implement the PostgreSQLInstanceReadinessCheck

Author: ThoSap

src/main/java/it/aboutbits/postgresql/MinioInstanceReadinessCheck.java

@@ -0,0 +1,65 @@
+package it.aboutbits.postgresql;
+
+import io.fabric8.kubernetes.client.KubernetesClient;
+import it.aboutbits.postgresql.core.PostgreSQLContextFactory;
+import it.aboutbits.postgresql.crd.connection.ClusterConnection;
+import lombok.RequiredArgsConstructor;
+import org.eclipse.microprofile.health.HealthCheck;
+import org.eclipse.microprofile.health.HealthCheckResponse;
+import org.eclipse.microprofile.health.HealthCheckResponseBuilder;
+import org.eclipse.microprofile.health.Readiness;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * MicroProfile readiness health check that verifies connectivity to all
+ * configured PostgreSQL instances. Each instance is probed with a lightweight
+ * operation, and the aggregated status is exposed.
+ */
+@NullMarked
+@Readiness
+@RequiredArgsConstructor
+public class PostgreSQLInstanceReadinessCheck implements HealthCheck {
+    private final PostgreSQLContextFactory postgreSQLContextFactory;
+
+    private final KubernetesClient kubernetesClient;
+
+    @Override
+    public HealthCheckResponse call() {
+        var builder = HealthCheckResponse.builder().name("PostgreSQL Instances");
+
+        var connections = kubernetesClient.resources(ClusterConnection.class).list().getItems();
+
+        boolean allUp = connections.stream()
+                .allMatch(connection -> checkInstance(
+                        connection,
+                        builder
+                ));
+
+        return builder.status(allUp).build();
+    }
+
+    private boolean checkInstance(
+            ClusterConnection clusterConnection,
+            HealthCheckResponseBuilder builder
+    ) {
+        var name = clusterConnection.getMetadata().getName();
+
+        try (var dsl = postgreSQLContextFactory.getDSLContext(clusterConnection)) {
+            var version = dsl.fetchSingle("select version()").into(String.class);
+
+            builder.withData(
+                    name,
+                    "UP (%s)".formatted(version)
+            );
+
+            return true;
+        } catch (Exception _) {
+            builder.withData(
+                    name,
+                    "DOWN"
+            );
+
+            return false;
+        }
+    }
+}

src/main/java/it/aboutbits/postgresql/PostgreSQLInstanceReadinessCheck.java

@@ -0,0 +1,82 @@
+package it.aboutbits.postgresql;
+
+import io.fabric8.kubernetes.client.KubernetesClient;
+import io.quarkus.test.junit.QuarkusTest;
+import it.aboutbits.postgresql._support.testdata.persisted.Given;
+import it.aboutbits.postgresql.crd.connection.ClusterConnection;
+import jakarta.inject.Inject;
+import org.eclipse.microprofile.health.HealthCheckResponse;
+import org.eclipse.microprofile.health.Readiness;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@QuarkusTest
+class PostgreSQLInstanceReadinessCheckTest {
+    @Inject
+    Given given;
+
+    @Inject
+    @Readiness
+    PostgreSQLInstanceReadinessCheck readinessCheck;
+
+    @Inject
+    KubernetesClient kubernetesClient;
+
+    @BeforeEach
+    void cleanUp() {
+        kubernetesClient.resources(ClusterConnection.class).delete();
+    }
+
+    @Test
+    void call_whenAllConnectionsUp_shouldReturnUp() {
+        given.one()
+                .clusterConnection()
+                .withName("test-db")
+                .returnFirst();
+
+        var response = readinessCheck.call();
+
+        assertThat(response.getStatus()).isEqualTo(
+                HealthCheckResponse.Status.UP
+        );
+
+        assertThat(response.getData())
+                .isPresent()
+                .get()
+                .satisfies(data -> {
+                    assertThat(data).containsKey("test-db");
+                    assertThat(data.get("test-db").toString()).startsWith("UP (PostgreSQL");
+                });
+    }
+
+    @Test
+    void call_whenSomeConnectionsDown_shouldReturnDown() {
+        given.one()
+                .clusterConnection()
+                .withName("db-1")
+                .returnFirst();
+
+        given.one()
+                .clusterConnection()
+                .withName("db-2")
+                .withHost("non-existent-host")
+                .returnFirst();
+
+        var response = readinessCheck.call();
+
+        assertThat(response.getStatus()).isEqualTo(
+                HealthCheckResponse.Status.DOWN
+        );
+
+        assertThat(response.getData())
+                .isPresent()
+                .get()
+                .satisfies(data -> {
+                    assertThat(data).containsKey("db-1");
+                    assertThat(data.get("db-1").toString()).startsWith("UP (PostgreSQL");
+                    assertThat(data).containsEntry("db-2", "DOWN");
+                });
+    }
+}

src/test/java/it/aboutbits/postgresql/PostgreSQLInstanceReadinessCheckTest.java

@@ -20,7 +20,6 @@
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
 
-import java.sql.SQLException;
 import java.time.OffsetDateTime;
 import java.time.ZoneOffset;
 import java.time.temporal.ChronoUnit;