Add core 'ports' functionality to docker context exporter, fix cross-platform Dockerfile write inconsistency

jib-core/src/main/java/com/google/cloud/tools/jib/docker/DockerContextGenerator.java

@@ -22,7 +22,6 @@
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
 import com.google.common.io.MoreFiles;
-import com.google.common.io.Resources;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.DirectoryNotEmptyException;
@@ -31,6 +30,7 @@
 import java.util.Collections;
 import java.util.List;
 import java.util.regex.Matcher;
+import java.util.stream.Collectors;
 import javax.annotation.Nullable;
 
 /**
@@ -46,12 +46,45 @@
  */
 public class DockerContextGenerator {
 
+  /**
+   * Formats a list for the Dockerfile's ENTRYPOINT or CMD.
+   *
+   * @see <a
+   *     href="https://docs.docker.com/engine/reference/builder/#exec-form-entrypoint-example">https://docs.docker.com/engine/reference/builder/#exec-form-entrypoint-example</a>
+   * @param items the list of items to join into an array.
+   * @return a string in the format: ["item1","item2",...]
+   */
+  @VisibleForTesting
+  static String joinAsJsonArray(List<String> items) {
+    return "["
+        + String.join(
+            ",",
+            items
+                .stream()
+                .map(item -> "\"" + item.replaceAll("\"", Matcher.quoteReplacement("\\\"")) + "\"")
+                .collect(Collectors.toList()))
+        + "]";
+  }
+
+  /**
+   * Builds a list of Dockerfile "EXPOSE" instructions.
+   *
+   * @param exposedPorts the list of ports numbers/ranges to expose
+   * @return a string containing an EXPOSE instruction for each of the entries
+   */
+  @VisibleForTesting
+  static String makeExposeInstructions(List<String> exposedPorts) {
+    return String.join(
+        "\n", exposedPorts.stream().map(port -> "EXPOSE " + port).collect(Collectors.toList()));
+  }
+
   private final SourceFilesConfiguration sourceFilesConfiguration;
 
   @Nullable private String baseImage;
   private List<String> jvmFlags = Collections.emptyList();
   private String mainClass = "";
   private List<String> javaArguments = Collections.emptyList();
+  private List<String> exposedPorts = Collections.emptyList();
 
   public DockerContextGenerator(SourceFilesConfiguration sourceFilesConfiguration) {
     this.sourceFilesConfiguration = sourceFilesConfiguration;
@@ -102,11 +135,22 @@ public DockerContextGenerator setJavaArguments(List<String> javaArguments) {
     return this;
   }
 
+  /**
+   * Sets the exposed ports.
+   *
+   * @param exposedPorts the list of port numbers/port ranges to expose
+   * @return this
+   */
+  public DockerContextGenerator setExposedPorts(List<String> exposedPorts) {
+    this.exposedPorts = exposedPorts;
+    return this;
+  }
+
   /**
    * Creates the Docker context in {@code #targetDirectory}.
    *
-   * @param targetDirectory the directory to generate the Docker context in.
-   * @throws IOException if the export fails.
+   * @param targetDirectory the directory to generate the Docker context in
+   * @throws IOException if the export fails
    */
   public void generate(Path targetDirectory) throws IOException {
     Preconditions.checkNotNull(baseImage);
@@ -141,56 +185,26 @@ public void generate(Path targetDirectory) throws IOException {
   }
 
