Merge 96a6cef0d6 into 75b09ff230

## Changes

Prior to this change, the output directory was part of the `renderer`
type and passed down to every `file` it produced. Every file knew its
absolute destination path. This is incompatible with the use of a filer,
where all operations are automatically anchored to some base path.

To make this compatible, this change updates:
* the `file` type to only know its own path relative to the instantiation root,
* the `renderer` type to no longer require or pass along the output directory,
* the `persistToDisk` function to take a context and filer argument,
* the `filer.WriteMode` to represent permission bits

## Tests

* Existing tests pass.
* Manually confirmed template initialization works as expected.

bundle/config/experimental.go

@@ -45,6 +45,12 @@ type PyDABs struct {
 	// These packages are imported to discover resources, resource generators, and mutators.
 	// This list can include namespace packages, which causes the import of nested packages.
 	Import []string `json:"import,omitempty"`
+
+	// LoadLocations is a flag to enable loading Python source locations from the PyDABs.
+	//
+	// Locations are only supported since PyDABs 0.6.0, and because of that,
+	// this flag is disabled by default.
+	LoadLocations bool `json:"load_locations,omitempty"`
 }
 
 type Command string

bundle/config/mutator/python/python_diagnostics.go

@@ -9,6 +9,7 @@ import (
 	"github.com/databricks/cli/libs/dyn"
 )
 
+// pythonDiagnostic is a single entry in diagnostics.json
 type pythonDiagnostic struct {
 	Severity pythonSeverity           `json:"severity"`
 	Summary  string                   `json:"summary"`

bundle/config/mutator/python/python_locations.go

@@ -0,0 +1,181 @@
+package python
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"path/filepath"
+
+	"github.com/databricks/cli/libs/dyn"
+)
+
+// generatedFileName is used as the virtual file name for YAML generated by PyDABs.
+//
+// mergePythonLocations replaces dyn.Location with generatedFileName with locations loaded
+// from locations.json
+const generatedFileName = "__generated_by_pydabs__.yml"
+
+// pythonLocations is data structure for efficient location lookup for a given path
+//
+// Locations form a tree, and we assign locations of the closest ancestor to each dyn.Value based on its path.
+// We implement it as a trie (prefix tree) where keys are components of the path. With that, lookups are O(n)
+// where n is the number of components in the path.
+//
+// For example, with locations.json:
+//
+//	{"path": "resources.jobs.job_0", "file": "src/examples/job_0.py", "line": 3, "column": 5}
+//	{"path": "resources.jobs.job_0.tasks[0].task_key", "file": "src/examples/job_0.py", "line": 10, "column": 5}
+//	{"path": "resources.jobs.job_1", "file": "src/examples/job_1.py", "line": 5, "column": 7}
+//
+// - resources.jobs.job_0.tasks[0].task_key is located at job_0.py:10:5
+//
+//   - resources.jobs.job_0.tasks[0].email_notifications is located at job_0.py:3:5,
+//     because we use the location of the job as the most precise approximation.
+type pythonLocations struct {
+	// descendants referenced by index, e.g. '.foo'
+	keys map[string]*pythonLocations
+
+	// descendants referenced by key, e.g. '[0]'
+	indexes map[int]*pythonLocations
+
+	// location for the current node if it exists
+	location dyn.Location
+
+	// if true, location is present
+	exists bool
+}
+
+// pythonLocationEntry is a single entry in locations.json
+type pythonLocationEntry struct {
+	Path   string `json:"path"`
+	File   string `json:"file"`
+	Line   int    `json:"line"`
+	Column int    `json:"column"`
+}
+
+// mergePythonLocations applies locations from Python mutator into given dyn.Value
+//
+// The primary use-case is to merge locations.json with output.json, so that any
+// validation errors will point to Python source code instead of generated YAML.
+func mergePythonLocations(value dyn.Value, locations *pythonLocations) (dyn.Value, error) {
+	return dyn.Walk(value, func(path dyn.Path, value dyn.Value) (dyn.Value, error) {
+		newLocation, ok := findPythonLocation(locations, path)
+		if !ok {
+			return value, nil
+		}
+
+		var newLocations []dyn.Location
+
+		// the first item in the list is the "last" location used for error reporting
+		newLocations = append(newLocations, newLocation)
+
+		for _, location := range value.Locations() {
+			// When loaded, dyn.Value created by PyDABs use the virtual file path as their location,
+			// we replace it with newLocation.
+			if filepath.Base(location.File) == generatedFileName {
+				continue
+			}
+
+			newLocations = append(newLocations, location)
+		}
+
+		return value.WithLocations(newLocations), nil
+	})
+}
+
+// parsePythonLocations parses locations.json from the Python mutator.
+//
+// locations file is newline-separated JSON objects with pythonLocationEntry structure.
+func parsePythonLocations(input io.Reader) (*pythonLocations, error) {
+	decoder := json.NewDecoder(input)
+	locations := newPythonLocations()
+
+	for decoder.More() {
+		var entry pythonLocationEntry
+
+		err := decoder.Decode(&entry)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse python location: %s", err)
+		}
+
+		path, err := dyn.NewPathFromString(entry.Path)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse python location: %s", err)
+		}
+
+		location := dyn.Location{
+			File:   entry.File,
+			Line:   entry.Line,
+			Column: entry.Column,
+		}
+
+		putPythonLocation(locations, path, location)
+	}
+
+	return locations, nil
+}
+
+// putPythonLocation puts the location to the trie for the given path
+func putPythonLocation(trie *pythonLocations, path dyn.Path, location dyn.Location) {
+	var currentNode = trie
+
+	for _, component := range path {
+		if key := component.Key(); key != "" {
+			if _, ok := currentNode.keys[key]; !ok {
+				currentNode.keys[key] = newPythonLocations()
+			}
+
+			currentNode = currentNode.keys[key]
+		} else {
+			index := component.Index()
+			if _, ok := currentNode.indexes[index]; !ok {
+				currentNode.indexes[index] = newPythonLocations()
+			}
+
+			currentNode = currentNode.indexes[index]
+		}
+	}
+
+	currentNode.location = location
+	currentNode.exists = true
+}
+
+// newPythonLocations creates a new trie node
+func newPythonLocations() *pythonLocations {
+	return &pythonLocations{
+		keys:    make(map[string]*pythonLocations),
+		indexes: make(map[int]*pythonLocations),
+	}
+}
+
+// findPythonLocation finds the location or closest ancestor location in the trie for the given path
+// if no ancestor or exact location is found, false is returned.
+func findPythonLocation(locations *pythonLocations, path dyn.Path) (dyn.Location, bool) {
+	var currentNode = locations
+	var lastLocation = locations.location
+	var exists = locations.exists
+
+	for _, component := range path {
+		if key := component.Key(); key != "" {
+			if _, ok := currentNode.keys[key]; !ok {
+				break
+			}
+
+			currentNode = currentNode.keys[key]
+		} else {
+			index := component.Index()
+			if _, ok := currentNode.indexes[index]; !ok {
+				break
+			}
+
+			currentNode = currentNode.indexes[index]
+		}
+
+		if currentNode.exists {
+			lastLocation = currentNode.location
+			exists = true
+		}
+	}
+
+	return lastLocation, exists
+}

bundle/config/mutator/python/python_locations_test.go

@@ -0,0 +1,124 @@
+package python
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/databricks/cli/libs/dyn"
+	assert "github.com/databricks/cli/libs/dyn/dynassert"
+)
+
+func TestMergeLocations(t *testing.T) {
+	pythonLocation := dyn.Location{File: "foo.py", Line: 1, Column: 1}
+	generatedLocation := dyn.Location{File: generatedFileName, Line: 1, Column: 1}
+	yamlLocation := dyn.Location{File: "foo.yml", Line: 1, Column: 1}
+
+	locations := newPythonLocations()
+	putPythonLocation(locations, dyn.MustPathFromString("foo"), pythonLocation)
+
+	input := dyn.NewValue(
+		map[string]dyn.Value{
+			"foo": dyn.NewValue(
+				map[string]dyn.Value{
+					"baz": dyn.NewValue("baz", []dyn.Location{yamlLocation}),
+					"qux": dyn.NewValue("baz", []dyn.Location{generatedLocation, yamlLocation}),
+				},
+				[]dyn.Location{},
+			),
+			"bar": dyn.NewValue("baz", []dyn.Location{generatedLocation}),
+		},
+		[]dyn.Location{yamlLocation},
+	)
+
+	expected := dyn.NewValue(
+		map[string]dyn.Value{
+			"foo": dyn.NewValue(
+				map[string]dyn.Value{
+					// pythonLocation is appended to the beginning of the list if absent
+					"baz": dyn.NewValue("baz", []dyn.Location{pythonLocation, yamlLocation}),
+					// generatedLocation is replaced by pythonLocation
+					"qux": dyn.NewValue("baz", []dyn.Location{pythonLocation, yamlLocation}),
+				},
+				[]dyn.Location{pythonLocation},
+			),
+			// if location is unknown, we keep it as-is
+			"bar": dyn.NewValue("baz", []dyn.Location{generatedLocation}),
+		},
+		[]dyn.Location{yamlLocation},
+	)
+
+	actual, err := mergePythonLocations(input, locations)
+
+	assert.NoError(t, err)
+	assert.Equal(t, expected, actual)
+}
+
+func TestFindLocation(t *testing.T) {
+	location0 := dyn.Location{File: "foo.py", Line: 1, Column: 1}
+	location1 := dyn.Location{File: "foo.py", Line: 2, Column: 1}
+
+	locations := newPythonLocations()
+	putPythonLocation(locations, dyn.MustPathFromString("foo"), location0)
+	putPythonLocation(locations, dyn.MustPathFromString("foo.bar"), location1)
+
+	actual, exists := findPythonLocation(locations, dyn.MustPathFromString("foo.bar"))
+
+	assert.True(t, exists)
+	assert.Equal(t, location1, actual)
+}
+
+func TestFindLocation_indexPathComponent(t *testing.T) {
+	location0 := dyn.Location{File: "foo.py", Line: 1, Column: 1}
+	location1 := dyn.Location{File: "foo.py", Line: 2, Column: 1}
+	location2 := dyn.Location{File: "foo.py", Line: 3, Column: 1}
+
+	locations := newPythonLocations()
+	putPythonLocation(locations, dyn.MustPathFromString("foo"), location0)
+	putPythonLocation(locations, dyn.MustPathFromString("foo.bar"), location1)
+	putPythonLocation(locations, dyn.MustPathFromString("foo.bar[0]"), location2)
+
+	actual, exists := findPythonLocation(locations, dyn.MustPathFromString("foo.bar[0]"))
+
+	assert.True(t, exists)
+	assert.Equal(t, location2, actual)
+}
+
+func TestFindLocation_closestAncestorLocation(t *testing.T) {
+	location0 := dyn.Location{File: "foo.py", Line: 1, Column: 1}
+	location1 := dyn.Location{File: "foo.py", Line: 2, Column: 1}
+
+	locations := newPythonLocations()
+	putPythonLocation(locations, dyn.MustPathFromString("foo"), location0)
+	putPythonLocation(locations, dyn.MustPathFromString("foo.bar"), location1)
+
+	actual, exists := findPythonLocation(locations, dyn.MustPathFromString("foo.bar.baz"))
+
+	assert.True(t, exists)
+	assert.Equal(t, location1, actual)
+}
+
+func TestFindLocation_unknownLocation(t *testing.T) {
+	location0 := dyn.Location{File: "foo.py", Line: 1, Column: 1}
+	location1 := dyn.Location{File: "foo.py", Line: 2, Column: 1}
+
+	locations := newPythonLocations()
+	putPythonLocation(locations, dyn.MustPathFromString("foo"), location0)
+	putPythonLocation(locations, dyn.MustPathFromString("foo.bar"), location1)
+
+	_, exists := findPythonLocation(locations, dyn.MustPathFromString("bar"))
+
+	assert.False(t, exists)
+}
+
+func TestParsePythonLocations(t *testing.T) {
+	expected := dyn.Location{File: "foo.py", Line: 1, Column: 2}
+
+	input := `{"path": "foo", "file": "foo.py", "line": 1, "column": 2}`
+	reader := bytes.NewReader([]byte(input))
+	locations, err := parsePythonLocations(reader)
+
+	assert.NoError(t, err)
+
+	assert.True(t, locations.keys["foo"].exists)
+	assert.Equal(t, expected, locations.keys["foo"].location)
+}

