Introduce backend-defaults package

Signed-off-by: Johan Haals <johan.haals@gmail.com>

packages/backend-defaults/src/CreateBackend.ts

@@ -0,0 +1,57 @@
+/*
+ * Copyright 2022 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 {
+  Backend,
+  cacheFactory,
+  configFactory,
+  createSpecializedBackend,
+  databaseFactory,
+  discoveryFactory,
+  httpRouterFactory,
+  loggerFactory,
+  permissionsFactory,
+  schedulerFactory,
+  tokenManagerFactory,
+  urlReaderFactory,
+} from '@backstage/backend-app-api';
+import { CreateBackendOptions } from './types';
+
+export const defaultServiceFactories = [
+  cacheFactory,
+  configFactory,
+  databaseFactory,
+  discoveryFactory,
+  loggerFactory,
+  permissionsFactory,
+  schedulerFactory,
+  tokenManagerFactory,
+  urlReaderFactory,
+  httpRouterFactory,
+];
+
+/**
+ * @public
+ */
+export function createBackend(options?: CreateBackendOptions): Backend {
+  // TODO: merge with provided APIs
+  return createSpecializedBackend({
+    serviceFactories: [
+      ...defaultServiceFactories,
+      ...(options?.serviceFactories || []),
+    ],
+  });
+}

packages/backend-defaults/src/index.ts

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+/*
+ * Copyright 2022 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 { CreateBackendOptions } from './types';
+export { createBackend } from './CreateBackend';

packages/backend-defaults/src/types.ts

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+/*
+ * Copyright 2022 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 { AnyServiceFactory } from '@backstage/backend-plugin-api';
+
+/**
+ * @public
+ */
+export interface CreateBackendOptions {
+  serviceFactories?: AnyServiceFactory[];
+}