Release v1.2.1

handler/build.gradle

@@ -5,7 +5,7 @@ plugins {
 }
 
 group = 'io.jeyong'
-version = '1.2.0'
+version = '1.2.1'
 
 ext {
     artifactName = 'k8s-sigterm-handler'

handler/src/main/java/io/jeyong/handler/ApplicationTerminator.java

@@ -4,8 +4,19 @@
 
 public abstract class ApplicationTerminator {
 
+    private final String terminationMessagePath;
+    private final String terminationMessage;
+
+    protected ApplicationTerminator(final String terminationMessagePath, final String terminationMessage) {
+        this.terminationMessagePath = terminationMessagePath;
+        this.terminationMessage = terminationMessage;
+    }
+
     public SignalHandler handleTermination() {
-        return signal -> System.exit(getExitCode());
+        return signal -> {
+            FileUtils.writeToFile(terminationMessagePath, terminationMessage);
+            System.exit(getExitCode());
+        };
     }
 
     protected abstract int getExitCode();

handler/src/main/java/io/jeyong/handler/FileUtils.java

@@ -0,0 +1,38 @@
+package io.jeyong.handler;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class FileUtils {
+
+    private static final Logger logger = LoggerFactory.getLogger(FileUtils.class);
+
+    private FileUtils() {
+    }
+
+    public static void writeToFile(final String filePath, final String message) {
+        if (filePath == null || filePath.isBlank()) {
+            return;
+        }
+
+        final File file = new File(filePath);
+        try {
+            createParentDirectories(file);
+            try (FileWriter writer = new FileWriter(file)) {
+                writer.write(message);
+            }
+        } catch (IOException e) {
+            logger.error("Failed to write to file {}: {}", filePath, e.getMessage());
+        }
+    }
+
+    private static void createParentDirectories(final File file) throws IOException {
+        final File parentDir = file.getParentFile();
+        if (parentDir != null && !parentDir.exists() && !parentDir.mkdirs()) {
+            throw new IOException("Failed to create parent directories for " + file.getAbsolutePath());
+        }
+    }
+}

handler/src/main/java/io/jeyong/handler/SigtermHandlerConfiguration.java

@@ -8,7 +8,7 @@
 
 @Configuration
 @ConditionalOnProperty(
-        prefix = "kubernetes.handler",
+        prefix = "kubernetes.sigterm-handler",
         name = "enabled",
         havingValue = "true",
         matchIfMissing = true
@@ -26,7 +26,8 @@ public SigtermHandlerConfiguration(final SigtermHandlerProperties sigtermHandler
 
     @Bean
     public ApplicationTerminator applicationTerminator(final ApplicationContext applicationContext) {
-        return new SpringContextTerminator(applicationContext, sigtermHandlerProperties.getExitCode());
+        return new SpringContextTerminator(applicationContext, sigtermHandlerProperties.getExitCode(),
+                sigtermHandlerProperties.getTerminationMessagePath(), sigtermHandlerProperties.getTerminationMessage());
     }
 
     @Bean

handler/src/main/java/io/jeyong/handler/SigtermHandlerProperties.java

@@ -1,53 +1,62 @@
 package io.jeyong.handler;
 
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
 // @formatter:off
-import org.springframework.boot.context.properties.ConfigurationProperties; /**
+/**
  * Configuration properties for Kubernetes SIGTERM handling.
  *
  * <p>
- * Allows customization of the SIGTERM handler's behavior, including whether it is enabled and the exit code to use
- * during graceful termination.
+ * Allows customization of the Sigterm Handler's behavior, including whether it is enabled,
+ * the exit code to use during graceful termination, and optional termination message settings.
  * </p>
  *
  * <ul>
- *     <li><b>kubernetes.handler.enabled:</b> Set whether the handler is enabled or disabled (default: true).</li>
- *     <li><b>kubernetes.handler.exit-code:</b> Sets the exit code for graceful application termination (default: 0).</li>
+ *     <li><b>kubernetes.sigterm-handler.enabled:</b> Set whether the handler is enabled or disabled. (default: true)</li>
+ *     <li><b>kubernetes.sigterm-handler.exit-code:</b> Set the exit code for graceful application termination. (default: 0)</li>
+ *     <li><b>kubernetes.sigterm-handler.termination-message-path:</b> Set the file path where the termination message should be written. (default: not set)</li>
+ *     <li><b>kubernetes.sigterm-handler.termination-message:</b> Set the content of the termination message written to the specified path. (default: SIGTERM signal received. Application has been terminated successfully.)</li>
  * </ul>
  *
  * <pre>
  * Example configuration (YAML):
  * {@code
  * kubernetes:
- *   handler:
+ *   sigterm-handler:
  *     enabled: true
- *     exit-code: 1
+ *     exit-code: 0
+ *     termination-message-path: /dev/termination-log
+ *     termination-message: SIGTERM signal received...
  * }
  * </pre>
  *
  * <pre>
  * Example configuration (Properties):
  * {@code
- * kubernetes.handler.enabled=true
- * kubernetes.handler.exit-code=1
+ * kubernetes.sigterm-handler.enabled=true
+ * kubernetes.sigterm-handler.exit-code=0
+ * kubernetes.sigterm-handler.termination-message-path=/dev/termination-log
+ * kubernetes.sigterm-handler.termination-message=SIGTERM signal received...
  * }
  * </pre>
  *
  * <p>
- * By default, the handler is enabled, and the application terminates with an exit code of 0,
- * marking the Kubernetes Pod as "Completed."
+ * The Sigterm Handler is primarily designed for Kubernetes
+ * but can also be utilized in Docker or other environments requiring signal handling functionality.
  * </p>
  *
  * @author jeyong
- * @since 1.0
+ * @since 1.2
  * @see SigtermHandlerConfiguration
  */
 // @formatter:on
-@ConfigurationProperties(prefix = "kubernetes.handler")
+@ConfigurationProperties(prefix = "kubernetes.sigterm-handler")
 public class SigtermHandlerProperties {
 
