Updated directory structure

oparl-server/oparl-server.gradle

@@ -0,0 +1,85 @@
+plugins {
+    id 'com.google.cloud.tools.jib' version '1.8.0' // jib build our docker images
+    id 'org.springframework.boot' version '2.2.4.RELEASE'
+    id 'io.spring.dependency-management' version '1.0.9.RELEASE'
+}
+
+configurations {
+    all {
+        exclude group: 'org.springframework.boot', module: 'spring-boot-starter-logging'
+    }
+    integrationTestImplementation.extendsFrom testImplementation
+}
+
+sourceSets {
+    integrationTest {
+        java {
+            compileClasspath += main.output + test.output
+            runtimeClasspath += main.output + test.output
+            srcDir file('src/integration-test/java')
+        }
+        resources.srcDir file('src/integration-test/resources')
+    }
+}
+
+dependencies {
+    implementation 'org.springframework.boot:spring-boot-starter-actuator'
+    implementation 'org.springframework.boot:spring-boot-starter-websocket'
+    implementation 'org.springframework.boot:spring-boot-starter-log4j2'
+    implementation 'io.micrometer:micrometer-registry-prometheus'
+    implementation 'org.springdoc:springdoc-openapi-ui:1.3.9'
+
+    annotationProcessor 'org.springframework.boot:spring-boot-configuration-processor'
+    developmentOnly 'org.springframework.boot:spring-boot-devtools'
+    testImplementation('org.springframework.boot:spring-boot-starter-test') {
+        // no support for junit 4 Tests
+        exclude group: 'org.junit.vintage', module: 'junit-vintage-engine'
+        // exclude hamcrest, we use asAbbringerFahrtLoeschenTypesertj in unit tests
+        exclude group: 'org.hamcrest', module: 'hamcrestv'
+    }
+    testImplementation 'org.testcontainers:testcontainers:1.12.5'
+    // add hamcrest only for mockMvcTest
+    // see https://github.com/spring-projects/spring-framework/issues/21178
+    testImplementation 'org.hamcrest:hamcrest:2.2'
+}
+
+bootJar {
+    manifest {
+        attributes 'Implementation-Title': archiveBaseName.get(),
+                'Implementation-Version': archiveVersion.get(),
+                'Implementation-Vendor': "Jim Martens"
+    }
+}
+
+task integrationTest(type: Test) {
+    useJUnitPlatform()
+    maxHeapSize = "4g"
+    group = 'verification'
+    workingDir = rootProject.projectDir
+    testClassesDirs = sourceSets.integrationTest.output.classesDirs
+    classpath = sourceSets.integrationTest.runtimeClasspath
+}
+
+tasks.jib.dependsOn(build)
+tasks.jibDockerBuild.dependsOn(build)
+
+jib {
+    from {
+        image = 'amazoncorretto:11'
+    }
+    to {
+        image = '2martens/oparl'
+        tags = ['latest', getProperty('version').toString().replace('+', '-')]
+    }
+    container {
+        jvmFlags = ['-Xms1g', '-Xmx1g', '-Dlog4j.configurationFile=log4j2-docker.xml']
+        mainClass = "org.springframework.boot.loader.JarLauncher"
+        // 8080 spring boot web, 8081 actuators (prometheus, healthchecks, ...), 9090 grpc
+        ports = ['8080', '8081', '9090']
+    }
+    containerizingMode = 'packaged'
+}
+
+tasks.build.dependsOn(integrationTest)
+tasks.integrationTest.mustRunAfter(test)
+

oparl-server/src/integration-test/java/de/twomartens/oparlservice/OParlServiceRestTests.java

