PCBC-969: move grpc dependencies to suggests section (#153)

Hard dependency on gRPC in PHP might be problematic, so by relaxing the
requirement we allow users to choose whether to install gRPC and instead
check its presence runtime and throw exception if couchbase2:// protocol
is being used while the extensions are not loaded.

.gitignore

@@ -45,6 +45,7 @@
 /mkinstalldirs
 /modules/
 /package.xml
+/composer.phar
 /phpunit.result.cache
 /run-tests.php
 /src/.idea/

Couchbase/Cluster.php

@@ -85,8 +85,17 @@ public static function connect(string $connectionString, ClusterOptions $options
         return ClusterRegistry::connect($connectionString, $options);
     }
 
+    /**
+     * @throws InvalidArgumentException if runtime dependencies are missing ("protobuf" and "grpc" modules)
+     */
     private static function enableProtostellar(): void
     {
+        if (!extension_loaded("protobuf")) {
+            throw new InvalidArgumentException("couchbase2:// protocol requires protobuf extension");
+        }
+        if (!extension_loaded("grpc")) {
+            throw new InvalidArgumentException("couchbase2:// protocol requires grpc extension");
+        }
         ClusterRegistry::registerConnectionHandler(
             "/^protostellar:\/\//",
             function (string $connectionString, ClusterOptions $options) {

composer.json

@@ -16,14 +16,16 @@
       "email": "[email protected]"
     }
   ],
-  "require": {
-    "ext-json": "*",
+  "suggest": {
     "ext-grpc": "^1.15",
     "ext-protobuf": "^3.21",
     "google/protobuf": "^3.21",
     "grpc/grpc": "^1.42",
     "google/common-protos": "^3.1"
   },
+  "require": {
+    "ext-json": "*"
+  },
   "require-dev": {
     "ext-sockets": "*",
     "phpunit/phpunit": "^9"