Add support for customizing the catalog graph relations using an API

Signed-off-by: Gustaf Räntilä <g.rantila@gmail.com>

.changeset/dull-eagles-sin.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-catalog-graph': patch
+---
+
+Support custom relations by using an API

packages/app/src/App.tsx

@@ -14,18 +14,6 @@
  * limitations under the License.
  */
 
-import {
-  RELATION_API_CONSUMED_BY,
-  RELATION_API_PROVIDED_BY,
-  RELATION_CONSUMES_API,
-  RELATION_DEPENDENCY_OF,
-  RELATION_DEPENDS_ON,
-  RELATION_HAS_PART,
-  RELATION_OWNED_BY,
-  RELATION_OWNER_OF,
-  RELATION_PART_OF,
-  RELATION_PROVIDES_API,
-} from '@backstage/catalog-model';
 import { createApp } from '@backstage/app-defaults';
 import { AppRouter, FeatureFlagged, FlatRoutes } from '@backstage/core-app-api';
 import {
@@ -158,18 +146,6 @@ const routes = (
         <CatalogGraphPage
           initialState={{
             selectedKinds: ['component', 'domain', 'system', 'api', 'group'],
-            selectedRelations: [
-              RELATION_OWNER_OF,
-              RELATION_OWNED_BY,
-              RELATION_CONSUMES_API,
-              RELATION_API_CONSUMED_BY,
-              RELATION_PROVIDES_API,
-              RELATION_API_PROVIDED_BY,
-              RELATION_HAS_PART,
-              RELATION_PART_OF,
-              RELATION_DEPENDS_ON,
-              RELATION_DEPENDENCY_OF,
-            ],
           }}
         />
       }

plugins/catalog-graph/README.md

@@ -50,18 +50,6 @@ To use the catalog graph plugin, you have to add some things to your Backstage a
        <CatalogGraphPage
          initialState={{
            selectedKinds: ['component', 'domain', 'system', 'api', 'group'],
-           selectedRelations: [
-             RELATION_OWNER_OF,
-             RELATION_OWNED_BY,
-             RELATION_CONSUMES_API,
-             RELATION_API_CONSUMED_BY,
-             RELATION_PROVIDES_API,
-             RELATION_API_PROVIDED_BY,
-             RELATION_HAS_PART,
-             RELATION_PART_OF,
-             RELATION_DEPENDS_ON,
-             RELATION_DEPENDENCY_OF,
-           ],
          }}
        />
      }
@@ -88,7 +76,7 @@ To use the catalog graph plugin, you have to add some things to your Backstage a
    </Grid>
    ```
 
-### Customization
+### Customizing the UI
 
 Copy the default implementation `DefaultRenderNode.tsx` and add more classes to the styles:
 
@@ -151,6 +139,44 @@ Once you have your custom implementation, you can follow these steps to modify t
 <EntityCatalogGraphCard variant=“gridItem” renderNode={MyCustomRenderNode} height={400} />
 ```
 
+### Custom relations
+
+Implementers with added custom relations can add them to the catalog graph plugin by overriding the default API. This also allows some relations to not be selected by default.
+
+In `packages/app/src/apis.ts`, import the api ref and create the API as:
+
+```ts
+import {
+  ALL_RELATIONS,
+  ALL_RELATION_PAIRS,
+  catalogGraphApiRef,
+  DefaultCatalogGraphApi,
+} from '@backstage/plugin-catalog-graph';
+
+// ...
+
+  createApiFactory({
+    api: catalogGraphApiRef,
+    deps: {},
+    factory: () =>
+      new DefaultCatalogGraphApi({
+        // The relations to support
+        knownRelations: [...ALL_RELATIONS, 'myRelationOf', 'myRelationFor'],
+        // The relation pairs to support
+        knownRelationPairs: [
+          ...ALL_RELATION_PAIRS,
+          ['myRelationOf', 'myRelationFor'],
+        ],
+        // Select what relations to be shown by default, either by including them,
+        // or excluding some from all known relations:
+        defaultRelationTypes: {
+          // Don't show/select these by default
+          exclude: ['myRelationOf', 'myRelationFor'],
+        },
+      }),
+  }),
+```
+
 ## Development
 
 Run `yarn` in the root of this plugin to install all dependencies and then `yarn start` to run a [development version](./dev/index.tsx) of this plugin.

plugins/catalog-graph/report.api.md

@@ -3,6 +3,7 @@
 > Do not edit this file. It is a report generated by [API Extractor](https://api-extractor.com/).
 
 ```ts
+import { ApiRef } from '@backstage/core-plugin-api';
 import { BackstagePlugin } from '@backstage/core-plugin-api';
 import { CompoundEntityRef } from '@backstage/catalog-model';
 import { DependencyGraphTypes } from '@backstage/core-components';
@@ -19,6 +20,19 @@ import { RouteRef } from '@backstage/core-plugin-api';
 // @public
 export const ALL_RELATION_PAIRS: RelationPairs;
 
+// @public
+export const ALL_RELATIONS: string[];
+
+// @public
+export interface CatalogGraphApi {
+  readonly defaultRelations: string[];
+  readonly knownRelationPairs: [string, string][];
+  readonly knownRelations: string[];
+}
+
+// @public
+export const catalogGraphApiRef: ApiRef<CatalogGraphApi>;
+
 // @public
 export const CatalogGraphPage: (
   props: {
@@ -62,6 +76,42 @@ export type CustomLabelClassKey = 'text' | 'secondary';
 // @public (undocumented)
 export type CustomNodeClassKey = 'node' | 'text' | 'clickable';
 
