Add comment for why we test two files for `bundle_uuid` (#1949)

## Changes
Addresses feedback from this thread
https://github.com/databricks/cli/pull/1947#discussion_r1865692479

.github/workflows/release-snapshot.yml

@@ -5,6 +5,7 @@ on:
     branches:
       - "main"
       - "demo-*"
+      - "bugbash-*"
 
   # Confirm that snapshot builds work if this file is modified.
   pull_request:

bundle/config/bundle.go

@@ -49,4 +49,8 @@ type Bundle struct {
 
 	// Databricks CLI version constraints required to run the bundle.
 	DatabricksCliVersion string `json:"databricks_cli_version,omitempty"`
+
+	// A stable generated UUID for the bundle. This is normally serialized by
+	// Databricks first party template when a user runs bundle init.
+	Uuid string `json:"uuid,omitempty"`
 }

bundle/config/mutator/mutator.go

@@ -26,7 +26,6 @@ func DefaultMutators() []bundle.Mutator {
 		ComputeIdToClusterId(),
 		InitializeVariables(),
 		DefineDefaultTarget(),
-		LoadGitDetails(),
 		pythonmutator.PythonMutator(pythonmutator.PythonMutatorPhaseLoad),
 
 		// Note: This mutator must run before the target overrides are merged.

bundle/phases/initialize.go

@@ -39,6 +39,7 @@ func Initialize() bundle.Mutator {
 			mutator.MergePipelineClusters(),
 			mutator.InitializeWorkspaceClient(),
 			mutator.PopulateCurrentUser(),
+			mutator.LoadGitDetails(),
 
 			mutator.DefineDefaultWorkspaceRoot(),
 			mutator.ExpandWorkspaceRoot(),

bundle/tests/environment_git_test.go

@@ -1,15 +1,19 @@
 package config_tests
 
 import (
+	"context"
 	"fmt"
 	"strings"
 	"testing"
 
+	"github.com/databricks/cli/bundle"
+	"github.com/databricks/cli/bundle/config/mutator"
 	"github.com/stretchr/testify/assert"
 )
 
 func TestGitAutoLoadWithEnvironment(t *testing.T) {
 	b := load(t, "./environments_autoload_git")
+	bundle.Apply(context.Background(), b, mutator.LoadGitDetails())
 	assert.True(t, b.Config.Bundle.Git.Inferred)
 	validUrl := strings.Contains(b.Config.Bundle.Git.OriginURL, "/cli") || strings.Contains(b.Config.Bundle.Git.OriginURL, "/bricks")
 	assert.True(t, validUrl, fmt.Sprintf("Expected URL to contain '/cli' or '/bricks', got %s", b.Config.Bundle.Git.OriginURL))
@@ -17,6 +21,7 @@ func TestGitAutoLoadWithEnvironment(t *testing.T) {
 
 func TestGitManuallySetBranchWithEnvironment(t *testing.T) {
 	b := loadTarget(t, "./environments_autoload_git", "production")
+	bundle.Apply(context.Background(), b, mutator.LoadGitDetails())
 	assert.False(t, b.Config.Bundle.Git.Inferred)
 	assert.Equal(t, "main", b.Config.Bundle.Git.Branch)
 	validUrl := strings.Contains(b.Config.Bundle.Git.OriginURL, "/cli") || strings.Contains(b.Config.Bundle.Git.OriginURL, "/bricks")

bundle/tests/git_test.go

@@ -14,6 +14,7 @@ import (
 
 func TestGitAutoLoad(t *testing.T) {
 	b := load(t, "./autoload_git")
+	bundle.Apply(context.Background(), b, mutator.LoadGitDetails())
 	assert.True(t, b.Config.Bundle.Git.Inferred)
 	validUrl := strings.Contains(b.Config.Bundle.Git.OriginURL, "/cli") || strings.Contains(b.Config.Bundle.Git.OriginURL, "/bricks")
 	assert.True(t, validUrl, fmt.Sprintf("Expected URL to contain '/cli' or '/bricks', got %s", b.Config.Bundle.Git.OriginURL))
@@ -21,6 +22,7 @@ func TestGitAutoLoad(t *testing.T) {
 