@@ -0,0 +1,62 @@
+package de.twomartens.oparlservice;
+
+import de.twomartens.oparlservice.entity.Greeting;
+import de.twomartens.oparlservice.interceptors.RequestTypeInterceptor;
+import de.twomartens.oparlservice.interceptors.TraceIdInterceptor;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.web.server.LocalServerPort;
+import org.springframework.http.ResponseEntity;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+import org.springframework.web.client.RestTemplate;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.springframework.boot.test.context.SpringBootTest.WebEnvironment.RANDOM_PORT;
+
+@SpringJUnitConfig
+@SpringBootTest(webEnvironment = RANDOM_PORT)
+class OParlServiceRestTests {
+
+  @Autowired
+  private RestTemplate restTemplate;
+
+  @LocalServerPort
+  int randomServerPort;
+
+  @Autowired
+  private RequestTypeInterceptor requestTypeInterceptor;
+
+  @Autowired
+  private TraceIdInterceptor traceIdInterceptor;
+
+  @BeforeEach
+  void setup() {
+    traceIdInterceptor.createNewTraceId();
+    requestTypeInterceptor.markAsIntegrationTest();
+  }
+
+  @Test
+  void testRestService() {
+    ResponseEntity<Greeting> result = restTemplate.getForEntity(getEndpoint(), Greeting.class);
+    assertThat(result.getStatusCode().is2xxSuccessful()).isTrue();
+    assertThat(result.getBody()).isNotNull();
+    assertThat(result.getBody().getMessage()).isEqualTo("Hello RestCheck!");
+  }
+
+  /*
+   * This method is so complicated because it uses the local-grpc-server configuration for grpc to create
+   * a correct link for the rest endpoints in the cloud
+   */
+  private String getEndpoint() {
+    String hostNameForGrpcServer = "127.0.0.1";
+    int port = randomServerPort;
+    String protocol = "http";
+
+    return String.format("%s://%s:%d/greeting?name=RestCheck",
+        protocol,
+        hostNameForGrpcServer,
+        port);
+  }
+}

oparl-server/src/main/java/de/twomartens/oparlservice/OParlServiceApplication.java

@@ -0,0 +1,29 @@
+package de.twomartens.oparlservice;
+
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.scheduling.annotation.EnableScheduling;
+
+import java.util.Optional;
+
+@Slf4j
+@SpringBootApplication
+@EnableScheduling
+public class OParlServiceApplication {
+
+    public static void main(String[] args) {
+        log.info(">>> {}:{} <<<", getTitle(), getVersion());
+        SpringApplication.run(OParlServiceApplication.class, args);
+    }
+
+    private static String getTitle() {
+        return Optional.ofNullable(OParlServiceApplication.class.getPackage().getImplementationTitle())
+                .orElse("start");
+    }
+
+    private static String getVersion() {
+        return Optional.ofNullable(OParlServiceApplication.class.getPackage().getImplementationVersion())
+                .orElse("snapshot");
+    }
+}

oparl-server/src/main/java/de/twomartens/oparlservice/actuator/AbstractHealthCheck.java