+// @public
+export class DefaultCatalogGraphApi implements CatalogGraphApi {
+  constructor(options?: DefaultCatalogGraphApiOptions);
+  // (undocumented)
+  readonly defaultRelations: string[];
+  // (undocumented)
+  readonly knownRelationPairs: [string, string][];
+  // (undocumented)
+  readonly knownRelations: string[];
+}
+
+// @public
+export interface DefaultCatalogGraphApiOptions {
+  // (undocumented)
+  readonly defaultRelationTypes?: DefaultRelations;
+  // (undocumented)
+  readonly knownRelationPairs?: RelationPairs;
+  // (undocumented)
+  readonly knownRelations?: string[];
+}
+
+// @public
+export type DefaultRelations =
+  | DefaultRelationsInclude
+  | DefaultRelationsExclude;
+
+// @public (undocumented)
+export type DefaultRelationsExclude = {
+  exclude: string[];
+};
+
+// @public (undocumented)
+export type DefaultRelationsInclude = {
+  include: string[];
+};
+
 // @public
 export enum Direction {
   BOTTOM_TOP = 'BT',

plugins/catalog-graph/src/api/CatalogGraphApi.ts

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2025 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { createApiRef } from '@backstage/core-plugin-api';
+
+/**
+ * Utility API reference for the {@link CatalogGraphApi}.
+ *
+ * @public
+ */
+export const catalogGraphApiRef = createApiRef<CatalogGraphApi>({
+  id: 'plugin.catalog-graph.service',
+});
+
+/** @public */
+export type DefaultRelationsInclude = { include: string[] };
+
+/** @public */
+export type DefaultRelationsExclude = { exclude: string[] };
+
+/**
+ * Default relations. Can either be a list of relations to use by default, or
+ * a list of relations to _not_ use, i.e. include all other relations.
+ *
+ * @public
+ */
+export type DefaultRelations =
+  | DefaultRelationsInclude
+  | DefaultRelationsExclude;
+
+/**
+ * API for driving catalog imports.
+ *
+ * @public
+ */
+export interface CatalogGraphApi {
+  /** All known relations */
+  readonly knownRelations: string[];
+
+  /** All known relation pairs */
+  readonly knownRelationPairs: [string, string][];
+
+  /** The default relations to show in the graph */
+  readonly defaultRelations: string[];
+}

plugins/catalog-graph/src/api/DefaultCatalogGraphApi.test.ts

@@ -0,0 +1,61 @@
+/*
+ * Copyright 2025 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { DefaultCatalogGraphApi } from './DefaultCatalogGraphApi';
+
+describe('DefaultCatalogGraphApi', () => {
+  it('default config', async () => {
+    const { defaultRelations } = new DefaultCatalogGraphApi();
+
+    expect(defaultRelations.includes('')).toBe(false);
+    expect(defaultRelations.includes('fooRelation')).toBe(false);
+    expect(defaultRelations.includes('ownedBy')).toBe(true);
+    expect(defaultRelations.includes('hasPart')).toBe(true);
+  });
+
+  it('empty include config', async () => {
+    const { defaultRelations } = new DefaultCatalogGraphApi({
+      defaultRelationTypes: { include: [] },
+    });
+
+    expect(defaultRelations.includes('')).toBe(false);
+    expect(defaultRelations.includes('fooRelation')).toBe(false);
+    expect(defaultRelations.includes('ownedBy')).toBe(false);
+    expect(defaultRelations.includes('hasPart')).toBe(false);
+  });
+
+  it('include config', async () => {
+    const { defaultRelations } = new DefaultCatalogGraphApi({
+      defaultRelationTypes: { include: ['ownedBy'] },
+    });
+
+    expect(defaultRelations.includes('')).toBe(false);
+    expect(defaultRelations.includes('fooRelation')).toBe(false);
+    expect(defaultRelations.includes('ownedBy')).toBe(true);
+    expect(defaultRelations.includes('hasPart')).toBe(false);
+  });
+
+  it('exclude config', async () => {
+    const { defaultRelations } = new DefaultCatalogGraphApi({
+      defaultRelationTypes: { exclude: ['ownedBy', 'ownerOf'] },
+    });
+
+    expect(defaultRelations.includes('')).toBe(false);
+    expect(defaultRelations.includes('fooRelation')).toBe(false);
+    expect(defaultRelations.includes('ownedBy')).toBe(false);
+    expect(defaultRelations.includes('hasPart')).toBe(true);
+  });
+});

plugins/catalog-graph/src/api/DefaultCatalogGraphApi.ts

@@ -0,0 +1,74 @@
+/*
+ * Copyright 2025 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { ALL_RELATION_PAIRS, ALL_RELATIONS, RelationPairs } from '../types';
+import {
+  CatalogGraphApi,
+  DefaultRelations,
+  DefaultRelationsExclude,
+  DefaultRelationsInclude,
+} from './CatalogGraphApi';
+
+/**
+ * Options for the {@link DefaultCatalogGraphApi}.
+ *
+ * @public
+ */
+export interface DefaultCatalogGraphApiOptions {
+  readonly knownRelations?: string[];
+  readonly knownRelationPairs?: RelationPairs;
+  readonly defaultRelationTypes?: DefaultRelations;
+}
+
+/**
+ * The default implementation of the {@link CatalogGraphApi}.
+ *
+ * @public
+ */
+export class DefaultCatalogGraphApi implements CatalogGraphApi {
+  readonly knownRelations: string[];
+  readonly knownRelationPairs: [string, string][];
+  readonly defaultRelations: string[];
+
+  constructor(
+    options: DefaultCatalogGraphApiOptions = {
+      knownRelations: ALL_RELATIONS,
+      knownRelationPairs: ALL_RELATION_PAIRS,
+      defaultRelationTypes: { exclude: [] },
+    },
+  ) {
+    this.knownRelations = options.knownRelations ?? ALL_RELATIONS;
+    this.knownRelationPairs = options.knownRelationPairs ?? ALL_RELATION_PAIRS;
+
+    const defaultRelations = options.defaultRelationTypes;
+
+    if (Array.isArray((defaultRelations as DefaultRelationsInclude).include)) {
+      const defaultRelationsInclude =
+        defaultRelations as DefaultRelationsInclude;
+
+      this.defaultRelations = this.knownRelations.filter(rel =>
+        defaultRelationsInclude.include.includes(rel),
+      );
+    } else {
+      const defaultRelationsExclude =
+        defaultRelations as DefaultRelationsExclude;
+
+      this.defaultRelations = this.knownRelations.filter(
+        rel => !defaultRelationsExclude.exclude.includes(rel),
+      );
+    }
+  }
+}

