Add option to enable logging into stdout using env variable (#123)

* Add option to log container into stdout

Signed-off-by: see-quick <maros.orsak159@gmail.com>

* update use only ENV variable

Signed-off-by: see-quick <maros.orsak159@gmail.com>

* remove un-necessary

Signed-off-by: see-quick <maros.orsak159@gmail.com>

* Add a few words into README.md

Signed-off-by: see-quick <maros.orsak159@gmail.com>

* oops

Signed-off-by: see-quick <maros.orsak159@gmail.com>

* update

Signed-off-by: see-quick <maros.orsak159@gmail.com>

---------

Signed-off-by: see-quick <maros.orsak159@gmail.com>

README.md

@@ -206,7 +206,7 @@ systemUnderTest.start();
 strimziKafkaContainer.getProxy().setConnectionCut(true);
 ```
 
-#### xi) Run a multi-node Kafka cluster
+#### x) Run a multi-node Kafka cluster
 
 To run a multi-node Kafka cluster, you can use the StrimziKafkaCluster class with the builder pattern.
 
@@ -235,6 +235,13 @@ StrimziKafkaCluster kafkaCluster = new StrimziKafkaCluster.StrimziKafkaClusterBu
 kafkaCluster.start();
 ```
 
+#### xi) Logging Kafka Container/Cluster Output to SLF4J
+
+If you want to enable logging of the Kafka container’s output to SLF4J, 
+you can set the environment variable STRIMZI_TEST_CONTAINER_LOGGING_ENABLED to true. 
+By default, this feature is disabled.
+This can help in debugging or monitoring the Kafka broker’s activities during tests.
+
 ### Running Mutation Testing
 
 To run mutation testing and assess your code’s robustness against small changes, use the following Maven command:

src/main/java/io/strimzi/test/container/StrimziKafkaContainer.java

@@ -15,6 +15,7 @@
 import org.testcontainers.containers.GenericContainer;
 import org.testcontainers.containers.Network;
 import org.testcontainers.containers.ToxiproxyContainer;
+import org.testcontainers.containers.output.Slf4jLogConsumer;
 import org.testcontainers.containers.wait.strategy.Wait;
 import org.testcontainers.containers.wait.strategy.WaitStrategy;
 import org.testcontainers.images.builder.Transferable;
@@ -78,6 +79,8 @@ public class StrimziKafkaContainer extends GenericContainer<StrimziKafkaContaine
      * Lazy image name provider
      */
     private final CompletableFuture<String> imageNameProvider;
+    private final boolean enableBrokerContainerSlf4jLogging = Boolean.parseBoolean(
+        System.getenv().getOrDefault("STRIMZI_TEST_CONTAINER_LOGGING_ENABLED", "false"));
 
     // instance attributes
     private int kafkaExposedPort;
@@ -186,6 +189,10 @@ protected void doStart() {
             this.addEnv("OAUTH_USERNAME_CLAIM", this.usernameClaim);
         }
 
+        if (this.enableBrokerContainerSlf4jLogging) {
+            this.withLogConsumer(new Slf4jLogConsumer(LoggerFactory.getLogger("StrimziKafkaContainer-" + this.brokerId)));
+        }
+
         super.setCommand("sh", "-c", runStarterScript());
         super.doStart();
     }