add heartbeat logger

oidc-playground-server/src/main/java/playground/PlaygroundServerApplication.java

@@ -10,13 +10,15 @@
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.autoconfigure.jmx.JmxAutoConfiguration;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
+import org.springframework.scheduling.annotation.EnableScheduling;
 import playground.api.ACR;
 
 @SpringBootApplication(exclude = {AuditAutoConfiguration.class, HttpTraceAutoConfiguration.class,
         JmxAutoConfiguration.class, JmxEndpointAutoConfiguration.class,
         JvmMetricsAutoConfiguration.class, MetricsAutoConfiguration.class, SimpleMetricsExportAutoConfiguration.class,
 })
 @EnableConfigurationProperties(ACR.class)
+@EnableScheduling
 public class PlaygroundServerApplication {
 
     public static void main(String[] args) {

oidc-playground-server/src/main/java/playground/heartbeat/HeartbeatLogger.java

@@ -0,0 +1,16 @@
+package playground.heartbeat;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Component;
+
+@Component
+public class HeartbeatLogger {
+    private static final Logger LOG = LoggerFactory.getLogger(HeartbeatLogger.class);
+
+    @Scheduled(cron = "0 0 * * * *")
+    public void mark() {
+        LOG.info("MARK");
+    }
+}

oidc-playground-server/src/test/java/playground/heartbeat/HeartbeatLoggerTest.java

@@ -0,0 +1,33 @@
+package playground.heartbeat;
+
+import ch.qos.logback.classic.Level;
+import ch.qos.logback.classic.Logger;
+import ch.qos.logback.classic.spi.ILoggingEvent;
+import ch.qos.logback.core.read.ListAppender;
+import org.junit.Test;
+import org.slf4j.LoggerFactory;
+
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+
+public class HeartbeatLoggerTest {
+
+    @Test
+    public void emitsMarkAtInfo() {
+        Logger logger = (Logger) LoggerFactory.getLogger(HeartbeatLogger.class);
+        ListAppender<ILoggingEvent> appender = new ListAppender<>();
+        appender.start();
+        logger.addAppender(appender);
+        try {
+            new HeartbeatLogger().mark();
+
+            List<ILoggingEvent> events = appender.list;
+            assertEquals(1, events.size());
+            assertEquals(Level.INFO, events.getFirst().getLevel());
+            assertEquals("MARK", events.getFirst().getFormattedMessage());
+        } finally {
+            logger.detachAppender(appender);
+        }
+    }
+}