plugins/catalog-graph/src/api/index.ts

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2025 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export * from './CatalogGraphApi';
+export * from './DefaultCatalogGraphApi';

plugins/catalog-graph/src/components/CatalogGraphCard/CatalogGraphCard.test.tsx

@@ -35,6 +35,7 @@ import { catalogGraphRouteRef } from '../../routes';
 import { CatalogGraphCard } from './CatalogGraphCard';
 import Button from '@material-ui/core/Button';
 import { translationApiRef } from '@backstage/core-plugin-api/alpha';
+import { catalogGraphApiRef, DefaultCatalogGraphApi } from '../../api';
 
 describe('<CatalogGraphCard/>', () => {
   let entity: Entity;
@@ -56,6 +57,7 @@ describe('<CatalogGraphCard/>', () => {
     apis = TestApiRegistry.from(
       [catalogApiRef, catalog],
       [translationApiRef, mockApis.translation()],
+      [catalogGraphApiRef, new DefaultCatalogGraphApi()],
     );
 
     wrapper = (

plugins/catalog-graph/src/components/CatalogGraphCard/CatalogGraphCard.tsx

@@ -32,7 +32,6 @@ import { MouseEvent, ReactNode, useCallback, useMemo } from 'react';
 import { useNavigate } from 'react-router-dom';
 import { catalogGraphRouteRef } from '../../routes';
 import {
-  ALL_RELATION_PAIRS,
   Direction,
   EntityNode,
   EntityRelationsGraph,
@@ -71,7 +70,7 @@ export const CatalogGraphCard = (
   const { t } = useTranslationRef(catalogGraphTranslationRef);
   const {
     variant = 'gridItem',
-    relationPairs = ALL_RELATION_PAIRS,
+    relationPairs,
     maxDepth = 1,
     unidirectional = true,
     mergeRelations = true,

plugins/catalog-graph/src/components/CatalogGraphPage/CatalogGraphPage.tsx

@@ -37,7 +37,6 @@ import ToggleButton from '@material-ui/lab/ToggleButton';
 import { MouseEvent, useCallback } from 'react';
 import { useNavigate } from 'react-router-dom';
 import {
-  ALL_RELATION_PAIRS,
   Direction,
   EntityNode,
   EntityRelationsGraph,
@@ -133,11 +132,7 @@ export const CatalogGraphPage = (
     };
   } & Partial<EntityRelationsGraphProps>,
 ) => {
-  const {
-    relationPairs = ALL_RELATION_PAIRS,
-    initialState,
-    entityFilter,
-  } = props;
+  const { relationPairs, initialState, entityFilter } = props;
   const { t } = useTranslationRef(catalogGraphTranslationRef);
   const navigate = useNavigate();
   const classes = useStyles();
@@ -224,7 +219,6 @@ export const CatalogGraphPage = (
               <SelectedRelationsFilter
                 value={selectedRelations}
                 onChange={setSelectedRelations}
-                relationPairs={relationPairs}
               />
               <DirectionFilter value={direction} onChange={setDirection} />
               <CurveFilter value={curve} onChange={setCurve} />

plugins/catalog-graph/src/components/CatalogGraphPage/SelectedRelationsFilter.test.tsx

@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+import { PropsWithChildren } from 'react';
+import { ApiProvider } from '@backstage/core-app-api';
 import {
   RELATION_CHILD_OF,
   RELATION_HAS_MEMBER,
@@ -21,18 +23,34 @@ import {
 } from '@backstage/catalog-model';
 import { waitFor, screen } from '@testing-library/react';
 import userEvent from '@testing-library/user-event';
-import { ALL_RELATION_PAIRS } from '../EntityRelationsGraph';
+import { ALL_RELATIONS } from '../../types';
 import { SelectedRelationsFilter } from './SelectedRelationsFilter';
-import { renderInTestApp } from '@backstage/test-utils';
+import { renderInTestApp, TestApiRegistry } from '@backstage/test-utils';
+import { catalogGraphApiRef, DefaultCatalogGraphApi } from '../../api';
+
+function GraphContext(props: PropsWithChildren<{}>) {
+  return (
+    <ApiProvider
+      apis={TestApiRegistry.from([
+        catalogGraphApiRef,
+        new DefaultCatalogGraphApi(),
+      ])}
+    >
+      {props.children}
+    </ApiProvider>
+  );
+}
 
 describe('<SelectedRelationsFilter/>', () => {
   test('should render current value', async () => {
     await renderInTestApp(
-      <SelectedRelationsFilter
-        relationPairs={ALL_RELATION_PAIRS}
-        value={[RELATION_OWNED_BY, RELATION_CHILD_OF]}
-        onChange={() => {}}
-      />,
+      <GraphContext>
+        <SelectedRelationsFilter
+          relations={ALL_RELATIONS}
+          value={[RELATION_OWNED_BY, RELATION_CHILD_OF]}
+          onChange={() => {}}
+        />
+      </GraphContext>,
     );
 
     expect(screen.getByText(RELATION_OWNED_BY)).toBeInTheDocument();
@@ -42,11 +60,13 @@ describe('<SelectedRelationsFilter/>', () => {
   test('should select value', async () => {
     const onChange = jest.fn();
     await renderInTestApp(
-      <SelectedRelationsFilter
-        relationPairs={ALL_RELATION_PAIRS}
-        value={[RELATION_OWNED_BY, RELATION_CHILD_OF]}
-        onChange={onChange}
-      />,
+      <GraphContext>
+        <SelectedRelationsFilter
+          relations={ALL_RELATIONS}
+          value={[RELATION_OWNED_BY, RELATION_CHILD_OF]}
+          onChange={onChange}
+        />
+      </GraphContext>,
     );
 
     await userEvent.click(screen.getByLabelText('Open'));
@@ -66,16 +86,16 @@ describe('<SelectedRelationsFilter/>', () => {
     });
   });
 
