Support standard maven interpolation

Replaces the regex-based property interpolation with the plexus classes
used typically by maven to perform interpolation.  This allows
references to things like ${project.build.directory} in the Dockerfile.
[fixes #871]

Signed-off-by: Scott Coplin <coplin.6@osu.edu>

src/main/asciidoc/inc/build/_overview.adoc

@@ -42,7 +42,7 @@ Except for the <<build-assembly,assembly configuration>> all other configuration
 [[build-filtering]]
 .Filtering
 fabric8-maven-plugin filters given Dockerfile with Maven properties, much like the `maven-resource-plugin` does. Filtering is enabled by default and can be switched off with a build config `<filter>false</filter>`. Properties which we want to replace are specified with the `${..}` syntax. 
-Only properties which are set in the Maven build are replaced, all other remain untouched. 
+Replacement includes Maven project properties such as `${project.artifactId}`, properties set in the build, command-line properties, and system properties. Unresolved properties remain untouched.
 
 This partial replacement means that you can easily mix it with Docker build arguments and environment variable reference, but you need to be careful.
 If you want to be more explicit about the property delimiter to clearly separate Docker properties and Maven properties you can redefine the delimiter.
@@ -53,8 +53,8 @@ For example, the default `<filter>${*}</filter>` parse Maven properties in the f
 If you specify a single character for `<filter>` then this delimiter is taken for both, the start and the end.
 E.g a `<filter>@</filter>` triggers on parameters in the format `@...@`, much like in the `maven-invoker-plugin`. 
 Use something like this if you want to clearly separate from Docker builds args.
-Property replacement works for Dockerfile only.
-For replacing other data in associated files targeted for the Docker image, please use the maven-resource-plugin to copy them over before. 
+This form of property replacement works for Dockerfile only.
+For replacing other data in other files targeted for the Docker image, please use the `maven-resource-plugin` or an <<build-assembly,assembly configuration>> with filtering to make them available in the docker build context. 
 
 .Example
 The following example uses a Dockerfile in the directory

src/main/java/io/fabric8/maven/docker/assembly/DockerAssemblyManager.java

@@ -29,7 +29,9 @@
 import org.codehaus.plexus.archiver.util.DefaultFileSet;
 import org.codehaus.plexus.component.annotations.Component;
 import org.codehaus.plexus.component.annotations.Requirement;
+import org.codehaus.plexus.interpolation.fixed.FixedStringSearchInterpolator;
 
+import com.google.common.base.Function;
 
 /**
  * Tool for creating a docker image tar ball including a Dockerfile for building
@@ -111,11 +113,9 @@ public File createDockerTarArchive(String imageName, MojoParameters params, Buil
                                                      buildConfig.getDockerFile() + "\" (resolved to \"" + dockerFile + "\") doesn't exist");
                 }
 
-                verifyGivenDockerfile(dockerFile, buildConfig, params.getProject(), log);
-                Properties interpolationProperties = new Properties();
-                interpolationProperties.putAll(params.getProject().getProperties());
-                interpolationProperties.putAll(params.getSession().getSystemProperties());
-                interpolateDockerfile(dockerFile, buildDirs, interpolationProperties, buildConfig.getFilter());
+                FixedStringSearchInterpolator interpolator = DockerFileUtil.createInterpolator(params, buildConfig.getFilter());
+                verifyGivenDockerfile(dockerFile, buildConfig, interpolator, log);
+                interpolateDockerfile(dockerFile, buildDirs, interpolator);
                 // User dedicated Dockerfile from extra directory
                 customizer = new ArchiverCustomizer() {
                     @Override
@@ -168,21 +168,20 @@ private void excludeDockerfile(DefaultFileSet fileSet, File dockerFile) {
         fileSet.setExcludes(excludes.toArray(new String[0]));
     }
 
-    private void interpolateDockerfile(File dockerFile, BuildDirs params, Properties properties, String filter) throws IOException {
+    private void interpolateDockerfile(File dockerFile, BuildDirs params, FixedStringSearchInterpolator interpolator) throws IOException {
         File targetDockerfile = new File(params.getOutputDirectory(), dockerFile.getName());
-        String dockerFileInterpolated =
-            DockerFileUtil.interpolate(dockerFile, properties, filter);
+        String dockerFileInterpolated = DockerFileUtil.interpolate(dockerFile, interpolator);
         try (Writer writer = new FileWriter(targetDockerfile)) {
             IOUtils.write(dockerFileInterpolated, writer);
         }
     }
 
