Add example of logging retries (#200)

* add base classes to perform and log retries to public api

* add app config and wiremock test

* add larger timeout to TimeControllerTest

* add proper wiremock dependencies for both wiremock modules

* add proper wiremock dependency to spring boot 3 module

* refactor happy path in test

* complete tests for spring boot 2 module

* add tests for spring boot 3 module

* refactor

* refactor

* refactoring

* refactor wiremock test

* Configure WireMock

* BOM

* Simplify tests

* Simplify retries

---------

Co-authored-by: m.zharinova <[email protected]>
Co-authored-by: Ivan Vakhrushev <[email protected]>

Author: 3 people

buildSrc/src/main/kotlin/sb-ot-demo.java-conventions.gradle.kts

@@ -56,6 +56,7 @@ tasks {
         useJUnitPlatform()
         dependsOn(pmdMain, pmdTest)
         finalizedBy(jacocoTestReport, jacocoTestCoverageVerification)
+        maxParallelForks = 1
     }
 
     jacocoTestCoverageVerification {
@@ -79,7 +80,7 @@ tasks {
                 limit {
                     counter = "LINE"
                     value = "MISSEDCOUNT"
-                    maximum = "8.0".toBigDecimal()
+                    maximum = "10.0".toBigDecimal()
                 }
             }
             rule {

config/pmd/pmd.xml

@@ -65,6 +65,12 @@
         </properties>
     </rule>
 
+    <rule ref="category/java/codestyle.xml/TooManyStaticImports">
+        <properties>
+            <property name="maximumStaticImports" value="8" />
+        </properties>
+    </rule>
+
     <rule ref="category/java/design.xml">
         <exclude name="LawOfDemeter"/>
         <exclude name="LoosePackageCoupling"/>

gradle.properties

@@ -0,0 +1,2 @@
+org.gradle.parallel=true
+org.gradle.daemon=true

spring-boot-2-demo-app/build.gradle.kts

@@ -16,6 +16,7 @@ dependencies {
     implementation(platform("org.springframework.cloud:spring-cloud-sleuth-otel-dependencies:1.1.4"))
 
     implementation("org.springframework.boot:spring-boot-starter-web")
+    implementation("org.springframework.boot:spring-boot-starter-webflux")
     implementation("org.springframework.boot:spring-boot-starter-actuator")
     implementation("io.micrometer:micrometer-registry-prometheus")
     implementation("org.springdoc:springdoc-openapi-ui")
@@ -38,6 +39,7 @@ dependencies {
         because("https://github.com/jdbc-observations/datasource-proxy/issues/111")
     }
 
+    testImplementation("org.springframework.cloud:spring-cloud-starter-contract-stub-runner")
     testImplementation("org.springframework.boot:spring-boot-starter-test")
     testImplementation("org.springframework.boot:spring-boot-starter-webflux")
     testImplementation("org.testcontainers:postgresql")

spring-boot-2-demo-app/src/main/java/io/github/mfvanek/spring/boot2/test/config/WebClientConfig.java

@@ -0,0 +1,18 @@
+package io.github.mfvanek.spring.boot2.test.config;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.reactive.function.client.WebClient;
+
+@Configuration
+public class WebClientConfig {
+
+    @Value("${app.external-base-url}")
+    private String external;
+
+    @Bean
+    public WebClient webClient() {
+        return WebClient.builder().baseUrl(external).build();
+    }
+}

spring-boot-2-demo-app/src/main/java/io/github/mfvanek/spring/boot2/test/controllers/TimeController.java

@@ -1,6 +1,7 @@
 package io.github.mfvanek.spring.boot2.test.controllers;
 
 import io.github.mfvanek.spring.boot2.test.service.KafkaSendingService;
+import io.github.mfvanek.spring.boot2.test.service.PublicApiService;
 import lombok.RequiredArgsConstructor;
 import lombok.SneakyThrows;
 import lombok.extern.slf4j.Slf4j;
@@ -22,6 +23,7 @@ public class TimeController {
     private final Tracer tracer;
     private final Clock clock;
     private final KafkaSendingService kafkaSendingService;
+    private final PublicApiService publicApiService;
 
     // http://localhost:8090/current-time
     @SneakyThrows
@@ -32,7 +34,8 @@ public LocalDateTime getNow() {
             .map(TraceContext::traceId)
             .orElse(null);
         log.info("Called method getNow. TraceId = {}", traceId);
-        final LocalDateTime now = LocalDateTime.now(clock);
+        final LocalDateTime nowFromRemote = publicApiService.getZonedTime();
+        final LocalDateTime now = nowFromRemote == null ? LocalDateTime.now(clock) : nowFromRemote;
         kafkaSendingService.sendNotification("Current time = " + now)
             .thenRun(() -> log.info("Awaiting acknowledgement from Kafka"))
             .get();

spring-boot-2-demo-app/src/main/java/io/github/mfvanek/spring/boot2/test/service/PublicApiService.java