     private boolean enabled = true;
-
     private int exitCode = 0;
+    private String terminationMessagePath;
+    private String terminationMessage = "SIGTERM signal received. Application has been terminated successfully.";
 
     public boolean isEnabled() {
         return enabled;
@@ -64,4 +73,20 @@ public int getExitCode() {
     public void setExitCode(final int exitCode) {
         this.exitCode = exitCode;
     }
+
+    public String getTerminationMessagePath() {
+        return terminationMessagePath;
+    }
+
+    public void setTerminationMessagePath(final String terminationMessagePath) {
+        this.terminationMessagePath = terminationMessagePath;
+    }
+
+    public String getTerminationMessage() {
+        return terminationMessage;
+    }
+
+    public void setTerminationMessage(final String terminationMessage) {
+        this.terminationMessage = terminationMessage;
+    }
 }

handler/src/main/java/io/jeyong/handler/SpringContextTerminator.java

@@ -8,7 +8,9 @@ public class SpringContextTerminator extends ApplicationTerminator {
     private final ApplicationContext applicationContext;
     private final int exitCode;
 
-    public SpringContextTerminator(final ApplicationContext applicationContext, final int exitCode) {
+    public SpringContextTerminator(final ApplicationContext applicationContext, final int exitCode,
+                                   final String terminationMessagePath, final String terminationMessage) {
+        super(terminationMessagePath, terminationMessage);
         this.applicationContext = applicationContext;
         this.exitCode = exitCode;
     }

test/src/test/java/io/jeyong/test/integration/SigtermHandlerTest.java

@@ -11,6 +11,7 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import org.apache.commons.io.FileUtils;
+import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
@@ -22,15 +23,26 @@
 @DisplayName("SigtermHandler Integration Test")
 public class SigtermHandlerTest {
 
+    private static final int EXPECTED_EXIT_CODE = 10;
+    private static final String TERMINATION_MESSAGE_PATH = "/app/termination-message.message";
+    private static final String TERMINATION_MESSAGE = "Test termination message";
+
+    private static Path codeDir;
     private static ImageFromDockerfile dockerImage;
 
     @BeforeAll
-    static void setUp() {
-        dockerImage = buildImage();
+    static void setUp() throws Exception {
+        codeDir = createCodeDirectory();
+        dockerImage = buildImage(codeDir);
+    }
+
+    @AfterAll
+    static void tearDown() throws Exception {
+        FileUtils.deleteDirectory(codeDir.toFile());
     }
 
     @Test
-    @DisplayName("Container should exit with code 0 on SIGTERM")
+    @DisplayName("Container should exit with expected code on SIGTERM")
     void testExitCode() throws Exception {
         // given
         GenericContainer<?> container = new GenericContainer<>(dockerImage)
@@ -42,7 +54,7 @@ void testExitCode() throws Exception {
 
         // then
         Long exitCode = container.getCurrentContainerInfo().getState().getExitCodeLong();
-        assertThat(exitCode).isEqualTo(0);
+        assertThat(exitCode).isEqualTo(EXPECTED_EXIT_CODE);
     }
 
     @Test
@@ -65,10 +77,52 @@ void testCleanUp() throws Exception {
         });
     }
 