-  test('should return undefined if all values are selected', async () => {
+  test('should return all known relations if all values are selected', async () => {
     const onChange = jest.fn();
     await renderInTestApp(
-      <SelectedRelationsFilter
-        relationPairs={ALL_RELATION_PAIRS}
-        value={ALL_RELATION_PAIRS.flatMap(p => p).filter(
-          r => r !== RELATION_HAS_MEMBER,
-        )}
-        onChange={onChange}
-      />,
+      <GraphContext>
+        <SelectedRelationsFilter
+          relations={ALL_RELATIONS}
+          value={ALL_RELATIONS.filter(r => r !== RELATION_HAS_MEMBER)}
+          onChange={onChange}
+        />
+      </GraphContext>,
     );
 
     await userEvent.click(screen.getByLabelText('Open'));
@@ -87,18 +107,26 @@ describe('<SelectedRelationsFilter/>', () => {
     await userEvent.click(screen.getByText(RELATION_HAS_MEMBER));
 
     await waitFor(() => {
-      expect(onChange).toHaveBeenCalledWith(undefined);
+      // Same as ALL_RELATIONS but with RELATION_HAS_MEMBER at the end
+      const allRelationsOrdered = [
+        ...ALL_RELATIONS.filter(rel => rel !== RELATION_HAS_MEMBER),
+        RELATION_HAS_MEMBER,
+      ];
+
+      expect(onChange).toHaveBeenCalledWith(allRelationsOrdered);
     });
   });
 
   test('should return all values when cleared', async () => {
     const onChange = jest.fn();
     await renderInTestApp(
-      <SelectedRelationsFilter
-        relationPairs={ALL_RELATION_PAIRS}
-        value={[]}
-        onChange={onChange}
-      />,
+      <GraphContext>
+        <SelectedRelationsFilter
+          relations={ALL_RELATIONS}
+          value={[]}
+          onChange={onChange}
+        />
+      </GraphContext>,
     );
 
     await userEvent.click(screen.getByRole('combobox'));

plugins/catalog-graph/src/components/CatalogGraphPage/SelectedRelationsFilter.tsx

@@ -24,9 +24,9 @@ import CheckBoxOutlineBlankIcon from '@material-ui/icons/CheckBoxOutlineBlank';
 import ExpandMoreIcon from '@material-ui/icons/ExpandMore';
 import Autocomplete from '@material-ui/lab/Autocomplete';
 import { useCallback, useMemo } from 'react';
-import { RelationPairs } from '../EntityRelationsGraph';
 import { useTranslationRef } from '@backstage/frontend-plugin-api';
 import { catalogGraphTranslationRef } from '../../translation';
+import { useRelations } from '../../hooks';
 
 /** @public */
 export type SelectedRelationsFilterClassKey = 'formControl';
@@ -41,25 +41,31 @@ const useStyles = makeStyles(
 );
 
 export type Props = {
-  relationPairs: RelationPairs;
+  relations?: string[];
   value: string[] | undefined;
   onChange: (value: string[] | undefined) => void;
 };
 
-export const SelectedRelationsFilter = ({
-  relationPairs,
-  value,
-  onChange,
-}: Props) => {
+export const SelectedRelationsFilter = (props: Props) => {
+  const { relations: incomingRelations, value, onChange } = props;
+
   const classes = useStyles();
-  const relations = useMemo(() => relationPairs.flat(), [relationPairs]);
+
+  const { relations, includeRelation } = useRelations({
+    relations: incomingRelations,
+  });
+
+  const defaultValue = useMemo(
+    () => relations.filter(rel => includeRelation(rel)),
+    [relations, includeRelation],
+  );
   const { t } = useTranslationRef(catalogGraphTranslationRef);
 
   const handleChange = useCallback(
     (_: unknown, v: string[]) => {
-      onChange(relations.every(r => v.includes(r)) ? undefined : v);
+      onChange(v);
     },
-    [relations, onChange],
+    [onChange],
   );
 
   const handleEmpty = useCallback(() => {
@@ -78,7 +84,7 @@ export const SelectedRelationsFilter = ({
         disableCloseOnSelect
         aria-label={t('catalogGraphPage.selectedRelationsFilter.title')}
         options={relations}
-        value={value ?? relations}
+        value={value ?? defaultValue}
         onChange={handleChange}
         onBlur={handleEmpty}
         renderOption={(option, { selected }) => (

plugins/catalog-graph/src/components/EntityRelationsGraph/EntityRelationsGraph.tsx

@@ -30,7 +30,7 @@ import classNames from 'classnames';
 import { MouseEvent, useEffect, useMemo } from 'react';
 import { DefaultRenderLabel } from './DefaultRenderLabel';
 import { DefaultRenderNode } from './DefaultRenderNode';
-import { ALL_RELATION_PAIRS, RelationPairs } from './relations';
+import { RelationPairs } from '../../types';
 import { Direction, EntityEdge, EntityNode } from './types';
 import { useEntityRelationNodesAndEdges } from './useEntityRelationNodesAndEdges';
 
@@ -109,7 +109,7 @@ export const EntityRelationsGraph = (props: EntityRelationsGraphProps) => {
     entityFilter,
     direction = Direction.LEFT_RIGHT,
     onNodeClick,
-    relationPairs = ALL_RELATION_PAIRS,
+    relationPairs,
     className,
     zoom = 'enabled',
     renderNode,

plugins/catalog-graph/src/components/EntityRelationsGraph/index.ts

@@ -18,8 +18,6 @@ export type {
   EntityRelationsGraphProps,
   EntityRelationsGraphClassKey,
 } from './EntityRelationsGraph';
-export { ALL_RELATION_PAIRS } from './relations';
-export type { RelationPairs } from './relations';
 export { Direction } from './types';
 export type {
   EntityEdgeData,

plugins/catalog-graph/src/components/EntityRelationsGraph/useEntityRelationGraph.test.tsx

