fix #4355: adding logic to set/validate the container name

CHANGELOG.md

@@ -18,6 +18,7 @@
 * Fix #4348: Introduce specific annotations for the generators
 * Refactor #4441: refactoring `TokenRefreshInterceptor`
 * Fix #4365: The Watch retry logic will handle more cases, as well as perform an exceptional close for events that are not properly handled.  Informers can directly provide those exceptional outcomes via the SharedIndexInformer.stopped CompletableFuture.
+* Fix #4355: for exec, attach, upload, and copy operations the container id/name will be validated or chosen prior to the remote call.  You may also use the kubectl.kubernetes.io/default-container annotation to specify the default container.  
 * Fix #4396: Provide more error context when @Group/@Version annotations are missing
 * Fix #4384: The Java generator now supports the generation of specific annotations (min, max, pattern, etc.), as defined by #4348
 * Fix #3864: Change ManagedOpenShiftClient OSGi ConfigurationPolicy to REQUIRE

kubernetes-client/src/main/java/io/fabric8/kubernetes/client/dsl/internal/core/v1/PodOperationsImpl.java

@@ -15,6 +15,7 @@
  */
 package io.fabric8.kubernetes.client.dsl.internal.core.v1;
 
+import io.fabric8.kubernetes.api.model.Container;
 import io.fabric8.kubernetes.api.model.DeleteOptions;
 import io.fabric8.kubernetes.api.model.HasMetadata;
 import io.fabric8.kubernetes.api.model.Pod;
@@ -59,6 +60,8 @@
 import io.fabric8.kubernetes.client.utils.Utils;
 import io.fabric8.kubernetes.client.utils.internal.Base64;
 import io.fabric8.kubernetes.client.utils.internal.PodOperationUtil;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import java.io.BufferedOutputStream;
 import java.io.File;
@@ -78,6 +81,7 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
+import java.util.List;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
@@ -90,6 +94,9 @@ public class PodOperationsImpl extends HasMetadataOperation<Pod, PodList, PodRes
   public static final int HTTP_TOO_MANY_REQUESTS = 429;
   private static final Integer DEFAULT_POD_LOG_WAIT_TIMEOUT = 5;
   private static final String[] EMPTY_COMMAND = { "/bin/sh", "-i" };
+  public static final String DEFAULT_CONTAINER_ANNOTATION_NAME = "kubectl.kubernetes.io/default-container";
+
+  static final transient Logger LOG = LoggerFactory.getLogger(PodOperationsImpl.class);
 
   private final PodOperationContext podOperationContext;
 
@@ -272,7 +279,7 @@ public PodOperationsImpl inContainer(
   public ExecWatch exec(String... command) {
     String[] actualCommands = command.length >= 1 ? command : EMPTY_COMMAND;
     try {
-      URL url = getExecURLWithCommandParams(actualCommands);
+      URL url = getURL("exec", actualCommands);
       return setupConnectionToPod(url.toURI());
     } catch (Throwable t) {
       throw KubernetesClientException.launderThrowable(forOperationType("exec"), t);
@@ -282,28 +289,55 @@ public ExecWatch exec(String... command) {
   @Override
   public ExecWatch attach() {
     try {
-      URL url = getAttachURL();
+      URL url = getURL("attach", null);
       return setupConnectionToPod(url.toURI());
     } catch (Throwable t) {
       throw KubernetesClientException.launderThrowable(forOperationType("attach"), t);
     }
   }
 
-  private URL getExecURLWithCommandParams(String[] commands) throws MalformedURLException {
-    String url = URLUtils.join(getResourceUrl().toString(), "exec");
+  private URL getURL(String operation, String[] commands) throws MalformedURLException {
+    String url = URLUtils.join(getResourceUrl().toString(), operation);
     URLBuilder httpUrlBuilder = new URLBuilder(url);
-    for (String cmd : commands) {
-      httpUrlBuilder.addQueryParameter("command", cmd);
+    if (commands != null) {
+      for (String cmd : commands) {
+        httpUrlBuilder.addQueryParameter("command", cmd);
+      }
     }
-    getContext().addQueryParameters(httpUrlBuilder);
+    PodOperationContext contextToUse = getContext();
+    contextToUse = contextToUse.withContainerId(validateOrDefaultContainerId(contextToUse.getContainerId()));
+    contextToUse.addQueryParameters(httpUrlBuilder);
     return httpUrlBuilder.build();
   }
 
-  private URL getAttachURL() throws MalformedURLException {
-    String url = URLUtils.join(getResourceUrl().toString(), "attach");
-    URLBuilder httpUrlBuilder = new URLBuilder(url);
-    getContext().addQueryParameters(httpUrlBuilder);
-    return httpUrlBuilder.build();
+  /**
+   * If not specified, choose an appropriate default container id
+   */
+  String validateOrDefaultContainerId(String name) {
+    Pod pod = this.require();
+    List<Container> containers = pod.getSpec().getContainers();
+    if (containers.isEmpty()) {
+      throw new KubernetesClientException("Pod has no containers!");
+    }
+    if (name == null) {
+      name = pod.getMetadata().getAnnotations().get(DEFAULT_CONTAINER_ANNOTATION_NAME);
+      if (name != null && !hasContainer(containers, name)) {
+        LOG.warn("Default container {} from annotation not found in pod {}", name, pod.getMetadata().getName());
+        name = null;
+      }
+      if (name == null) {
+        name = containers.get(0).getName();
+        LOG.debug("using first container {} in pod {}", name, pod.getMetadata().getName());
+      }
+    } else if (!hasContainer(containers, name)) {
+      throw new KubernetesClientException(
+          String.format("container %s not found in pod %s", name, pod.getMetadata().getName()));
+    }
+    return name;
+  }
+
+  private boolean hasContainer(List<Container> containers, String toFind) {
+    return containers.stream().map(Container::getName).anyMatch(s -> s.equals(toFind));
   }
 
   private ExecWebSocketListener setupConnectionToPod(URI uri) {

kubernetes-client/src/main/java/io/fabric8/kubernetes/client/dsl/internal/uploadable/PodUpload.java

@@ -63,10 +63,6 @@ private static interface UploadProcessor {
 
   private static boolean upload(PodOperationsImpl operation, String command, UploadProcessor processor) throws IOException {
     operation = operation.redirectingInput().terminateOnError();
-    String containerId = operation.getContext().getContainerId();
-    if (Utils.isNotNullOrEmpty(containerId)) {
-      operation = operation.inContainer(containerId);
-    }
     CompletableFuture<Integer> exitFuture;
     try (ExecWatch execWatch = operation.exec("sh", "-c", command)) {
       OutputStream out = execWatch.getInput();