-    private static ImageFromDockerfile buildImage() {
-        Path tempDir = createTempDirectory();
+    @Test
+    @DisplayName("Check termination message file inside container")
+    void testTerminationMessageFile() throws Exception {
+        // given
+        GenericContainer<?> container = new GenericContainer<>(dockerImage)
+                .waitingFor(forLogMessage(".*Started TestApplication.*\\n", 1));
+        container.start();
+
+        // when
+        sendSigtermToContainer(container);
+
+        // then
+        String fileContent = container.copyFileFromContainer(
+                TERMINATION_MESSAGE_PATH,
+                content -> new String(content.readAllBytes())
+        );
+        assertThat(fileContent).isEqualTo(TERMINATION_MESSAGE);
+    }
+
+    private static Path createCodeDirectory() throws Exception {
+        Path codeDir = Files.createTempDirectory("docker-context");
+        copyFile("../gradlew", codeDir.resolve("gradlew"));
+        copyDirectory("../gradle", codeDir.resolve("gradle"));
+        copyFile("../settings.gradle", codeDir.resolve("settings.gradle"));
+        copyDirectory("../handler", codeDir.resolve("handler"));
+        copyDirectory("../test", codeDir.resolve("test"));
+        createApplicationYaml(codeDir.resolve("test/src/main/resources"));
+        return codeDir;
+    }
+
+    private static void createApplicationYaml(Path resourcesDir) throws Exception {
+        Files.createDirectories(resourcesDir);
+        Path applicationYaml = resourcesDir.resolve("application.yml");
+        String yamlContent = String.format("""
+                kubernetes:
+                  sigterm-handler:
+                    exit-code: %d
+                    termination-message-path: %s
+                    termination-message: %s
+                """, EXPECTED_EXIT_CODE, TERMINATION_MESSAGE_PATH, TERMINATION_MESSAGE);
+        Files.writeString(applicationYaml, yamlContent);
+    }
+
+    private static ImageFromDockerfile buildImage(Path sourceCodeDir) {
         return new ImageFromDockerfile()
-                .withFileFromPath(".", tempDir)
+                .withFileFromPath(".", sourceCodeDir)
                 .withDockerfileFromBuilder(builder -> {
                     builder.from("eclipse-temurin:17")
                             .workDir("/app")
@@ -84,20 +138,6 @@ private static ImageFromDockerfile buildImage() {
                 });
     }
 
-    private static Path createTempDirectory() {
-        try {
-            Path tempDir = Files.createTempDirectory("docker-context");
-            copyFile("../gradlew", tempDir.resolve("gradlew"));
-            copyDirectory("../gradle", tempDir.resolve("gradle"));
-            copyFile("../settings.gradle", tempDir.resolve("settings.gradle"));
-            copyDirectory("../handler", tempDir.resolve("handler"));
-            copyDirectory("../test", tempDir.resolve("test"));
-            return tempDir;
-        } catch (Exception e) {
-            throw new RuntimeException("Failed to create temp directory for Docker context", e);
-        }
-    }
-
     private static void copyFile(String source, Path destination) throws Exception {
         FileUtils.copyFile(new File(source), destination.toFile());
     }

test/src/test/java/io/jeyong/test/unit/ApplicationTerminatorTest.java

@@ -4,20 +4,48 @@
 import static org.assertj.core.api.Assertions.assertThat;
 
 import io.jeyong.handler.ApplicationTerminator;
+import java.io.File;
+import java.nio.file.Files;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
 import sun.misc.SignalHandler;
 
 @DisplayName("ApplicationTerminator Unit Test")
 public class ApplicationTerminatorTest {
 
+    @Test
+    @DisplayName("FileUtils.writeToFile should create a file with correct content")
+    void testFileCreationAndContent() throws Exception {
+        // given
+        File tempFile = Files.createTempFile("termination-", ".txt").toFile();
+        String terminationMessagePath = tempFile.getAbsolutePath();
+        String expectedMessage = "Test termination message";
+
+        ApplicationTerminator terminator = new ApplicationTerminator(terminationMessagePath, expectedMessage) {
+
+            @Override
+            protected int getExitCode() {
+                return 0;
+            }
+        };
+
+        // when
+        catchSystemExit(() -> terminator.handleTermination().handle(null));
+
+        // then
+        assertThat(Files.readString(tempFile.toPath())).isEqualTo(expectedMessage);
+
+        // Clean up
+        Files.deleteIfExists(tempFile.toPath());
+    }
+
     @Test
     @DisplayName("System.exit should be called with the expected exit code")
     void testHandleTerminationCallsSystemExit() throws Exception {
         // given
         int expectedExitCode = 0;
-        ApplicationTerminator terminator = new ApplicationTerminator() {
-            
+        ApplicationTerminator terminator = new ApplicationTerminator(null, null) {
+
             @Override
             protected int getExitCode() {
                 return expectedExitCode;

test/src/test/java/io/jeyong/test/unit/SignalHandlerRegistrarTest.java

@@ -19,7 +19,7 @@ void testSignalHandlerRegistration() {
         String signalType = "TERM";
         int exitCode = 0;
         SignalHandler expectedHandler = signal -> System.exit(exitCode);
-        ApplicationTerminator terminator = new ApplicationTerminator() {
+        ApplicationTerminator terminator = new ApplicationTerminator(null, null) {
 
             @Override
             public SignalHandler handleTermination() {