Update Kafka config dynamically (testcontainers#4316)

* Update Kafka config dynamically

* Simplify further, fix the Kafka Cluster example

Author: bsideup

core/src/main/java/org/testcontainers/containers/GenericContainer.java

@@ -135,7 +135,7 @@ public class GenericContainer<SELF extends GenericContainer<SELF>>
     @NonNull
     private String networkMode;
 
-    @NonNull
+    @Nullable
     private Network network;
 
     @NonNull

modules/kafka/src/main/java/org/testcontainers/containers/KafkaContainer.java

@@ -2,12 +2,8 @@
 
 import com.github.dockerjava.api.command.InspectContainerResponse;
 import lombok.SneakyThrows;
-import org.testcontainers.images.builder.Transferable;
 import org.testcontainers.utility.DockerImageName;
 
-import java.nio.charset.StandardCharsets;
-import java.util.Comparator;
-
 /**
  * This container wraps Confluent Kafka and Zookeeper (optionally)
  *
@@ -17,20 +13,14 @@ public class KafkaContainer extends GenericContainer<KafkaContainer> {
     private static final DockerImageName DEFAULT_IMAGE_NAME = DockerImageName.parse("confluentinc/cp-kafka");
     private static final String DEFAULT_TAG = "5.4.3";
 
-    private static final String STARTER_SCRIPT = "/testcontainers_start.sh";
-
     public static final int KAFKA_PORT = 9093;
 
     public static final int ZOOKEEPER_PORT = 2181;
 
     private static final String DEFAULT_INTERNAL_TOPIC_RF = "1";
 
-    private static final int PORT_NOT_ASSIGNED = -1;
-
     protected String externalZookeeperConnect = null;
 
-    private int port = PORT_NOT_ASSIGNED;
-
     /**
      * @deprecated use {@link KafkaContainer(DockerImageName)} instead
      */
@@ -80,83 +70,59 @@ public KafkaContainer withExternalZookeeper(String connectString) {
     }
 
     public String getBootstrapServers() {
-        if (port == PORT_NOT_ASSIGNED) {
-            throw new IllegalStateException("You should start Kafka container first");
-        }
-        return String.format("PLAINTEXT://%s:%s", getHost(), port);
-    }
-
-    @Override
-    protected void doStart() {
-        withCommand("sh", "-c", "while [ ! -f " + STARTER_SCRIPT + " ]; do sleep 0.1; done; " + STARTER_SCRIPT);
-
-        if (externalZookeeperConnect == null) {
-            addExposedPort(ZOOKEEPER_PORT);
-        }
-
-        super.doStart();
+        return String.format("PLAINTEXT://%s:%s", getHost(), getMappedPort(KAFKA_PORT));
     }
 
     @Override
-    @SneakyThrows
-    protected void containerIsStarting(InspectContainerResponse containerInfo, boolean reused) {
-        super.containerIsStarting(containerInfo, reused);
-
-        port = getMappedPort(KAFKA_PORT);
-
-        if (reused) {
-            return;
-        }
+    protected void configure() {
+        withEnv(
+            "KAFKA_ADVERTISED_LISTENERS",
+            String.format(
+                "BROKER://%s:9092",
+                getNetwork() != null
+                    ? getNetworkAliases().get(0)
+                    : "localhost"
+            )
+        );
 
         String command = "#!/bin/bash\n";
-        final String zookeeperConnect;
         if (externalZookeeperConnect != null) {
-            zookeeperConnect = externalZookeeperConnect;
+            withEnv("KAFKA_ZOOKEEPER_CONNECT", externalZookeeperConnect);
         } else {
-            zookeeperConnect = "localhost:" + ZOOKEEPER_PORT;
+            addExposedPort(ZOOKEEPER_PORT);
+            withEnv("KAFKA_ZOOKEEPER_CONNECT", "localhost:" + ZOOKEEPER_PORT);
             command += "echo 'clientPort=" + ZOOKEEPER_PORT + "' > zookeeper.properties\n";
             command += "echo 'dataDir=/var/lib/zookeeper/data' >> zookeeper.properties\n";
             command += "echo 'dataLogDir=/var/lib/zookeeper/log' >> zookeeper.properties\n";
             command += "zookeeper-server-start zookeeper.properties &\n";
         }
 
-        command += "export KAFKA_ZOOKEEPER_CONNECT='" + zookeeperConnect + "'\n";
-
-        command += "export KAFKA_ADVERTISED_LISTENERS='" + String.join(",", getBootstrapServers(), brokerAdvertisedListener(containerInfo)) + "'\n";
-
-        command += ". /etc/confluent/docker/bash-config \n";
-        command += "/etc/confluent/docker/configure \n";
-        command += "/etc/confluent/docker/launch \n";
+        // Optimization: skip the checks
+        command += "echo '' > /etc/confluent/docker/ensure \n";
+        // Run the original command
+        command += "/etc/confluent/docker/run \n";
+        withCommand("sh", "-c", command);
+    }
 
-        copyFileToContainer(
-            Transferable.of(command.getBytes(StandardCharsets.UTF_8), 0777),
-            STARTER_SCRIPT
+    @Override
+    @SneakyThrows
+    protected void containerIsStarted(InspectContainerResponse containerInfo) {
+        String brokerAdvertisedListener = brokerAdvertisedListener(containerInfo);
+        ExecResult result = execInContainer(
+            "kafka-configs",
+            "--alter",
+            "--bootstrap-server", brokerAdvertisedListener,
+            "--entity-type", "brokers",
+            "--entity-name", getEnvMap().get("KAFKA_BROKER_ID"),
+            "--add-config",
+            "advertised.listeners=[" + String.join(",", getBootstrapServers(), brokerAdvertisedListener) + "]"
         );
+        if (result.getExitCode() != 0) {
+            throw new IllegalStateException(result.getStderr());
+        }
     }
 
     protected String brokerAdvertisedListener(InspectContainerResponse containerInfo) {
-        // Kafka supports only one INTER_BROKER listener, so we have to pick one.
-        // The current algorithm uses the following order of resolving the IP:
-        // 1. Custom network's IP set via `withNetwork`
-        // 2. Bridge network's IP
-        // 3. Best effort fallback to getNetworkSettings#ipAddress
-        String ipAddress = containerInfo.getNetworkSettings().getNetworks().entrySet()
-            .stream()
-            .filter(it -> it.getValue().getIpAddress() != null)
-            .max(Comparator.comparingInt(entry -> {
-                if (getNetwork() != null && getNetwork().getId().equals(entry.getValue().getNetworkID())) {
-                    return 2;
-                }
-
-                if ("bridge".equals(entry.getKey())) {
-                    return 1;
-                }
-
-                return 0;
-            }))
-            .map(it -> it.getValue().getIpAddress())
-            .orElseGet(() -> containerInfo.getNetworkSettings().getIpAddress());
-
-        return String.format("BROKER://%s:%s", ipAddress, "9092");
+        return String.format("BROKER://%s:%s", containerInfo.getConfig().getHostName(), "9092");
     }
 }