tasks.js

/**
 * Copyright 2017, Google, Inc.
 * 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.
 */

'use strict';

// [START build_service]
// By default, the client will authenticate using the service account file
// specified by the GOOGLE_APPLICATION_CREDENTIALS environment variable and use
// the project specified by the GCLOUD_PROJECT environment variable. See
// https://googlecloudplatform.github.io/google-cloud-node/#/docs/datastore/latest/guides/authentication
const Datastore = require('@google-cloud/datastore');

// Instantiates a client
const datastore = Datastore();
// [END build_service]

/*
Installation and setup instructions.
1. Download the TaskList sample application from [here]
(https://github.com/GoogleCloudPlatform/nodejs-docs-samples/archive/master.zip).

2. Unzip the download:
```sh
unzip nodejs-docs-samples-master.zip
```

3. Change directories to the TaskList application:
```sh
cd nodejs-docs-samples-master/datastore
```

4. Install the dependencies and link the application:
```sh
npm install
```

5. With the gcloud SDK, be sure you are authenticated:
```sh
gcloud beta auth application-default login
```

6. At a command prompt, run the following, where `<project-id>` is the ID of
your Google Cloud Platform project.
```sh
export GCLOUD_PROJECT=<project-id>
```

7. Run the application!
```sh
node tasks <command>
```
*/

// [START add_entity]
function addTask (description) {
  const taskKey = datastore.key('Task');
  const entity = {
    key: taskKey,
    data: [
      {
        name: 'created',
        value: new Date().toJSON()
      },
      {
        name: 'description',
        value: description,
        excludeFromIndexes: true
      },
      {
        name: 'done',
        value: false
      }
    ]
  };

  datastore.save(entity)
    .then(() => {
      console.log(`Task ${taskKey.id} created successfully.`);
    })
    .catch((err) => {
      console.error('ERROR:', err);
    });
}
// [END add_entity]

// [START update_entity]
function markDone (taskId) {
  const transaction = datastore.transaction();
  const taskKey = datastore.key([
    'Task',
    taskId
  ]);

  transaction.run()
    .then(() => transaction.get(taskKey))
    .then((results) => {
      const task = results[0];
      task.done = true;
      transaction.save({
        key: taskKey,
        data: task
      });
      return transaction.commit();
    })
    .then(() => {
      // The transaction completed successfully.
      console.log(`Task ${taskId} updated successfully.`);
    })
    .catch(() => transaction.rollback());
}
// [END update_entity]

// [START retrieve_entities]
function listTasks () {
  const query = datastore.createQuery('Task')
    .order('created');

  datastore.runQuery(query)
    .then((results) => {
      const tasks = results[0];

      console.log('Tasks:');
      tasks.forEach((task) => {
        const taskKey = task[datastore.KEY];
        console.log(taskKey.id, task);
      });
    })
    .catch((err) => {
      console.error('ERROR:', err);
    });
}
// [END retrieve_entities]

// [START delete_entity]
function deleteTask (taskId) {
  const taskKey = datastore.key([
    'Task',
    taskId
  ]);

  datastore.delete(taskKey)
    .then(() => {
      console.log(`Task ${taskId} deleted successfully.`);
    })
    .catch((err) => {
      console.error('ERROR:', err);
    });
}
// [END delete_entity]

require(`yargs`) // eslint-disable-line
  .demand(1)
  .command(
    `new <description>`,
    `Adds a task with a description <description>.`,
    {},
    (opts) => addTask(opts.description)
  )
  .command(
    `done <taskId>`,
    `Marks the specified task as done.`,
    {},
    (opts) => markDone(opts.taskId)
  )
  .command(
    `list`,
    `Lists all tasks ordered by creation time.`,
    {},
    listTasks
  )
  .command(
    `delete <taskId>`,
    `Deletes a task.`,
    {},
    (opts) => deleteTask(opts.taskId)
  )
  .example(`node $0 new "Buy milk"`, `Adds a task with description "Buy milk".`)
  .example(`node $0 done 12345`, `Marks task 12345 as Done.`)
  .example(`node $0 list`, `Lists all tasks ordered by creation time`)
  .example(`node $0 delete 12345`, `Deletes task 12345.`)
  .wrap(120)
  .recommendCommands()
  .epilogue(`For more information, see https://cloud.google.com/datastore/docs`)
  .help()
  .strict()
  .argv;