bundle/config/mutator/python/python_mutator.go

@@ -7,9 +7,12 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"io/fs"
 	"os"
 	"path/filepath"
 
+	"github.com/databricks/cli/bundle/config/mutator/paths"
+
 	"github.com/databricks/databricks-sdk-go/logger"
 	"github.com/fatih/color"
 
@@ -108,7 +111,12 @@ func (m *pythonMutator) Apply(ctx context.Context, b *bundle.Bundle) diag.Diagno
 			return dyn.InvalidValue, fmt.Errorf("failed to create cache dir: %w", err)
 		}
 
-		rightRoot, diags := m.runPythonMutator(ctx, cacheDir, b.BundleRootPath, pythonPath, leftRoot)
+		rightRoot, diags := m.runPythonMutator(ctx, leftRoot, runPythonMutatorOpts{
+			cacheDir:       cacheDir,
+			bundleRootPath: b.BundleRootPath,
+			pythonPath:     pythonPath,
+			loadLocations:  experimental.PyDABs.LoadLocations,
+		})
 		mutateDiags = diags
 		if diags.HasError() {
 			return dyn.InvalidValue, mutateDiagsHasError
@@ -152,13 +160,21 @@ func createCacheDir(ctx context.Context) (string, error) {
 	return os.MkdirTemp("", "-pydabs")
 }
 
-func (m *pythonMutator) runPythonMutator(ctx context.Context, cacheDir string, rootPath string, pythonPath string, root dyn.Value) (dyn.Value, diag.Diagnostics) {
-	inputPath := filepath.Join(cacheDir, "input.json")
-	outputPath := filepath.Join(cacheDir, "output.json")
-	diagnosticsPath := filepath.Join(cacheDir, "diagnostics.json")
+type runPythonMutatorOpts struct {
+	cacheDir       string
+	bundleRootPath string
+	pythonPath     string
+	loadLocations  bool
+}
+
+func (m *pythonMutator) runPythonMutator(ctx context.Context, root dyn.Value, opts runPythonMutatorOpts) (dyn.Value, diag.Diagnostics) {
+	inputPath := filepath.Join(opts.cacheDir, "input.json")
+	outputPath := filepath.Join(opts.cacheDir, "output.json")
+	diagnosticsPath := filepath.Join(opts.cacheDir, "diagnostics.json")
+	locationsPath := filepath.Join(opts.cacheDir, "locations.json")
 
 	args := []string{
-		pythonPath,
+		opts.pythonPath,
 		"-m",
 		"databricks.bundles.build",
 		"--phase",
@@ -171,6 +187,10 @@ func (m *pythonMutator) runPythonMutator(ctx context.Context, cacheDir string, r
 		diagnosticsPath,
 	}
 
+	if opts.loadLocations {
+		args = append(args, "--locations", locationsPath)
+	}
+
 	if err := writeInputFile(inputPath, root); err != nil {
 		return dyn.InvalidValue, diag.Errorf("failed to write input file: %s", err)
 	}
@@ -185,7 +205,7 @@ func (m *pythonMutator) runPythonMutator(ctx context.Context, cacheDir string, r
 	_, processErr := process.Background(
 		ctx,
 		args,
-		process.WithDir(rootPath),
+		process.WithDir(opts.bundleRootPath),
 		process.WithStderrWriter(stderrWriter),
 		process.WithStdoutWriter(stdoutWriter),
 	)
@@ -221,7 +241,12 @@ func (m *pythonMutator) runPythonMutator(ctx context.Context, cacheDir string, r
 		return dyn.InvalidValue, diag.Errorf("failed to load diagnostics: %s", pythonDiagnosticsErr)
 	}
 
-	output, outputDiags := loadOutputFile(rootPath, outputPath)
+	locations, err := loadLocationsFile(locationsPath)
+	if err != nil {
+		return dyn.InvalidValue, diag.Errorf("failed to load locations: %s", err)
+	}
+
+	output, outputDiags := loadOutputFile(opts.bundleRootPath, outputPath, locations)
 	pythonDiagnostics = pythonDiagnostics.Extend(outputDiags)
 
 	// we pass through pythonDiagnostic because it contains warnings
@@ -266,7 +291,21 @@ func writeInputFile(inputPath string, input dyn.Value) error {
 	return os.WriteFile(inputPath, rootConfigJson, 0600)
 }
 
-func loadOutputFile(rootPath string, outputPath string) (dyn.Value, diag.Diagnostics) {
+// loadLocationsFile loads locations.json containing source locations for generated YAML.
+func loadLocationsFile(locationsPath string) (*pythonLocations, error) {
+	locationsFile, err := os.Open(locationsPath)
+	if errors.Is(err, fs.ErrNotExist) {
+		return newPythonLocations(), nil
+	} else if err != nil {
+		return nil, fmt.Errorf("failed to open locations file: %w", err)
+	}
+
+	defer locationsFile.Close()
+
+	return parsePythonLocations(locationsFile)
+}
+
+func loadOutputFile(rootPath string, outputPath string, locations *pythonLocations) (dyn.Value, diag.Diagnostics) {
 	outputFile, err := os.Open(outputPath)
 	if err != nil {
 		return dyn.InvalidValue, diag.FromErr(fmt.Errorf("failed to open output file: %w", err))
@@ -277,12 +316,12 @@ func loadOutputFile(rootPath string, outputPath string) (dyn.Value, diag.Diagnos
 	// we need absolute path because later parts of pipeline assume all paths are absolute
 	// and this file will be used as location to resolve relative paths.
 	//
-	// virtualPath has to stay in rootPath, because locations outside root path are not allowed:
+	// virtualPath has to stay in bundleRootPath, because locations outside root path are not allowed:
 	//
 	//   Error: path /var/folders/.../pydabs/dist/*.whl is not contained in bundle root path
 	//
 	// for that, we pass virtualPath instead of outputPath as file location
-	virtualPath, err := filepath.Abs(filepath.Join(rootPath, "__generated_by_pydabs__.yml"))
+	virtualPath, err := filepath.Abs(filepath.Join(rootPath, generatedFileName))
 	if err != nil {
 		return dyn.InvalidValue, diag.FromErr(fmt.Errorf("failed to get absolute path: %w", err))
 	}
@@ -292,7 +331,25 @@ func loadOutputFile(rootPath string, outputPath string) (dyn.Value, diag.Diagnos
 		return dyn.InvalidValue, diag.FromErr(fmt.Errorf("failed to parse output file: %w", err))
 	}
 
-	return strictNormalize(config.Root{}, generated)
+	// paths are resolved relative to locations of their values, if we change location
+	// we have to update each path, until we simplify that, we don't update locations
+	// for such values, so we don't change how paths are resolved
+	_, err = paths.VisitJobPaths(generated, func(p dyn.Path, kind paths.PathKind, v dyn.Value) (dyn.Value, error) {
+		putPythonLocation(locations, p, v.Location())
+		return v, nil
+	})
+	if err != nil {
+		return dyn.InvalidValue, diag.FromErr(fmt.Errorf("failed to update locations: %w", err))
+	}
+
+	// generated has dyn.Location as if it comes from generated YAML file
+	// earlier we loaded locations.json with source locations in Python code
+	generatedWithLocations, err := mergePythonLocations(generated, locations)
+	if err != nil {
+		return dyn.InvalidValue, diag.FromErr(fmt.Errorf("failed to update locations: %w", err))
+	}
+
+	return strictNormalize(config.Root{}, generatedWithLocations)
 }
 
 func strictNormalize(dst any, generated dyn.Value) (dyn.Value, diag.Diagnostics) {

bundle/config/mutator/python/python_mutator_test.go

@@ -6,7 +6,6 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
-	"reflect"
 	"runtime"
 	"testing"
 