@@ -0,0 +1,68 @@
+package de.twomartens.oparlservice.actuator;
+
+import de.twomartens.oparlservice.interceptors.RequestTypeInterceptor;
+import de.twomartens.oparlservice.interceptors.TraceIdInterceptor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.boot.actuate.health.Health;
+import org.springframework.boot.actuate.health.HealthIndicator;
+
+@Slf4j
+public abstract class AbstractHealthCheck implements HealthIndicator {
+
+  private static final String DEFAULT_HOST = "localhost";
+  private static final String HEALTH_KEY_ENDPOINT = "endpoint";
+
+  private final String endpoint;
+
+  private final TraceIdInterceptor traceIdInterceptor;
+
+  private final RequestTypeInterceptor requestTypeInterceptor;
+
+  private final int port;
+
+  public AbstractHealthCheck(int port,
+      TraceIdInterceptor traceIdInterceptor,
+      RequestTypeInterceptor requestTypeInterceptor) {
+    this.traceIdInterceptor = traceIdInterceptor;
+    this.requestTypeInterceptor = requestTypeInterceptor;
+    this.port = port;
+    this.endpoint = mkEndpoint();
+  }
+
+  @Override
+  public Health health() {
+    requestTypeInterceptor.markAsHealthCheck();
+    traceIdInterceptor.createNewTraceId();
+    Health result;
+    try {
+      if (isEndpointAvailable()) {
+        result = Health.up().withDetail(HEALTH_KEY_ENDPOINT, getEndpoint()).build();
+      } else {
+        result = Health.down().withDetail(HEALTH_KEY_ENDPOINT, getEndpoint()).build();
+      }
+    } catch (Exception e) {
+      result = Health.down().withDetail(HEALTH_KEY_ENDPOINT, getEndpoint()).withException(e).build();
+    }
+    log.info("health check invoked for '{}' with status '{}'", getMethodName(), result.getStatus());
+    return result;
+  }
+
+  String getHost() {
+    return DEFAULT_HOST;
+  }
+
+  int getPort() {
+    return this.port;
+  }
+
+  String getEndpoint() {
+    return this.endpoint;
+  }
+
+  abstract boolean isEndpointAvailable();
+
+  abstract String getMethodName();
+
+  abstract String mkEndpoint();
+
+}

oparl-server/src/main/java/de/twomartens/oparlservice/actuator/RestHealthCheck.java

@@ -0,0 +1,56 @@
+package de.twomartens.oparlservice.actuator;
+
+import de.twomartens.oparlservice.entity.Greeting;
+import de.twomartens.oparlservice.interceptors.RequestTypeInterceptor;
+import de.twomartens.oparlservice.interceptors.TraceIdInterceptor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.boot.actuate.health.HealthIndicator;
+import org.springframework.boot.autoconfigure.web.ServerProperties;
+import org.springframework.http.ResponseEntity;
+import org.springframework.stereotype.Component;
+import org.springframework.web.client.RestClientException;
+import org.springframework.web.client.RestTemplate;
+
+import java.util.Optional;
+
+/**
+ * A Health check which checks if the rest services are working.]
+ */
+@Slf4j
+@Component
+public class RestHealthCheck extends AbstractHealthCheck implements HealthIndicator {
+
+  private final RestTemplate restTemplate;
+
+  public RestHealthCheck(ServerProperties serverProperties,
+      TraceIdInterceptor traceIdInterceptor,
+      RequestTypeInterceptor requestTypeInterceptor,
+      RestTemplate restTemplate) {
+    super(Optional.ofNullable(serverProperties.getPort()).orElse(8080),
+        traceIdInterceptor, requestTypeInterceptor);
+    this.restTemplate = restTemplate;
+  }
+
+  @Override
+  boolean isEndpointAvailable() {
+    try {
+      ResponseEntity<Greeting> result = restTemplate.getForEntity(getEndpoint(), Greeting.class);
+      Greeting body = result.getBody();
+      if (body == null) {
+        return false;
+      }
+      return !body.getMessage().isEmpty();
+    } catch (RestClientException e) {
+      return false;
+    }
+  }
+
+  @Override
+  String getMethodName() {
+    return "template-service-rest";
+  }
+
+  String mkEndpoint() {
+    return String.format("http://%s:%d/greeting?name=RestHealthCheck", getHost(), getPort());
+  }
+}

oparl-server/src/main/java/de/twomartens/oparlservice/configs/OParlServiceProperties.java

