Updates the Transform Service to accept Python extra packages through…

… the Java API

runners/core-construction-java/src/main/java/org/apache/beam/runners/core/construction/TransformUpgrader.java

@@ -108,7 +108,7 @@ public RunnerApi.Pipeline upgradeTransformsViaTransformService(
     } else if (options.getTransformServiceBeamVersion() != null) {
       String projectName = UUID.randomUUID().toString();
       int port = findAvailablePort();
-      service = TransformServiceLauncher.forProject(projectName, port);
+      service = TransformServiceLauncher.forProject(projectName, port, null);
       service.setBeamVersion(options.getTransformServiceBeamVersion());
 
       // Starting the transform service.

sdks/java/extensions/python/src/main/java/org/apache/beam/sdk/extensions/python/PythonExternalTransform.java

@@ -495,6 +495,20 @@ public OutputT expand(InputT input) {
         boolean pythonAvailable = isPythonAvailable();
         boolean dockerAvailable = isDockerAvailable();
 
+        File requirementsFile = null;
+        if (!extraPackages.isEmpty()) {
+          requirementsFile = File.createTempFile("requirements", ".txt");
+          requirementsFile.deleteOnExit();
+          try (Writer fout =
+              new OutputStreamWriter(
+                  new FileOutputStream(requirementsFile.getAbsolutePath()), Charsets.UTF_8)) {
+            for (String pkg : extraPackages) {
+              fout.write(pkg);
+              fout.write('\n');
+            }
+          }
+        }
+
         // We use the transform service if either of the following is true.
         // * It was explicitly requested.
         // * Python executable is not available in the system but Docker is available.
@@ -514,19 +528,16 @@ public OutputT expand(InputT input) {
               projectName,
               port);
 
-          TransformServiceLauncher service = TransformServiceLauncher.forProject(projectName, port);
+          String pythonRequirementsFile =
+              requirementsFile != null ? requirementsFile.getAbsolutePath() : null;
+          TransformServiceLauncher service =
+              TransformServiceLauncher.forProject(projectName, port, pythonRequirementsFile);
           service.setBeamVersion(ReleaseInfo.getReleaseInfo().getSdkVersion());
-          // TODO(https://github.com/apache/beam/issues/26833): add support for installing extra
-          // packages.
-          if (!extraPackages.isEmpty()) {
-            throw new RuntimeException(
-                "Transform Service does not support installing extra packages yet");
-          }
           try {
             // Starting the transform service.
             service.start();
             // Waiting the service to be ready.
-            service.waitTillUp(15000);
+            service.waitTillUp(-1);
             // Expanding the transform.
             output = apply(input, String.format("localhost:%s", port), payload);
           } finally {
@@ -539,17 +550,7 @@ public OutputT expand(InputT input) {
           ImmutableList.Builder<String> args = ImmutableList.builder();
           args.add(
               "--port=" + port, "--fully_qualified_name_glob=*", "--pickle_library=cloudpickle");
-          if (!extraPackages.isEmpty()) {
-            File requirementsFile = File.createTempFile("requirements", ".txt");
-            requirementsFile.deleteOnExit();
-            try (Writer fout =
-                new OutputStreamWriter(
-                    new FileOutputStream(requirementsFile.getAbsolutePath()), Charsets.UTF_8)) {
-              for (String pkg : extraPackages) {
-                fout.write(pkg);
-                fout.write('\n');
-              }
-            }
+          if (requirementsFile != null) {
             args.add("--requirements_file=" + requirementsFile.getAbsolutePath());
           }
           PythonService service =

sdks/java/transform-service/docker-compose/.env

@@ -12,6 +12,14 @@
 
 BEAM_VERSION=$BEAM_VERSION
 CREDENTIALS_VOLUME=$CREDENTIALS_VOLUME
+DEPENDENCIES_VOLUME=$DEPENDENCIES_VOLUME
+
+# A requirements file with either of the following
+# *  PyPi packages
+# Locally available packages relative to the directory provided to
+# DEPENDENCIES_VOLUME.
+PYTHON_REQUIREMENTS_FILE_NAME=$PYTHON_REQUIREMENTS_FILE_NAME
+
 GOOGLE_APPLICATION_CREDENTIALS_FILE_NAME=application_default_credentials.json
 COMPOSE_PROJECT_NAME=apache.beam.transform.service
 TRANSFORM_SERVICE_PORT=$TRANSFORM_SERVICE_PORT

