Add support for a cmdline modifier to K3sContainer (#319)

Author: Donnerbart

src/main/java/com/dajudge/kindcontainer/K3sContainer.java

@@ -26,15 +26,22 @@
  * SOFTWARE.
  */
 
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import org.testcontainers.containers.BindMode;
 
+import java.util.ArrayList;
 import java.util.HashMap;
+import java.util.List;
+import java.util.function.Function;
 
 import static com.dajudge.kindcontainer.KubernetesVersionEnum.latest;
 import static com.dajudge.kindcontainer.client.KubeConfigUtils.replaceServerInKubeconfig;
 import static com.github.dockerjava.api.model.DockerObjectAccessor.overrideRawValue;
+import static java.util.Arrays.asList;
 
 public class K3sContainer<SELF extends K3sContainer<SELF>> extends KubernetesWithKubeletContainer<SELF> {
+    private static final Logger LOG = LoggerFactory.getLogger(K3sContainer.class);
     private static final int INTERNAL_API_SERVER_PORT = 6443;
     private static final HashMap<String, String> TMP_FILESYSTEMS = new HashMap<String, String>() {{
         put("/run", "");
@@ -43,6 +50,7 @@ public class K3sContainer<SELF extends K3sContainer<SELF>> extends KubernetesWit
     private final K3sContainerVersion version;
     private int minNodePort = 30000;
     private int maxNodePort = 32767;
+    private Function<List<String>, List<String>> cmdLineModifier = Function.identity();
 
     public K3sContainer() {
         this(latest(K3sContainerVersion.class));
@@ -65,12 +73,14 @@ public K3sContainer(final KubernetesImageSpec<K3sContainerVersion> imageSpec) {
 
     @Override
     public void start() {
-        this.withCommand(
+        final List<String> cmdLine = cmdLineModifier.apply(new ArrayList<>(asList(
                 "server",
                 getDisabledComponentsCmdlineArg(),
-                "--tls-san=" + this.getHost(),
+                String.format("--tls-san=%s", this.getHost()),
                 String.format("--service-node-port-range=%d-%d", minNodePort, maxNodePort)
-        );
+        )));
+        LOG.debug("K3s command line: {}", cmdLine);
+        this.withCommand(cmdLine.toArray(new String[0]));
         super.start();
     }
 
@@ -82,12 +92,23 @@ private String getDisabledComponentsCmdlineArg() {
     }
 
     @Override
-    public SELF withNodePortRange(int minPort, int maxPort) {
+    public SELF withNodePortRange(final int minPort, final int maxPort) {
         this.minNodePort = minPort;
         this.maxNodePort = maxPort;
         return self();
     }
 
+    /**
+     * Sets a command line modifier for the K3s container, e.g. to configure etcd or the K8s API server.
+     *
+     * @param modifier the command line modifier
+     * @return <code>this</code>
+     */
+    public SELF withCommandLineModifier(final Function<List<String>, List<String>> modifier) {
+        this.cmdLineModifier = modifier;
+        return self();
+    }
+
     @Override
     public int getInternalPort() {
         return INTERNAL_API_SERVER_PORT;

src/test/java/com/dajudge/kindcontainer/ConfigurableCmdlineOptionsTest.java

@@ -0,0 +1,40 @@
+package com.dajudge.kindcontainer;
+
+import com.dajudge.kindcontainer.util.ContainerVersionHelpers.KubernetesTestPackage;
+import org.junit.jupiter.api.DynamicTest;
+import org.junit.jupiter.api.TestFactory;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static com.dajudge.kindcontainer.util.ContainerVersionHelpers.k3sContainers;
+import static com.dajudge.kindcontainer.util.ContainerVersionHelpers.runWithK8s;
+import static java.util.Arrays.asList;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+public class ConfigurableCmdlineOptionsTest {
+    @TestFactory
+    public Stream<DynamicTest> adds_cmdline_options() {
+        return k3sContainers(this::assertCmdlineOptions);
+    }
+
+    private void assertCmdlineOptions(final KubernetesTestPackage<? extends K3sContainer<?>> container) {
+        runWithK8s(container.newContainer()
+                .withCommandLineModifier(cmdLine -> {
+                    cmdLine.addAll(asList("--debug", "-v", "1"));
+                    return cmdLine;
+                }), k8s -> {
+            List<String> commandParts = Arrays.stream(k8s.getCommandParts()).collect(Collectors.toList());
+            // assert that default cmdline options are still present
+            assertEquals("server", commandParts.get(0));
+            assertTrue(commandParts.get(1).contains("traefik"));
+            // assert that custom cmdline options are present
+            assertTrue(commandParts.contains("--debug"));
+            assertTrue(commandParts.contains("-v"));
+            assertTrue(commandParts.contains("1"));
+        });
+    }
+}