 func TestGitManuallySetBranch(t *testing.T) {
 	b := loadTarget(t, "./autoload_git", "production")
+	bundle.Apply(context.Background(), b, mutator.LoadGitDetails())
 	assert.False(t, b.Config.Bundle.Git.Inferred)
 	assert.Equal(t, "main", b.Config.Bundle.Git.Branch)
 	validUrl := strings.Contains(b.Config.Bundle.Git.OriginURL, "/cli") || strings.Contains(b.Config.Bundle.Git.OriginURL, "/bricks")
@@ -34,6 +36,7 @@ func TestGitBundleBranchValidation(t *testing.T) {
 	})
 
 	b := load(t, "./git_branch_validation")
+	bundle.Apply(context.Background(), b, mutator.LoadGitDetails())
 	assert.False(t, b.Config.Bundle.Git.Inferred)
 	assert.Equal(t, "feature-a", b.Config.Bundle.Git.Branch)
 	assert.Equal(t, "feature-b", b.Config.Bundle.Git.ActualBranch)

libs/template/helpers.go

@@ -35,6 +35,13 @@ var cachedUser *iam.User
 var cachedIsServicePrincipal *bool
 var cachedCatalog *string
 
+// UUID that is stable for the duration of the template execution. This can be used
+// to populate the `bundle.uuid` field in databricks.yml by template authors.
+//
+// It's automatically logged in our telemetry logs when `databricks bundle init`
+// is run and can be used to attribute DBU revenue to bundle templates.
+var bundleUuid = uuid.New().String()
+
 func loadHelpers(ctx context.Context) template.FuncMap {
 	w := root.WorkspaceClient(ctx)
 	return template.FuncMap{
@@ -57,6 +64,9 @@ func loadHelpers(ctx context.Context) template.FuncMap {
 		"uuid": func() string {
 			return uuid.New().String()
 		},
+		"bundle_uuid": func() string {
+			return bundleUuid
+		},
 		// A key value pair. This is used with the map function to generate maps
 		// to use inside a template
 		"pair": func(k string, v any) pair {

libs/template/helpers_test.go

@@ -32,6 +32,29 @@ func TestTemplatePrintStringWithoutProcessing(t *testing.T) {
 	assert.Equal(t, `{{ fail "abc" }}`, cleanContent)
 }
 
+func TestTemplateBundleUuidFunction(t *testing.T) {
+	ctx := context.Background()
+
+	ctx = root.SetWorkspaceClient(ctx, nil)
+	helpers := loadHelpers(ctx)
+	r, err := newRenderer(ctx, nil, helpers, os.DirFS("."), "./testdata/bundle-uuid/template", "./testdata/bundle-uuid/library")
+	require.NoError(t, err)
+
+	err = r.walk()
+	assert.NoError(t, err)
+
+	// We test the content of two generated files to ensure that the same UUID
+	// is used across all files generated by the template. Each file content is
+	// generated by a separate (*template.Template).Execute call, so testing different
+	// files ensures that the UUID is stable across all template execution calls.
+	copy := strings.Clone(bundleUuid)
+	assert.Len(t, r.files, 2)
+	c1 := strings.Trim(string(r.files[0].(*inMemoryFile).content), "\n\r")
+	assert.Equal(t, strings.Repeat(copy, 3), c1)
+	c2 := strings.Trim(string(r.files[1].(*inMemoryFile).content), "\n\r")
+	assert.Equal(t, strings.Repeat(copy, 5), c2)
+}
+
 func TestTemplateRegexpCompileFunction(t *testing.T) {
 	ctx := context.Background()
 

libs/template/testdata/bundle-uuid/template/bar.txt.tmpl

@@ -0,0 +1 @@
+{{bundle_uuid}}{{bundle_uuid}}{{bundle_uuid}}

libs/template/testdata/bundle-uuid/template/foo.txt.tmpl

@@ -0,0 +1 @@
+{{bundle_uuid}}{{bundle_uuid}}{{bundle_uuid}}{{bundle_uuid}}{{bundle_uuid}}