-    private void verifyGivenDockerfile(File dockerFile, BuildImageConfiguration buildConfig, MavenProject project, Logger log) throws IOException {
+    private void verifyGivenDockerfile(File dockerFile, BuildImageConfiguration buildConfig, FixedStringSearchInterpolator interpolator, Logger log) throws IOException {
         AssemblyConfiguration assemblyConfig = buildConfig.getAssemblyConfiguration();
         if (assemblyConfig != null) {
             String name = assemblyConfig.getName();
             for (String keyword : new String[] { "ADD", "COPY" }) {
-                List<String[]> lines = DockerFileUtil.extractLines(dockerFile, keyword, project.getProperties(), buildConfig.getFilter());
+                List<String[]> lines = DockerFileUtil.extractLines(dockerFile, keyword, interpolator);
                 for (String[] line : lines) {
                     // contains an ADD/COPY ... targetDir .... All good.
                     if (!line[0].startsWith("#") && line.length > 1 && line[1].contains(name)) {

src/main/java/io/fabric8/maven/docker/service/BuildService.java

@@ -230,8 +230,7 @@ private String extractBaseFromDockerfile(BuildImageConfiguration buildConfig, Bu
             File fullDockerFilePath = buildConfig.getAbsoluteDockerFilePath(buildContext.getMojoParameters());
             fromImage = DockerFileUtil.extractBaseImage(
                 fullDockerFilePath,
-                buildContext.getMojoParameters().getProject().getProperties(),
-                buildConfig.getFilter());
+                DockerFileUtil.createInterpolator(buildContext.getMojoParameters(), buildConfig.getFilter()));
         } catch (IOException e) {
             // Cant extract base image, so we wont try an auto pull. An error will occur later anyway when
             // building the image, so we are passive here.

src/main/java/io/fabric8/maven/docker/util/DockerFileUtil.java

@@ -18,10 +18,15 @@
 import java.io.*;
 import java.util.ArrayList;
 import java.util.List;
-import java.util.Properties;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import org.apache.maven.plugin.assembly.interpolation.AssemblyInterpolator;
+import org.apache.maven.plugin.assembly.io.DefaultAssemblyReader;
+import org.codehaus.plexus.interpolation.fixed.FixedStringSearchInterpolator;
+
+import io.fabric8.maven.docker.assembly.DockerAssemblyConfigurationSource;
+
 
 /**
  * Utility class for dealing with dockerfiles
@@ -37,11 +42,11 @@ private DockerFileUtil() {}
      * taken.
      *
      * @param dockerFile file from where to extract the base image
-     * @param properties holding values used for interpolation
-     *@param filter @return the base image name or <code>null</code> if none is found.
+     * @param interpolator interpolator for replacing properties
+     * @param filter @return the base image name or <code>null</code> if none is found.
      */
-    public static String extractBaseImage(File dockerFile, Properties properties, String filter) throws IOException {
-        List<String[]> fromLines = extractLines(dockerFile, "FROM", properties, filter);
+    public static String extractBaseImage(File dockerFile, FixedStringSearchInterpolator interpolator) throws IOException {
+        List<String[]> fromLines = extractLines(dockerFile, "FROM", interpolator);
         if (!fromLines.isEmpty()) {
             String[] parts = fromLines.get(0);
             if (parts.length > 1) {
@@ -56,15 +61,15 @@ public static String extractBaseImage(File dockerFile, Properties properties, St
      *
      * @param dockerFile dockerfile to examine
      * @param keyword keyword to extract the lines for
+     * @param interpolator interpolator for replacing properties
      * @return list of matched lines or an empty list
      */
-    public static List<String[]> extractLines(File dockerFile, String keyword, Properties props, String filter) throws IOException {
+    public static List<String[]> extractLines(File dockerFile, String keyword, FixedStringSearchInterpolator interpolator) throws IOException {
         List<String[]> ret = new ArrayList<>();
-        String[] delimiters = extractDelimiters(filter);
         try (BufferedReader reader = new BufferedReader(new FileReader(dockerFile))) {
             String line;
             while ((line = reader.readLine()) != null) {
-                String lineInterpolated = interpolateLine(line, props, delimiters);
+                String lineInterpolated = interpolator.interpolate(line);
                 String[] lineParts = lineInterpolated.split("\\s+");
                 if (lineParts.length > 0 && lineParts[0].equalsIgnoreCase(keyword)) {
                     ret.add(lineParts);
@@ -78,40 +83,41 @@ public static List<String[]> extractLines(File dockerFile, String keyword, Prope
      * Interpolate a docker file with the given properties and filter
      *
      * @param dockerFile docker file to interpolate
-     * @param properties properties to replace
-     * @param filter filter holding delimeters
-     * @return
+     * @param interpolator interpolator for replacing properties
+     * @return The interpolated contents of the file.
      * @throws IOException
      */
-    public static String interpolate(File dockerFile, Properties properties, String filter) throws IOException {
+    public static String interpolate(File dockerFile, FixedStringSearchInterpolator interpolator) throws IOException {
         StringBuilder ret = new StringBuilder();
-        String[] delimiters = extractDelimiters(filter);
         try (BufferedReader reader = new BufferedReader(new FileReader(dockerFile))) {
             String line;
             while ((line = reader.readLine()) != null) {
-                ret.append(interpolateLine(line, properties, delimiters)).append(System.lineSeparator());
+                ret.append(interpolator.interpolate(line)).append(System.lineSeparator());
             }
         }
         return ret.toString();
     }
 