   /**
-   * Makes a {@code Dockerfile} from the {@code DockerfileTemplate}.
-   *
-   * @return the {@code Dockerfile} contents.
-   * @throws IOException if reading the Dockerfile template fails.
-   */
-  @VisibleForTesting
-  String makeDockerfile() throws IOException {
-    Preconditions.checkNotNull(baseImage);
-
-    String dockerfileTemplate =
-        Resources.toString(Resources.getResource("DockerfileTemplate"), StandardCharsets.UTF_8);
-
-    return dockerfileTemplate
-        .replace("@@BASE_IMAGE@@", baseImage)
-        .replace(
-            "@@DEPENDENCIES_PATH_ON_IMAGE@@", sourceFilesConfiguration.getDependenciesPathOnImage())
-        .replace("@@RESOURCES_PATH_ON_IMAGE@@", sourceFilesConfiguration.getResourcesPathOnImage())
-        .replace("@@CLASSES_PATH_ON_IMAGE@@", sourceFilesConfiguration.getClassesPathOnImage())
-        .replace(
-            "@@ENTRYPOINT@@",
-            joinAsJsonArray(
-                EntrypointBuilder.makeEntrypoint(sourceFilesConfiguration, jvmFlags, mainClass)))
-        .replace("@@CMD@@", joinAsJsonArray(javaArguments));
-  }
-
-  /**
-   * Formats a list for the Dockerfile's ENTRYPOINT or CMD.
+   * Makes the contents of a {@code Dockerfile} using configuration data.
    *
-   * @see <a
-   *     href="https://docs.docker.com/engine/reference/builder/#exec-form-entrypoint-example">https://docs.docker.com/engine/reference/builder/#exec-form-entrypoint-example</a>
-   * @param items the list of items to join into an array.
-   * @return a string in the format: ["item1","item2",...]
+   * @return the {@code Dockerfile} contents
    */
   @VisibleForTesting
-  static String joinAsJsonArray(List<String> items) {
-    StringBuilder resultString = new StringBuilder("[");
-    boolean firstComponent = true;
-    for (String item : items) {
-      if (!firstComponent) {
-        resultString.append(',');
-      }
-
-      // Escapes quotes.
-      item = item.replaceAll("\"", Matcher.quoteReplacement("\\\""));
-
-      resultString.append('"').append(item).append('"');
-      firstComponent = false;
-    }
-    resultString.append(']');
-
-    return resultString.toString();
+  String makeDockerfile() {
+    return "FROM "
+        + Preconditions.checkNotNull(baseImage)
+        + "\n\nCOPY libs "
+        + sourceFilesConfiguration.getDependenciesPathOnImage()
+        + "\nCOPY resources "
+        + sourceFilesConfiguration.getResourcesPathOnImage()
+        + "\nCOPY classes "
+        + sourceFilesConfiguration.getClassesPathOnImage()
+        + "\n\n"
+        + makeExposeInstructions(exposedPorts)
+        + "\nENTRYPOINT "
+        + joinAsJsonArray(
+            EntrypointBuilder.makeEntrypoint(sourceFilesConfiguration, jvmFlags, mainClass))
+        + "\nCMD "
+        + joinAsJsonArray(javaArguments);
   }
 }

jib-core/src/test/java/com/google/cloud/tools/jib/docker/DockerContextGeneratorTest.java

@@ -113,7 +113,7 @@ public void testGenerate() throws IOException, URISyntaxException {
   }
 
   @Test
-  public void testMakeDockerList() {
+  public void testJoinAsJsonArray() {
     Assert.assertEquals(
         "[\"java\",\"-cp\",\"/app/libs/*:/app/resources/:/app/classes/\",\"\"]",
         DockerContextGenerator.joinAsJsonArray(
@@ -129,22 +129,34 @@ public void testMakeDockerList() {
   }
 
   @Test
-  public void testMakeDockerfile() throws IOException, URISyntaxException {
+  public void testMakeExposeInstructions() {
+    Assert.assertEquals(
+        "EXPOSE 1000\nEXPOSE 2000-2010",
+        DockerContextGenerator.makeExposeInstructions(ImmutableList.of("1000", "2000-2010")));
+  }
+
+  @Test
+  public void testMakeDockerfile() throws IOException {
     String expectedBaseImage = "somebaseimage";
     List<String> expectedJvmFlags = Arrays.asList("-flag", "another\"Flag");
     String expectedMainClass = "SomeMainClass";
     List<String> expectedJavaArguments = Arrays.asList("arg1", "arg2");
+    List<String> exposedPorts = Arrays.asList("1000/tcp", "2000-2010/udp");
 
     String dockerfile =
         new DockerContextGenerator(mockSourceFilesConfiguration)
             .setBaseImage(expectedBaseImage)
             .setJvmFlags(expectedJvmFlags)
             .setMainClass(expectedMainClass)
             .setJavaArguments(expectedJavaArguments)
+            .setExposedPorts(exposedPorts)
             .makeDockerfile();
 
-    Path sampleDockerfile = Paths.get(Resources.getResource("sampleDockerfile").toURI());
+    // Need to split/rejoin the string here to avoid cross-platform troubles
+    List<String> sampleDockerfile =
+        Resources.readLines(Resources.getResource("sampleDockerfile"), StandardCharsets.UTF_8);
     Assert.assertArrayEquals(
-        Files.readAllBytes(sampleDockerfile), dockerfile.getBytes(StandardCharsets.UTF_8));
+        String.join("\n", sampleDockerfile).getBytes(StandardCharsets.UTF_8),
+        dockerfile.getBytes(StandardCharsets.UTF_8));
   }
 }

jib-core/src/test/resources/sampleDockerfile

@@ -4,5 +4,7 @@ COPY libs /app/libs/
 COPY resources /app/resources/
 COPY classes /app/classes/
 
+EXPOSE 1000/tcp
+EXPOSE 2000-2010/udp
 ENTRYPOINT ["java","-flag","another\"Flag","-cp","/app/libs/*:/app/resources/:/app/classes/","SomeMainClass"]
 CMD ["arg1","arg2"]