@@ -0,0 +1,64 @@
+package io.github.mfvanek.spring.boot2.test.service;
+
+
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import io.github.mfvanek.spring.boot2.test.service.dto.CurrentTime;
+import io.github.mfvanek.spring.boot2.test.service.dto.ParsedDateTime;
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.http.MediaType;
+import org.springframework.lang.Nullable;
+import org.springframework.retry.ExhaustedRetryException;
+import org.springframework.stereotype.Service;
+import org.springframework.web.reactive.function.client.WebClient;
+import reactor.core.publisher.Mono;
+import reactor.util.retry.Retry;
+
+import java.time.Duration;
+import java.time.LocalDateTime;
+import java.util.TimeZone;
+
+@Slf4j
+@Service
+@RequiredArgsConstructor
+public class PublicApiService {
+
+    @Value("${app.retries}")
+    private int retries;
+
+    private final ObjectMapper mapper;
+    private final WebClient webClient;
+
+    @Nullable
+    public LocalDateTime getZonedTime() {
+        try {
+            final ParsedDateTime result = getZonedTimeFromWorldTimeApi().getDatetime();
+            return result.toLocalDateTime();
+        } catch (ExhaustedRetryException e) {
+            log.warn("Failed to get response", e);
+        } catch (JsonProcessingException e) {
+            log.warn("Failed to convert response", e);
+        }
+        return null;
+    }
+
+    private CurrentTime getZonedTimeFromWorldTimeApi() throws JsonProcessingException {
+        final String zoneNames = TimeZone.getDefault().getID();
+        final Mono<String> response = webClient.get()
+            .uri(String.join("/", zoneNames))
+            .accept(MediaType.APPLICATION_JSON)
+            .retrieve()
+            .bodyToMono(String.class)
+            .retryWhen(Retry.fixedDelay(retries, Duration.ofSeconds(2))
+                .doBeforeRetry(retrySignal -> log.info("Retrying request to {}, attempt {}/{} due to error:",
+                    webClient.options().uri(String.join("", zoneNames)), retries, retrySignal.totalRetries() + 1, retrySignal.failure()))
+                .onRetryExhaustedThrow((retryBackoffSpec, retrySignal) -> {
+                    log.error("Request to {} failed after {} attempts.", webClient.options().uri(String.join("", zoneNames)), retrySignal.totalRetries() + 1);
+                    return new ExhaustedRetryException("Retries exhausted", retrySignal.failure());
+                })
+            );
+        return mapper.readValue(response.block(), CurrentTime.class);
+    }
+}

spring-boot-2-demo-app/src/main/java/io/github/mfvanek/spring/boot2/test/service/dto/CurrentTime.java

@@ -0,0 +1,17 @@
+package io.github.mfvanek.spring.boot2.test.service.dto;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.extern.jackson.Jacksonized;
+
+@Jacksonized
+@Builder
+@AllArgsConstructor
+@JsonIgnoreProperties(ignoreUnknown = true)
+@Getter
+public class CurrentTime {
+    private final ParsedDateTime datetime;
+}

spring-boot-2-demo-app/src/main/java/io/github/mfvanek/spring/boot2/test/service/dto/ParsedDateTime.java

@@ -0,0 +1,38 @@
+package io.github.mfvanek.spring.boot2.test.service.dto;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+import java.time.LocalDateTime;
+import javax.annotation.Nonnull;
+import javax.annotation.concurrent.Immutable;
+
+@AllArgsConstructor
+@JsonIgnoreProperties(ignoreUnknown = true)
+@Getter
+@Immutable
+public class ParsedDateTime {
+
+    private final int year;
+    private final int monthValue;
+    private final int dayOfMonth;
+    private final int hour;
+    private final int minute;
+
+    @Nonnull
+    public LocalDateTime toLocalDateTime() {
+        return LocalDateTime.of(year, monthValue, dayOfMonth, hour, minute);
+    }
+
+    @Nonnull
+    public static ParsedDateTime from(final LocalDateTime localDateTime) {
+        return new ParsedDateTime(
+            localDateTime.getYear(),
+            localDateTime.getMonthValue(),
+            localDateTime.getDayOfMonth(),
+            localDateTime.getHour(),
+            localDateTime.getMinute()
+        );
+    }
+}

spring-boot-2-demo-app/src/main/resources/application.yml

@@ -1,3 +1,7 @@
+app:
+    external-base-url: "http://worldtimeapi.org/api/timezone/"
+    retries: 3
+
 server:
     port: 8090
     # See also https://docs.spring.io/spring-boot/docs/2.7.9/reference/html/application-properties.html#appendix.application-properties.server