Bael 8958: Introduction to New Relic for Java

libraries-apm/README.md

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+## Relevant Articles

libraries-apm/new-relic/currency-converter/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>3.4.1</version>
+        <relativePath/> <!-- lookup parent from repository -->
+    </parent>
+    <groupId>com.baeldung</groupId>
+    <artifactId>currency-converter</artifactId>
+    <version>0.0.1</version>
+    <name>Currency Converter</name>
+    <description>Currency Converter Demo</description>
+
+    <properties>
+        <java.version>21</java.version>
+        <maven.compiler.source>21</maven.compiler.source>
+        <maven.compiler.target>21</maven.compiler.target>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-cache</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-redis</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-devtools</artifactId>
+            <scope>runtime</scope>
+            <optional>true</optional>
+        </dependency>
+        <dependency>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
+            <optional>true</optional>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-logging</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.squareup.okhttp3</groupId>
+            <artifactId>okhttp</artifactId>
+            <version>4.12.0</version>
+        </dependency>
+
+        <dependency>
+            <groupId>com.newrelic.agent.java</groupId>
+            <artifactId>newrelic-java</artifactId>
+            <version>8.17.0</version>
+            <scope>provided</scope>
+            <type>zip</type>
+        </dependency>
+
+        <dependency>
+            <groupId>com.newrelic.agent.java</groupId>
+            <artifactId>newrelic-api</artifactId>
+            <version>8.17.0</version>
+        </dependency>
+    </dependencies>
+
+</project>

libraries-apm/new-relic/currency-converter/src/main/java/com/baeldung/currency_converter/CurrencyConverterApplication.java

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+package com.baeldung.currency_converter;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class CurrencyConverterApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(CurrencyConverterApplication.class, args);
+    }
+}

libraries-apm/new-relic/currency-converter/src/main/java/com/baeldung/currency_converter/config/AppConfig.java

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+package com.baeldung.currency_converter.config;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.web.client.RestTemplate;
+
+@Configuration
+public class AppConfig {
+    @Bean
+    public RestTemplate restTemplate() {
+        return new RestTemplate();
+    }
+}

libraries-apm/new-relic/currency-converter/src/main/java/com/baeldung/currency_converter/config/RedisConfig.java

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+package com.baeldung.currency_converter.config;
+
+import java.time.Duration;
+
+import org.springframework.cache.annotation.EnableCaching;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.redis.cache.RedisCacheConfiguration;
+import org.springframework.data.redis.cache.RedisCacheManager;
+import org.springframework.data.redis.connection.RedisConnectionFactory;
+import org.springframework.data.redis.core.RedisTemplate;
+import org.springframework.data.redis.serializer.GenericToStringSerializer;
+import org.springframework.data.redis.serializer.StringRedisSerializer;
+
+@Configuration
+@EnableCaching
+public class RedisConfig {
+    @Bean
+    public RedisCacheManager cacheManager(RedisConnectionFactory redisConnectionFactory) {
+        RedisCacheConfiguration cacheConfiguration = RedisCacheConfiguration.defaultCacheConfig()
+                .entryTtl(Duration.ofSeconds(90));
+
+        return RedisCacheManager.builder(redisConnectionFactory)
+                .cacheDefaults(cacheConfiguration)
+                .build();
+    }
+
+    @Bean
+    public RedisTemplate<String, Double> redisTemplate(RedisConnectionFactory connectionFactory) {
+        RedisTemplate<String, Double> template = new RedisTemplate<>();
+        template.setConnectionFactory(connectionFactory);
+        template.setKeySerializer(new StringRedisSerializer());
+        template.setValueSerializer(new GenericToStringSerializer<>(Double.class));
+        return template;
+    }
+}

libraries-apm/new-relic/currency-converter/src/main/java/com/baeldung/currency_converter/controller/CurrencyConverterController.java