@@ -47,6 +46,7 @@ func TestPythonMutator_load(t *testing.T) {
         pydabs:
           enabled: true
           venv_path: .venv
+          load_locations: true
       resources:
         jobs:
           job0:
@@ -65,7 +65,8 @@ func TestPythonMutator_load(t *testing.T) {
 			"experimental": {
 				"pydabs": {
 					"enabled": true,
-					"venv_path": ".venv"
+					"venv_path": ".venv",
+					"load_locations": true
 				}
 			},
 			"resources": {
@@ -80,6 +81,8 @@ func TestPythonMutator_load(t *testing.T) {
 			}
 		}`,
 		`{"severity": "warning", "summary": "job doesn't have any tasks", "location": {"file": "src/examples/file.py", "line": 10, "column": 5}}`,
+		`{"path": "resources.jobs.job0", "file": "src/examples/job0.py", "line": 3, "column": 5}
+		{"path": "resources.jobs.job1", "file": "src/examples/job1.py", "line": 5, "column": 7}`,
 	)
 
 	mutator := PythonMutator(PythonMutatorPhaseLoad)
@@ -97,6 +100,25 @@ func TestPythonMutator_load(t *testing.T) {
 		assert.Equal(t, "job_1", job1.Name)
 	}
 
+	// output of locations.json should be applied to underlying dyn.Value
+	err := b.Config.Mutate(func(v dyn.Value) (dyn.Value, error) {
+		name1, err := dyn.GetByPath(v, dyn.MustPathFromString("resources.jobs.job1.name"))
+		if err != nil {
+			return dyn.InvalidValue, err
+		}
+
+		assert.Equal(t, []dyn.Location{
+			{
+				File:   "src/examples/job1.py",
+				Line:   5,
+				Column: 7,
+			},
+		}, name1.Locations())
+
+		return v, nil
+	})
+	assert.NoError(t, err)
+
 	assert.Equal(t, 1, len(diags))
 	assert.Equal(t, "job doesn't have any tasks", diags[0].Summary)
 	assert.Equal(t, []dyn.Location{
@@ -106,7 +128,6 @@ func TestPythonMutator_load(t *testing.T) {
 			Column: 5,
 		},
 	}, diags[0].Locations)
-
 }
 
 func TestPythonMutator_load_disallowed(t *testing.T) {
@@ -146,7 +167,7 @@ func TestPythonMutator_load_disallowed(t *testing.T) {
 					}
 				}
 			}
-		}`, "")
+		}`, "", "")
 
 	mutator := PythonMutator(PythonMutatorPhaseLoad)
 	diag := bundle.Apply(ctx, b, mutator)
@@ -191,7 +212,7 @@ func TestPythonMutator_init(t *testing.T) {
 					}
 				}
 			}
-		}`, "")
+		}`, "", "")
 
 	mutator := PythonMutator(PythonMutatorPhaseInit)
 	diag := bundle.Apply(ctx, b, mutator)
@@ -252,7 +273,7 @@ func TestPythonMutator_badOutput(t *testing.T) {
 					}
 				}
 			}
-		}`, "")
+		}`, "", "")
 
 	mutator := PythonMutator(PythonMutatorPhaseLoad)
 	diag := bundle.Apply(ctx, b, mutator)
@@ -588,7 +609,7 @@ or activate the environment before running CLI commands:
 	assert.Equal(t, expected, out)
 }
 
-func withProcessStub(t *testing.T, args []string, output string, diagnostics string) context.Context {
+func withProcessStub(t *testing.T, args []string, output string, diagnostics string, locations string) context.Context {
 	ctx := context.Background()
 	ctx, stub := process.WithStub(ctx)
 
@@ -600,32 +621,51 @@ func withProcessStub(t *testing.T, args []string, output string, diagnostics str
 
 	inputPath := filepath.Join(cacheDir, "input.json")
 	outputPath := filepath.Join(cacheDir, "output.json")
+	locationsPath := filepath.Join(cacheDir, "locations.json")
 	diagnosticsPath := filepath.Join(cacheDir, "diagnostics.json")
 
-	args = append(args, "--input", inputPath)
-	args = append(args, "--output", outputPath)
-	args = append(args, "--diagnostics", diagnosticsPath)
-
 	stub.WithCallback(func(actual *exec.Cmd) error {
 		_, err := os.Stat(inputPath)
 		assert.NoError(t, err)
 
-		if reflect.DeepEqual(actual.Args, args) {
-			err := os.WriteFile(outputPath, []byte(output), 0600)
+		actualInputPath := getArg(actual.Args, "--input")
+		actualOutputPath := getArg(actual.Args, "--output")
+		actualDiagnosticsPath := getArg(actual.Args, "--diagnostics")
+		actualLocationsPath := getArg(actual.Args, "--locations")
+
+		require.Equal(t, inputPath, actualInputPath)
+		require.Equal(t, outputPath, actualOutputPath)
+		require.Equal(t, diagnosticsPath, actualDiagnosticsPath)
+
+		// locations is an optional argument
+		if locations != "" {
+			require.Equal(t, locationsPath, actualLocationsPath)
+
+			err = os.WriteFile(locationsPath, []byte(locations), 0600)
+			require.NoError(t, err)
+		}
+
+		err = os.WriteFile(outputPath, []byte(output), 0600)
 		require.NoError(t, err)
 
 		err = os.WriteFile(diagnosticsPath, []byte(diagnostics), 0600)
 		require.NoError(t, err)
 
 		return nil
-		} else {
-			return fmt.Errorf("unexpected command: %v", actual.Args)
-		}
 	})
 
 	return ctx
 }
 
+func getArg(args []string, name string) string {
+	for i := 0; i < len(args); i++ {
+		if args[i] == name {
+			return args[i+1]
+		}
+	}
+	return ""
+}
+
 func loadYaml(name string, content string) *bundle.Bundle {
 	v, diag := config.LoadFromBytes(name, []byte(content))
 

cmd/bundle/init.go

@@ -3,6 +3,7 @@ package bundle
 import (
 	"errors"
 	"fmt"
+	"io/fs"
 	"os"
 	"path/filepath"
 	"slices"
@@ -109,6 +110,24 @@ func getUrlForNativeTemplate(name string) string {
 	return ""
 }
 
+func getFsForNativeTemplate(name string) (fs.FS, error) {
+	builtin, err := template.Builtin()
+	if err != nil {
+		return nil, err
+	}
+
+	// If this is a built-in template, the return value will be non-nil.
+	var templateFS fs.FS
+	for _, entry := range builtin {
+		if entry.Name == name {
+			templateFS = entry.FS
+			break
+		}
+	}
+
+	return templateFS, nil
+}
+
 func isRepoUrl(url string) bool {
 	result := false
 	for _, prefix := range gitUrlPrefixes {
@@ -198,9 +217,20 @@ See https://docs.databricks.com/en/dev-tools/bundles/templates.html for more inf
 			if templateDir != "" {
 				return errors.New("--template-dir can only be used with a Git repository URL")
 			}
+
+			templateFS, err := getFsForNativeTemplate(templatePath)
+			if err != nil {
+				return err
+			}
+
+			// If this is not a built-in template, then it must be a local file system path.
+			if templateFS == nil {
+				templateFS = os.DirFS(templatePath)
+			}
+
 			// skip downloading the repo because input arg is not a URL. We assume
 			// it's a path on the local file system in that case
-			return template.Materialize(ctx, configFile, templatePath, outputDir)
+			return template.Materialize(ctx, configFile, templateFS, outputDir)
 		}
 
 		// Create a temporary directory with the name of the repository.  The '*'
@@ -224,7 +254,8 @@ See https://docs.databricks.com/en/dev-tools/bundles/templates.html for more inf
 
 		// Clean up downloaded repository once the template is materialized.
 		defer os.RemoveAll(repoDir)
-		return template.Materialize(ctx, configFile, filepath.Join(repoDir, templateDir), outputDir)
+		templateFS := os.DirFS(filepath.Join(repoDir, templateDir))
+		return template.Materialize(ctx, configFile, templateFS, outputDir)
 	}
 	return cmd
 }

internal/bundle/helpers.go

@@ -42,7 +42,7 @@ func initTestTemplateWithBundleRoot(t *testing.T, ctx context.Context, templateN
 	cmd := cmdio.NewIO(flags.OutputJSON, strings.NewReader(""), os.Stdout, os.Stderr, "", "bundles")
 	ctx = cmdio.InContext(ctx, cmd)
 
-	err = template.Materialize(ctx, configFilePath, templateRoot, bundleRoot)
+	err = template.Materialize(ctx, configFilePath, os.DirFS(templateRoot), bundleRoot)
 	return bundleRoot, err
 }
 

libs/filer/filer.go

@@ -7,13 +7,24 @@ import (
 	"io/fs"
 )
 
+// WriteMode captures intent when writing a file.
+//
+// The first 9 bits are reserved for the [fs.FileMode] permission bits.
+// These are used only by the local filer implementation and have
+// no effect for the other implementations.
 type WriteMode int
 
+// writeModePerm is a mask to extract permission bits from a WriteMode.
+const writeModePerm = WriteMode(fs.ModePerm)
+
 const (
-	OverwriteIfExists WriteMode = 1 << iota
+	// Note: these constants are defined as powers of 2 to support combining them using a bit-wise OR.
+	// They starts from the 10th bit (permission mask + 1) to avoid conflicts with the permission bits.
+	OverwriteIfExists WriteMode = (writeModePerm + 1) << iota
 	CreateParentDirectories
 )
 
+// DeleteMode captures intent when deleting a file.
 type DeleteMode int
 
 const (

libs/filer/filer_test.go

@@ -0,0 +1,12 @@
+package filer
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestWriteMode(t *testing.T) {
+	assert.Equal(t, 512, int(OverwriteIfExists))
+	assert.Equal(t, 1024, int(CreateParentDirectories))
+}

libs/filer/local_client.go

@@ -28,6 +28,15 @@ func (w *LocalClient) Write(ctx context.Context, name string, reader io.Reader,
 		return err
 	}
 
+	// Retrieve permission mask from the [WriteMode], if present.
+	perm := fs.FileMode(0644)
+	for _, m := range mode {
+		bits := m & writeModePerm
+		if bits != 0 {
+			perm = fs.FileMode(bits)
+		}
+	}
+
 	flags := os.O_WRONLY | os.O_CREATE
 	if slices.Contains(mode, OverwriteIfExists) {
 		flags |= os.O_TRUNC
@@ -35,7 +44,7 @@ func (w *LocalClient) Write(ctx context.Context, name string, reader io.Reader,
 		flags |= os.O_EXCL
 	}
 