@@ -0,0 +1,19 @@
+package de.twomartens.oparlservice.configs;
+
+import lombok.Data;
+import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.context.annotation.Configuration;
+
+@Data
+@Configuration
+@ConfigurationProperties(prefix = "de.twomartens.oparlservice")
+public class OParlServiceProperties {
+
+  private final Template template = new Template();
+
+  @Data
+  public static class Template {
+
+    private String greeting;
+  }
+}

oparl-server/src/main/java/de/twomartens/oparlservice/configs/WebConfig.java

@@ -0,0 +1,47 @@
+package de.twomartens.oparlservice.configs;
+
+import de.twomartens.oparlservice.interceptors.RequestTypeInterceptor;
+import de.twomartens.oparlservice.interceptors.TraceIdInterceptor;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.http.client.ClientHttpRequestInterceptor;
+import org.springframework.util.CollectionUtils;
+import org.springframework.web.client.RestTemplate;
+import org.springframework.web.servlet.config.annotation.EnableWebMvc;
+import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
+import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
+import org.springframework.web.servlet.view.InternalResourceViewResolver;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@EnableWebMvc
+@Configuration
+public class WebConfig implements WebMvcConfigurer {
+
+    @Override
+    public void addInterceptors(InterceptorRegistry registry) {
+        registry.addInterceptor(new TraceIdInterceptor());
+        registry.addInterceptor(new RequestTypeInterceptor());
+    }
+
+    @Bean
+    public InternalResourceViewResolver defaultViewResolver() {
+        return new InternalResourceViewResolver();
+    }
+
+    @Bean
+    public RestTemplate restTemplate() {
+        RestTemplate restTemplate = new RestTemplate();
+
+        List<ClientHttpRequestInterceptor> interceptors
+                = restTemplate.getInterceptors();
+        if (CollectionUtils.isEmpty(interceptors)) {
+            interceptors = new ArrayList<>();
+        }
+        interceptors.add(new TraceIdInterceptor());
+        interceptors.add(new RequestTypeInterceptor());
+        restTemplate.setInterceptors(interceptors);
+        return restTemplate;
+    }
+}

oparl-server/src/main/java/de/twomartens/oparlservice/control/GreetingController.java

@@ -0,0 +1,24 @@
+package de.twomartens.oparlservice.control;
+
+import de.twomartens.oparlservice.entity.Greeting;
+import de.twomartens.oparlservice.service.GreetingService;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.ResponseBody;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class GreetingController {
+
+    private final GreetingService service;
+
+    GreetingController(GreetingService service) {
+        this.service = service;
+    }
+
+    @GetMapping("/greeting")
+    @ResponseBody
+    public Greeting greeting(@RequestParam(value = "name", defaultValue = "World") String name) {
+        return Greeting.builder().message(service.createGreeting(name)).build();
+    }
+}

oparl-server/src/main/java/de/twomartens/oparlservice/entity/Greeting.java

@@ -0,0 +1,18 @@
+package de.twomartens.oparlservice.entity;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.*;
+
+@Builder
+@Getter
+@ToString
+@EqualsAndHashCode
+@AllArgsConstructor(access = AccessLevel.PRIVATE)
+@NoArgsConstructor(force = true, access = AccessLevel.PRIVATE)
+public class Greeting {
+
+  @NonNull
+  @Schema(description = "This message is displayed")
+  private final String message;
+
+}

oparl-server/src/main/java/de/twomartens/oparlservice/interceptors/RequestTypeInterceptor.java

@@ -0,0 +1,52 @@
+package de.twomartens.oparlservice.interceptors;
+
+import lombok.NoArgsConstructor;
+import org.slf4j.MDC;
+import org.springframework.http.HttpRequest;
+import org.springframework.http.client.ClientHttpRequestExecution;
+import org.springframework.http.client.ClientHttpRequestInterceptor;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.stereotype.Component;
+import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+/**
+ * marks requests of certain types like health check or integration test for better logging
+ */
+@Component
+@NoArgsConstructor
+public class RequestTypeInterceptor extends HandlerInterceptorAdapter
+    implements ClientHttpRequestInterceptor {
+
+  private static final String LOGGER_ID = "REQTYPE";
+  private static final String HEADER_FIELD_ID = "x-type";
+
+  public void markAsHealthCheck() {
+    MDC.put(LOGGER_ID, "HEALTH_CHECK");
+  }
+
+  public void markAsIntegrationTest() {
+    MDC.put(LOGGER_ID, "INTEGRATION_TEST");
+  }
+
+  // web client interceptor
+  @Override
+  public ClientHttpResponse intercept(
+      HttpRequest request,
+      byte[] body,
+      ClientHttpRequestExecution execution) throws IOException {
+    request.getHeaders().add(HEADER_FIELD_ID, MDC.get(LOGGER_ID));
+    return execution.execute(request, body);
+  }
+
+  // web server interceptor
+  @Override
+  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
+    MDC.put(LOGGER_ID, request.getHeader(HEADER_FIELD_ID));
+    return true;
+  }
+
+}