sdks/java/transform-service/docker-compose/docker-compose.yml

@@ -32,8 +32,9 @@ services:
   expansion-service-2:
     image: "apache/beam_python_expansion_service:${BEAM_VERSION}"
     restart: on-failure
-    command: -id expansion-service-2 -port 5001
+    command: -id expansion-service-2 -port 5001 -requirements_file ${PYTHON_REQUIREMENTS_FILE_NAME} -dependencies_dir '/dependencies_volume'
     volumes:
       - ${CREDENTIALS_VOLUME}:/credentials_volume
+      - ${DEPENDENCIES_VOLUME}:/dependencies_volume
     environment:
       - GOOGLE_APPLICATION_CREDENTIALS=/credentials_volume/${GOOGLE_APPLICATION_CREDENTIALS_FILE_NAME}

sdks/java/transform-service/launcher/build.gradle

@@ -45,6 +45,9 @@ dependencies {
     shadow library.java.args4j
     shadow library.java.error_prone_annotations
     permitUnusedDeclared(library.java.error_prone_annotations)
+    testImplementation library.java.junit
+    testImplementation library.java.mockito_core
+    testImplementation project(path: ":sdks:java:core")
 }
 
 sourceSets {

sdks/java/transform-service/launcher/src/main/java/org/apache/beam/sdk/transformservice/launcher/TransformServiceLauncher.java

@@ -17,9 +17,11 @@
  */
 package org.apache.beam.sdk.transformservice.launcher;
 
+import java.io.BufferedWriter;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.ArrayList;
@@ -28,6 +30,7 @@
 import java.util.Locale;
 import java.util.Map;
 import java.util.concurrent.TimeoutException;
+import java.util.stream.Stream;
 import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableList;
 import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.io.ByteStreams;
 import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.io.Files;
@@ -62,9 +65,9 @@ public class TransformServiceLauncher {
   private static final int STATUS_LOGGER_WAIT_TIME = 3000;
 
   @SuppressWarnings("argument")
-  private TransformServiceLauncher(@Nullable String projectName, int port) throws IOException {
-    LOG.info("Initializing the Beam Transform Service {}.", projectName);
-
+  private TransformServiceLauncher(
+      @Nullable String projectName, int port, @Nullable String pythonRequirementsFile)
+      throws IOException {
     String tmpDirLocation = System.getProperty("java.io.tmpdir");
     // We use Docker Compose project name as the name of the temporary directory to isolate
     // different transform service instances that may be running in the same machine.
@@ -83,6 +86,7 @@ private TransformServiceLauncher(@Nullable String projectName, int port) throws
       ByteStreams.copy(getClass().getResourceAsStream("/.env"), fout);
     }
 
+    // Setting up the credentials directory.
     File credentialsDir = Paths.get(tmpDir, "credentials_dir").toFile();
     LOG.info(
         "Creating a temporary directory for storing credentials: "
@@ -124,10 +128,84 @@ private TransformServiceLauncher(@Nullable String projectName, int port) throws
       }
     }
 
+    // Setting up the dependencies directory.
+    File dependenciesDir = Paths.get(tmpDir, "dependencies_dir").toFile();
+    Path updatedRequirementsFilePath = Paths.get(dependenciesDir.toString(), "requirements.txt");
+    LOG.info(
+        "Creating a temporary directory for storing dependencies: "
+            + dependenciesDir.getAbsolutePath());
+    if (dependenciesDir.exists()) {
+      LOG.info("Reusing the existing dependencies directory " + dependenciesDir.getAbsolutePath());
+    } else {
+      if (!dependenciesDir.mkdir()) {
+        throw new IOException(
+            "Could not create a temporary directory for storing dependencies: "
+                + dependenciesDir.getAbsolutePath());
+      }
+
+      // We create a requirements file with extra dependencies.
+      // If there are no extra dependencies, we just provide an empty requirements file.
+      File file = updatedRequirementsFilePath.toFile();
+      if (!file.createNewFile()) {
+        throw new IOException(
+            "Could not create the new requirements file " + updatedRequirementsFilePath);
+      }
+
+      // Updating dependencies.
+      if (pythonRequirementsFile != null) {
+        Path requirementsFilePath = Paths.get(pythonRequirementsFile);
+        List<String> updatedLines = new ArrayList<>();
+
+        try (Stream<String> lines = java.nio.file.Files.lines(requirementsFilePath)) {
+          lines.forEachOrdered(
+              line -> {
+                Path dependencyFilePath = Paths.get(line);
+                if (java.nio.file.Files.exists(dependencyFilePath)) {
+                  Path fileName = dependencyFilePath.getFileName();
+                  if (fileName == null) {
+                    throw new IllegalArgumentException(
+                        "Could not determine the filename of the local artifact "
+                            + dependencyFilePath);
+                  }
+                  try {
+                    java.nio.file.Files.copy(
+                        dependencyFilePath,
+                        Paths.get(dependenciesDir.toString(), fileName.toString()));
+                  } catch (IOException e) {
+                    throw new RuntimeException(e);
+                  }
+                  updatedLines.add(fileName.toString());
+                } else {
+                  updatedLines.add(line);
+                }
+              });
+        }
+
+        try (BufferedWriter writer =
+            java.nio.file.Files.newBufferedWriter(file.toPath(), StandardCharsets.UTF_8)) {
+          for (String line : updatedLines) {
+            writer.write(line);
+            writer.newLine();
+          }
+          writer.flush();
+        }
+      }
+    }
+
     // Setting environment variables used by the docker-compose.yml file.
     environmentVariables.put("CREDENTIALS_VOLUME", credentialsDir.getAbsolutePath());
+    environmentVariables.put("DEPENDENCIES_VOLUME", dependenciesDir.getAbsolutePath());
     environmentVariables.put("TRANSFORM_SERVICE_PORT", String.valueOf(port));
 