-	f, err := os.OpenFile(absPath, flags, 0644)
+	f, err := os.OpenFile(absPath, flags, perm)
 	if errors.Is(err, fs.ErrNotExist) && slices.Contains(mode, CreateParentDirectories) {
 		// Create parent directories if they don't exist.
 		err = os.MkdirAll(filepath.Dir(absPath), 0755)
@@ -43,7 +52,7 @@ func (w *LocalClient) Write(ctx context.Context, name string, reader io.Reader,
 			return err
 		}
 		// Try again.
-		f, err = os.OpenFile(absPath, flags, 0644)
+		f, err = os.OpenFile(absPath, flags, perm)
 	}
 
 	if err != nil {

libs/jsonschema/schema.go

@@ -3,7 +3,9 @@ package jsonschema
 import (
 	"encoding/json"
 	"fmt"
+	"io/fs"
 	"os"
+	"path/filepath"
 	"regexp"
 	"slices"
 
@@ -255,7 +257,12 @@ func (schema *Schema) validate() error {
 }
 
 func Load(path string) (*Schema, error) {
-	b, err := os.ReadFile(path)
+	dir, file := filepath.Split(path)
+	return LoadFS(os.DirFS(dir), file)
+}
+
+func LoadFS(fsys fs.FS, path string) (*Schema, error) {
+	b, err := fs.ReadFile(fsys, path)
 	if err != nil {
 		return nil, err
 	}

libs/jsonschema/schema_test.go

@@ -1,6 +1,7 @@
 package jsonschema
 
 import (
+	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -305,3 +306,9 @@ func TestValidateSchemaSkippedPropertiesHaveDefaults(t *testing.T) {
 	err = s.validate()
 	assert.NoError(t, err)
 }
+
+func TestSchema_LoadFS(t *testing.T) {
+	fsys := os.DirFS("./testdata/schema-load-int")
+	_, err := LoadFS(fsys, "schema-valid.json")
+	assert.NoError(t, err)
+}

libs/template/builtin.go

@@ -0,0 +1,47 @@
+package template
+
+import (
+	"embed"
+	"io/fs"
+)
+
+//go:embed all:templates
+var builtinTemplates embed.FS
+
+// BuiltinTemplate represents a template that is built into the CLI.
+type BuiltinTemplate struct {
+	Name string
+	FS   fs.FS
+}
+
+// Builtin returns the list of all built-in templates.
+func Builtin() ([]BuiltinTemplate, error) {
+	templates, err := fs.Sub(builtinTemplates, "templates")
+	if err != nil {
+		return nil, err
+	}
+
+	entries, err := fs.ReadDir(templates, ".")
+	if err != nil {
+		return nil, err
+	}
+
+	var out []BuiltinTemplate
+	for _, entry := range entries {
+		if !entry.IsDir() {
+			continue
+		}
+
+		templateFS, err := fs.Sub(templates, entry.Name())
+		if err != nil {
+			return nil, err
+		}
+
+		out = append(out, BuiltinTemplate{
+			Name: entry.Name(),
+			FS:   templateFS,
+		})
+	}
+
+	return out, nil
+}

libs/template/builtin_test.go

@@ -0,0 +1,28 @@
+package template
+
+import (
+	"io/fs"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestBuiltin(t *testing.T) {
+	out, err := Builtin()
+	require.NoError(t, err)
+	assert.Len(t, out, 3)
+
+	// Confirm names.
+	assert.Equal(t, "dbt-sql", out[0].Name)
+	assert.Equal(t, "default-python", out[1].Name)
+	assert.Equal(t, "default-sql", out[2].Name)
+
+	// Confirm that the filesystems work.
+	_, err = fs.Stat(out[0].FS, `template/{{.project_name}}/dbt_project.yml.tmpl`)
+	assert.NoError(t, err)
+	_, err = fs.Stat(out[1].FS, `template/{{.project_name}}/tests/main_test.py.tmpl`)
+	assert.NoError(t, err)
+	_, err = fs.Stat(out[2].FS, `template/{{.project_name}}/src/orders_daily.sql.tmpl`)
+	assert.NoError(t, err)
+}

libs/template/config.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"io/fs"
 
 	"github.com/databricks/cli/libs/cmdio"
 	"github.com/databricks/cli/libs/jsonschema"
@@ -28,9 +29,8 @@ type config struct {
 	schema *jsonschema.Schema
 }
 
-func newConfig(ctx context.Context, schemaPath string) (*config, error) {
-	// Read config schema
-	schema, err := jsonschema.Load(schemaPath)
+func newConfig(ctx context.Context, templateFS fs.FS, schemaPath string) (*config, error) {
+	schema, err := jsonschema.LoadFS(templateFS, schemaPath)
 	if err != nil {
 		return nil, err
 	}

libs/template/config_test.go

@@ -3,6 +3,8 @@ package template
 import (
 	"context"
 	"fmt"
+	"os"
+	"path"
 	"path/filepath"
 	"testing"
 	"text/template"
@@ -16,7 +18,7 @@ func TestTemplateConfigAssignValuesFromFile(t *testing.T) {
 	testDir := "./testdata/config-assign-from-file"
 
 	ctx := context.Background()
-	c, err := newConfig(ctx, filepath.Join(testDir, "schema.json"))
+	c, err := newConfig(ctx, os.DirFS(testDir), "schema.json")
 	require.NoError(t, err)
 
 	err = c.assignValuesFromFile(filepath.Join(testDir, "config.json"))
@@ -32,7 +34,7 @@ func TestTemplateConfigAssignValuesFromFileDoesNotOverwriteExistingConfigs(t *te
 	testDir := "./testdata/config-assign-from-file"
 
 	ctx := context.Background()
-	c, err := newConfig(ctx, filepath.Join(testDir, "schema.json"))
+	c, err := newConfig(ctx, os.DirFS(testDir), "schema.json")
 	require.NoError(t, err)
 
 	c.values = map[string]any{
@@ -52,7 +54,7 @@ func TestTemplateConfigAssignValuesFromFileForInvalidIntegerValue(t *testing.T)
 	testDir := "./testdata/config-assign-from-file-invalid-int"
 
 	ctx := context.Background()
-	c, err := newConfig(ctx, filepath.Join(testDir, "schema.json"))
+	c, err := newConfig(ctx, os.DirFS(testDir), "schema.json")
 	require.NoError(t, err)
 
 	err = c.assignValuesFromFile(filepath.Join(testDir, "config.json"))
@@ -63,7 +65,7 @@ func TestTemplateConfigAssignValuesFromFileFiltersPropertiesNotInTheSchema(t *te
 	testDir := "./testdata/config-assign-from-file-unknown-property"
 
 	ctx := context.Background()
-	c, err := newConfig(ctx, filepath.Join(testDir, "schema.json"))
+	c, err := newConfig(ctx, os.DirFS(testDir), "schema.json")
 	require.NoError(t, err)
 
 	err = c.assignValuesFromFile(filepath.Join(testDir, "config.json"))
@@ -78,10 +80,10 @@ func TestTemplateConfigAssignValuesFromDefaultValues(t *testing.T) {
 	testDir := "./testdata/config-assign-from-default-value"
 
 	ctx := context.Background()
-	c, err := newConfig(ctx, filepath.Join(testDir, "schema.json"))
+	c, err := newConfig(ctx, os.DirFS(testDir), "schema.json")
 	require.NoError(t, err)
 
-	r, err := newRenderer(ctx, nil, nil, "./testdata/empty/template", "./testdata/empty/library", t.TempDir())
+	r, err := newRenderer(ctx, nil, nil, os.DirFS("."), "./testdata/empty/template", "./testdata/empty/library")
 	require.NoError(t, err)
 
 	err = c.assignDefaultValues(r)
@@ -97,10 +99,10 @@ func TestTemplateConfigAssignValuesFromTemplatedDefaultValues(t *testing.T) {
 	testDir := "./testdata/config-assign-from-templated-default-value"
 
 	ctx := context.Background()
-	c, err := newConfig(ctx, filepath.Join(testDir, "schema.json"))
+	c, err := newConfig(ctx, os.DirFS(testDir), "schema.json")
 	require.NoError(t, err)
 
-	r, err := newRenderer(ctx, nil, nil, filepath.Join(testDir, "template/template"), filepath.Join(testDir, "template/library"), t.TempDir())
+	r, err := newRenderer(ctx, nil, nil, os.DirFS("."), path.Join(testDir, "template/template"), path.Join(testDir, "template/library"))
 	require.NoError(t, err)
 
 	// Note: only the string value is templated.
@@ -116,7 +118,7 @@ func TestTemplateConfigAssignValuesFromTemplatedDefaultValues(t *testing.T) {
 
 func TestTemplateConfigValidateValuesDefined(t *testing.T) {
 	ctx := context.Background()
-	c, err := newConfig(ctx, "testdata/config-test-schema/test-schema.json")
+	c, err := newConfig(ctx, os.DirFS("testdata/config-test-schema"), "test-schema.json")
 	require.NoError(t, err)
 
 	c.values = map[string]any{
@@ -131,7 +133,7 @@ func TestTemplateConfigValidateValuesDefined(t *testing.T) {
 
 func TestTemplateConfigValidateTypeForValidConfig(t *testing.T) {
 	ctx := context.Background()
-	c, err := newConfig(ctx, "testdata/config-test-schema/test-schema.json")
+	c, err := newConfig(ctx, os.DirFS("testdata/config-test-schema"), "test-schema.json")
 	require.NoError(t, err)
 
 	c.values = map[string]any{
@@ -147,7 +149,7 @@ func TestTemplateConfigValidateTypeForValidConfig(t *testing.T) {
 
 func TestTemplateConfigValidateTypeForUnknownField(t *testing.T) {
 	ctx := context.Background()
-	c, err := newConfig(ctx, "testdata/config-test-schema/test-schema.json")
+	c, err := newConfig(ctx, os.DirFS("testdata/config-test-schema"), "test-schema.json")
 	require.NoError(t, err)
 
 	c.values = map[string]any{
@@ -164,7 +166,7 @@ func TestTemplateConfigValidateTypeForUnknownField(t *testing.T) {
 
 func TestTemplateConfigValidateTypeForInvalidType(t *testing.T) {
 	ctx := context.Background()
-	c, err := newConfig(ctx, "testdata/config-test-schema/test-schema.json")
+	c, err := newConfig(ctx, os.DirFS("testdata/config-test-schema"), "test-schema.json")
 	require.NoError(t, err)
 
 	c.values = map[string]any{
@@ -271,7 +273,8 @@ func TestTemplateEnumValidation(t *testing.T) {
 }
 
 func TestTemplateSchemaErrorsWithEmptyDescription(t *testing.T) {
-	_, err := newConfig(context.Background(), "./testdata/config-test-schema/invalid-test-schema.json")
+	ctx := context.Background()
+	_, err := newConfig(ctx, os.DirFS("./testdata/config-test-schema"), "invalid-test-schema.json")
 	assert.EqualError(t, err, "template property property-without-description is missing a description")
 }
 

libs/template/file.go

@@ -1,11 +1,10 @@
 package template
 
 import (
+	"bytes"
 	"context"
-	"io"
 	"io/fs"
-	"os"
-	"path/filepath"
+	"slices"
 
