fix(core): retry exposing host port up to 5 times

core/src/main/java/io/zeebe/containers/ZeebeBrokerNode.java

@@ -15,9 +15,9 @@
  */
 package io.zeebe.containers;
 
+import io.zeebe.containers.util.HostPortForwarder;
 import org.apiguardian.api.API;
 import org.apiguardian.api.API.Status;
-import org.testcontainers.Testcontainers;
 import org.testcontainers.containers.GenericContainer;
 import org.testcontainers.utility.MountableFile;
 
@@ -88,15 +88,14 @@ default T withZeebeData(final ZeebeData data) {
   }
 
   /**
-   * Injects an instance of the debug exporter into the container, which will push records out to
-   * http://host.testcontainers.internal:{@code port}/records.
+   * Injects an instance of the debug exporter into the container.
    *
    * @param port the host port of the {@link io.zeebe.containers.exporter.DebugReceiver}
    * @return this container for chaining
    */
   @API(status = Status.EXPERIMENTAL)
   default T withDebugExporter(final int port) {
-    Testcontainers.exposeHostPorts(port);
+    final int containerPort = HostPortForwarder.forwardHostPort(port, 5);
 
     //noinspection resource
     withCopyToContainer(
@@ -106,7 +105,7 @@ default T withDebugExporter(final int port) {
             "ZEEBE_BROKER_EXPORTERS_DEBUG_CLASSNAME", "io.zeebe.containers.exporter.DebugExporter")
         .withEnv(
             "ZEEBE_BROKER_EXPORTERS_DEBUG_ARGS_URL",
-            "http://host.testcontainers.internal:" + port + "/records");
+            "http://host.testcontainers.internal:" + containerPort + "/records");
 
     return self();
   }

core/src/main/java/io/zeebe/containers/util/HostPortForwarder.java

@@ -0,0 +1,74 @@
+/*
+ * Copyright © 2022 camunda services GmbH (info@camunda.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.zeebe.containers.util;
+
+import java.util.HashMap;
+import java.util.Map;
+import org.agrona.collections.MutableInteger;
+import org.apiguardian.api.API;
+import org.apiguardian.api.API.Status;
+import org.rnorth.ducttape.unreliables.Unreliables;
+import org.testcontainers.Testcontainers;
+
+@API(status = Status.INTERNAL)
+public final class HostPortForwarder {
+  private final PortForwarder portForwarder;
+
+  public HostPortForwarder() {
+    this(Testcontainers::exposeHostPorts);
+  }
+
+  public HostPortForwarder(final PortForwarder portForwarder) {
+    this.portForwarder = portForwarder;
+  }
+
+  public static int forwardHostPort(final int port, final int retryCount) {
+    return new HostPortForwarder().forward(port, retryCount);
+  }
+
+  /**
+   * Exposes a given host port to your containers, accessible via host.testcontainers.internal:PORT.
+   * See <a
+   * href="https://www.testcontainers.org/features/networking/#exposing-host-ports-to-the-container">the
+   * docs</a> for more.
+   *
+   * <p>This method is mostly here as a QoL improvement to retry on I/O errors.
+   *
+   * @param port the port on the host to expose
+   * @param retryCount the number of times to retry on I/O errors
+   * @return the container port to use
+   */
+  public int forward(final int port, final int retryCount) {
+    final MutableInteger attempts = new MutableInteger();
+    return Unreliables.retryUntilSuccess(
+        retryCount,
+        () -> {
+          // since the port-forwarding requests are cached, use the attempt count to increment the
+          // container port value, such that the request is always fresh on every retry
+          final int containerPort = port + attempts.getAndIncrement();
+          final Map<Integer, Integer> portMapping = new HashMap<>();
+          portMapping.put(port, containerPort);
+
+          portForwarder.forwardPort(portMapping);
+          return containerPort;
+        });
+  }
+
+  @FunctionalInterface
+  public interface PortForwarder {
+    void forwardPort(final Map<Integer, Integer> portMapping);
+  }
+}

core/src/test/java/io/zeebe/containers/util/HostPortForwarderTest.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright © 2022 camunda services GmbH (info@camunda.com)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.zeebe.containers.util;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import io.zeebe.containers.util.HostPortForwarder.PortForwarder;
+import java.util.HashSet;
+import java.util.Set;
+import org.agrona.collections.MutableInteger;
+import org.junit.jupiter.api.Test;
+
+final class HostPortForwarderTest {
+  @Test
+  void shouldRetryUpToRetryCount() {
+    // given
+    final int retryCount = 5;
+    final MutableInteger attempts = new MutableInteger();
+    final PortForwarder forwarder =
+        mapping -> {
+          if (attempts.incrementAndGet() >= retryCount) {
+            return;
+          }
+
+          throw new RuntimeException("failure");
+        };
+    final HostPortForwarder portForwarder = new HostPortForwarder(forwarder);
+
+    // when
+    portForwarder.forward(1024, retryCount);
+
+    // then
+    assertThat(attempts.value).isEqualTo(retryCount);
+  }
+
+  @Test
+  void shouldChangeContainerPortOnRetry() {
+    // given
+    final int retryCount = 5;
+    final MutableInteger attempts = new MutableInteger();
+    final Set<Integer> containerPorts = new HashSet<>();
+    final PortForwarder forwarder =
+        mapping -> {
+          containerPorts.add(mapping.get(1024));
+
+          if (attempts.incrementAndGet() >= retryCount) {
+            return;
+          }
+
+          throw new RuntimeException("failure");
+        };
+    final HostPortForwarder portForwarder = new HostPortForwarder(forwarder);
+
+    // when
+    portForwarder.forward(1024, retryCount);
+
+    // then
+    assertThat(containerPorts).hasSize(retryCount);
+  }
+}