ci: stop shared test containers and close gRPC/http clients after test run

Author: bevzzz

pom.xml

@@ -264,7 +264,13 @@
                 @see: https://www.oracle.com/corporate/features/understanding-java-9-modules.html
               -->
               --add-opens=java.base/java.lang=ALL-UNNAMED
-            </argLine>
+              </argLine>
+              <properties>
+                <property>
+                  <name>listener</name>
+                  <value>io.weaviate.containers.TestListener</value>
+                </property>
+              </properties>
           </configuration>
         </plugin>
         <plugin>

src/it/java/io/weaviate/containers/Container.java

@@ -18,9 +18,27 @@ public class Container {
   public static final Contextionary CONTEXTIONARY = Contextionary.createDefault();
 
   static {
+    startAll();
+  }
+
+  /** Start all shared Testcontainers. */
+  // TODO: start lazily?
+  static void startAll() {
     WEAVIATE.start();
   }
 
+  /**
+   * Stop all shared Testcontainers created in {@link #startAll}.
+   * <p>
+   * Testcontainer's Ryuk will reap any dangling containers after the tests
+   * finish. However, since {@link Weaviate} instances also hold a
+   * {@link WeaviateClient}, we want to stop them proactively to
+   * close client connections.
+   */
+  static void stopAll() {
+    WEAVIATE.stop();
+  }
+
   public static Group compose(Weaviate weaviate, GenericContainer<?>... containers) {
     return new Group(weaviate, containers);
   }

src/it/java/io/weaviate/containers/Weaviate.java

@@ -10,18 +10,22 @@
 import io.weaviate.client6.WeaviateClient;
 
 public class Weaviate extends WeaviateContainer {
-  private static WeaviateClient CLIENT;
+  private static WeaviateClient clientInstance;
 
   public static final String VERSION = "1.29.0";
   public static final String DOCKER_IMAGE = "semitechnologies/weaviate";
 
+  /**
+   * Get a client for the current Weaviate container.
+   * As we aren't running tests in parallel at the moment,
+   * this is not made thread-safe.
+   */
   public WeaviateClient getClient() {
-    if (CLIENT == null) {
+    if (clientInstance == null) {
       var config = new Config("http", getHttpHostAddress(), getGrpcHostAddress());
-      CLIENT = new WeaviateClient(config);
-      System.out.println("create Weaviate client -- ONCE");
+      clientInstance = new WeaviateClient(config);
     }
-    return CLIENT;
+    return clientInstance;
   }
 
   public static Weaviate createDefault() {
@@ -104,7 +108,7 @@ public void stop() {
     // not shut down properly.
     super.stop();
     try {
-      CLIENT.close();
+      clientInstance.close();
     } catch (IOException e) {
       // TODO: log error
     }