 	"github.com/databricks/cli/libs/filer"
 )
@@ -13,89 +12,69 @@ import (
 // Interface representing a file to be materialized from a template into a project
 // instance
 type file interface {
-	// Destination path for file. This is where the file will be created when
-	// PersistToDisk is called.
-	DstPath() *destinationPath
+	// Path of the file relative to the root of the instantiated template.
+	// This is where the file is written to when persisting the template to disk.
+	// Must be slash-separated.
+	RelPath() string
 
 	// Write file to disk at the destination path.
-	PersistToDisk() error
-}
+	Write(ctx context.Context, out filer.Filer) error
 
-type destinationPath struct {
-	// Root path for the project instance. This path uses the system's default
-	// file separator. For example /foo/bar on Unix and C:\foo\bar on windows
-	root string
-
-	// Unix like file path relative to the "root" of the instantiated project. Is used to
-	// evaluate whether the file should be skipped by comparing it to a list of
-	// skip glob patterns.
-	relPath string
-}
-
-// Absolute path of the file, in the os native format. For example /foo/bar on
-// Unix and C:\foo\bar on windows
-func (f *destinationPath) absPath() string {
-	return filepath.Join(f.root, filepath.FromSlash(f.relPath))
+	// contents returns the file contents as a byte slice.
+	// This is used for testing purposes.
+	contents() ([]byte, error)
 }
 
 type copyFile struct {
-	ctx context.Context
-
 	// Permissions bits for the destination file
 	perm fs.FileMode
 
-	dstPath *destinationPath
+	// Destination path for the file.
+	relPath string
 
-	// Filer rooted at template root. Used to read srcPath.
-	srcFiler filer.Filer
+	// [fs.FS] rooted at template root. Used to read srcPath.
+	srcFS fs.FS
 
 	// Relative path from template root for file to be copied.
 	srcPath string
 }
 
-func (f *copyFile) DstPath() *destinationPath {
-	return f.dstPath
+func (f *copyFile) RelPath() string {
+	return f.relPath
 }
 
-func (f *copyFile) PersistToDisk() error {
-	path := f.DstPath().absPath()
-	err := os.MkdirAll(filepath.Dir(path), 0755)
+func (f *copyFile) Write(ctx context.Context, out filer.Filer) error {
+	src, err := f.srcFS.Open(f.srcPath)
 	if err != nil {
 		return err
 	}
-	srcFile, err := f.srcFiler.Read(f.ctx, f.srcPath)
-	if err != nil {
-		return err
+	defer src.Close()
+	return out.Write(ctx, f.relPath, src, filer.CreateParentDirectories, filer.WriteMode(f.perm))
 }
-	defer srcFile.Close()
-	dstFile, err := os.OpenFile(path, os.O_CREATE|os.O_EXCL|os.O_WRONLY, f.perm)
-	if err != nil {
-		return err
-	}
-	defer dstFile.Close()
-	_, err = io.Copy(dstFile, srcFile)
-	return err
+
+func (f *copyFile) contents() ([]byte, error) {
+	return fs.ReadFile(f.srcFS, f.srcPath)
 }
 
 type inMemoryFile struct {
-	dstPath *destinationPath
-
-	content []byte
-
 	// Permissions bits for the destination file
 	perm fs.FileMode
+
+	// Destination path for the file.
+	relPath string
+
+	// Contents of the file.
+	content []byte
 }
 
-func (f *inMemoryFile) DstPath() *destinationPath {
-	return f.dstPath
+func (f *inMemoryFile) RelPath() string {
+	return f.relPath
 }
 
-func (f *inMemoryFile) PersistToDisk() error {
-	path := f.DstPath().absPath()
+func (f *inMemoryFile) Write(ctx context.Context, out filer.Filer) error {
+	return out.Write(ctx, f.relPath, bytes.NewReader(f.content), filer.CreateParentDirectories, filer.WriteMode(f.perm))
+}
 
-	err := os.MkdirAll(filepath.Dir(path), 0755)
-	if err != nil {
-		return err
-	}
-	return os.WriteFile(path, f.content, f.perm)
+func (f *inMemoryFile) contents() ([]byte, error) {
+	return slices.Clone(f.content), nil
 }

libs/template/file_test.go

@@ -13,76 +13,51 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func testInMemoryFile(t *testing.T, perm fs.FileMode) {
+func testInMemoryFile(t *testing.T, ctx context.Context, perm fs.FileMode) {
 	tmpDir := t.TempDir()
 
 	f := &inMemoryFile{
-		dstPath: &destinationPath{
-			root:    tmpDir,
-			relPath: "a/b/c",
-		},
 		perm:    perm,
+		relPath: "a/b/c",
 		content: []byte("123"),
 	}
-	err := f.PersistToDisk()
+
+	out, err := filer.NewLocalClient(tmpDir)
+	require.NoError(t, err)
+	err = f.Write(ctx, out)
 	assert.NoError(t, err)
 
 	assertFileContent(t, filepath.Join(tmpDir, "a/b/c"), "123")
 	assertFilePermissions(t, filepath.Join(tmpDir, "a/b/c"), perm)
 }
 
-func testCopyFile(t *testing.T, perm fs.FileMode) {
+func testCopyFile(t *testing.T, ctx context.Context, perm fs.FileMode) {
 	tmpDir := t.TempDir()
-
-	templateFiler, err := filer.NewLocalClient(tmpDir)
-	require.NoError(t, err)
-	err = os.WriteFile(filepath.Join(tmpDir, "source"), []byte("qwerty"), perm)
+	err := os.WriteFile(filepath.Join(tmpDir, "source"), []byte("qwerty"), perm)
 	require.NoError(t, err)
 
 	f := &copyFile{
-		ctx: context.Background(),
-		dstPath: &destinationPath{
-			root:    tmpDir,
-			relPath: "a/b/c",
-		},
 		perm:    perm,
+		relPath: "a/b/c",
+		srcFS:   os.DirFS(tmpDir),
 		srcPath: "source",
-		srcFiler: templateFiler,
 	}
-	err = f.PersistToDisk()
+
+	out, err := filer.NewLocalClient(tmpDir)
+	require.NoError(t, err)
+	err = f.Write(ctx, out)
 	assert.NoError(t, err)
 
 	assertFileContent(t, filepath.Join(tmpDir, "a/b/c"), "qwerty")
 	assertFilePermissions(t, filepath.Join(tmpDir, "a/b/c"), perm)
 }
 
-func TestTemplateFileDestinationPath(t *testing.T) {
-	if runtime.GOOS == "windows" {
-		t.SkipNow()
-	}
-	f := &destinationPath{
-		root:    `a/b/c`,
-		relPath: "d/e",
-	}
-	assert.Equal(t, `a/b/c/d/e`, f.absPath())
-}
-
-func TestTemplateFileDestinationPathForWindows(t *testing.T) {
-	if runtime.GOOS != "windows" {
-		t.SkipNow()
-	}
-	f := &destinationPath{
-		root:    `c:\a\b\c`,
-		relPath: "d/e",
-	}
-	assert.Equal(t, `c:\a\b\c\d\e`, f.absPath())
-}
-
 func TestTemplateInMemoryFilePersistToDisk(t *testing.T) {
 	if runtime.GOOS == "windows" {
 		t.SkipNow()
 	}
-	testInMemoryFile(t, 0755)
+	ctx := context.Background()
+	testInMemoryFile(t, ctx, 0755)
 }
 
 func TestTemplateInMemoryFilePersistToDiskForWindows(t *testing.T) {
@@ -91,14 +66,16 @@ func TestTemplateInMemoryFilePersistToDiskForWindows(t *testing.T) {
 	}
 	// we have separate tests for windows because of differences in valid
 	// fs.FileMode values we can use for different operating systems.
-	testInMemoryFile(t, 0666)
+	ctx := context.Background()
+	testInMemoryFile(t, ctx, 0666)
 }
 
 func TestTemplateCopyFilePersistToDisk(t *testing.T) {
 	if runtime.GOOS == "windows" {
 		t.SkipNow()
 	}
-	testCopyFile(t, 0644)
+	ctx := context.Background()
+	testCopyFile(t, ctx, 0644)
 }
 
 func TestTemplateCopyFilePersistToDiskForWindows(t *testing.T) {
@@ -107,5 +84,6 @@ func TestTemplateCopyFilePersistToDiskForWindows(t *testing.T) {
 	}
 	// we have separate tests for windows because of differences in valid
 	// fs.FileMode values we can use for different operating systems.
-	testCopyFile(t, 0666)
+	ctx := context.Background()
+	testCopyFile(t, ctx, 0666)
 }

libs/template/helpers_test.go

@@ -18,11 +18,10 @@ import (
 
 func TestTemplatePrintStringWithoutProcessing(t *testing.T) {
 	ctx := context.Background()
-	tmpDir := t.TempDir()
 
 	ctx = root.SetWorkspaceClient(ctx, nil)
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/print-without-processing/template", "./testdata/print-without-processing/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/print-without-processing/template", "./testdata/print-without-processing/library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -35,11 +34,10 @@ func TestTemplatePrintStringWithoutProcessing(t *testing.T) {
 
 func TestTemplateRegexpCompileFunction(t *testing.T) {
 	ctx := context.Background()
-	tmpDir := t.TempDir()
 
 	ctx = root.SetWorkspaceClient(ctx, nil)
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/regexp-compile/template", "./testdata/regexp-compile/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/regexp-compile/template", "./testdata/regexp-compile/library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -53,11 +51,10 @@ func TestTemplateRegexpCompileFunction(t *testing.T) {
 
 func TestTemplateRandIntFunction(t *testing.T) {
 	ctx := context.Background()
-	tmpDir := t.TempDir()
 
 	ctx = root.SetWorkspaceClient(ctx, nil)
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/random-int/template", "./testdata/random-int/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/random-int/template", "./testdata/random-int/library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -71,11 +68,10 @@ func TestTemplateRandIntFunction(t *testing.T) {
 
 func TestTemplateUuidFunction(t *testing.T) {
 	ctx := context.Background()
-	tmpDir := t.TempDir()
 
 	ctx = root.SetWorkspaceClient(ctx, nil)
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/uuid/template", "./testdata/uuid/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/uuid/template", "./testdata/uuid/library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -88,11 +84,10 @@ func TestTemplateUuidFunction(t *testing.T) {
 
 func TestTemplateUrlFunction(t *testing.T) {
 	ctx := context.Background()
-	tmpDir := t.TempDir()
 
 	ctx = root.SetWorkspaceClient(ctx, nil)
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/urlparse-function/template", "./testdata/urlparse-function/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/urlparse-function/template", "./testdata/urlparse-function/library")
 
 	require.NoError(t, err)
 
