Better example code for Spring Boot

transactionoutbox-spring/pom.xml

@@ -54,6 +54,12 @@
       <artifactId>lombok</artifactId>
     </dependency>
     <!-- Test -->
+    <dependency>
+      <groupId>com.gruelbox</groupId>
+      <artifactId>transactionoutbox-jackson</artifactId>
+      <scope>test</scope>
+      <version>${project.version}</version>
+    </dependency>
     <dependency>
       <groupId>ch.qos.logback</groupId>
       <artifactId>logback-classic</artifactId>
@@ -100,5 +106,11 @@
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter-params</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.awaitility</groupId>
+      <artifactId>awaitility</artifactId>
+      <version>4.2.0</version>
+      <scope>test</scope>
+    </dependency>
   </dependencies>
 </project>

transactionoutbox-spring/src/main/java/com/gruelbox/transactionoutbox/spring/SpringTransactionOutboxConfiguration.java

@@ -3,6 +3,10 @@
 import org.springframework.context.annotation.Configuration;
 import org.springframework.context.annotation.Import;
 
+/**
+ * @deprecated Just {@code @Import} the components you need.
+ */
 @Configuration
+@Deprecated(forRemoval = true)
 @Import({SpringTransactionManager.class, SpringInstantiator.class})
 public class SpringTransactionOutboxConfiguration {}

transactionoutbox-spring/src/test/java/com/gruelbox/transactionoutbox/spring/acceptance/Customer.java → transactionoutbox-spring/src/test/java/com/gruelbox/transactionoutbox/spring/example/Customer.java

@@ -1,4 +1,4 @@
-package com.gruelbox.transactionoutbox.spring.acceptance;
+package com.gruelbox.transactionoutbox.spring.example;
 
 import jakarta.persistence.Column;
 import jakarta.persistence.Entity;

transactionoutbox-spring/src/test/java/com/gruelbox/transactionoutbox/spring/acceptance/CustomerRepository.java → transactionoutbox-spring/src/test/java/com/gruelbox/transactionoutbox/spring/example/CustomerRepository.java

@@ -1,4 +1,4 @@
-package com.gruelbox.transactionoutbox.spring.acceptance;
+package com.gruelbox.transactionoutbox.spring.example;
 
 import org.springframework.data.repository.CrudRepository;
 import org.springframework.stereotype.Repository;

transactionoutbox-spring/src/test/java/com/gruelbox/transactionoutbox/spring/example/EventuallyConsistentController.java

@@ -0,0 +1,37 @@
+package com.gruelbox.transactionoutbox.spring.example;
+
+import static org.springframework.http.HttpStatus.NOT_FOUND;
+
+import com.gruelbox.transactionoutbox.TransactionOutbox;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.transaction.annotation.Transactional;
+import org.springframework.web.bind.annotation.*;
+import org.springframework.web.server.ResponseStatusException;
+
+@SuppressWarnings("unused")
+@RestController
+class EventuallyConsistentController {
+
+  private static final Logger LOGGER =
+      LoggerFactory.getLogger(EventuallyConsistentController.class);
+
+  @Autowired private CustomerRepository customerRepository;
+  @Autowired private TransactionOutbox outbox;
+
+  @SuppressWarnings("SameReturnValue")
+  @PostMapping(path = "/customer")
+  @Transactional
+  public void createCustomer(@RequestBody Customer customer) {
+    customerRepository.save(customer);
+    outbox.schedule(ExternalQueueService.class).sendCustomerCreatedEvent(customer);
+  }
+
+  @GetMapping("/customer/{id}")
+  public Customer getCustomer(@PathVariable long id) {
+    return customerRepository
+        .findById(id)
+        .orElseThrow(() -> new ResponseStatusException(NOT_FOUND));
+  }
+}

transactionoutbox-spring/src/test/java/com/gruelbox/transactionoutbox/spring/example/EventuallyConsistentControllerTest.java

