GH-8558 Make Ryuk shutdown hook configurable.

core/src/main/java/org/testcontainers/utility/RyukResourceReaper.java

@@ -77,18 +77,20 @@ private synchronized void maybeStart() {
 
         ryukContainer.start();
 
-        Runtime
-            .getRuntime()
-            .addShutdownHook(
-                new Thread(
-                    DockerClientFactory.TESTCONTAINERS_THREAD_GROUP,
-                    () -> {
-                        this.dockerClient.killContainerCmd(this.ryukContainer.getContainerId())
-                            .withSignal("SIGTERM")
-                            .exec();
-                    }
-                )
-            );
+        if (TestcontainersConfiguration.getInstance().isRyukShutdownHookEnabled()) {
+            Runtime
+                .getRuntime()
+                .addShutdownHook(
+                    new Thread(
+                        DockerClientFactory.TESTCONTAINERS_THREAD_GROUP,
+                        () -> {
+                            this.dockerClient.killContainerCmd(this.ryukContainer.getContainerId())
+                                .withSignal("SIGTERM")
+                                .exec();
+                        }
+                    )
+                );
+        }
 
         CountDownLatch ryukScheduledLatch = new CountDownLatch(1);
 

core/src/main/java/org/testcontainers/utility/TestcontainersConfiguration.java

@@ -179,6 +179,10 @@ public boolean isDisableChecks() {
         return Boolean.parseBoolean(getEnvVarOrUserProperty("checks.disable", "false"));
     }
 
+    public boolean isRyukShutdownHookEnabled() {
+        return Boolean.parseBoolean(getEnvVarOrUserProperty("ryuk.container.shutdownhook", "false"));
+    }
+
     @UnstableAPI
     public boolean environmentSupportsReuse() {
         // specifically not supported as an environment variable or classpath property

core/src/test/java/org/testcontainers/utility/TestcontainersConfigurationTest.java

@@ -225,6 +225,35 @@ public void shouldTrimImageNames() {
             .isEqualTo("testcontainers/ryuk:0.3.2");
     }
 
+    @Test
+    public void shouldNotReadRyukShutdownHookClasspathProperties() {
+        assertThat(newConfig().isRyukShutdownHookEnabled()).as("Ryuk shutdown hook disabled by default").isFalse();
+
+        classpathProperties.setProperty("ryuk.container.shutdownhook", "true");
+        assertThat(newConfig().isRyukShutdownHookEnabled())
+            .as("Ryuk shutdown hook is not affected by classpath properties")
+            .isFalse();
+    }
+
+    @Test
+    public void shouldReadRyukShutdownHookFromUserProperties() {
+        assertThat(newConfig().isRyukShutdownHookEnabled()).as("Ryuk shutdown hook disabled by default").isFalse();
+
+        userProperties.setProperty("ryuk.container.shutdownhook", "true");
+        assertThat(newConfig().isRyukShutdownHookEnabled())
+            .as("Ryuk shutdown hook enabled via user properties")
+            .isTrue();
+    }
+
+    @Test
+    public void shouldReadRyukShutdownHookFromEnvironment() {
+        assertThat(newConfig().isRyukShutdownHookEnabled()).as("Ryuk shutdown hook disabled by default").isFalse();
+
+        userProperties.remove("ryuk.container.shutdownhook");
+        environment.put("TESTCONTAINERS_RYUK_CONTAINER_SHUTDOWNHOOK", "true");
+        assertThat(newConfig().isRyukShutdownHookEnabled()).as("Ryuk shutdown hook enabled via env var").isTrue();
+    }
+
     private TestcontainersConfiguration newConfig() {
         return new TestcontainersConfiguration(userProperties, classpathProperties, environment);
     }

docs/features/configuration.md

@@ -79,13 +79,16 @@ Some companies disallow the usage of Docker Hub, but you can override `*.image`
 > **ryuk.container.privileged = true**
 > In some environments ryuk must be started in privileged mode to work properly (--privileged flag)
 
+> **ryuk.container.shutdownhook = true**
+> In order to improve the termination process you may configure a shutdown hook which will send a SIGTERM to the Ryuk container causing it to finish sooner.
+
 ### Disabling Ryuk
 Ryuk must be started as a privileged container.  
 If your environment already implements automatic cleanup of containers after the execution,
 but does not allow starting privileged containers, you can turn off the Ryuk container by setting
 `TESTCONTAINERS_RYUK_DISABLED` **environment variable** to `true`.
 
-!!!tip
+!!! tip
     Note that Testcontainers will continue doing the cleanup at JVM's shutdown, unless you `kill -9` your JVM process.
 
 ## Customizing image pull behaviour