add loading options

modules/k3s/src/main/java/org/testcontainers/k3s/K3sContainer.java

@@ -5,17 +5,26 @@
 import com.fasterxml.jackson.databind.node.ObjectNode;
 import com.fasterxml.jackson.databind.node.TextNode;
 import com.fasterxml.jackson.dataformat.yaml.YAMLFactory;
+import com.github.dockerjava.api.command.CopyArchiveToContainerCmd;
 import com.github.dockerjava.api.command.InspectContainerResponse;
+import com.github.dockerjava.api.command.SaveImageCmd;
 import lombok.SneakyThrows;
 import org.apache.commons.io.IOUtils;
 import org.testcontainers.containers.BindMode;
+import org.testcontainers.containers.Container;
 import org.testcontainers.containers.GenericContainer;
 import org.testcontainers.containers.wait.strategy.Wait;
 import org.testcontainers.utility.DockerImageName;
 
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
 import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.StandardCopyOption;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Set;
 
 /**
  * Testcontainers implementation for K3S
@@ -50,6 +59,50 @@ public K3sContainer(DockerImageName dockerImageName) {
         setWaitStrategy(Wait.forLogMessage(".*Node controller sync successful.*", 1));
     }
 
+    /**
+     * import images into the running k3s instance. Images are assumed to be present
+     * on the host already.
+     *
+     * @param images images to be imported into the k3s.
+     * @throws IOException in case temporary directory/files needed for the import can not be created
+     * @throws InterruptedException thrown when the thread is interrupted
+     */
+    public void loadImages(Set<String> images) throws IOException, InterruptedException {
+        if (images != null && !images.isEmpty()) {
+            // create temporary directory on the host where all tar(s) will reside
+            File tarsTempFolder = Files.createTempDirectory("").toFile();
+            File tarFile = File.createTempFile("images", ".tar", tarsTempFolder);
+
+            for (String image : images) {
+                try (SaveImageCmd saveImageCmd = getDockerClient().saveImageCmd(image)) {
+                    InputStream imageStream = saveImageCmd.exec();
+                    // tar file for a single image
+                    Files.copy(imageStream, tarFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
+                    importTar(tarFile, true);
+                }
+            }
+
+            // at this point, directory is empty
+            Files.deleteIfExists(tarsTempFolder.toPath());
+        }
+    }
+
+    /**
+     * Import this tar file into the running k3s.
+     *
+     * @param paths absolute paths of the tar files on the host.
+     * @throws IOException in case temporary directory/files needed for the import can not be created
+     * @throws InterruptedException thrown when the thread is interrupted
+     */
+    public void loadImageFromTar(Set<String> paths) throws IOException, InterruptedException {
+        if (paths != null && !paths.isEmpty()) {
+            for (String path : paths) {
+                File tarFile = new File(path);
+                importTar(tarFile, false);
+            }
+        }
+    }
+
     @Override
     protected void containerIsStarted(InspectContainerResponse containerInfo) {
         String rawKubeConfig = copyFileFromContainer(
@@ -103,4 +156,20 @@ private String kubeConfigWithServerUrl(String kubeConfigYaml, String serverUrl)
 
         return objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(kubeConfigObjectNode);
     }
+
+    private void importTar(File tarFile, boolean deleteAfterCopy) throws IOException, InterruptedException {
+        try (CopyArchiveToContainerCmd copyCmd = getDockerClient().copyArchiveToContainerCmd(getContainerId())) {
+            String remotePathName = "/tmp/" + tarFile.getName();
+            copyCmd.withHostResource(tarFile.getAbsolutePath()).withRemotePath("/tmp").exec();
+            Container.ExecResult result = execInContainer("ctr", "i", "import", remotePathName);
+            boolean noErrors = result.getStderr() == null || result.getStderr().isEmpty();
+            if (!noErrors) {
+                throw new RuntimeException(result.getStderr());
+            }
+        } finally {
+            if (deleteAfterCopy) {
+                Files.deleteIfExists(tarFile.toPath());
+            }
+        }
+    }
 }

modules/k3s/src/test/java/org/testcontainers/k3s/K3sLoadImagesTest.java

@@ -0,0 +1,56 @@
+package org.testcontainers.k3s;
+
+import com.github.dockerjava.api.command.PullImageCmd;
+import com.github.dockerjava.api.command.SaveImageCmd;
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.testcontainers.containers.Container;
+import org.testcontainers.utility.DockerImageName;
+
+import java.io.File;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.StandardCopyOption;
+import java.util.Collections;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class K3sLoadImagesTest {
+
+    @ClassRule
+    public static K3sContainer k3s = new K3sContainer(DockerImageName.parse("rancher/k3s:v1.21.3-k3s1"));
+
+    @Test
+    public void testLoadImages() throws Exception {
+        try (PullImageCmd pullImageCmd = k3s.getDockerClient().pullImageCmd("busybox:1.35")) {
+            pullImageCmd.start().awaitCompletion();
+
+            k3s.loadImages(Collections.singleton("busybox:1.35"));
+            Container.ExecResult result = k3s.execInContainer("crictl", "images");
+            assertThat(result.getStdout()).contains("busybox");
+        }
+    }
+
+    @Test
+    public void testLoadImageFromTar() throws Exception {
+        try (PullImageCmd pullImageCmd = k3s.getDockerClient().pullImageCmd("busybox:1.35")) {
+            pullImageCmd.start().awaitCompletion();
+
+            File tarsTempFolder = Files.createTempDirectory("").toFile();
+            File tarFile = File.createTempFile("images", ".tar", tarsTempFolder);
+
+            try (SaveImageCmd saveImageCmd = k3s.getDockerClient().saveImageCmd("busybox:1.35")) {
+                InputStream imageStream = saveImageCmd.exec();
+                Files.copy(imageStream, tarFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
+
+                k3s.loadImageFromTar(Collections.singleton(tarFile.getAbsolutePath()));
+
+                Container.ExecResult result = k3s.execInContainer("crictl", "images");
+                assertThat(result.getStdout()).contains("busybox");
+            } finally {
+                Files.delete(tarFile.toPath());
+                Files.delete(tarsTempFolder.toPath());
+            }
+        }
+    }
+}