@@ -105,11 +100,10 @@ func TestTemplateUrlFunction(t *testing.T) {
 
 func TestTemplateMapPairFunction(t *testing.T) {
 	ctx := context.Background()
-	tmpDir := t.TempDir()
 
 	ctx = root.SetWorkspaceClient(ctx, nil)
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/map-pair/template", "./testdata/map-pair/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/map-pair/template", "./testdata/map-pair/library")
 
 	require.NoError(t, err)
 
@@ -122,7 +116,6 @@ func TestTemplateMapPairFunction(t *testing.T) {
 
 func TestWorkspaceHost(t *testing.T) {
 	ctx := context.Background()
-	tmpDir := t.TempDir()
 
 	w := &databricks.WorkspaceClient{
 		Config: &workspaceConfig.Config{
@@ -132,7 +125,7 @@ func TestWorkspaceHost(t *testing.T) {
 	ctx = root.SetWorkspaceClient(ctx, w)
 
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/workspace-host/template", "./testdata/map-pair/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/workspace-host/template", "./testdata/map-pair/library")
 
 	require.NoError(t, err)
 
@@ -149,7 +142,6 @@ func TestWorkspaceHostNotConfigured(t *testing.T) {
 	ctx := context.Background()
 	cmd := cmdio.NewIO(flags.OutputJSON, strings.NewReader(""), os.Stdout, os.Stderr, "", "template")
 	ctx = cmdio.InContext(ctx, cmd)
-	tmpDir := t.TempDir()
 
 	w := &databricks.WorkspaceClient{
 		Config: &workspaceConfig.Config{},
@@ -157,7 +149,7 @@ func TestWorkspaceHostNotConfigured(t *testing.T) {
 	ctx = root.SetWorkspaceClient(ctx, w)
 
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/workspace-host/template", "./testdata/map-pair/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/workspace-host/template", "./testdata/map-pair/library")
 
 	assert.NoError(t, err)
 

libs/template/materialize.go

@@ -2,54 +2,32 @@ package template
 
 import (
 	"context"
-	"embed"
 	"errors"
 	"fmt"
 	"io/fs"
-	"os"
-	"path"
-	"path/filepath"
 
 	"github.com/databricks/cli/libs/cmdio"
+	"github.com/databricks/cli/libs/filer"
 )
 
 const libraryDirName = "library"
 const templateDirName = "template"
 const schemaFileName = "databricks_template_schema.json"
 
-//go:embed all:templates
-var builtinTemplates embed.FS
-
 // This function materializes the input templates as a project, using user defined
 // configurations.
 // Parameters:
 //
 //	ctx: 			context containing a cmdio object. This is used to prompt the user
 //	configFilePath: file path containing user defined config values
-//	templateRoot: 	root of the template definition
+//	templateFS: 	root of the template definition
 //	outputDir: 	root of directory where to initialize the template
-func Materialize(ctx context.Context, configFilePath, templateRoot, outputDir string) error {
-	// Use a temporary directory in case any builtin templates like default-python are used
-	tempDir, err := os.MkdirTemp("", "templates")
-	defer os.RemoveAll(tempDir)
-	if err != nil {
-		return err
-	}
-	templateRoot, err = prepareBuiltinTemplates(templateRoot, tempDir)
-	if err != nil {
-		return err
+func Materialize(ctx context.Context, configFilePath string, templateFS fs.FS, outputDir string) error {
+	if _, err := fs.Stat(templateFS, schemaFileName); errors.Is(err, fs.ErrNotExist) {
+		return fmt.Errorf("not a bundle template: expected to find a template schema file at %s", schemaFileName)
 	}
 
-	templatePath := filepath.Join(templateRoot, templateDirName)
-	libraryPath := filepath.Join(templateRoot, libraryDirName)
-	schemaPath := filepath.Join(templateRoot, schemaFileName)
-	helpers := loadHelpers(ctx)
-
-	if _, err := os.Stat(schemaPath); errors.Is(err, fs.ErrNotExist) {
-		return fmt.Errorf("not a bundle template: expected to find a template schema file at %s", schemaPath)
-	}
-
-	config, err := newConfig(ctx, schemaPath)
+	config, err := newConfig(ctx, templateFS, schemaFileName)
 	if err != nil {
 		return err
 	}
@@ -62,7 +40,8 @@ func Materialize(ctx context.Context, configFilePath, templateRoot, outputDir st
 		}
 	}
 
-	r, err := newRenderer(ctx, config.values, helpers, templatePath, libraryPath, outputDir)
+	helpers := loadHelpers(ctx)
+	r, err := newRenderer(ctx, config.values, helpers, templateFS, templateDirName, libraryDirName)
 	if err != nil {
 		return err
 	}
@@ -94,7 +73,12 @@ func Materialize(ctx context.Context, configFilePath, templateRoot, outputDir st
 		return err
 	}
 
-	err = r.persistToDisk()
+	out, err := filer.NewLocalClient(outputDir)
+	if err != nil {
+		return err
+	}
+
+	err = r.persistToDisk(ctx, out)
 	if err != nil {
 		return err
 	}
@@ -111,44 +95,3 @@ func Materialize(ctx context.Context, configFilePath, templateRoot, outputDir st
 	}
 	return nil
 }
-
-// If the given templateRoot matches
-func prepareBuiltinTemplates(templateRoot string, tempDir string) (string, error) {
-	// Check that `templateRoot` is a clean basename, i.e. `some_path` and not `./some_path` or "."
-	// Return early if that's not the case.
-	if templateRoot == "." || path.Base(templateRoot) != templateRoot {
-		return templateRoot, nil
-	}
-
-	_, err := fs.Stat(builtinTemplates, path.Join("templates", templateRoot))
-	if err != nil {
-		// The given path doesn't appear to be using out built-in templates
-		return templateRoot, nil
-	}
-
-	// We have a built-in template with the same name as templateRoot!
-	// Now we need to make a fully copy of the builtin templates to a real file system
-	// since template.Parse() doesn't support embed.FS.
-	err = fs.WalkDir(builtinTemplates, "templates", func(path string, entry fs.DirEntry, err error) error {
-		if err != nil {
-			return err
-		}
-
-		targetPath := filepath.Join(tempDir, path)
-		if entry.IsDir() {
-			return os.Mkdir(targetPath, 0755)
-		} else {
-			content, err := fs.ReadFile(builtinTemplates, path)
-			if err != nil {
-				return err
-			}
-			return os.WriteFile(targetPath, content, 0644)
-		}
-	})
-
-	if err != nil {
-		return "", err
-	}
-
-	return filepath.Join(tempDir, "templates", templateRoot), nil
-}

libs/template/materialize_test.go

@@ -3,7 +3,7 @@ package template
 import (
 	"context"
 	"fmt"
-	"path/filepath"
+	"os"
 	"testing"
 
 	"github.com/databricks/cli/cmd/root"
@@ -19,6 +19,6 @@ func TestMaterializeForNonTemplateDirectory(t *testing.T) {
 	ctx := root.SetWorkspaceClient(context.Background(), w)
 
 	// Try to materialize a non-template directory.
-	err = Materialize(ctx, "", tmpDir, "")
-	assert.EqualError(t, err, fmt.Sprintf("not a bundle template: expected to find a template schema file at %s", filepath.Join(tmpDir, schemaFileName)))
+	err = Materialize(ctx, "", os.DirFS(tmpDir), "")
+	assert.EqualError(t, err, fmt.Sprintf("not a bundle template: expected to find a template schema file at %s", schemaFileName))
 }

libs/template/renderer.go

@@ -6,9 +6,7 @@ import (
 	"fmt"
 	"io"
 	"io/fs"
-	"os"
 	"path"
-	"path/filepath"
 	"regexp"
 	"slices"
 	"sort"
@@ -52,32 +50,38 @@ type renderer struct {
 	// do not match any glob patterns from this list
 	skipPatterns []string
 
-	// Filer rooted at template root. The file tree from this root is walked to
-	// generate the project
-	templateFiler filer.Filer
-
-	// Root directory for the project instantiated from the template
-	instanceRoot string
+	// [fs.FS] that holds the template's file tree.
+	srcFS fs.FS
 }
 
-func newRenderer(ctx context.Context, config map[string]any, helpers template.FuncMap, templateRoot, libraryRoot, instanceRoot string) (*renderer, error) {
+func newRenderer(
+	ctx context.Context,
+	config map[string]any,
+	helpers template.FuncMap,
+	templateFS fs.FS,
+	templateDir string,
+	libraryDir string,
+) (*renderer, error) {
 	// Initialize new template, with helper functions loaded
 	tmpl := template.New("").Funcs(helpers)
 
-	// Load user defined associated templates from the library root
-	libraryGlob := filepath.Join(libraryRoot, "*")
-	matches, err := filepath.Glob(libraryGlob)
+	// Find user-defined templates in the library directory
+	matches, err := fs.Glob(templateFS, path.Join(libraryDir, "*"))
 	if err != nil {
 		return nil, err
 	}
+
+	// Parse user-defined templates.
+	// Note: we do not call [ParseFS] with the glob directly because
+	// it returns an error if no files match the pattern.
 	if len(matches) != 0 {
-		tmpl, err = tmpl.ParseFiles(matches...)
+		tmpl, err = tmpl.ParseFS(templateFS, matches...)
 		if err != nil {
 			return nil, err
 		}
 	}
 
