docs(samples): Add fs_update_document_increment snippet

firestore/README.md

@@ -128,6 +128,7 @@ To run the Cloud Firestore Samples:
       subcollection-ref                    Get a reference to a subcollection document.
       update-doc                           Update a document.
       update-doc-array                     Update a document array field.
+      update-doc-increment                 Update a document number field using Increment.
       update-nested-fields                 Update fields in nested data.
       update-server-timestamp              Update field with server timestamp.
       where-order-by-limit-query           Combine where with order by and limit in a query.

firestore/firestore.php

@@ -706,6 +706,23 @@
     })
 );
 
+// Update Document Increment command
+$application->add((new Command('update-doc-increment'))
+    ->setDefinition($inputDefinition)
+    ->setDescription('Update a document number field using Increment.')
+    ->setHelp(<<<EOF
+The <info>%command.name%</info> command updates a document number field using the Google Cloud Firestore API.
+
+    <info>php %command.full_name%</info>
+
+EOF
+    )
+    ->setCode(function ($input, $output) {
+        $projectId = $input->getArgument('project');
+        update_doc_increment($projectId);
+    })
+);
+
 // Set Document Merge command
 $application->add((new Command('set-document-merge'))
     ->setDefinition($inputDefinition)

firestore/src/update_doc_increment.php

@@ -0,0 +1,50 @@
+<?php
+/**
+ * Copyright 2019 Google LLC.
+ *
+ * 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.
+ */
+
+/**
+ * For instructions on how to run the full sample:
+ *
+ * @see https://github.com/GoogleCloudPlatform/php-docs-samples/tree/master/firestore/README.md
+ */
+
+namespace Google\Cloud\Samples\Firestore;
+
+use Google\Cloud\Firestore\FieldValue;
+use Google\Cloud\Firestore\FirestoreClient;
+
+/**
+ * Update a document array field.
+ * ```
+ * update_doc_array('your-project-id');
+ * ```
+ */
+function update_doc_increment($projectId)
+{
+    // Create the Cloud Firestore client
+    $db = new FirestoreClient([
+        'projectId' => $projectId,
+    ]);
+    # [START fs_update_doc_array]
+    $cityRef = $db->collection('cities')->document('DC');
+
+    // Atomically increment the population of the city by 50.
+    $cityRef->update([
+        ['path' => 'regions', 'value' => FieldValue::incremet(50)]
+    ]);
+    # [END fs_update_doc_array]
+    printf('Updated the population of the DC document in the cities collection.' . PHP_EOL);
+}