@@ -0,0 +1,64 @@
+package com.gruelbox.transactionoutbox.spring.example;
+
+import static java.util.concurrent.TimeUnit.SECONDS;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.awaitility.Awaitility.await;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.net.URL;
+import javax.inject.Inject;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.boot.test.web.server.LocalServerPort;
+
+@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+class EventuallyConsistentControllerTest {
+
+  @SuppressWarnings("unused")
+  @LocalServerPort
+  private int port;
+
+  private URL base;
+
+  @SuppressWarnings("unused")
+  @Inject
+  private TestRestTemplate template;
+
+  @Inject private ExternalQueueService externalQueueService;
+
+  @BeforeEach
+  void setUp() throws Exception {
+    this.base = new URL("http://localhost:" + port + "/");
+  }
+
+  @Test
+  void testCheck() throws Exception {
+
+    var joe = new Customer(1L, "Joe", "Strummer");
+    var dave = new Customer(2L, "Dave", "Grohl");
+    var neil = new Customer(3L, "Neil", "Diamond");
+    var tupac = new Customer(4L, "Tupac", "Shakur");
+    var jeff = new Customer(5L, "Jeff", "Mills");
+    var customer = base.toString() + "/customer";
+
+    assertTrue(template.postForEntity(customer, joe, Void.class).getStatusCode().is2xxSuccessful());
+    assertTrue(
+        template.postForEntity(customer, dave, Void.class).getStatusCode().is2xxSuccessful());
+    assertTrue(
+        template.postForEntity(customer, neil, Void.class).getStatusCode().is2xxSuccessful());
+    assertTrue(
+        template.postForEntity(customer, tupac, Void.class).getStatusCode().is2xxSuccessful());
+    assertTrue(
+        template.postForEntity(customer, jeff, Void.class).getStatusCode().is2xxSuccessful());
+
+    await()
+        .atMost(10, SECONDS)
+        .pollDelay(1, SECONDS)
+        .untilAsserted(
+            () ->
+                assertThat(externalQueueService.getSent())
+                    .containsExactlyInAnyOrder(joe, dave, neil, tupac, jeff));
+  }
+}

transactionoutbox-spring/src/test/java/com/gruelbox/transactionoutbox/spring/example/ExternalQueueService.java

@@ -0,0 +1,24 @@
+package com.gruelbox.transactionoutbox.spring.example;
+
+import lombok.Getter;
+import org.springframework.stereotype.Service;
+
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.CopyOnWriteArrayList;
+
+@Getter
+@Service
+class ExternalQueueService {
+
+  private final Set<Long> attempted = new HashSet<>();
+  private final List<Customer> sent = new CopyOnWriteArrayList<>();
+
+  void sendCustomerCreatedEvent(Customer customer) {
+    if (attempted.add(customer.getId())) {
+      throw new RuntimeException("Temporary failure, try again");
+    }
+    sent.add(customer);
+  }
+}

transactionoutbox-spring/src/test/java/com/gruelbox/transactionoutbox/spring/example/ExternalsConfiguration.java

@@ -0,0 +1,10 @@
+package com.gruelbox.transactionoutbox.spring.example;
+
+import com.gruelbox.transactionoutbox.spring.SpringInstantiator;
+import com.gruelbox.transactionoutbox.spring.SpringTransactionManager;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+
+@Configuration
+@Import({SpringInstantiator.class, SpringTransactionManager.class})
+class ExternalsConfiguration {}

transactionoutbox-spring/src/test/java/com/gruelbox/transactionoutbox/spring/example/TransactionOutboxBackgroundProcessor.java

@@ -0,0 +1,31 @@
+package com.gruelbox.transactionoutbox.spring.example;
+
+import com.gruelbox.transactionoutbox.TransactionOutbox;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.scheduling.annotation.Scheduled;
+import org.springframework.stereotype.Component;
+
+/**
+ * Simple implementation of a background processor for {@link TransactionOutbox}. You don't need to
+ * use this if you need different semantics, but this is a good start for most purposes.
+ */
+@Component
+@Slf4j
+@RequiredArgsConstructor(onConstructor_ = {@Autowired})
+class TransactionOutboxBackgroundProcessor {
+
+  private final TransactionOutbox outbox;
+
+  @Scheduled(fixedRateString = "${outbox.repeatEvery}")
+  void poll() {
+    try {
+      do {
+        log.info("Flushing");
+      } while (outbox.flush());
+    } catch (Exception e) {
+      log.error("Error flushing transaction outbox. Pausing", e);
+    }
+  }
+}