Change recommended production deployment path from /Shared to /Users (#1091)

## Changes

This PR changes the default and `mode: production` recommendation to
target `/Users` for deployment. Previously, we used `/Shared`, but
because of a lack of POSIX-like permissions in WorkspaceFS this meant
that files inside would be readable and writable by other users in the
workspace.

Detailed change:
* `default-python` no longer uses a path that starts with `/Shared`
* `mode: production` no longer requires a path that starts with
`/Shared`
 
## Related PRs

Docs: https://github.com/databricks/docs/pull/14585
Examples: https://github.com/databricks/bundle-examples/pull/17

## Tests

* Manual tests
* Template unit tests (with an extra check to avoid /Shared)

bundle/config/mutator/process_target_mode.go

@@ -101,29 +101,25 @@ func transformDevelopmentMode(b *bundle.Bundle) error {
 }
 
 func validateDevelopmentMode(b *bundle.Bundle) error {
-	if path := findIncorrectPath(b, config.Development); path != "" {
+	if path := findNonUserPath(b); path != "" {
 		return fmt.Errorf("%s must start with '~/' or contain the current username when using 'mode: development'", path)
 	}
 	return nil
 }
 
-func findIncorrectPath(b *bundle.Bundle, mode config.Mode) string {
+func findNonUserPath(b *bundle.Bundle) string {
 	username := b.Config.Workspace.CurrentUser.UserName
-	containsExpected := true
-	if mode == config.Production {
-		containsExpected = false
-	}
 
-	if strings.Contains(b.Config.Workspace.RootPath, username) != containsExpected && b.Config.Workspace.RootPath != "" {
+	if b.Config.Workspace.RootPath != "" && !strings.Contains(b.Config.Workspace.RootPath, username) {
 		return "root_path"
 	}
-	if strings.Contains(b.Config.Workspace.StatePath, username) != containsExpected {
+	if b.Config.Workspace.StatePath != "" && !strings.Contains(b.Config.Workspace.StatePath, username) {
 		return "state_path"
 	}
-	if strings.Contains(b.Config.Workspace.FilePath, username) != containsExpected {
+	if b.Config.Workspace.FilePath != "" && !strings.Contains(b.Config.Workspace.FilePath, username) {
 		return "file_path"
 	}
-	if strings.Contains(b.Config.Workspace.ArtifactPath, username) != containsExpected {
+	if b.Config.Workspace.ArtifactPath != "" && !strings.Contains(b.Config.Workspace.ArtifactPath, username) {
 		return "artifact_path"
 	}
 	return ""
@@ -138,23 +134,12 @@ func validateProductionMode(ctx context.Context, b *bundle.Bundle, isPrincipalUs
 	r := b.Config.Resources
 	for i := range r.Pipelines {
 		if r.Pipelines[i].Development {
-			return fmt.Errorf("target with 'mode: production' cannot specify a pipeline with 'development: true'")
+			return fmt.Errorf("target with 'mode: production' cannot include a pipeline with 'development: true'")
 		}
 	}
 
-	if !isPrincipalUsed {
-		if path := findIncorrectPath(b, config.Production); path != "" {
-			message := "%s must not contain the current username when using 'mode: production'"
-			if path == "root_path" {
-				return fmt.Errorf(message+"\n  tip: set workspace.root_path to a shared path such as /Shared/.bundle/${bundle.name}/${bundle.target}", path)
-			} else {
-				return fmt.Errorf(message, path)
-			}
-		}
-
-		if !isRunAsSet(r) {
-			return fmt.Errorf("'run_as' must be set for all jobs when using 'mode: production'")
-		}
+	if !isPrincipalUsed && !isRunAsSet(r) {
+		return fmt.Errorf("'run_as' must be set for all jobs when using 'mode: production'")
 	}
 	return nil
 }

bundle/config/mutator/process_target_mode_test.go

@@ -205,7 +205,7 @@ func TestProcessTargetModeProduction(t *testing.T) {
 	b := mockBundle(config.Production)
 
 	err := validateProductionMode(context.Background(), b, false)
-	require.ErrorContains(t, err, "state_path")
+	require.ErrorContains(t, err, "run_as")
 
 	b.Config.Workspace.StatePath = "/Shared/.bundle/x/y/state"
 	b.Config.Workspace.ArtifactPath = "/Shared/.bundle/x/y/artifacts"

libs/template/templates/default-python/template/{{.project_name}}/databricks.yml.tmpl

@@ -32,11 +32,19 @@ targets:
     mode: production
     workspace:
       host: {{workspace_host}}
-      # We only have a single deployment copy for production, so we use a shared path.
-      root_path: /Shared/.bundle/prod/${bundle.name}
-    {{- if not is_service_principal}}
+      # We always use /Users/{{user_name}} for all resources to make sure we only have a single copy.
+      {{- /*
+      Internal note 2023-12: CLI versions v0.211.0 and before would show an error when using `mode: production`
+      with a path that doesn't say "/Shared". For now, we'll include an extra comment in the template
+      to explain that customers should update if they see this.
+      */}}
+      # If this path results in an error, please make sure you have a recent version of the CLI installed.
+      root_path: /Users/{{user_name}}/.bundle/${bundle.name}/${bundle.target}
     run_as:
-      # This runs as {{user_name}} in production. We could also use a service principal here
-      # using service_principal_name (see https://docs.databricks.com/dev-tools/bundles/permissions.html).
+      {{- if is_service_principal}}
+      service_principal_name: {{user_name}}
+      {{- else}}
+      # This runs as {{user_name}} in production. We could also use a service principal here,
+      # see https://docs.databricks.com/dev-tools/bundles/permissions.html.
       user_name: {{user_name}}
-    {{end -}}
+      {{- end}}