-    private static String interpolateLine(String line, Properties properties, String[] delimiters) {
-        if (delimiters == null || delimiters.length == 0) {
-            return line;
-        }
-        Pattern propertyPattern =
-            Pattern.compile("(?<variable>" + Pattern.quote(delimiters[0]) + "(?<prop>.*?)" + Pattern.quote(delimiters[1]) + ")");
-        Matcher matcher = propertyPattern.matcher(line);
-        StringBuffer ret = new StringBuffer();
-        while (matcher.find()) {
-            String prop = matcher.group("prop");
-            String value = properties.containsKey(prop) ?
-                properties.getProperty(prop) :
-                matcher.group("variable");
-            matcher.appendReplacement(ret, value.replace("$","\\$"));
+    /**
+     * Create an interpolator for the given maven parameters and filter configuration.
+     *
+     * @param params The maven parameters.
+     * @param filter The filter configuration.
+     * @return An interpolator for replacing maven properties.
+     */
+    public static FixedStringSearchInterpolator createInterpolator(MojoParameters params, String filter) {
+        String[] delimiters = extractDelimiters(filter);
+        if (delimiters == null) {
+            // Don't interpolate anything
+            return FixedStringSearchInterpolator.create();
         }
-        matcher.appendTail(ret);
-        return ret.toString();
+
+        DockerAssemblyConfigurationSource configSource = new DockerAssemblyConfigurationSource(params, null, null);
+        // Patterned after org.apache.maven.plugin.assembly.interpolation.AssemblyExpressionEvaluator
+        return AssemblyInterpolator
+                .fullInterpolator(params.getProject(),
+                        DefaultAssemblyReader.createProjectInterpolator(params.getProject()), configSource)
+                .withExpressionMarkers(delimiters[0], delimiters[1]);
     }
 
     private static String[] extractDelimiters(String filter) {

src/test/java/io/fabric8/maven/docker/util/DockerFileUtilTest.java

@@ -17,14 +17,24 @@
 
 import java.io.*;
 import java.nio.file.Files;
+import java.util.Collections;
+import java.util.Date;
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Properties;
 
 import org.apache.commons.io.FileUtils;
+import org.apache.maven.artifact.repository.ArtifactRepository;
+import org.apache.maven.execution.MavenSession;
+import org.apache.maven.project.MavenProject;
+import org.apache.maven.settings.Settings;
+import org.codehaus.plexus.interpolation.fixed.FixedStringSearchInterpolator;
 import org.codehaus.plexus.util.IOUtil;
 import org.junit.Test;
 
+import mockit.Mock;
+import mockit.MockUp;
+
 import static io.fabric8.maven.docker.util.PathTestUtil.createTmpFile;
 import static org.junit.Assert.assertEquals;
 
@@ -38,7 +48,7 @@ public class DockerFileUtilTest {
     public void testSimple() throws Exception {
         File toTest = copyToTempDir("Dockerfile_from_simple");
         assertEquals("fabric8/s2i-java", DockerFileUtil.extractBaseImage(
-            toTest, null, "false"));
+            toTest, FixedStringSearchInterpolator.create()));
     }
 
     private File copyToTempDir(String resource) throws IOException {
@@ -52,12 +62,7 @@ private File copyToTempDir(String resource) throws IOException {
 