@@ -13,16 +13,20 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+import { PropsWithChildren } from 'react';
+import { ApiProvider } from '@backstage/core-app-api';
 import {
   RELATION_HAS_PART,
   RELATION_OWNED_BY,
   RELATION_OWNER_OF,
   RELATION_PART_OF,
 } from '@backstage/catalog-model';
+import { TestApiRegistry } from '@backstage/test-utils';
 import { renderHook } from '@testing-library/react';
 import { pick } from 'lodash';
 import { useEntityRelationGraph } from './useEntityRelationGraph';
 import { useEntityStore as useEntityStoreMocked } from './useEntityStore';
+import { catalogGraphApiRef, DefaultCatalogGraphApi } from '../../api';
 
 jest.mock('./useEntityStore');
 
@@ -30,6 +34,19 @@ const useEntityStore = useEntityStoreMocked as jest.Mock<
   ReturnType<typeof useEntityStoreMocked>
 >;
 
+function GraphContext(props: PropsWithChildren<{}>) {
+  return (
+    <ApiProvider
+      apis={TestApiRegistry.from([
+        catalogGraphApiRef,
+        new DefaultCatalogGraphApi(),
+      ])}
+    >
+      {props.children}
+    </ApiProvider>
+  );
+}
+
 describe('useEntityRelationGraph', () => {
   const requestEntities = jest.fn();
 
@@ -171,8 +188,9 @@ describe('useEntityRelationGraph', () => {
       requestEntities,
     });
 
-    const { result } = renderHook(() =>
-      useEntityRelationGraph({ rootEntityRefs: [] }),
+    const { result } = renderHook(
+      () => useEntityRelationGraph({ rootEntityRefs: [] }),
+      { wrapper: GraphContext },
     );
     const { entities, loading, error } = result.current;
 
@@ -190,8 +208,9 @@ describe('useEntityRelationGraph', () => {
       requestEntities,
     });
 
-    const { result } = renderHook(() =>
-      useEntityRelationGraph({ rootEntityRefs: [] }),
+    const { result } = renderHook(
+      () => useEntityRelationGraph({ rootEntityRefs: [] }),
+      { wrapper: GraphContext },
     );
     const { entities, loading, error } = result.current;
 
@@ -210,8 +229,9 @@ describe('useEntityRelationGraph', () => {
       requestEntities,
     });
 
-    const { result } = renderHook(() =>
-      useEntityRelationGraph({ rootEntityRefs: [] }),
+    const { result } = renderHook(
+      () => useEntityRelationGraph({ rootEntityRefs: [] }),
+      { wrapper: GraphContext },
     );
     const { entities, loading, error } = result.current;
 
@@ -222,8 +242,9 @@ describe('useEntityRelationGraph', () => {
   });
 
   test('should walk relation tree', async () => {
-    const { result, rerender } = renderHook(() =>
-      useEntityRelationGraph({ rootEntityRefs: ['b:d/c'] }),
+    const { result, rerender } = renderHook(
+      () => useEntityRelationGraph({ rootEntityRefs: ['b:d/c'] }),
+      { wrapper: GraphContext },
     );
 
     // Simulate rerendering as this is triggered automatically due to the mock
@@ -256,11 +277,13 @@ describe('useEntityRelationGraph', () => {
   });
 
   test('should limit max depth', async () => {
-    const { result, rerender } = renderHook(() =>
-      useEntityRelationGraph({
-        rootEntityRefs: ['b:d/c'],
-        filter: { maxDepth: 1 },
-      }),
+    const { result, rerender } = renderHook(
+      () =>
+        useEntityRelationGraph({
+          rootEntityRefs: ['b:d/c'],
+          filter: { maxDepth: 1 },
+        }),
+      { wrapper: GraphContext },
     );
 
     // Simulate rerendering as this is triggered automatically due to the mock
@@ -277,11 +300,13 @@ describe('useEntityRelationGraph', () => {
 
   test('should update on filter change', async () => {
     let maxDepth: number = Number.POSITIVE_INFINITY;
-    const { result, rerender } = renderHook(() =>
-      useEntityRelationGraph({
-        rootEntityRefs: ['b:d/c'],
-        filter: { maxDepth },
-      }),
+    const { result, rerender } = renderHook(
+      () =>
+        useEntityRelationGraph({
+          rootEntityRefs: ['b:d/c'],
+          filter: { maxDepth },
+        }),
+      { wrapper: GraphContext },
     );
 
     // Simulate rerendering as this is triggered automatically due to the mock
@@ -310,13 +335,15 @@ describe('useEntityRelationGraph', () => {
   });
 
   test('should filter by relation', async () => {
-    const { result, rerender } = renderHook(() =>
-      useEntityRelationGraph({
-        rootEntityRefs: ['b:d/c'],
-        filter: {
-          relations: [RELATION_HAS_PART, RELATION_PART_OF],
-        },
-      }),
+    const { result, rerender } = renderHook(
+      () =>
+        useEntityRelationGraph({
+          rootEntityRefs: ['b:d/c'],
+          filter: {
+            relations: [RELATION_HAS_PART, RELATION_PART_OF],
+          },
+        }),
+      { wrapper: GraphContext },
     );
 
     // Simulate rerendering as this is triggered automatically due to the mock
@@ -332,14 +359,16 @@ describe('useEntityRelationGraph', () => {
   });
 
   test('should filter by kind', async () => {
-    const { result, rerender } = renderHook(() =>
-      useEntityRelationGraph({
-        rootEntityRefs: ['b:d/c'],
-        filter: {
-          relations: [RELATION_OWNED_BY, RELATION_OWNER_OF],
-          kinds: ['k'],
-        },
-      }),
+    const { result, rerender } = renderHook(
+      () =>
+        useEntityRelationGraph({
+          rootEntityRefs: ['b:d/c'],
+          filter: {
+            relations: [RELATION_OWNED_BY, RELATION_OWNER_OF],
+            kinds: ['k'],
+          },
+        }),
+      { wrapper: GraphContext },
     );
 
