feat: updates backend processing to use google/cloud-functions-framework (#232)

Author: bshaffer

background-processing/backend/Dockerfile

@@ -2,19 +2,27 @@ FROM gcr.io/gae-runtimes/php73:php73_20190827_7_3_7_RC03
 
 WORKDIR /srv/
 
-# Copy over all application files
-COPY . .
+# NOTE: The entrypoint "/start", which starts up NGINX and PHP-FPM,
+# is configured by creating a `.googleconfig/app_start.json` file with the
+# contents:
+#
+#     {"entrypointContents": "CUSTOM_ENTRYPOINT"}
+#
+# We configure it to use the `router.php` file included in this package.
+RUN mkdir .googleconfig && \
+    echo '{"entrypointContents": "serve vendor/bin/router.php"}' > .googleconfig/app_start.json
 
-# Run "composer install"
+# Copy over composer files and run "composer install"
+COPY composer.* php.ini ./
 COPY --from=composer:1 /usr/bin/composer /usr/local/bin
 RUN composer install --no-dev
 
-# Set a runtime name and the function to use
-ENV GAE_RUNTIME php73
-ENV FUNCTION_TARGET translateString
+# Copy over all application files
+COPY . .
 
-# Start NGINX and PHP-FPM
-# NOTE: You can configure the container to serve a different endpoint by
-# creating a `.googleconfig/app_start.json` file with the contents
-# {"entrypointContents": "some entrypoint"}
-ENTRYPOINT ["/start"]
+# Set a runtime name
+ENV GAE_RUNTIME=php73 \
+    # Set the function to use
+    FUNCTION_TARGET=translateString \
+    # This function will respond to Pub/Sub events
+    FUNCTION_SIGNATURE_TYPE=event

background-processing/backend/composer.json

@@ -2,11 +2,6 @@
   "require": {
     "google/cloud-translate": "^1.4",
     "google/cloud-firestore": "^1.7",
-    "symfony/http-foundation": "^5.0.0"
-  },
-  "autoload": {
-    "files": [
-      "functions.php"
-    ]
+    "google/cloud-functions-framework": "^0.4.0"
   }
 }

background-processing/backend/functions.php

@@ -1,23 +1,63 @@
 <?php
 
-require __DIR__ . '/vendor/autoload.php';
+# [START getting_started_background_translate]
+# [START getting_started_background_translate_setup]
+use Google\Cloud\Firestore\FirestoreClient;
+use Google\Cloud\Firestore\Transaction;
+use Google\Cloud\Translate\TranslateClient;
 
-use Symfony\Component\HttpFoundation\Request;
+# [END getting_started_background_translate_setup]
 
-(function () {
-    $target = getenv('FUNCTION_TARGET', true);
-    if ($target === false) {
-        throw new \Exception('FUNCTION_TARGET is not set');
+/**
+ * @param array $data {
+ *     The PubSub message data containing text and target language.
+ *
+ *     @type string $text
+ *           The full text to translate.
+ *     @type string $language
+ *           The target language for the translation.
+ * }
+ */
+function translateString(array $data)
+{
+    if (empty($data['language']) || empty($data['text'])) {
+        throw new Exception('Error parsing translation data');
     }
 
-    $request = Request::createFromGlobals();
-    $message = json_decode($request->getContent(), true);
-    if (empty($message['message']['data'])) {
-        throw new \Exception('No message received');
-    }
-    $data = json_decode(base64_decode($message['message']['data']), true);
-    if (!$data) {
-        throw new \Exception('Error decoding data from message');
-    }
-    call_user_func_array($target, [$data]);
-})();
+    # [START getting_started_background_translate_init]
+    $firestore = new FirestoreClient();
+    $translate = new TranslateClient();
+
+    $translation = [
+        'original' => $data['text'],
+        'lang' => $data['language'],
+    ];
+    # [END getting_started_background_translate_init]
+
+    # [START getting_started_background_translate_transaction]
+    $docId = sprintf('%s:%s', $data['language'], base64_encode($data['text']));
+    $docRef = $firestore->collection('translations')->document($docId);
+
+    $firestore->runTransaction(
+        function (Transaction $transaction) use ($translate, $translation, $docRef) {
+            $snapshot = $transaction->snapshot($docRef);
+            if ($snapshot->exists()) {
+                return; // Do nothing if the document already exists
+            }
+
+            # [START getting_started_background_translate_string]
+            $result = $translate->translate($translation['original'], [
+                'target' => $translation['lang'],
+            ]);
+            # [END getting_started_background_translate_string]
+            $transaction->set($docRef, $translation + [
+                'translated' => $result['text'],
+                'originalLang' => $result['source'],
+            ]);
+        }
+    );
+    # [END getting_started_background_translate_transaction]
+
+    echo "Done.";
+}
+# [END getting_started_background_translate]

background-processing/backend/index.php

@@ -18,7 +18,7 @@
 use Google\Cloud\Firestore\FirestoreClient;
 use PHPUnit\Framework\TestCase;
 
-require_once __DIR__ . '/../../backend/functions.php';
+require_once __DIR__ . '/../../backend/index.php';
 
 class translateTest extends TestCase
 {