     @Test
     public void interpolate() throws Exception {
-        Properties props = new Properties();
-        props.put("base", "java");
-        props.put("name", "guenther");
-        props.put("age", "42");
-        props.put("ext", "png");
-
+        MojoParameters params = mockMojoParams();
         Map<String, String> filterMapping = new HashMap<>();
         filterMapping.put("none", "false");
         filterMapping.put("var", "${*}");
@@ -68,9 +73,10 @@ public void interpolate() throws Exception {
                 File dockerFile = getDockerfilePath(i, entry.getKey());
                 File expectedDockerFile = new File(dockerFile.getParent(), dockerFile.getName() + ".expected");
                 File actualDockerFile = createTmpFile(dockerFile.getName());
-                FileUtils.write(actualDockerFile,
-                        DockerFileUtil.interpolate(dockerFile, props, entry.getValue()), "UTF-8");
-                FileUtils.contentEqualsIgnoreEOL(expectedDockerFile, actualDockerFile, "UTF-8");
+                FixedStringSearchInterpolator interpolator = DockerFileUtil.createInterpolator(params, entry.getValue());
+                FileUtils.write(actualDockerFile, DockerFileUtil.interpolate(dockerFile, interpolator), "UTF-8");
+                // Compare text lines without regard to EOL delimiters
+                assertEquals(FileUtils.readLines(expectedDockerFile), FileUtils.readLines(actualDockerFile));
             }
         }
     }
@@ -81,4 +87,27 @@ private File getDockerfilePath(int i, String dir) {
             String.format("interpolate/%s/Dockerfile_%d", dir, i)).getFile());
     }
 
+    private MojoParameters mockMojoParams() {
+        MavenProject project = new MavenProject();
+        project.setArtifactId("docker-maven-plugin");
+
+        Properties projectProperties = project.getProperties();
+        projectProperties.put("base", "java");
+        projectProperties.put("name", "guenther");
+        projectProperties.put("age", "42");
+        projectProperties.put("ext", "png");
+
+        Settings settings = new Settings();
+        ArtifactRepository localRepository = new MockUp<ArtifactRepository>() {
+            @Mock
+            public String getBasedir() {
+                return "repository";
+            }
+        }.getMockInstance();
+        @SuppressWarnings("deprecation")
+        MavenSession session = new MavenSession(null, settings, localRepository, null, null, Collections.<String>emptyList(), ".", null, null, new Date(System.currentTimeMillis()));
+        session.getUserProperties().setProperty("cliOverride", "cliValue"); // Maven CLI override: -DcliOverride=cliValue
+        session.getSystemProperties().put("user.name", "somebody"); // Java system property: -Duser.name=somebody
+        return new MojoParameters(session, project, null, null, null, settings, "src", "target", Collections.singletonList(project));
+    }
 }

src/test/resources/interpolate/at/Dockerfile_1

@@ -1,3 +1,3 @@
 FROM @base@
-LABEL name ${name} @age@ ${ext} blub @unknown@ @
+LABEL name ${name} @age@ ${ext} blub @unknown@ @project.artifactId@ @
 ENV @name@ @ext@

src/test/resources/interpolate/at/Dockerfile_1.expected

@@ -1,3 +1,3 @@
 FROM java
-LABEL name ${name} 42 ${ext} blub @unknown@ @
+LABEL name ${name} 42 ${ext} blub @unknown@ docker-maven-plugin @
 ENV guenther png

src/test/resources/interpolate/var/Dockerfile_1

@@ -1,3 +1,5 @@
 FROM ${base}
-LABEL name ${name} @age@ ${ext} ${unknown}
+LABEL name ${name} @age@ ${ext} ${unknown} ${project.artifactId}
 ENV ${name} ${age}
+ENV cli=${cliOverride}
+USER ${user.name}

src/test/resources/interpolate/var/Dockerfile_1.expected

@@ -1,3 +1,5 @@
 FROM java
-LABEL name guenther @age@ png ${unknown}
+LABEL name guenther @age@ png ${unknown} docker-maven-plugin
 ENV guenther 42
+ENV cli=cliValue
+USER somebody