     // Simulate rerendering as this is triggered automatically due to the mock
@@ -354,13 +383,15 @@ describe('useEntityRelationGraph', () => {
   });
 
   test('should filter by func', async () => {
-    const { result, rerender } = renderHook(() =>
-      useEntityRelationGraph({
-        rootEntityRefs: ['b:d/c'],
-        filter: {
-          entityFilter: e => e.metadata.name !== 'c2',
-        },
-      }),
+    const { result, rerender } = renderHook(
+      () =>
+        useEntityRelationGraph({
+          rootEntityRefs: ['b:d/c'],
+          filter: {
+            entityFilter: e => e.metadata.name !== 'c2',
+          },
+        }),
+      { wrapper: GraphContext },
     );
 
     // Simulate rerendering as this is triggered automatically due to the mock
@@ -376,10 +407,12 @@ describe('useEntityRelationGraph', () => {
   });
 
   test('should support multiple roots by kind', async () => {
-    const { result, rerender } = renderHook(() =>
-      useEntityRelationGraph({
-        rootEntityRefs: ['b:d/c', 'b:d/c2'],
-      }),
+    const { result, rerender } = renderHook(
+      () =>
+        useEntityRelationGraph({
+          rootEntityRefs: ['b:d/c', 'b:d/c2'],
+        }),
+      { wrapper: GraphContext },
     );
 
     // Simulate rerendering as this is triggered automatically due to the mock

plugins/catalog-graph/src/components/EntityRelationsGraph/useEntityRelationGraph.ts

@@ -17,6 +17,7 @@ import { Entity } from '@backstage/catalog-model';
 import { useEffect, useMemo } from 'react';
 import { useEntityStore } from './useEntityStore';
 import { pickBy } from 'lodash';
+import { useRelations } from '../../hooks/useRelations';
 
 /**
  * Discover the graph of entities connected by relations, starting from a set of
@@ -45,6 +46,7 @@ export function useEntityRelationGraph({
   error?: Error;
 } {
   const { entities, loading, error, requestEntities } = useEntityStore();
+  const { includeRelation } = useRelations({ relations });
 
   useEffect(() => {
     const expectedEntities = new Set([...rootEntityRefs]);
@@ -74,7 +76,7 @@ export function useEntityRelationGraph({
           }
           for (const rel of entity.relations) {
             if (
-              (!relations || relations.includes(rel.type)) &&
+              includeRelation(rel.type) &&
               (!kinds ||
                 kinds.some(kind =>
                   rel.targetRef.startsWith(
@@ -98,7 +100,7 @@ export function useEntityRelationGraph({
     entities,
     rootEntityRefs,
     maxDepth,
-    relations,
+    includeRelation,
     kinds,
     entityFilter,
     requestEntities,

plugins/catalog-graph/src/components/EntityRelationsGraph/useEntityRelationNodesAndEdges.test.tsx

@@ -13,6 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+import { PropsWithChildren } from 'react';
 import {
   DEFAULT_NAMESPACE,
   Entity,
@@ -22,11 +23,14 @@ import {
   RELATION_PART_OF,
   stringifyEntityRef,
 } from '@backstage/catalog-model';
+import { ApiProvider } from '@backstage/core-app-api';
+import { TestApiRegistry } from '@backstage/test-utils';
 import { renderHook, waitFor } from '@testing-library/react';
 import { filter, keyBy } from 'lodash';
 import { useEntityRelationGraph as useEntityRelationGraphMocked } from './useEntityRelationGraph';
 import { useEntityRelationNodesAndEdges } from './useEntityRelationNodesAndEdges';
 import { EntityNode } from './types';
+import { catalogGraphApiRef, DefaultCatalogGraphApi } from '../../api';
 
 jest.mock('./useEntityRelationGraph');
 
@@ -129,6 +133,19 @@ function deprecatedProperties(entity: Entity): Partial<EntityNode> {
   };
 }
 
+function GraphContext(props: PropsWithChildren<{}>) {
+  return (
+    <ApiProvider
+      apis={TestApiRegistry.from([
+        catalogGraphApiRef,
+        new DefaultCatalogGraphApi(),
+      ])}
+    >
+      {props.children}
+    </ApiProvider>
+  );
+}
+
 describe('useEntityRelationNodesAndEdges', () => {
   beforeEach(() => {
     useEntityRelationGraph.mockImplementation(({ filter: { kinds } }) => ({
@@ -149,10 +166,12 @@ describe('useEntityRelationNodesAndEdges', () => {
       loading: true,
     });
 
-    const { result } = renderHook(() =>
-      useEntityRelationNodesAndEdges({
-        rootEntityRefs: ['b:d/c'],
-      }),
+    const { result } = renderHook(
+      () =>
+        useEntityRelationNodesAndEdges({
+          rootEntityRefs: ['b:d/c'],
+        }),
+      { wrapper: GraphContext },
     );
 
     const { nodes, edges, loading, error } = result.current;
@@ -170,10 +189,12 @@ describe('useEntityRelationNodesAndEdges', () => {
       error: returnError,
     });
 
