Issue fabric8io#1185 Prevent docker:save failing when no images are d…

…efined.

Signed-off-by: William Rose <william.rose@nuance.com>

src/main/java/io/fabric8/maven/docker/SaveMojo.java

@@ -43,7 +43,27 @@ protected void executeInternal(ServiceHub serviceHub) throws DockerAccessExcepti
 		if (skipSave) {
 			return;
 		}
-		String imageName = getImageName();
+
+		List<ImageConfiguration> images = getResolvedImages();
+		List<ImageConfiguration> buildImages = getImagesWithBuildConfig(images);
+		String imageName;
+
+		if (saveName == null && saveAlias == null) {
+			if (buildImages.isEmpty()) {
+				log.info("No images have a build configuration defined: save skipped");
+				return;
+			}
+			if (buildImages.size() == 1) {
+				imageName = buildImages.get(0).getName();
+			} else {
+				throw new MojoExecutionException("More than one image with build configuration is defined. Please specify the image with 'docker.name' or 'docker.alias'.");
+			}
+		} else if (saveName != null && saveAlias != null) {
+			throw new MojoExecutionException("Cannot specify both name and alias.");
+		} else  {
+			imageName = getImageName(images);
+		}
+
 		String fileName = getFileName(imageName);
 		ensureSaveDir(fileName);
 		log.info("Saving image %s to %s", imageName, fileName);
@@ -52,7 +72,6 @@ protected void executeInternal(ServiceHub serviceHub) throws DockerAccessExcepti
 		}
 
 		serviceHub.getDockerAccess().saveImage(imageName, fileName, ArchiveCompression.fromFileName(fileName));
-
 	}
 
 	private String getFileName(String iName) throws MojoExecutionException {
@@ -96,19 +115,7 @@ private void ensureSaveDir(String fileName) throws MojoExecutionException {
         }
     }
 
-    private String getImageName() throws MojoExecutionException {
-		List<ImageConfiguration> images = getResolvedImages();
-		// specify image by name or alias
-		if (saveName == null && saveAlias == null) {
-			List<ImageConfiguration> buildImages = getImagesWithBuildConfig(images);
-			if (buildImages.size() == 1) {
-                return buildImages.get(0).getName();
-			}
-			throw new MojoExecutionException("More than one image with build configuration is defined. Please specify the image with 'docker.name' or 'docker.alias'.");
-		}
-		if (saveName != null && saveAlias != null) {
-			throw new MojoExecutionException("Cannot specify both name and alias.");
-		}
+    private String getImageName(List<ImageConfiguration> images) throws MojoExecutionException {
 		for (ImageConfiguration ic : images) {
 			if (equalName(ic) || equalAlias(ic)) {
 				return ic.getName();

src/test/java/io/fabric8/maven/docker/SaveMojoTest.java

@@ -0,0 +1,81 @@
+package io.fabric8.maven.docker;
+
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+
+import org.apache.maven.plugin.MojoExecutionException;
+import org.junit.Test;
+
+import io.fabric8.maven.docker.access.DockerAccessException;
+import io.fabric8.maven.docker.config.BuildImageConfiguration;
+import io.fabric8.maven.docker.config.ImageConfiguration;
+import io.fabric8.maven.docker.service.ServiceHub;
+import io.fabric8.maven.docker.util.Logger;
+import mockit.Deencapsulation;
+import mockit.Injectable;
+import mockit.Mocked;
+import mockit.Tested;
+
+public class SaveMojoTest {
+
+    @Injectable
+    Logger log;
+
+    @Tested(fullyInitialized = false)
+    private SaveMojo saveMojo;
+
+    @Mocked
+    ServiceHub serviceHub;
+
+    @Test
+    public void noFailureWithEmptyImageList() throws DockerAccessException, MojoExecutionException {
+        Deencapsulation.setField(saveMojo, "images", Collections.<ImageConfiguration>emptyList());
+        Deencapsulation.setField(saveMojo, "resolvedImages", Collections.<ImageConfiguration>emptyList());
+
+        saveMojo.executeInternal(serviceHub);
+    }
+
+    @Test
+    public void noFailureWithEmptyBuildImageList() throws DockerAccessException, MojoExecutionException {
+        ImageConfiguration image = new ImageConfiguration.Builder()
+                .name("example:latest")
+                .build();
+        Deencapsulation.setField(saveMojo, "images", Collections.singletonList(image));
+        Deencapsulation.setField(saveMojo, "resolvedImages", Collections.singletonList(image));
+
+        saveMojo.executeInternal(serviceHub);
+    }
+
+    @Test(expected = MojoExecutionException.class)
+    public void failureWithMultipleBuildImageList() throws DockerAccessException, MojoExecutionException {
+        ImageConfiguration image1 = new ImageConfiguration.Builder()
+                .name("example1:latest")
+                .buildConfig(new BuildImageConfiguration.Builder()
+                        .from("scratch")
+                        .build())
+                .build();
+        ImageConfiguration image2 = new ImageConfiguration.Builder()
+                .name("example2:latest")
+                .buildConfig(new BuildImageConfiguration.Builder()
+                        .from("scratch")
+                        .build())
+                .build();
+
+        List<ImageConfiguration> images = Arrays.asList(image1, image2);
+        Deencapsulation.setField(saveMojo, "images", images);
+        Deencapsulation.setField(saveMojo, "resolvedImages", images);
+
+        saveMojo.executeInternal(serviceHub);
+    }
+
+    @Test(expected = MojoExecutionException.class)
+    public void failureWithSaveAliasAndName() throws DockerAccessException, MojoExecutionException {
+        Deencapsulation.setField(saveMojo, "saveAlias", "not-null");
+        Deencapsulation.setField(saveMojo, "saveName", "not-null");
+        Deencapsulation.setField(saveMojo, "images", Collections.singletonList(new ImageConfiguration()));
+        Deencapsulation.setField(saveMojo, "resolvedImages", Collections.singletonList(new ImageConfiguration()));
+
+        saveMojo.executeInternal(serviceHub);
+    }
+}