Added template structure

template-server/src/main/java/de/twomartens/templateservice/actuator/AbstractHealthCheck.java

@@ -0,0 +1,68 @@
+package de.twomartens.templateservice.actuator;
+
+import de.twomartens.templateservice.interceptors.RequestTypeInterceptor;
+import de.twomartens.templateservice.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();
+
+}

template-server/src/main/java/de/twomartens/templateservice/actuator/RestHealthCheck.java

@@ -0,0 +1,64 @@
+package de.twomartens.templateservice.actuator;
+
+import de.twomartens.templateservice.entity.Greeting;
+import de.twomartens.templateservice.interceptors.RequestTypeInterceptor;
+import de.twomartens.templateservice.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 Healtcheck which checks if the rest services are working.
+ *
+ * If you have a complex service behind grpc, you should think about an easy greeting or echo service, which only tests
+ * the network/service stack and not the full application.
+ *
+ * The healthcheck will be called by kubernetes to check if the container/pod shuold be in loadbalancing. It is possible
+ * to have as much healthchecks as you loke.
+ *
+ * There should be a healtcheck which is ok not before all data is loaded.
+ */
+@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 "infodb-rest";
+  }
+
+  String mkEndpoint() {
+    return String.format("http://%s:%d/greeting?name=RestHealthCheck", getHost(), getPort());
+  }
+}

template-server/src/main/java/de/twomartens/templateservice/configs/TemplateServiceProperties.java

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

template-server/src/main/java/de/twomartens/templateservice/configs/WebConfig.java

@@ -0,0 +1,41 @@
+package de.twomartens.templateservice.configs;
+
+import de.twomartens.templateservice.interceptors.RequestTypeInterceptor;
+import de.twomartens.templateservice.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 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 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;
+  }
+}

template-server/src/main/java/de/twomartens/templateservice/control/GreetingController.java

@@ -0,0 +1,24 @@
+package de.twomartens.templateservice.control;
+
+import de.twomartens.templateservice.entity.Greeting;
+import de.twomartens.templateservice.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();
+    }
+}

template-server/src/main/java/de/twomartens/templateservice/entity/Greeting.java

@@ -0,0 +1,16 @@
+package de.twomartens.templateservice.entity;
+
+import lombok.*;
+
+@Builder
+@Getter
+@ToString
+@EqualsAndHashCode
+@AllArgsConstructor(access = AccessLevel.PRIVATE)
+@NoArgsConstructor(force = true, access = AccessLevel.PRIVATE)
+public class Greeting {
+
+  @NonNull
+  private final String message;
+
+}

template-server/src/main/java/de/twomartens/templateservice/interceptors/RequestTypeInterceptor.java

@@ -0,0 +1,52 @@
+package de.twomartens.templateservice.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;
+  }
+
+}

template-server/src/main/java/de/twomartens/templateservice/interceptors/TraceIdInterceptor.java

@@ -0,0 +1,87 @@
+package de.twomartens.templateservice.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;
+  }
+}

template-server/src/main/java/de/twomartens/templateservice/service/GreetingService.java

@@ -0,0 +1,30 @@
+package de.twomartens.templateservice.service;
+
+import de.twomartens.templateservice.configs.TemplateServiceProperties;
+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 TemplateServiceProperties properties;
+  private final Counter counter;
+
+  public GreetingService(MeterRegistry meterRegistry, TemplateServiceProperties 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);
+  }
+}