[JENKINS-54128] More efficient implementation of getLogFile that just uses the existing file when possible

pom.xml

@@ -28,7 +28,7 @@
     <parent>
         <groupId>org.jenkins-ci.plugins</groupId>
         <artifactId>plugin</artifactId>
-        <version>3.25</version>
+        <version>3.28</version>
         <relativePath />
     </parent>
     <groupId>org.jenkins-ci.plugins.workflow</groupId>

src/main/java/org/jenkinsci/plugins/workflow/job/WorkflowRun.java

@@ -109,6 +109,7 @@
 import org.jenkinsci.plugins.workflow.graph.FlowEndNode;
 import org.jenkinsci.plugins.workflow.graph.FlowNode;
 import org.jenkinsci.plugins.workflow.job.console.NewNodeConsoleNote;
+import org.jenkinsci.plugins.workflow.log.FileLogStorage;
 import org.jenkinsci.plugins.workflow.log.LogStorage;
 import org.jenkinsci.plugins.workflow.log.TaskListenerDecorator;
 import org.jenkinsci.plugins.workflow.steps.FlowInterruptedException;
@@ -1019,7 +1020,7 @@ private final class NodePrintListener implements GraphListener.Synchronous {
     @Override public InputStream getLogInputStream() throws IOException {
         // Inefficient but probably rarely used anyway.
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
-        writeLogTo(getLogText()::writeLogTo, baos);
+        writeLogTo(getLogText()::writeRawLogTo, baos);
         return new ByteArrayInputStream(baos.toByteArray());
     }
 
@@ -1081,16 +1082,22 @@ private void writeLogTo(WriteMethod method, OutputStream os) throws IOException
     @Deprecated
     @Override public File getLogFile() {
         LOGGER.log(Level.WARNING, "Avoid calling getLogFile on " + this, new UnsupportedOperationException());
-        try {
-            File f = File.createTempFile("deprecated", ".log", getRootDir());
-            f.deleteOnExit();
-            try (OutputStream os = new FileOutputStream(f)) {
-                getLogText().writeRawLogTo(0, os);
+        File f = super.getLogFile();
+        if (LogStorage.of(asFlowExecutionOwner()) instanceof FileLogStorage) {
+            // FileLogStorage does write a file with the same name and the same format as before JEP-210, so accept it if it is there.
+            // This is the normal case if no additional plugin is installed.
+        } else {
+            // Some other storage, perhaps cloud-based. Cache under the traditional name, but load from the defined source on each call.
+            try {
+                f.deleteOnExit();
+                try (OutputStream os = new FileOutputStream(f)) {
+                    writeLogTo(getLogText()::writeRawLogTo, os);
+                }
+            } catch (IOException x) {
+                throw new RuntimeException(x);
             }
-            return f;
-        } catch (IOException x) {
-            throw new RuntimeException(x);
         }
+        return f;
     }
 
     static void alias() {

src/test/java/org/jenkinsci/plugins/workflow/job/WorkflowRunTest.java

@@ -82,6 +82,7 @@
 import org.xml.sax.SAXException;
 
 import javax.annotation.Nonnull;
+import org.apache.commons.io.IOUtils;
 
 public class WorkflowRunTest {
 
@@ -503,4 +504,13 @@ private void assertCulprits(WorkflowRun b, String... expectedIds) throws IOExcep
         r.assertLogContains(message, r.buildAndAssertSuccess(p));
     }
 
+    @Issue("JENKINS-54128")
+    @SuppressWarnings("deprecation")
+    @Test public void getLogFile() throws Exception {
+        WorkflowJob p = r.jenkins.createProject(WorkflowJob.class, "p");
+        p.setDefinition(new CpsFlowDefinition("echo 'sample text'", true));
+        WorkflowRun b = r.buildAndAssertSuccess(p);
+        assertEquals(IOUtils.toString(b.getLogInputStream()), FileUtils.readFileToString(b.getLogFile()));
+    }
+
 }