 4: Python notebook foo.py is deleted, and its remote name is used in change.delete
+	foo.remove(t)
+	assert.NoError(t, err)
+	files, err = fileSet.All()
+	assert.NoError(t, err)
+	change, err = state.diff(files)
+	assert.NoError(t, err)
+	assert.Len(t, change.delete, 1)
+	assert.Len(t, change.put, 0)
+	assert.Contains(t, change.delete, "foo")
+	assert.Len(t, state.LastUpdatedTimes, 0)
+	assert.Equal(t, map[string]string{}, state.LocalToRemoteNames)
+	assert.Equal(t, map[string]string{}, state.RemoteToLocalNames)
+}
+
+func TestErrorWhenIdenticalRemoteName(t *testing.T) {
+	// Create temp project dir
+	projectDir := t.TempDir()
+	fileSet := git.NewFileSet(projectDir)
+	state := Snapshot{
+		LastUpdatedTimes:   make(map[string]time.Time),
+		LocalToRemoteNames: make(map[string]string),
+		RemoteToLocalNames: make(map[string]string),
+	}
+
+	// upload should work since they point to different destinations
+	pythonFoo := createFile(t, filepath.Join(projectDir, "foo.py"))
+	defer pythonFoo.close(t)
+	vanillaFoo := createFile(t, filepath.Join(projectDir, "foo"))
+	defer vanillaFoo.close(t)
+	files, err := fileSet.All()
+	assert.NoError(t, err)
+	change, err := state.diff(files)
+	assert.NoError(t, err)
+	assert.Len(t, change.delete, 0)
+	assert.Len(t, change.put, 2)
+	assert.Contains(t, change.put, "foo.py")
+	assert.Contains(t, change.put, "foo")
+
+	// errors out because they point to the same destination
+	pythonFoo.overwrite(t, "# Databricks notebook source\nprint(\"def\")")
+	files, err = fileSet.All()
+	assert.NoError(t, err)
+	change, err = state.diff(files)
+	assert.ErrorContains(t, err, "both foo and foo.py point to the same remote file location foo. Please remove one of them from your local project")
 }

cmd/sync/watchdog.go

@@ -31,6 +31,18 @@ type watchdog struct {
 // rate limits
 const MaxRequestsInFlight = 20
 
+// path: The local path of the file in the local file system
+//
+// The API calls for a python script foo.py would be
+// `PUT foo.py`
+// `DELETE foo.py`
+//
+// The API calls for a python notebook foo.py would be
+// `PUT foo.py`
+// `DELETE foo`
+//
+// The workspace file system backend strips .py from the file name if the python
+// file is a notebook
 func putFile(ctx context.Context, path string, content io.Reader) error {
 	wsc := project.Get(ctx).WorkspacesClient()
 	// workspace mkdirs is idempotent
@@ -48,6 +60,7 @@ func putFile(ctx context.Context, path string, content io.Reader) error {
 	return apiClient.Post(ctx, apiPath, content, nil)
 }
 
+// path: The remote path of the file in the workspace
 func deleteFile(ctx context.Context, path string, wsc *workspaces.WorkspacesClient) error {
 	err := wsc.Workspace.Delete(ctx,
 		workspace.Delete{
@@ -75,29 +88,30 @@ func getRemoteSyncCallback(ctx context.Context, root, remoteDir string, wsc *wor
 		// Allow MaxRequestLimit maxiumum concurrent api calls
 		g.SetLimit(MaxRequestsInFlight)
 
-		for _, fileName := range d.delete {
-			// Copy of fileName created to make this safe for concurrent use.
-			// directly using fileName can cause race conditions since the loop
-			// might iterate over to the next fileName before the go routine function
+		for _, remoteName := range d.delete {
+			// Copy of remoteName created to make this safe for concurrent use.
+			// directly using remoteName can cause race conditions since the loop
+			// might iterate over to the next remoteName before the go routine function
 			// is evaluated
-			localFileName := fileName
+			remoteNameCopy := remoteName
 			g.Go(func() error {
-				err := deleteFile(ctx, path.Join(remoteDir, localFileName), wsc)
+				err := deleteFile(ctx, path.Join(remoteDir, remoteNameCopy), wsc)
 				if err != nil {
 					return err
 				}
-				log.Printf("[INFO] Deleted %s", localFileName)
+				log.Printf("[INFO] Deleted %s", remoteNameCopy)
 				return nil
 			})
 		}
-		for _, fileName := range d.put {
-			localFileName := fileName
+		for _, localName := range d.put {
+			// Copy of localName created to make this safe for concurrent use.
+			localNameCopy := localName
 			g.Go(func() error {
-				f, err := os.Open(filepath.Join(root, localFileName))
+				f, err := os.Open(filepath.Join(root, localNameCopy))
 				if err != nil {
 					return err
 				}
-				err = putFile(ctx, path.Join(remoteDir, localFileName), f)
+				err = putFile(ctx, path.Join(remoteDir, localNameCopy), f)
 				if err != nil {
 					return fmt.Errorf("failed to upload file: %s", err)
 				}
@@ -105,7 +119,7 @@ func getRemoteSyncCallback(ctx context.Context, root, remoteDir string, wsc *wor
 				if err != nil {
 					return err
 				}
-				log.Printf("[INFO] Uploaded %s", localFileName)
+				log.Printf("[INFO] Uploaded %s", localNameCopy)
 				return nil
 			})
 		}
@@ -162,7 +176,11 @@ func (w *watchdog) main(ctx context.Context, applyDiff func(diff) error, remoteP
 				w.failure = err
 				return
 			}
-			change := snapshot.diff(all)
+			change, err := snapshot.diff(all)
+			if err != nil {
+				w.failure = err
+				return
+			}
 			if change.IsEmpty() {
 				onlyOnceInitLog.Do(func() {
 					log.Printf("[INFO] Initial Sync Complete")