+    Path updatedRequirementsFileName = updatedRequirementsFilePath.getFileName();
+    if (updatedRequirementsFileName == null) {
+      throw new IllegalArgumentException(
+          "Could not determine the file name of the updated requirements file "
+              + updatedRequirementsFilePath);
+    }
+    environmentVariables.put(
+        "PYTHON_REQUIREMENTS_FILE_NAME", updatedRequirementsFileName.toString());
+
     // Building the Docker Compose command.
     dockerComposeStartCommandPrefix.add("docker-compose");
     dockerComposeStartCommandPrefix.add("-p");
@@ -136,21 +214,37 @@ private TransformServiceLauncher(@Nullable String projectName, int port) throws
     dockerComposeStartCommandPrefix.add(dockerComposeFile.getAbsolutePath());
   }
 
+  /**
+   * Specifies the Beam version to get containers for the transform service.
+   *
+   * <p>Could be a release Beam version with containers in Docker Hub or an unreleased Beam version
+   * for which containers are available locally.
+   *
+   * @param beamVersion a Beam version to get containers from.
+   */
   public void setBeamVersion(String beamVersion) {
     environmentVariables.put("BEAM_VERSION", beamVersion);
   }
 
-  public void setPythonExtraPackages(String pythonExtraPackages) {
-    environmentVariables.put("$PYTHON_EXTRA_PACKAGES", pythonExtraPackages);
-  }
-
+  /**
+   * Initializes a client for managing transform service instances.
+   *
+   * @param projectName project name for the transform service.
+   * @param port port exposed by the transform service.
+   * @param pythonRequirementsFile a requirements file with extra dependencies for the Python
+   *     expansion services.
+   * @return an initialized client for managing the transform service.
+   * @throws IOException
+   */
   public static synchronized TransformServiceLauncher forProject(
-      @Nullable String projectName, int port) throws IOException {
+      @Nullable String projectName, int port, @Nullable String pythonRequirementsFile)
+      throws IOException {
     if (projectName == null || projectName.isEmpty()) {
       projectName = DEFAULT_PROJECT_NAME;
     }
     if (!launchers.containsKey(projectName)) {
-      launchers.put(projectName, new TransformServiceLauncher(projectName, port));
+      launchers.put(
+          projectName, new TransformServiceLauncher(projectName, port, pythonRequirementsFile));
     }
     return launchers.get(projectName);
   }
@@ -238,6 +332,8 @@ private static class ArgConfig {
     static final String PORT_ARG_NAME = "port";
     static final String BEAM_VERSION_ARG_NAME = "beam_version";
 
+    static final String PYTHON_REQUIREMENTS_FILE_ARG_NAME = "python_requirements_file";
+
     @Option(name = "--" + PROJECT_NAME_ARG_NAME, usage = "Docker compose project name")
     private String projectName = "";
 
@@ -249,6 +345,11 @@ private static class ArgConfig {
 
     @Option(name = "--" + BEAM_VERSION_ARG_NAME, usage = "Beam version to use.")
     private String beamVersion = "";
+
+    @Option(
+        name = "--" + PYTHON_REQUIREMENTS_FILE_ARG_NAME,
+        usage = "Extra Python packages in the form of an requirements file.")
+    private String pythonRequirementsFile = "";
   }
 
   public static void main(String[] args) throws IOException, TimeoutException {
@@ -288,8 +389,12 @@ public static void main(String[] args) throws IOException, TimeoutException {
                 : ("port " + Integer.toString(config.port) + ".")));
     System.out.println("===================================================");
 
+    String pythonRequirementsFile =
+        config.pythonRequirementsFile.isEmpty() ? config.pythonRequirementsFile : null;
+
     TransformServiceLauncher service =
-        TransformServiceLauncher.forProject(config.projectName, config.port);
+        TransformServiceLauncher.forProject(
+            config.projectName, config.port, pythonRequirementsFile);
     if (!config.beamVersion.isEmpty()) {
       service.setBeamVersion(config.beamVersion);
     }