-    const { result } = renderHook(() =>
-      useEntityRelationNodesAndEdges({
-        rootEntityRefs: ['b:d/c'],
-      }),
+    const { result } = renderHook(
+      () =>
+        useEntityRelationNodesAndEdges({
+          rootEntityRefs: ['b:d/c'],
+        }),
+      { wrapper: GraphContext },
     );
 
     const { nodes, edges, loading, error } = result.current;
@@ -185,12 +206,14 @@ describe('useEntityRelationNodesAndEdges', () => {
   });
 
   test('should generate unidirectional graph with merged relations', async () => {
-    const { result } = renderHook(() =>
-      useEntityRelationNodesAndEdges({
-        rootEntityRefs: ['b:d/c'],
-        unidirectional: true,
-        mergeRelations: true,
-      }),
+    const { result } = renderHook(
+      () =>
+        useEntityRelationNodesAndEdges({
+          rootEntityRefs: ['b:d/c'],
+          unidirectional: true,
+          mergeRelations: true,
+        }),
+      { wrapper: GraphContext },
     );
 
     await waitFor(() => {
@@ -260,12 +283,14 @@ describe('useEntityRelationNodesAndEdges', () => {
   });
 
   test('should generate unidirectional graph', async () => {
-    const { result } = renderHook(() =>
-      useEntityRelationNodesAndEdges({
-        rootEntityRefs: ['b:d/c'],
-        unidirectional: true,
-        mergeRelations: false,
-      }),
+    const { result } = renderHook(
+      () =>
+        useEntityRelationNodesAndEdges({
+          rootEntityRefs: ['b:d/c'],
+          unidirectional: true,
+          mergeRelations: false,
+        }),
+      { wrapper: GraphContext },
     );
 
     await waitFor(() => {
@@ -359,12 +384,14 @@ describe('useEntityRelationNodesAndEdges', () => {
   });
 
   test('should generate bidirectional graph with merged relations', async () => {
-    const { result } = renderHook(() =>
-      useEntityRelationNodesAndEdges({
-        rootEntityRefs: ['b:d/c'],
-        unidirectional: false,
-        mergeRelations: true,
-      }),
+    const { result } = renderHook(
+      () =>
+        useEntityRelationNodesAndEdges({
+          rootEntityRefs: ['b:d/c'],
+          unidirectional: false,
+          mergeRelations: true,
+        }),
+      { wrapper: GraphContext },
     );
 
     await waitFor(() => {
@@ -434,12 +461,14 @@ describe('useEntityRelationNodesAndEdges', () => {
   });
 
   test('should generate bidirectional graph with all relations', async () => {
-    const { result } = renderHook(() =>
-      useEntityRelationNodesAndEdges({
-        rootEntityRefs: ['b:d/c'],
-        unidirectional: false,
-        mergeRelations: false,
-      }),
+    const { result } = renderHook(
+      () =>
+        useEntityRelationNodesAndEdges({
+          rootEntityRefs: ['b:d/c'],
+          unidirectional: false,
+          mergeRelations: false,
+        }),
+      { wrapper: GraphContext },
     );
 
     await waitFor(() => {
@@ -533,10 +562,12 @@ describe('useEntityRelationNodesAndEdges', () => {
   });
 
   test('should generate graph with multiple root nodes', async () => {
-    const { result } = renderHook(() =>
-      useEntityRelationNodesAndEdges({
-        rootEntityRefs: ['b:d/c', 'b:d/c2'],
-      }),
+    const { result } = renderHook(
+      () =>
+        useEntityRelationNodesAndEdges({
+          rootEntityRefs: ['b:d/c', 'b:d/c2'],
+        }),
+      { wrapper: GraphContext },
     );
 
     await waitFor(() => {
@@ -606,11 +637,13 @@ describe('useEntityRelationNodesAndEdges', () => {
   });
 
   test('should filter by relation', async () => {
-    const { result } = renderHook(() =>
-      useEntityRelationNodesAndEdges({
-        rootEntityRefs: ['b:d/c'],
-        relations: [RELATION_OWNER_OF],
-      }),
+    const { result } = renderHook(
+      () =>
+        useEntityRelationNodesAndEdges({
+          rootEntityRefs: ['b:d/c'],
+          relations: [RELATION_OWNER_OF],
+        }),
+      { wrapper: GraphContext },
     );
 
     await waitFor(() => {
@@ -662,11 +695,13 @@ describe('useEntityRelationNodesAndEdges', () => {
   });
 
   test('should filter by kind', async () => {
-    const { result } = renderHook(() =>
-      useEntityRelationNodesAndEdges({
-        rootEntityRefs: ['b:d/c'],
-        kinds: ['b'],
-      }),
+    const { result } = renderHook(
+      () =>
+        useEntityRelationNodesAndEdges({
+          rootEntityRefs: ['b:d/c'],
+          kinds: ['b'],
+        }),
+      { wrapper: GraphContext },
     );
 
     await waitFor(() => {

plugins/catalog-graph/src/components/EntityRelationsGraph/useEntityRelationNodesAndEdges.ts

@@ -15,10 +15,11 @@
  */
 import { MouseEvent, useState } from 'react';
 import useDebounce from 'react-use/esm/useDebounce';
-import { RelationPairs, ALL_RELATION_PAIRS } from './relations';
+import { RelationPairs } from '../../types';
 import { EntityEdge, EntityNode } from './types';
 import { useEntityRelationGraph } from './useEntityRelationGraph';
 import { Entity, DEFAULT_NAMESPACE } from '@backstage/catalog-model';
+import { useRelations } from '../../hooks/useRelations';
 
 /**
  * Generate nodes and edges to render the entity graph.
@@ -32,7 +33,7 @@ export function useEntityRelationNodesAndEdges({
   relations,
   entityFilter,
   onNodeClick,
-  relationPairs = ALL_RELATION_PAIRS,
+  relationPairs: incomingRelationPairs,
 }: {
   rootEntityRefs: string[];
   maxDepth?: number;
@@ -63,6 +64,11 @@ export function useEntityRelationNodesAndEdges({
     },
   });
 
+  const { relationPairs, includeRelation } = useRelations({
+    relations,
+    relationPairs: incomingRelationPairs,
+  });
+
   useDebounce(
     () => {
       if (!entities || Object.keys(entities).length === 0) {
@@ -124,7 +130,7 @@ export function useEntityRelationNodesAndEdges({
               return;
             }
 
-            if (relations && !relations.includes(rel.type)) {
+            if (!includeRelation(rel.type)) {
               return;
             }
 
