[8.x] 🌊 Streams: Centralize stream name helpers (#208148) (#208162)

# Backport

This will backport the following commits from `main` to `8.x`:
- [🌊 Streams: Centralize stream name helpers
(#208148)](#208148)

<!--- Backport version: 9.4.3 -->

### Questions ?
Please refer to the [Backport tool
documentation](https://github.com/sqren/backport)

<!--BACKPORT [{"author":{"name":"Joe
Reuter","email":"[email protected]"},"sourceCommit":{"committedDate":"2025-01-24T10:25:56Z","message":"🌊
Streams: Centralize stream name helpers (#208148)\n\nMost helpers for
dealing with stream names are already centralized in\nthe `hierarchy.ts`
helper, something non-trivial we did in multiple\nplaces is listing out
all ancestors.\n\nThis PR is centralizing that as well - the idea is
that we never mess\nwith `split('.')` and `join('.')` directly
throughout the code base. If\nwe decide later on to give more structure
to stream names (e.g. special\nhandling for DSNS names), it will be much
easier to change
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Streams: Centralize stream name
helpers","number":208148,"url":"https://github.com/elastic/kibana/pull/208148","mergeCommit":{"message":"🌊
Streams: Centralize stream name helpers (#208148)\n\nMost helpers for
dealing with stream names are already centralized in\nthe `hierarchy.ts`
helper, something non-trivial we did in multiple\nplaces is listing out
all ancestors.\n\nThis PR is centralizing that as well - the idea is
that we never mess\nwith `split('.')` and `join('.')` directly
throughout the code base. If\nwe decide later on to give more structure
to stream names (e.g. special\nhandling for DSNS names), it will be much
easier to change
it.","sha":"d75ffa914a2d5035d67f9dd4a77e87bdb38026c8"}},"sourceBranch":"main","suggestedTargetBranches":["8.x"],"targetPullRequestStates":[{"branch":"main","label":"v9.0.0","branchLabelMappingKey":"^v9.0.0$","isSourceBranch":true,"state":"MERGED","url":"https://github.com/elastic/kibana/pull/208148","number":208148,"mergeCommit":{"message":"🌊
Streams: Centralize stream name helpers (#208148)\n\nMost helpers for
dealing with stream names are already centralized in\nthe `hierarchy.ts`
helper, something non-trivial we did in multiple\nplaces is listing out
all ancestors.\n\nThis PR is centralizing that as well - the idea is
that we never mess\nwith `split('.')` and `join('.')` directly
throughout the code base. If\nwe decide later on to give more structure
to stream names (e.g. special\nhandling for DSNS names), it will be much
easier to change
it.","sha":"d75ffa914a2d5035d67f9dd4a77e87bdb38026c8"}},{"branch":"8.x","label":"v8.18.0","branchLabelMappingKey":"^v8.18.0$","isSourceBranch":false,"state":"NOT_CREATED"}]}]
BACKPORT-->

Co-authored-by: Joe Reuter <[email protected]>

x-pack/solutions/observability/packages/kbn-streams-schema/src/helpers/hierarchy.ts

@@ -34,3 +34,11 @@ export function getAncestors(id: string) {
   const parts = id.split('.');
   return parts.slice(0, parts.length - 1).map((_, index) => parts.slice(0, index + 1).join('.'));
 }
+
+export function getAncestorsAndSelf(id: string) {
+  return getAncestors(id).concat(id);
+}
+
+export function getSegments(id: string) {
+  return id.split('.');
+}

x-pack/solutions/observability/plugins/streams/server/lib/streams/index_templates/generate_index_template.ts

@@ -5,14 +5,14 @@
  * 2.0.
  */
 
+import { getAncestorsAndSelf } from '@kbn/streams-schema';
 import { ASSET_VERSION } from '../../../../common/constants';
 import { getProcessingPipelineName } from '../ingest_pipelines/name';
 import { getIndexTemplateName } from './name';
 
 export function generateIndexTemplate(id: string, isServerless: boolean) {
-  const composedOf = id.split('.').reduce((acc, _, index, array) => {
-    const parent = array.slice(0, index + 1).join('.');
-    return [...acc, `${parent}@stream.layer`];
+  const composedOf = getAncestorsAndSelf(id).reduce((acc, ancestorId) => {
+    return [...acc, `${ancestorId}@stream.layer`];
   }, [] as string[]);
 
   return {

x-pack/solutions/observability/plugins/streams_app/public/components/stream_detail_routing/index.tsx

@@ -41,6 +41,7 @@ import {
   isDescendantOf,
   RoutingDefinition,
   IngestUpsertRequest,
+  getAncestorsAndSelf,
 } from '@kbn/streams-schema';
 import { useUnsavedChangesPrompt } from '@kbn/unsaved-changes-prompt';
 import { AbortableAsyncState } from '@kbn/observability-utils-browser/hooks/use_abortable_async';
@@ -818,8 +819,7 @@ function ChildStreamList({
 
 function CurrentStreamEntry({ definition }: { definition: ReadStreamDefinition }) {
   const router = useStreamsAppRouter();
-  const breadcrumbs: EuiBreadcrumb[] = definition.name.split('.').map((_part, pos, parts) => {
-    const parentId = parts.slice(0, pos + 1).join('.');
+  const breadcrumbs: EuiBreadcrumb[] = getAncestorsAndSelf(definition.name).map((parentId) => {
     const isBreadcrumbsTail = parentId === definition.name;
 
     return {

x-pack/solutions/observability/plugins/streams_app/public/components/streams_list/index.tsx

@@ -22,6 +22,7 @@ import { euiThemeVars } from '@kbn/ui-theme';
 import { css } from '@emotion/css';
 import {
   StreamDefinition,
+  getSegments,
   isDescendantOf,
   isUnwiredStreamDefinition,
   isWiredStreamDefinition,
@@ -41,12 +42,12 @@ export interface StreamTree {
 function asTrees(definitions: StreamDefinition[]) {
   const trees: StreamTree[] = [];
   const wiredDefinitions = definitions.filter((definition) => isWiredStreamDefinition(definition));
-  wiredDefinitions.sort((a, b) => a.name.split('.').length - b.name.split('.').length);
+  wiredDefinitions.sort((a, b) => getSegments(a.name).length - getSegments(b.name).length);
 
   wiredDefinitions.forEach((definition) => {
     let currentTree = trees;
     let existingNode: StreamTree | undefined;
-    const segments = definition.name.split('.');
+    const segments = getSegments(definition.name);
     // traverse the tree following the prefix of the current id.
     // once we reach the leaf, the current id is added as child - this works because the ids are sorted by depth
     while (