Throw exception if Dataflow template file writing fails.

CHANGES.md

@@ -95,12 +95,12 @@
 
 ## Bugfixes
 
-* Fix data loss issues when reading gzipped files with TextIO (Python) ([#18390](https://github.com/apache/beam/issues/18390), [#31040](https://github.com/apache/beam/issues/31040)).
-* Fixed X (Java/Python) ([#X](https://github.com/apache/beam/issues/X)).
+* Fix data loss issues when reading gzipped files with TextIO (Python) ([#18390](https://github.com/apache/beam/issues/18390), [#31040](https://github.com/apache/beam/issues/31040)). 
 * [BigQueryIO] Fixed an issue where Storage Write API sometimes doesn't pick up auto-schema updates ([#33231](https://github.com/apache/beam/pull/33231))
 * Prism
   * Fixed an edge case where Bundle Finalization might not become enabled. ([#33493](https://github.com/apache/beam/issues/33493)).
   * Fixed session window aggregation, which wasn't being performed per-key. ([#33542](https://github.com/apache/beam/issues/33542)).)
+* Fixed a Dataflow template creation issue that ignores template file creation errors (Java) ([#33636](https://github.com/apache/beam/issues/33636))
 
 ## Security Fixes
 * Fixed (CVE-YYYY-NNNN)[https://www.cve.org/CVERecord?id=CVE-YYYY-NNNN] (Java/Python/Go) ([#X](https://github.com/apache/beam/issues/X)).

runners/google-cloud-dataflow-java/build.gradle

@@ -128,7 +128,7 @@ dependencies {
   testImplementation project(path: ":sdks:java:extensions:python", configuration: "testRuntimeMigration")
   testImplementation library.java.google_cloud_dataflow_java_proto_library_all
   testImplementation library.java.jackson_dataformat_yaml
-  testImplementation library.java.mockito_core
+  testImplementation library.java.mockito_inline
   validatesRunner project(path: ":sdks:java:core", configuration: "shadowTest")
   validatesRunner project(path: project.path, configuration: "testRuntimeMigration")
   validatesRunner library.java.hamcrest

runners/google-cloud-dataflow-java/src/main/java/org/apache/beam/runners/dataflow/DataflowRunner.java

@@ -39,12 +39,10 @@
 import com.google.api.services.dataflow.model.WorkerPool;
 import com.google.auto.service.AutoService;
 import com.google.auto.value.AutoValue;
-import java.io.BufferedWriter;
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStreamWriter;
-import java.io.PrintWriter;
 import java.nio.channels.Channels;
 import java.nio.channels.ReadableByteChannel;
 import java.util.ArrayList;
@@ -1524,15 +1522,9 @@ public DataflowPipelineJob run(Pipeline pipeline) {
           fileLocation.startsWith("/") || fileLocation.startsWith("gs://"),
           "Location must be local or on Cloud Storage, got %s.",
           fileLocation);
-      ResourceId fileResource = FileSystems.matchNewResource(fileLocation, false /* isDirectory */);
-      String workSpecJson = DataflowPipelineTranslator.jobToString(newJob);
-      try (PrintWriter printWriter =
-          new PrintWriter(
-              new BufferedWriter(
-                  new OutputStreamWriter(
-                      Channels.newOutputStream(FileSystems.create(fileResource, MimeTypes.TEXT)),
-                      UTF_8)))) {
-        printWriter.print(workSpecJson);
+
+      try {
+        printWorkSpecJsonToFile(fileLocation, newJob);
         LOG.info("Printed job specification to {}", fileLocation);
       } catch (IOException ex) {
         String error = String.format("Cannot create output file at %s", fileLocation);
@@ -1542,6 +1534,7 @@ public DataflowPipelineJob run(Pipeline pipeline) {
           LOG.warn(error, ex);
         }
       }
+
       if (isTemplate) {
         LOG.info("Template successfully created.");
         return new DataflowTemplateJob();
@@ -1629,6 +1622,18 @@ public DataflowPipelineJob run(Pipeline pipeline) {
     return dataflowPipelineJob;
   }
 
+  private static void printWorkSpecJsonToFile(String fileLocation, Job job) throws IOException {
+    String workSpecJson = DataflowPipelineTranslator.jobToString(job);
+    ResourceId fileResource = FileSystems.matchNewResource(fileLocation, false /* isDirectory */);
+    try (OutputStreamWriter writer =
+        new OutputStreamWriter(
+            Channels.newOutputStream(FileSystems.create(fileResource, MimeTypes.TEXT)), UTF_8)) {
+      // Not using PrintWriter as it swallows IOException.
+      // Not using BufferedWriter as this invokes write() only once.
+      writer.write(workSpecJson);
+    }
+  }
+
   private static EnvironmentInfo getEnvironmentInfoFromEnvironmentId(
       String environmentId, RunnerApi.Pipeline pipelineProto) {
     RunnerApi.Environment environment =