@@ -230,7 +236,7 @@ export function useEntityRelationNodesAndEdges({
       entities,
       rootEntityRefs,
       kinds,
-      relations,
+      includeRelation,
       unidirectional,
       mergeRelations,
       onNodeClick,

plugins/catalog-graph/src/hooks/index.ts

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2025 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export type { UseRelationsOptions, UseRelationsResult } from './useRelations';
+export { useRelations } from './useRelations';

plugins/catalog-graph/src/hooks/useRelations.ts

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2025 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import { useCallback, useMemo } from 'react';
+
+import { useApi } from '@backstage/core-plugin-api';
+
+import { catalogGraphApiRef } from '../api';
+import { RelationPairs } from '../types';
+
+export interface UseRelationsOptions {
+  relations?: string[];
+  relationPairs?: RelationPairs;
+}
+
+export interface UseRelationsResult {
+  relations: string[];
+  relationPairs: RelationPairs;
+  defaultRelations: string[];
+  includeRelation: (type: string) => boolean;
+}
+
+/**
+ * Given an optional list of specific relations and/or relation pairs,
+ * this hook returns the relations, relation pairs and default relations (to
+ * show/select), falling back to the configured setting.
+ * It also returns a function `includeRelation` to filter whether a relation
+ * should be included or not.
+ */
+export function useRelations(
+  opts: UseRelationsOptions = {},
+): UseRelationsResult {
+  const { knownRelations, knownRelationPairs, defaultRelations } =
+    useApi(catalogGraphApiRef);
+
+  const relations = opts.relations ?? knownRelations;
+  const relationPairs = opts.relationPairs ?? knownRelationPairs;
+
+  const includeRelation = useCallback(
+    (type: string) => {
+      if (opts.relations) {
+        return opts.relations.includes(type);
+      }
+      return defaultRelations.includes(type);
+    },
+    [opts.relations, defaultRelations],
+  );
+
+  return useMemo(
+    () => ({
+      relations,
+      relationPairs,
+      defaultRelations,
+      includeRelation,
+    }),
+    [relations, relationPairs, defaultRelations, includeRelation],
+  );
+}

plugins/catalog-graph/src/index.ts

@@ -23,5 +23,8 @@
 
 export * from './components';
 export { CatalogGraphPage, EntityCatalogGraphCard } from './extensions';
+export * from './api';
 export { catalogGraphPlugin } from './plugin';
 export { catalogGraphRouteRef } from './routes';
+export { ALL_RELATIONS, ALL_RELATION_PAIRS } from './types';
+export type { RelationPairs } from './types';

plugins/catalog-graph/src/plugin.ts

@@ -13,8 +13,9 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-import { createPlugin } from '@backstage/core-plugin-api';
+import { createApiFactory, createPlugin } from '@backstage/core-plugin-api';
 import { catalogEntityRouteRef, catalogGraphRouteRef } from './routes';
+import { catalogGraphApiRef, DefaultCatalogGraphApi } from './api';
 
 /**
  * Catalog Graph Plugin instance.
@@ -28,4 +29,11 @@ export const catalogGraphPlugin = createPlugin({
   externalRoutes: {
     catalogEntity: catalogEntityRouteRef,
   },
+  apis: [
+    createApiFactory({
+      api: catalogGraphApiRef,
+      deps: {},
+      factory: () => new DefaultCatalogGraphApi(),
+    }),
+  ],
 });

plugins/catalog-graph/src/types/index.ts

@@ -0,0 +1,18 @@
+/*
+ * Copyright 2025 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+export { ALL_RELATIONS, ALL_RELATION_PAIRS } from './relations';
+export type { RelationPairs } from './relations';

plugins/catalog-graph/src/types/relations.ts

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import {
+  RELATION_API_CONSUMED_BY,
+  RELATION_API_PROVIDED_BY,
+  RELATION_CHILD_OF,
+  RELATION_CONSUMES_API,
+  RELATION_DEPENDENCY_OF,
+  RELATION_DEPENDS_ON,
+  RELATION_HAS_MEMBER,
+  RELATION_HAS_PART,
+  RELATION_MEMBER_OF,
+  RELATION_OWNED_BY,
+  RELATION_OWNER_OF,
+  RELATION_PARENT_OF,
+  RELATION_PART_OF,
+  RELATION_PROVIDES_API,
+} from '@backstage/catalog-model';
+
+/**
+ * A pair of two relations that describe the opposite of each other. The first
+ * relation is considered as the primary relation.
+ *
+ * @public
+ */
+export type RelationPairs = [string, string][];
+
+/**
+ * A list of built-in relations
+ *
+ * @public
+ */
+export const ALL_RELATIONS: string[] = [
+  RELATION_API_CONSUMED_BY,
+  RELATION_API_PROVIDED_BY,
+  RELATION_CHILD_OF,
+  RELATION_CONSUMES_API,
+  RELATION_DEPENDENCY_OF,
+  RELATION_DEPENDS_ON,
+  RELATION_HAS_MEMBER,
+  RELATION_HAS_PART,
+  RELATION_MEMBER_OF,
+  RELATION_OWNED_BY,
+  RELATION_OWNER_OF,
+  RELATION_PARENT_OF,
+  RELATION_PART_OF,
+  RELATION_PROVIDES_API,
+];
+
+/**
+ * A list of pairs of entity relations, used to define which relations are
+ * merged together and which the primary relation is.
+ *
+ * @public
+ */
+export const ALL_RELATION_PAIRS: RelationPairs = [
+  [RELATION_OWNER_OF, RELATION_OWNED_BY],
+  [RELATION_CONSUMES_API, RELATION_API_CONSUMED_BY],
+  [RELATION_API_PROVIDED_BY, RELATION_PROVIDES_API],
+  [RELATION_HAS_PART, RELATION_PART_OF],
+  [RELATION_PARENT_OF, RELATION_CHILD_OF],
+  [RELATION_HAS_MEMBER, RELATION_MEMBER_OF],
+  [RELATION_DEPENDS_ON, RELATION_DEPENDENCY_OF],
+];