From 0cb716e5f8a9c7d0f6bb29ac332363bbee8fc6fc Mon Sep 17 00:00:00 2001
From: Chris Price <cprice404@users.noreply.github.com>
Date: Tue, 7 Nov 2023 10:07:31 -0800
Subject: [PATCH] feat: add `close` method for explicitly closing client (#174)

This is intended to help us determine whether or not a persistent
gRPC connection that gets into a bad state can be explicitly
closed and re-opened to restore the environment to a healthy state.
---
 src/Cache/CacheClient.php                    | 13 +++++++++++++
 src/Cache/Internal/ControlGrpcManager.php    | 11 ++++++++---
 src/Cache/Internal/IdleDataClientWrapper.php |  4 ++++
 src/Cache/Internal/ScsControlClient.php      |  4 ++++
 tests/Cache/CacheClientTest.php              | 11 +++++++++++
 5 files changed, 40 insertions(+), 3 deletions(-)

diff --git a/src/Cache/CacheClient.php b/src/Cache/CacheClient.php
index db111b0f..62f0ef97 100644
--- a/src/Cache/CacheClient.php
+++ b/src/Cache/CacheClient.php
@@ -96,6 +96,19 @@ public function __construct(
         }
     }
 
+    /**
+     * Close the client and free up all associated resources. NOTE: the client object will not be usable after calling
+     * this method.
+     */
+    public function close(): void
+    {
+        $this->controlClient->close();
+        foreach ($this->dataClients as $dataClient) {
+            $dataClient->close();
+        }
+    }
+
+
     /**
      * Assigns a LoggerInterface logging object to the client.
      *
diff --git a/src/Cache/Internal/ControlGrpcManager.php b/src/Cache/Internal/ControlGrpcManager.php
index 2a8b3ec7..019a5b09 100644
--- a/src/Cache/Internal/ControlGrpcManager.php
+++ b/src/Cache/Internal/ControlGrpcManager.php
@@ -16,6 +16,7 @@ class ControlGrpcManager
 {
 
     public ScsControlClient $client;
+    private Channel $channel;
 
     public function __construct(ICredentialProvider $authProvider)
     {
@@ -24,14 +25,18 @@ public function __construct(ICredentialProvider $authProvider)
         if ($authProvider->getTrustedControlEndpointCertificateName()) {
             $channelArgs["grpc.ssl_target_name_override"] = $authProvider->getTrustedControlEndpointCertificateName();
         }
-        $channel = new Channel($endpoint, $channelArgs);
+        $this->channel = new Channel($endpoint, $channelArgs);
         $interceptors = [
             new AuthorizationInterceptor($authProvider->getAuthToken()),
             new AgentInterceptor(),
         ];
-        $channel = Interceptor::intercept($channel, $interceptors);
+        $interceptedChannel = Interceptor::intercept($this->channel, $interceptors);
         $options = [];
-        $this->client = new ScsControlClient($endpoint, $options, $channel);
+        $this->client = new ScsControlClient($endpoint, $options, $interceptedChannel);
+    }
+
+    public function close(): void {
+        $this->channel->close();
     }
 
 }
diff --git a/src/Cache/Internal/IdleDataClientWrapper.php b/src/Cache/Internal/IdleDataClientWrapper.php
index 929744b0..71ffc61c 100644
--- a/src/Cache/Internal/IdleDataClientWrapper.php
+++ b/src/Cache/Internal/IdleDataClientWrapper.php
@@ -42,6 +42,10 @@ public function getClient(): ScsDataClient {
         return $this->client;
     }
 
+    public function close(): void {
+        $this->client->close();
+    }
+
     private function getMilliseconds(): int {
         return (int)(gettimeofday(true) * 1000);
     }
diff --git a/src/Cache/Internal/ScsControlClient.php b/src/Cache/Internal/ScsControlClient.php
index 9fe8f2c2..f6b9178a 100644
--- a/src/Cache/Internal/ScsControlClient.php
+++ b/src/Cache/Internal/ScsControlClient.php
@@ -45,6 +45,10 @@ public function __construct(ILoggerFactory $loggerFactory, ICredentialProvider $
         $this->setLogger($this->loggerFactory->getLogger(get_class($this)));
     }
 
+    public function close(): void {
+        $this->grpcManager->close();
+    }
+
     public function setLogger(LoggerInterface $logger): void
     {
         $this->logger = $logger;
diff --git a/tests/Cache/CacheClientTest.php b/tests/Cache/CacheClientTest.php
index ca004eb3..4ab9758a 100644
--- a/tests/Cache/CacheClientTest.php
+++ b/tests/Cache/CacheClientTest.php
@@ -68,6 +68,17 @@ private function getConfigurationWithDeadline(int $deadline)
         return new Configuration($loggerFactory, $transportStrategy);
     }
 
+    public function testCreateAndCloseClient() {
+        $client = new CacheClient($this->configuration, $this->authProvider, $this->DEFAULT_TTL_SECONDS);
+        $response = $client->listCaches();
+        $this->assertNull($response->asError());
+        $client->close();
+        $client = new CacheClient($this->configuration, $this->authProvider, $this->DEFAULT_TTL_SECONDS);
+        $response = $client->listCaches();
+        $this->assertNull($response->asError());
+        $client->close();
+    }
+
     // Happy path test
 
     public function testCreateSetGetDelete()