cli: create command factory foundations

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

packages/cli/src/commands/create/FactoryRegistry.ts

@@ -0,0 +1,76 @@
+/*
+ * 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 inquirer from 'inquirer';
+import { AnyFactory } from './types';
+import * as factories from './factories';
+import partition from 'lodash/partition';
+
+export class FactoryRegistry {
+  private static factoryMap = new Map<string, AnyFactory>(
+    Object.values(factories).map(factory => [factory.name, factory]),
+  );
+
+  static async interactiveSelect(preselected?: string): Promise<AnyFactory> {
+    let selected = preselected;
+
+    if (!selected) {
+      const answers = await inquirer.prompt<{ name: string }>([
+        {
+          type: 'list',
+          name: 'name',
+          message: 'What do you want to create?',
+          choices: Array.from(this.factoryMap.values()).map(factory => ({
+            name: `${factory.name} - ${factory.description}`,
+            value: factory.name,
+          })),
+        },
+      ]);
+      selected = answers.name;
+    }
+
+    const factory = this.factoryMap.get(selected);
+    if (!factory) {
+      throw new Error(`Unknown selection '${selected}'`);
+    }
+    return factory;
+  }
+
+  static async populateOptions(
+    factory: AnyFactory,
+    provided: Record<string, string>,
+  ): Promise<Record<string, string>> {
+    const [hasAnswers, needsAnswers] = partition(
+      factory.options,
+      option => option.name in provided,
+    );
+
+    for (const option of hasAnswers) {
+      const value = provided[option.name];
+
+      if (option.validate) {
+        const result = option.validate(value);
+        if (result !== true) {
+          throw new Error(`Invalid option '${option.name}'. ${result}`);
+        }
+      }
+    }
+
+    const answers = await inquirer.prompt(needsAnswers);
+
+    return { ...provided, ...answers };
+  }
+}

packages/cli/src/commands/create/create.ts

@@ -15,6 +15,7 @@
  */
 
 import { Command } from 'commander';
+import { FactoryRegistry } from './FactoryRegistry';
 
 function parseOptions(optionStrings: string[]): Record<string, string> {
   const options: Record<string, string> = {};
@@ -34,9 +35,13 @@ function parseOptions(optionStrings: string[]): Record<string, string> {
 }
 
 export default async (cmd: Command) => {
-  const selected = cmd.opts().select;
-  console.log('DEBUG: selected =', selected);
+  const factory = await FactoryRegistry.interactiveSelect(cmd.opts().select);
 
-  const options = parseOptions(cmd.opts().option);
-  console.log('DEBUG: options =', options);
+  const providedOptions = parseOptions(cmd.opts().option);
+  const options = await FactoryRegistry.populateOptions(
+    factory,
+    providedOptions,
+  );
+
+  await factory.create(options);
 };

packages/cli/src/commands/create/factories/frontendPlugin.ts

@@ -0,0 +1,46 @@
+/*
+ * 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 { createFactory } from '../types';
+
+type Options = {
+  id: string;
+};
+
+export const frontendPlugin = createFactory<Options>({
+  name: 'plugin',
+  description: 'A new frontend plugin',
+  options: [
+    {
+      type: 'input',
+      name: 'id',
+      message: 'Enter an ID for the plugin',
+      validate: (value: string) => {
+        if (!value) {
+          return 'Please enter an ID for the plugin';
+        } else if (!/^[a-z0-9]+(-[a-z0-9]+)*$/.test(value)) {
+          return 'Plugin IDs must be lowercase and contain only letters, digits, and dashes.';
+        }
+        return true;
+      },
+    },
+  ],
+  async create(options: Options) {
+    console.log(
+      `Creating ${this.name} with options ${JSON.stringify(options)}`,
+    );
+  },
+});

packages/cli/src/commands/create/factories/index.ts

@@ -0,0 +1,17 @@
+/*
+ * 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.
+ */
+
+export { frontendPlugin } from './frontendPlugin';

packages/cli/src/commands/create/types.ts

@@ -0,0 +1,34 @@
+/*
+ * 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 { DistinctQuestion } from 'inquirer';
+
+export type AnyOptions = Record<string, string>;
+
+export interface Factory<Options extends AnyOptions> {
+  name: string;
+  description: string;
+  options: ReadonlyArray<DistinctQuestion<Options> & { name: string }>;
+  create(options: Options): Promise<void>;
+}
+
+export type AnyFactory = Factory<AnyOptions>;
+
+export function createFactory<Options extends AnyOptions>(
+  config: Factory<Options>,
+): AnyFactory {
+  return config as AnyFactory;
+}