Allow specifying image configuration via Maps. (#360)

This allows merging of configuration using the normal Maven behavior.

Signed-off-by: Wolfgang Kritzinger <wkritzinger@atlassian.com>

src/main/asciidoc/inc/_image-configuration.adoc

@@ -13,4 +13,13 @@ Either a `<build>` or `<run>` section must be present (except when you are using
 
 include::image/_example.adoc[]
 
+When using Maven profiles, it can be useful to override settings
+of a particular image. To facilitate this, the element `<imagesMap>`
+can be used alongside the `<images>` element. Each entry in `<imagesMap>`
+translates to an image configuration where the **alias** of the image
+is set to the map entry's **key**. The examples above and below produce
+identical image configurations.
+
+include::image/_example_imagesMap.adoc[]
+
 include::image/_naming.adoc[]

src/main/asciidoc/inc/image/_example_imagesMap.adoc

@@ -0,0 +1,15 @@
+
+.Example
+[source,xml]
+----
+<configuration>
+  ....
+  <imagesMap>
+    <service>
+      <name>%g/docker-demo:0.1</name>
+      <run>....</run>
+      <build>....</build>
+    </service>
+  </images>
+</configuration>
+----

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

@@ -4,8 +4,10 @@
 import java.io.IOException;
 import java.util.Date;
 import java.util.List;
+import java.util.Map;
 import java.util.Properties;
 
+import com.google.common.collect.ImmutableList;
 import io.fabric8.maven.docker.access.DockerAccess;
 import io.fabric8.maven.docker.access.ExecException;
 import io.fabric8.maven.docker.config.BuildImageConfiguration;
@@ -181,6 +183,12 @@ public abstract class AbstractDockerMojo extends AbstractMojo implements Context
     @Parameter
     private List<ImageConfiguration> images;
 
+    /**
+     * Image configurations configured via maps to allow overriding.
+     */
+    @Parameter
+    private Map<String, ImageConfiguration> imagesMap;
+
     // Docker-machine configuration
     @Parameter
     private DockerMachineConfiguration machine;
@@ -216,7 +224,7 @@ public void execute() throws MojoExecutionException, MojoFailureException {
 
                 LogOutputSpecFactory logSpecFactory = new LogOutputSpecFactory(useColor, logStdout, logDate);
 
-                ConfigHelper.validateExternalPropertyActivation(project, images);
+                ConfigHelper.validateExternalPropertyActivation(project, getAllImages());
 
                 DockerAccess access = null;
                 try {
@@ -324,7 +332,7 @@ private String initImageConfiguration(Date buildTimeStamp)  {
         // Resolve images
         resolvedImages = ConfigHelper.resolveImages(
             log,
-            images,                  // Unresolved images
+                getAllImages(), // Unresolved images
             new ConfigHelper.Resolver() {
                     @Override
                     public List<ImageConfiguration> resolve(ImageConfiguration image) {
@@ -417,6 +425,22 @@ protected LogDispatcher getLogDispatcher(ServiceHub hub) {
         return dispatcher;
     }
 
+    private ImmutableList<ImageConfiguration> getAllImages() {
+        ImmutableList.Builder<ImageConfiguration> allImages = ImmutableList.builder();
+        if (images != null) {
+            allImages.addAll(images);
+        }
+        if (imagesMap != null) {
+            imagesMap.forEach((alias, config) -> {
+                if (config.getAlias() == null) {
+                    config.setAlias(alias);
+                }
+                allImages.add(config);
+            });
+        }
+        return allImages.build();
+    }
+
     public ImagePullManager getImagePullManager(String imagePullPolicy, String autoPull) {
         return new ImagePullManager(getSessionCacheStore(), imagePullPolicy, autoPull);
     }

src/main/java/io/fabric8/maven/docker/config/ImageConfiguration.java

@@ -77,6 +77,10 @@ public String getAlias() {
         return alias;
     }
 
+    public void setAlias(String alias) {
+        this.alias = alias;
+    }
+
     public String getStopNamePattern() {
         return stopNamePattern;
     }