chore: upgrade datastore tutorial to new sample format (GoogleCloudPlatform#1648)

Author: bshaffer

datastore/tutorial/README.md

@@ -25,4 +25,12 @@ or
 1. Download the json key file of the service account.
 1. Set GOOGLE_APPLICATION_CREDENTIALS environment variable pointing to that file.
 
-Then you can run the command: `php tasks.php`
+Then you can run the code samples:
+
+1.  Execute the snippets in the [src/](src/) directory by running:
+
+    ```text
+    $ php src/SNIPPET_NAME.php
+    ```
+
+    The usage will print for each if no arguments are provided.

datastore/tutorial/composer.json

@@ -1,10 +1,5 @@
 {
     "require": {
-        "google/cloud-datastore": "^1.2",
-        "symfony/console": "^5.0"
-    },
-    "autoload": {
-        "psr-4": { "Google\\Cloud\\Samples\\Datastore\\Tasks\\": "src" },
-        "files": ["src/functions.php"]
+        "google/cloud-datastore": "^1.2"
     }
 }

datastore/tutorial/src/CreateTaskCommand.php

@@ -0,0 +1,51 @@
+<?php
+/**
+ * Copyright 2016 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.
+ */
+
+namespace Google\Cloud\Samples\Datastore\Tasks;
+
+use DateTime;
+// [START datastore_add_entity]
+use Google\Cloud\Datastore\DatastoreClient;
+
+/**
+ * Create a new task with a given description.
+ *
+ * @param string $projectId The Google Cloud project ID.
+ * @param string $description
+ */
+function add_task(string $projectId, string $description)
+{
+    $datastore = new DatastoreClient(['projectId' => $projectId]);
+
+    $taskKey = $datastore->key('Task');
+    $task = $datastore->entity(
+        $taskKey,
+        [
+            'created' => new DateTime(),
+            'description' => $description,
+            'done' => false
+        ],
+        ['excludeFromIndexes' => ['description']]
+    );
+    $datastore->insert($task);
+    printf('Created new task with ID %d.' . PHP_EOL, $task->key()->pathEnd()['id']);
+}
+// [END datastore_add_entity]
+
+// The following 2 lines are only needed to execute the samples on the CLI
+require_once __DIR__ . '/../../../testing/sample_helpers.php';
+\Google\Cloud\Samples\execute_sample(__FILE__, __NAMESPACE__, $argv);

datastore/tutorial/src/DeleteTaskCommand.php

@@ -0,0 +1,37 @@
+<?php
+/**
+ * Copyright 2016 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.
+ */
+
+namespace Google\Cloud\Samples\Datastore\Tasks;
+
+if (isset($argv)) {
+    return print("This file is for example only and cannot be executed\n");
+}
+
+// [START datastore_build_service]
+use Google\Cloud\Datastore\DatastoreClient;
+
+/**
+ * Create a Cloud Datastore client.
+ *
+ * @param string $projectId The Google Cloud project ID.
+ */
+function build_service(string $projectId)
+{
+    $datastore = new DatastoreClient(['projectId' => $projectId]);
+    return $datastore;
+}
+// [END datastore_build_service]