oparl-server/src/main/java/de/twomartens/oparlservice/interceptors/TraceIdInterceptor.java

@@ -0,0 +1,87 @@
+package de.twomartens.oparlservice.interceptors;
+
+import lombok.NoArgsConstructor;
+import org.slf4j.MDC;
+import org.springframework.http.HttpRequest;
+import org.springframework.http.client.ClientHttpRequestExecution;
+import org.springframework.http.client.ClientHttpRequestInterceptor;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.stereotype.Component;
+import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
+
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+import java.util.UUID;
+
+@Component
+@NoArgsConstructor
+public class TraceIdInterceptor extends HandlerInterceptorAdapter
+    implements ClientHttpRequestInterceptor {
+
+  private static final String LOGGER_TRACE_ID = "TraceID";
+  private static final String HEADER_FIELD_TRACE_ID = "X-TraceId";
+
+  /**
+   * Gets the TraceId from the MDC or create a new one and put it to the MDC
+   */
+  public String getTraceId() {
+    String traceId = MDC.get(LOGGER_TRACE_ID);
+    if (traceId == null || traceId.trim().isEmpty()) {
+      traceId = UUID.randomUUID().toString();
+      MDC.put(LOGGER_TRACE_ID, traceId);
+    }
+    return traceId;
+  }
+
+
+  /**
+   * A failsafe method to set a TraceId to the MDC.
+   *
+   * @param traceId should be a traceId, if it is null or empty a new one will be created.
+   * @return the traceId param, or a new one, if it was empty
+   */
+  public String setOrCreateTraceId(String traceId) {
+    if (traceId == null || traceId.trim().isEmpty()) {
+      traceId = UUID.randomUUID().toString();
+    }
+    MDC.put(LOGGER_TRACE_ID, traceId);
+    return traceId;
+  }
+
+  /**
+   * Removes the traceId from the MDC.
+   */
+  public void resetTraceId() {
+    MDC.remove(LOGGER_TRACE_ID);
+  }
+
+  /**
+   * Creates a new traceId for this thread.
+   *
+   * An old one will be overwritten!
+   */
+  public void createNewTraceId() {
+    resetTraceId();
+    getTraceId();
+  }
+
+  // client interceptor web
+  @Override
+  public ClientHttpResponse intercept(
+      HttpRequest request,
+      byte[] body,
+      ClientHttpRequestExecution execution) throws IOException {
+    request.getHeaders().add(HEADER_FIELD_TRACE_ID, getTraceId());
+    return execution.execute(request, body);
+  }
+
+  // server interceptor web
+  @Override
+  public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
+    String traceId = request.getHeader(HEADER_FIELD_TRACE_ID);
+    setOrCreateTraceId(traceId);
+    response.addHeader(HEADER_FIELD_TRACE_ID, getTraceId());
+    return true;
+  }
+}

oparl-server/src/main/java/de/twomartens/oparlservice/service/GreetingService.java

