Merge pull request #22 from ralf-ueberfuhr-ars/feature/observability

Observability

customer-api-provider/pom.xml

@@ -92,6 +92,10 @@
       <groupId>io.quarkus</groupId>
       <artifactId>quarkus-jdbc-h2</artifactId>
     </dependency>
+    <dependency>
+      <groupId>io.quarkus</groupId>
+      <artifactId>quarkus-smallrye-health</artifactId>
+    </dependency>
   </dependencies>
 
   <build>

customer-api-provider/src/main/java/de/schulung/sample/quarkus/infrastructure/LongRunningStartup.java

@@ -0,0 +1,64 @@
+package de.schulung.sample.quarkus.infrastructure;
+
+import io.quarkus.runtime.Startup;
+import io.smallrye.mutiny.Uni;
+import io.smallrye.mutiny.infrastructure.Infrastructure;
+import jakarta.enterprise.context.ApplicationScoped;
+import jakarta.enterprise.inject.Produces;
+import org.eclipse.microprofile.health.HealthCheck;
+import org.eclipse.microprofile.health.HealthCheckResponse;
+import org.eclipse.microprofile.health.Liveness;
+import org.eclipse.microprofile.health.Readiness;
+
+@ApplicationScoped
+public class LongRunningStartup {
+
+  private volatile boolean initialized = false;
+  private volatile boolean initializingFailed = false;
+
+  // check during startup: http://localhost:9090/q/health/ready
+
+  private Uni<Void> doLongRunningInitialization() {
+    try {
+      Thread.sleep(5000);
+      initialized = true;
+      return Uni.createFrom().voidItem();
+    } catch (InterruptedException e) {
+      initializingFailed = true;
+      return Uni.createFrom().failure(e);
+    }
+  }
+
+  @Startup
+  public void init() {
+    Uni
+      .createFrom()
+      .voidItem()
+      .emitOn(Infrastructure.getDefaultWorkerPool())
+      .subscribe()
+      .with(v -> this.doLongRunningInitialization());
+  }
+
+  @Produces
+  @ApplicationScoped
+  @Liveness
+  public HealthCheck myStartupLiveness() {
+    return () -> {
+      final var result = HealthCheckResponse
+        .named("My long-running startup");
+      return (initializingFailed ? result.down() : result.up()).build();
+    };
+  }
+
+  @Produces
+  @ApplicationScoped
+  @Readiness
+  public HealthCheck myStartupReadyness() {
+    return () -> {
+      final var result = HealthCheckResponse
+        .named("My long-running startup");
+      return (initialized ? result.up() : result.down()).build();
+    };
+  }
+
+}

customer-api-provider/src/main/resources/application.properties

@@ -19,4 +19,15 @@ persistence.sink.implementation=panache
 %dev.quarkus.hibernate-orm.database.generation=update
 
 
+# Observability - serve on another port
+# https://quarkus.io/guides/management-interface-reference
+# https://quarkus.io/guides/smallrye-health
+# https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/
+# https://developers.redhat.com/blog/2020/11/10/you-probably-need-liveness-and-readiness-probes
+quarkus.management.enabled=true
+quarkus.management.port=9090
+%dev.quarkus.management.host=localhost
+quarkus.datasource.health.enabled=true
 
+# Liveness: if fails -> container must be restarted
+# Readyness: if fails -> container is just initializing