Merge pull request #22 from frankliu20/frank/reliable-java-9-10

feat: add sample to define health probe with spring-acutator

config/application.yml

@@ -39,6 +39,11 @@ spring.cloud.refresh.refreshable: false
 # Logging
 logging.level.org.springframework: INFO
 
+# enable health probes
+management.health.livenessState.enabled: true
+management.health.readinessState.enabled: true
+management.endpoint.health.probes.enabled: true
+
 # Metrics
 management:
   endpoint:

docs/02_lab_migrate/0203_application.yml

@@ -43,6 +43,11 @@ spring.cloud.refresh.refreshable: false
 # Logging
 logging.level.org.springframework: INFO
 
+# enable health probes
+management.health.livenessState.enabled: true
+management.health.readinessState.enabled: true
+management.endpoint.health.probes.enabled: true
+
 # Metrics
 management:
   endpoint:

src/spring-petclinic-customers-service/src/main/java/org/springframework/samples/petclinic/customers/health/ServiceHealthIndicator.java

@@ -0,0 +1,47 @@
+package org.springframework.samples.petclinic.customers.health;
+
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.HealthIndicator;
+import org.springframework.samples.petclinic.customers.model.OwnerRepository;
+import org.springframework.stereotype.Component;
+
+import lombok.extern.slf4j.Slf4j;
+
+@Component
+@Slf4j
+public class ServiceHealthIndicator implements HealthIndicator {
+
+    private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
+    private boolean isHealthy = false;
+
+    private OwnerRepository ownerRepo;
+
+    public ServiceHealthIndicator(OwnerRepository ownerRepo) {
+        this.ownerRepo = ownerRepo;
+        scheduler.scheduleAtFixedRate(() -> {
+            checkDatabaseStatus();
+            if (isHealthy) {
+                scheduler.shutdown();
+            }
+        }, 10, 5, TimeUnit.SECONDS);
+    }
+
+    private void checkDatabaseStatus() {
+        boolean databaseReady = ownerRepo.findAll().size() > 0;
+        if (databaseReady) {
+            isHealthy = true;
+            log.info("Database is healthy. Stopping checks.");
+        } else {
+            log.info("Database is not healthy. Checking again in 5 seconds.");
+        }
+    }
+
+    @Override
+    public Health health() {
+        return isHealthy ? Health.up().build() : Health.down().build();
+    }
+}