@@ -0,0 +1,30 @@
+package de.twomartens.oparlservice.service;
+
+import de.twomartens.oparlservice.configs.OParlServiceProperties;
+import io.micrometer.core.instrument.Counter;
+import io.micrometer.core.instrument.MeterRegistry;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.stereotype.Service;
+
+@Slf4j
+@Service
+public class GreetingService {
+
+  private final MeterRegistry meterRegistry;
+  private final OParlServiceProperties properties;
+  private final Counter counter;
+
+  public GreetingService(MeterRegistry meterRegistry, OParlServiceProperties properties) {
+    this.meterRegistry = meterRegistry;
+    this.properties = properties;
+    counter = meterRegistry.counter("infodb.callCounter");
+  }
+
+  public String createGreeting(String name) {
+    log.info("Create greeting for '{}'", name);
+    counter.increment();
+    meterRegistry.gauge("infodb.nameLength", name.length());
+    String greeting = properties.getTemplate().getGreeting();
+    return String.format(greeting, name);
+  }
+}

oparl-server/src/main/resources/log4j2.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Configuration status="warn" monitorInterval="30">
+    <Appenders>
+        <Console name="console" target="SYSTEM_OUT">
+            <PatternLayout pattern="%5p %d{HH:mm:ss.SSS} (%F:%L) [%X{REQTYPE}] %m%n%xEx{full}"
+                           alwaysWriteExceptions="true"/>
+        </Console>
+    </Appenders>
+    <Loggers>
+        <Root level="WARN">
+            <AppenderRef ref="console"/>
+        </Root>
+        <Logger name="de.twomartens" level="TRACE" additivity="true"/>
+    </Loggers>
+</Configuration>

oparl-server/src/test/java/de/twomartens/oparlservice/control/GreetingControllerTests.java

@@ -0,0 +1,37 @@
+package de.twomartens.oparlservice.control;
+
+import de.twomartens.oparlservice.service.GreetingService;
+import org.hamcrest.Matchers;
+import org.junit.jupiter.api.Test;
+import org.mockito.BDDMockito;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.WebMvcTest;
+import org.springframework.boot.test.mock.mockito.MockBean;
+import org.springframework.http.MediaType;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.request.MockMvcRequestBuilders;
+import org.springframework.test.web.servlet.result.MockMvcResultMatchers;
+
+@WebMvcTest(GreetingController.class)
+class GreetingControllerTests {
+
+  @Autowired
+  private MockMvc mvc;
+
+  @MockBean
+  private GreetingService service;
+
+  @Test
+  void testGreetingRest() throws Exception {
+    BDDMockito.given(service.createGreeting("Template"))
+        .willReturn("Hello Template!");
+
+    mvc.perform(MockMvcRequestBuilders.get("/greeting")
+        .param("name", "Template")
+        .contentType(MediaType.APPLICATION_JSON))
+        .andExpect(MockMvcResultMatchers.status().isOk())
+        .andExpect(MockMvcResultMatchers.jsonPath("$", Matchers.aMapWithSize(1)))
+        .andExpect(MockMvcResultMatchers.jsonPath("$.message", Matchers.is("Hello Template!")))
+        .andReturn();
+  }
+}

oparl-server/src/test/java/de/twomartens/oparlservice/service/GreetingServiceTest.java

@@ -0,0 +1,37 @@
+package de.twomartens.oparlservice.service;
+
+import de.twomartens.oparlservice.configs.OParlServiceProperties;
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
+import org.assertj.core.api.Assertions;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import static org.mockito.BDDMockito.given;
+
+@ExtendWith(MockitoExtension.class)
+class GreetingServiceTest {
+
+  private GreetingService service;
+
+  @Mock
+  private OParlServiceProperties properties;
+
+  @Mock
+  private OParlServiceProperties.Template template;
+
+  @BeforeEach
+  void beforeEach() {
+    given(template.getGreeting()).willReturn("Hello %s");
+    given(properties.getTemplate()).willReturn(template);
+    service = new GreetingService(new SimpleMeterRegistry(), properties);
+  }
+
+  @Test
+  void createGreeting() {
+    String result = service.createGreeting("Test");
+    Assertions.assertThat(result).isEqualTo("Hello Test");
+  }
+}