Enable gRPC GCP channel management library for the spanner API

Spanner/src/Connection/Grpc.php

@@ -46,6 +46,8 @@
 use Google\Protobuf\ListValue;
 use Google\Protobuf\Struct;
 use Google\Protobuf\Value;
+use Grpc\Gcp\ApiConfig;
+use Grpc\Gcp\Config;
 use Grpc\UnaryCall;
 
 /**
@@ -120,11 +122,25 @@ class Grpc implements ConnectionInterface
      */
     private $longRunningGrpcClients;
 
+    private function enableConnectionManagement($hostName, $confPath)
+    {
+        // TODO(ddyihai): move this function to GrpcTrait, if we are going
+        // to enable the grpc-gcp library for other apis.
+        $conf = new ApiConfig();
+        $conf->mergeFromJsonString(file_get_contents($confPath));
+        $config = new Config($hostName, $conf);
+        return $config;
+    }
+
     /**
      * @param array $config [optional]
      */
     public function __construct(array $config = [])
     {
+        if (getenv("ENABLE_GCP_OPTIMIZER") === false) {
+            // Enable the GCP optimizer by default.
+            putenv('ENABLE_GCP_OPTIMIZER=TRUE');
+        }
         $this->serializer = new Serializer([
             'commit_timestamp' => function ($v) {
                 return $this->formatTimestampFromApi($v);
@@ -152,6 +168,20 @@ public function __construct(array $config = [])
                 ? $config['authHttpHandler']
                 : null
         );
+
+        if (getenv('ENABLE_GCP_OPTIMIZER') == 'TRUE') {
+            if (extension_loaded('sysvshm')) {
+                $api = 'spanner';
+                $confPath = __DIR__. "/../V1/resources/$api.grpc.config";
+                $grpcGcpConfig = $this->enableConnectionManagement('spanner.googleapis.com', $confPath);
+                $grpcConfig['transportConfig']['grpc'] = [
+                    'stubOpts' => [
+                        'grpc_call_invoker' => $grpcGcpConfig->callInvoker()
+                    ]
+                ];
+            }
+        }
+
         $this->spannerClient = isset($config['gapicSpannerClient'])
             ? $config['gapicSpannerClient']
             : new SpannerClient($grpcConfig);

Spanner/src/V1/resources/spanner.grpc.config

@@ -0,0 +1,30 @@
+{
+    "channelPool":{"maxSize":10,"maxConcurrentStreamsLowWatermark":1},
+    "method":[
+      {"name":["/google.spanner.v1.Spanner/CreateSession"],
+        "affinity":{"command":"BIND", "affinityKey":"name"}},
+      {"name":["/google.spanner.v1.Spanner/GetSession"],
+        "affinity":{"command":"BOUND", "affinityKey":"name"}},
+      {"name":["/google.spanner.v1.Spanner/DeleteSession"],
+        "affinity":{"command":"UNBIND", "affinityKey":"name"}},
+      {"name":["/google.spanner.v1.Spanner/ExecuteSql"],
+        "affinity":{"command":"BOUND", "affinityKey":"session"}},
+      {"name":["/google.spanner.v1.Spanner/ExecuteStreamingSql"],
+        "affinity":{"command":"BOUND", "affinityKey":"session"}},
+      {"name":["/google.spanner.v1.Spanner/Read"],
+        "affinity":{"command":"BOUND", "affinityKey":"session"}},
+      {"name":["/google.spanner.v1.Spanner/StreamingRead"],
+        "affinity":{"command":"BOUND", "affinityKey":"session"}},
+      {"name":["/google.spanner.v1.Spanner/BeginTransaction"],
+        "affinity":{"command":"BOUND", "affinityKey":"session"}},
+      {"name":["/google.spanner.v1.Spanner/Commit"],
+        "affinity":{"command":"BOUND", "affinityKey":"session"}},
+      {"name":["/google.spanner.v1.Spanner/Rollback"],
+        "affinity":{"command":"BOUND", "affinityKey":"session"}},
+      {"name":["/google.spanner.v1.Spanner/PartitionQuery"],
+        "affinity":{"command":"BOUND", "affinityKey":"session"}},
+      {"name":["/google.spanner.v1.Spanner/PartitionRead"],
+        "affinity":{"command":"BOUND", "affinityKey":"session"}}
+      ]
+}
+

composer.json

@@ -50,7 +50,8 @@
         "monolog/monolog": "~1",
         "psr/http-message": "1.0.*",
         "ramsey/uuid": "~3",
-        "google/gax": "^0.36"
+        "google/gax": "^0.36",
+        "google/grpc-gcp": "v0.1.0"
     },
     "require-dev": {
         "phpunit/phpunit": "^4.8|^5.0",