-	templateFiler, err := filer.NewLocalClient(templateRoot)
+	srcFS, err := fs.Sub(templateFS, path.Clean(templateDir))
 	if err != nil {
 		return nil, err
 	}
@@ -90,8 +94,7 @@ func newRenderer(ctx context.Context, config map[string]any, helpers template.Fu
 		baseTemplate: tmpl,
 		files:        make([]file, 0),
 		skipPatterns: make([]string, 0),
-		templateFiler: templateFiler,
-		instanceRoot:  instanceRoot,
+		srcFS:        srcFS,
 	}, nil
 }
 
@@ -141,7 +144,7 @@ func (r *renderer) executeTemplate(templateDefinition string) (string, error) {
 
 func (r *renderer) computeFile(relPathTemplate string) (file, error) {
 	// read file permissions
-	info, err := r.templateFiler.Stat(r.ctx, relPathTemplate)
+	info, err := fs.Stat(r.srcFS, relPathTemplate)
 	if err != nil {
 		return nil, err
 	}
@@ -157,14 +160,10 @@ func (r *renderer) computeFile(relPathTemplate string) (file, error) {
 	// over as is, without treating it as a template
 	if !strings.HasSuffix(relPathTemplate, templateExtension) {
 		return &copyFile{
-			dstPath: &destinationPath{
-				root:    r.instanceRoot,
-				relPath: relPath,
-			},
 			perm:    perm,
-			ctx:      r.ctx,
+			relPath: relPath,
+			srcFS:   r.srcFS,
 			srcPath: relPathTemplate,
-			srcFiler: r.templateFiler,
 		}, nil
 	} else {
 		// Trim the .tmpl suffix from file name, if specified in the template
@@ -173,7 +172,7 @@ func (r *renderer) computeFile(relPathTemplate string) (file, error) {
 	}
 
 	// read template file's content
-	templateReader, err := r.templateFiler.Read(r.ctx, relPathTemplate)
+	templateReader, err := r.srcFS.Open(relPathTemplate)
 	if err != nil {
 		return nil, err
 	}
@@ -194,11 +193,8 @@ func (r *renderer) computeFile(relPathTemplate string) (file, error) {
 	}
 
 	return &inMemoryFile{
-		dstPath: &destinationPath{
-			root:    r.instanceRoot,
-			relPath: relPath,
-		},
 		perm:    perm,
+		relPath: relPath,
 		content: []byte(content),
 	}, nil
 }
@@ -263,7 +259,7 @@ func (r *renderer) walk() error {
 		//
 		// 2. For directories: They are appended to a slice, which acts as a queue
 		//     allowing BFS traversal of the template file tree
-		entries, err := r.templateFiler.ReadDir(r.ctx, currentDirectory)
+		entries, err := fs.ReadDir(r.srcFS, currentDirectory)
 		if err != nil {
 			return err
 		}
@@ -283,7 +279,7 @@ func (r *renderer) walk() error {
 			if err != nil {
 				return err
 			}
-			logger.Infof(r.ctx, "added file to list of possible project files: %s", f.DstPath().relPath)
+			logger.Infof(r.ctx, "added file to list of possible project files: %s", f.RelPath())
 			r.files = append(r.files, f)
 		}
 
@@ -291,17 +287,17 @@ func (r *renderer) walk() error {
 	return nil
 }
 
-func (r *renderer) persistToDisk() error {
+func (r *renderer) persistToDisk(ctx context.Context, out filer.Filer) error {
 	// Accumulate files which we will persist, skipping files whose path matches
 	// any of the skip patterns
 	filesToPersist := make([]file, 0)
 	for _, file := range r.files {
-		match, err := isSkipped(file.DstPath().relPath, r.skipPatterns)
+		match, err := isSkipped(file.RelPath(), r.skipPatterns)
 		if err != nil {
 			return err
 		}
 		if match {
-			log.Infof(r.ctx, "skipping file: %s", file.DstPath())
+			log.Infof(r.ctx, "skipping file: %s", file.RelPath())
 			continue
 		}
 		filesToPersist = append(filesToPersist, file)
@@ -309,8 +305,8 @@ func (r *renderer) persistToDisk() error {
 
 	// Assert no conflicting files exist
 	for _, file := range filesToPersist {
-		path := file.DstPath().absPath()
-		_, err := os.Stat(path)
+		path := file.RelPath()
+		_, err := out.Stat(ctx, path)
 		if err == nil {
 			return fmt.Errorf("failed to initialize template, one or more files already exist: %s", path)
 		}
@@ -321,7 +317,7 @@ func (r *renderer) persistToDisk() error {
 
 	// Persist files to disk
 	for _, file := range filesToPersist {
-		err := file.PersistToDisk()
+		err := file.Write(ctx, out)
 		if err != nil {
 			return err
 		}

libs/template/renderer_test.go

@@ -3,9 +3,9 @@ package template
 import (
 	"context"
 	"fmt"
-	"io"
 	"io/fs"
 	"os"
+	"path"
 	"path/filepath"
 	"runtime"
 	"strings"
@@ -18,6 +18,7 @@ import (
 	"github.com/databricks/cli/cmd/root"
 	"github.com/databricks/cli/internal/testutil"
 	"github.com/databricks/cli/libs/diag"
+	"github.com/databricks/cli/libs/filer"
 	"github.com/databricks/cli/libs/tags"
 	"github.com/databricks/databricks-sdk-go"
 	workspaceConfig "github.com/databricks/databricks-sdk-go/config"
@@ -41,9 +42,8 @@ func assertFilePermissions(t *testing.T, path string, perm fs.FileMode) {
 func assertBuiltinTemplateValid(t *testing.T, template string, settings map[string]any, target string, isServicePrincipal bool, build bool, tempDir string) {
 	ctx := context.Background()
 
-	templatePath, err := prepareBuiltinTemplates(template, tempDir)
+	templateFS, err := fs.Sub(builtinTemplates, path.Join("templates", template))
 	require.NoError(t, err)
-	libraryPath := filepath.Join(templatePath, "library")
 
 	w := &databricks.WorkspaceClient{
 		Config: &workspaceConfig.Config{Host: "https://myhost.com"},
@@ -58,16 +58,18 @@ func assertBuiltinTemplateValid(t *testing.T, template string, settings map[stri
 	ctx = root.SetWorkspaceClient(ctx, w)
 	helpers := loadHelpers(ctx)
 
-	renderer, err := newRenderer(ctx, settings, helpers, templatePath, libraryPath, tempDir)
+	renderer, err := newRenderer(ctx, settings, helpers, templateFS, templateDirName, libraryDirName)
 	require.NoError(t, err)
 
 	// Evaluate template
 	err = renderer.walk()
 	require.NoError(t, err)
-	err = renderer.persistToDisk()
+	out, err := filer.NewLocalClient(tempDir)
+	require.NoError(t, err)
+	err = renderer.persistToDisk(ctx, out)
 	require.NoError(t, err)
 
-	b, err := bundle.Load(ctx, filepath.Join(tempDir, "template", "my_project"))
+	b, err := bundle.Load(ctx, filepath.Join(tempDir, "my_project"))
 	require.NoError(t, err)
 	diags := bundle.Apply(ctx, b, phases.LoadNamedTarget(target))
 	require.NoError(t, diags.Error())
@@ -96,18 +98,6 @@ func assertBuiltinTemplateValid(t *testing.T, template string, settings map[stri
 	}
 }
 
-func TestPrepareBuiltInTemplatesWithRelativePaths(t *testing.T) {
-	// CWD should not be resolved as a built in template
-	dir, err := prepareBuiltinTemplates(".", t.TempDir())
-	assert.NoError(t, err)
-	assert.Equal(t, ".", dir)
-
-	// relative path should not be resolved as a built in template
-	dir, err = prepareBuiltinTemplates("./default-python", t.TempDir())
-	assert.NoError(t, err)
-	assert.Equal(t, "./default-python", dir)
-}
-
 func TestBuiltinPythonTemplateValid(t *testing.T) {
 	// Test option combinations
 	options := []string{"yes", "no"}
@@ -194,13 +184,14 @@ func TestRendererWithAssociatedTemplateInLibrary(t *testing.T) {
 	ctx := context.Background()
 	ctx = root.SetWorkspaceClient(ctx, nil)
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/email/template", "./testdata/email/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/email/template", "./testdata/email/library")
 	require.NoError(t, err)
 
 	err = r.walk()
 	require.NoError(t, err)
-
-	err = r.persistToDisk()
+	out, err := filer.NewLocalClient(tmpDir)
+	require.NoError(t, err)
+	err = r.persistToDisk(ctx, out)
 	require.NoError(t, err)
 
 	b, err := os.ReadFile(filepath.Join(tmpDir, "my_email"))
@@ -325,45 +316,34 @@ func TestRendererPersistToDisk(t *testing.T) {
 
 	r := &renderer{
 		ctx:          ctx,
-		instanceRoot: tmpDir,
 		skipPatterns: []string{"a/b/c", "mn*"},
 		files: []file{
 			&inMemoryFile{
-				dstPath: &destinationPath{
-					root:    tmpDir,
+				perm:    0444,
 				relPath: "a/b/c",
-				},
-				perm:    0444,
 				content: nil,
 			},
 			&inMemoryFile{
-				dstPath: &destinationPath{
-					root:    tmpDir,
+				perm:    0444,
 				relPath: "mno",
-				},
-				perm:    0444,
 				content: nil,
 			},
 			&inMemoryFile{
-				dstPath: &destinationPath{
-					root:    tmpDir,
-					relPath: "a/b/d",
-				},
 				perm:    0444,
+				relPath: "a/b/d",
 				content: []byte("123"),
 			},
 			&inMemoryFile{
-				dstPath: &destinationPath{
-					root:    tmpDir,
-					relPath: "mmnn",
-				},
 				perm:    0444,
+				relPath: "mmnn",
 				content: []byte("456"),
 			},
 		},
 	}
 
-	err := r.persistToDisk()
+	out, err := filer.NewLocalClient(tmpDir)
+	require.NoError(t, err)
+	err = r.persistToDisk(ctx, out)
 	require.NoError(t, err)
 
 	assert.NoFileExists(t, filepath.Join(tmpDir, "a", "b", "c"))
@@ -378,10 +358,9 @@ func TestRendererPersistToDisk(t *testing.T) {
 func TestRendererWalk(t *testing.T) {
 	ctx := context.Background()
 	ctx = root.SetWorkspaceClient(ctx, nil)
-	tmpDir := t.TempDir()
 
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/walk/template", "./testdata/walk/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/walk/template", "./testdata/walk/library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -389,21 +368,12 @@ func TestRendererWalk(t *testing.T) {
 
 	getContent := func(r *renderer, path string) string {
 		for _, f := range r.files {
-			if f.DstPath().relPath != path {
+			if f.RelPath() != path {
 				continue
 			}
-			switch v := f.(type) {
-			case *inMemoryFile:
-				return strings.Trim(string(v.content), "\r\n")
-			case *copyFile:
-				r, err := r.templateFiler.Read(context.Background(), v.srcPath)
-				require.NoError(t, err)
-				b, err := io.ReadAll(r)
+			b, err := f.contents()
 			require.NoError(t, err)
 			return strings.Trim(string(b), "\r\n")
-			default:
-				require.FailNow(t, "execution should not reach here")
-			}
 		}
 		require.FailNow(t, "file is absent: "+path)
 		return ""
@@ -419,10 +389,9 @@ func TestRendererWalk(t *testing.T) {
 func TestRendererFailFunction(t *testing.T) {
 	ctx := context.Background()
 	ctx = root.SetWorkspaceClient(ctx, nil)
-	tmpDir := t.TempDir()
 
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/fail/template", "./testdata/fail/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/fail/template", "./testdata/fail/library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -432,10 +401,9 @@ func TestRendererFailFunction(t *testing.T) {
 func TestRendererSkipsDirsEagerly(t *testing.T) {
 	ctx := context.Background()
 	ctx = root.SetWorkspaceClient(ctx, nil)
-	tmpDir := t.TempDir()
 
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/skip-dir-eagerly/template", "./testdata/skip-dir-eagerly/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/skip-dir-eagerly/template", "./testdata/skip-dir-eagerly/library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -452,7 +420,7 @@ func TestRendererSkipAllFilesInCurrentDirectory(t *testing.T) {
 	tmpDir := t.TempDir()
 
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/skip-all-files-in-cwd/template", "./testdata/skip-all-files-in-cwd/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/skip-all-files-in-cwd/template", "./testdata/skip-all-files-in-cwd/library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -460,7 +428,9 @@ func TestRendererSkipAllFilesInCurrentDirectory(t *testing.T) {
 	// All 3 files are executed and have in memory representations
 	require.Len(t, r.files, 3)
 
-	err = r.persistToDisk()
+	out, err := filer.NewLocalClient(tmpDir)
+	require.NoError(t, err)
+	err = r.persistToDisk(ctx, out)
 	require.NoError(t, err)
 
 	entries, err := os.ReadDir(tmpDir)
@@ -472,10 +442,9 @@ func TestRendererSkipAllFilesInCurrentDirectory(t *testing.T) {
 func TestRendererSkipPatternsAreRelativeToFileDirectory(t *testing.T) {
 	ctx := context.Background()
 	ctx = root.SetWorkspaceClient(ctx, nil)
-	tmpDir := t.TempDir()
 
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/skip-is-relative/template", "./testdata/skip-is-relative/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/skip-is-relative/template", "./testdata/skip-is-relative/library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -493,7 +462,7 @@ func TestRendererSkip(t *testing.T) {
 	tmpDir := t.TempDir()
 
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/skip/template", "./testdata/skip/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/skip/template", "./testdata/skip/library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -502,7 +471,9 @@ func TestRendererSkip(t *testing.T) {
 	// This is because "dir2/*" matches the files in dir2, but not dir2 itself
 	assert.Len(t, r.files, 6)
 
-	err = r.persistToDisk()
+	out, err := filer.NewLocalClient(tmpDir)
+	require.NoError(t, err)
+	err = r.persistToDisk(ctx, out)
 	require.NoError(t, err)
 
 	assert.FileExists(t, filepath.Join(tmpDir, "file1"))
@@ -520,12 +491,11 @@ func TestRendererReadsPermissionsBits(t *testing.T) {
 	if runtime.GOOS != "linux" && runtime.GOOS != "darwin" {
 		t.SkipNow()
 	}
-	tmpDir := t.TempDir()
 	ctx := context.Background()
 	ctx = root.SetWorkspaceClient(ctx, nil)
 
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/executable-bit-read/template", "./testdata/executable-bit-read/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/executable-bit-read/template", "./testdata/executable-bit-read/library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -533,7 +503,7 @@ func TestRendererReadsPermissionsBits(t *testing.T) {
 
 	getPermissions := func(r *renderer, path string) fs.FileMode {
 		for _, f := range r.files {
-			if f.DstPath().relPath != path {
+			if f.RelPath() != path {
 				continue
 			}
 			switch v := f.(type) {
@@ -556,6 +526,7 @@ func TestRendererReadsPermissionsBits(t *testing.T) {
 
 func TestRendererErrorOnConflictingFile(t *testing.T) {
 	tmpDir := t.TempDir()
+	ctx := context.Background()
 
 	f, err := os.Create(filepath.Join(tmpDir, "a"))
 	require.NoError(t, err)
@@ -566,17 +537,16 @@ func TestRendererErrorOnConflictingFile(t *testing.T) {
 		skipPatterns: []string{},
 		files: []file{
 			&inMemoryFile{
-				dstPath: &destinationPath{
-					root:    tmpDir,
-					relPath: "a",
-				},
 				perm:    0444,
+				relPath: "a",
 				content: []byte("123"),
 			},
 		},
 	}
-	err = r.persistToDisk()
-	assert.EqualError(t, err, fmt.Sprintf("failed to initialize template, one or more files already exist: %s", filepath.Join(tmpDir, "a")))
+	out, err := filer.NewLocalClient(tmpDir)
+	require.NoError(t, err)
+	err = r.persistToDisk(ctx, out)
+	assert.EqualError(t, err, fmt.Sprintf("failed to initialize template, one or more files already exist: %s", "a"))
 }
 
 func TestRendererNoErrorOnConflictingFileIfSkipped(t *testing.T) {
@@ -593,16 +563,15 @@ func TestRendererNoErrorOnConflictingFileIfSkipped(t *testing.T) {
 		skipPatterns: []string{"a"},
 		files: []file{
 			&inMemoryFile{
-				dstPath: &destinationPath{
-					root:    tmpDir,
-					relPath: "a",
-				},
 				perm:    0444,
+				relPath: "a",
 				content: []byte("123"),
 			},
 		},
 	}
-	err = r.persistToDisk()
+	out, err := filer.NewLocalClient(tmpDir)
+	require.NoError(t, err)
+	err = r.persistToDisk(ctx, out)
 	// No error is returned even though a conflicting file exists. This is because
 	// the generated file is being skipped
 	assert.NoError(t, err)
@@ -612,10 +581,9 @@ func TestRendererNoErrorOnConflictingFileIfSkipped(t *testing.T) {
 func TestRendererNonTemplatesAreCreatedAsCopyFiles(t *testing.T) {
 	ctx := context.Background()
 	ctx = root.SetWorkspaceClient(ctx, nil)
-	tmpDir := t.TempDir()
 
 	helpers := loadHelpers(ctx)
-	r, err := newRenderer(ctx, nil, helpers, "./testdata/copy-file-walk/template", "./testdata/copy-file-walk/library", tmpDir)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/copy-file-walk/template", "./testdata/copy-file-walk/library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -623,7 +591,7 @@ func TestRendererNonTemplatesAreCreatedAsCopyFiles(t *testing.T) {
 
 	assert.Len(t, r.files, 1)
 	assert.Equal(t, r.files[0].(*copyFile).srcPath, "not-a-template")
-	assert.Equal(t, r.files[0].DstPath().absPath(), filepath.Join(tmpDir, "not-a-template"))
+	assert.Equal(t, r.files[0].RelPath(), "not-a-template")
 }
 
 func TestRendererFileTreeRendering(t *testing.T) {
@@ -635,7 +603,7 @@ func TestRendererFileTreeRendering(t *testing.T) {
 	r, err := newRenderer(ctx, map[string]any{
 		"dir_name":  "my_directory",
 		"file_name": "my_file",
-	}, helpers, "./testdata/file-tree-rendering/template", "./testdata/file-tree-rendering/library", tmpDir)
+	}, helpers, os.DirFS("."), "./testdata/file-tree-rendering/template", "./testdata/file-tree-rendering/library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -643,9 +611,11 @@ func TestRendererFileTreeRendering(t *testing.T) {
 
 	// Assert in memory representation is created.
 	assert.Len(t, r.files, 1)
-	assert.Equal(t, r.files[0].DstPath().absPath(), filepath.Join(tmpDir, "my_directory", "my_file"))
+	assert.Equal(t, r.files[0].RelPath(), "my_directory/my_file")
 
-	err = r.persistToDisk()
+	out, err := filer.NewLocalClient(tmpDir)
+	require.NoError(t, err)
+	err = r.persistToDisk(ctx, out)
 	require.NoError(t, err)
 
 	// Assert files and directories are correctly materialized.
@@ -667,8 +637,7 @@ func TestRendererSubTemplateInPath(t *testing.T) {
 	// https://learn.microsoft.com/en-us/windows/win32/fileio/naming-a-file.
 	testutil.Touch(t, filepath.Join(templateDir, "template/{{template `dir_name`}}/{{template `file_name`}}"))
 
-	tmpDir := t.TempDir()
-	r, err := newRenderer(ctx, nil, nil, filepath.Join(templateDir, "template"), filepath.Join(templateDir, "library"), tmpDir)
+	r, err := newRenderer(ctx, nil, nil, os.DirFS(templateDir), "template", "library")
 	require.NoError(t, err)
 
 	err = r.walk()
@@ -676,7 +645,6 @@ func TestRendererSubTemplateInPath(t *testing.T) {
 
 	if assert.Len(t, r.files, 2) {
 		f := r.files[1]
-		assert.Equal(t, filepath.Join(tmpDir, "my_directory", "my_file"), f.DstPath().absPath())
-		assert.Equal(t, "my_directory/my_file", f.DstPath().relPath)
+		assert.Equal(t, "my_directory/my_file", f.RelPath())
 	}
 }