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+package com.baeldung.currency_converter.controller;
+
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.baeldung.currency_converter.service.CurrencyConverterService;
+
+@RestController
+@RequestMapping("/api/currency")
+public class CurrencyConverterController {
+    private final CurrencyConverterService currencyConverterService;
+
+    public CurrencyConverterController(CurrencyConverterService currencyConverterService) {
+        this.currencyConverterService = currencyConverterService;
+    }
+
+    @GetMapping("/convert")
+    public double convertCurrency(@RequestParam String targetCurrency,
+                                  @RequestParam double amount) {
+        return currencyConverterService.getConvertedAmount(targetCurrency, amount);
+    }
+}

libraries-apm/new-relic/currency-converter/src/main/java/com/baeldung/currency_converter/dto/ExchangeRateResponse.java

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+package com.baeldung.currency_converter.dto;
+
+import java.util.Map;
+
+public class ExchangeRateResponse {
+    private String disclaimer;
+    private String license;
+    private Long timestamp;
+    private String base;
+    private Map<String, Double> rates;
+
+    public String getDisclaimer() {
+        return disclaimer;
+    }
+
+    public void setDisclaimer(String disclaimer) {
+        this.disclaimer = disclaimer;
+    }
+
+    public String getLicense() {
+        return license;
+    }
+
+    public void setLicense(String license) {
+        this.license = license;
+    }
+
+    public Long getTimestamp() {
+        return timestamp;
+    }
+
+    public void setTimestamp(Long timestamp) {
+        this.timestamp = timestamp;
+    }
+
+    public String getBase() {
+        return base;
+    }
+
+    public void setBase(String base) {
+        this.base = base;
+    }
+
+    public Map<String, Double> getRates() {
+        return rates;
+    }
+
+    public void setRates(Map<String, Double> rates) {
+        this.rates = rates;
+    }
+
+    @Override
+    public String toString() {
+        return "ExchangeRateResponse{" +
+                "disclaimer='" + disclaimer + '\'' +
+                ", license='" + license + '\'' +
+                ", timestamp=" + timestamp +
+                ", base='" + base + '\'' +
+                ", rates=" + rates +
+                '}';
+    }
+}

libraries-apm/new-relic/currency-converter/src/main/java/com/baeldung/currency_converter/service/CurrencyConverterService.java

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+package com.baeldung.currency_converter.service;
+
+import org.springframework.stereotype.Service;
+import com.baeldung.currency_converter.dto.ExchangeRateResponse;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.newrelic.api.agent.NewRelic;
+import com.newrelic.api.agent.Trace;
+
+import okhttp3.OkHttpClient;
+import okhttp3.Request;
+import okhttp3.Response;
+import java.util.Map;
+import java.util.concurrent.TimeUnit;
+
+import org.springframework.beans.factory.annotation.Value;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import org.springframework.data.redis.core.RedisTemplate;
+import java.time.Duration;
+
+@Service
+public class CurrencyConverterService {
+    private static final Logger logger = LoggerFactory.getLogger(CurrencyConverterService.class);
+
+    @Value("${openexchangerates.url}")
+    private String openApiUrl;
+
+    @Value("${openexchangerates.app_id}")
+    private String openApiAppId;
+
+    @Value("${openexchangerates.base_currency}")
+    public String baseCurrency;
+
+    private final OkHttpClient client;
+    private final ObjectMapper objectMapper;
+    private final RedisTemplate<String, Double> redisTemplate;
+
+    public CurrencyConverterService(RedisTemplate<String, Double> redisTemplate) {
+        this.client = new OkHttpClient();
+        this.objectMapper = new ObjectMapper();
+        this.redisTemplate = redisTemplate;
+    }
+
+    @Trace(metricName="CurrencyConversionCalc")
+    public double getConvertedAmount(String targetCurrency, double amount) {
+        String cacheKey = baseCurrency + "-" + targetCurrency;
+
+        // Try to get rate from cache first
+        Double cachedRate = redisTemplate.opsForValue().get(cacheKey);
+        if (cachedRate != null) {
+            logger.info("Cache hit for key: {}", cacheKey);
+            return amount * cachedRate;
+        } else {
+            logger.info("Cache miss for key: {}, fetching from API", cacheKey);
+            NewRelic.incrementCounter("Custom/CacheMisses");
+        }
+
+        // Original API call logic
+        String url = String.format("%s/latest.json?app_id=%s", openApiUrl, openApiAppId);
+        logger.info("Fetching exchange rates from {}", url);
+
+        try {            
+            Request request = new Request.Builder()
+                .url(url)
+                .build();
+
+            long startTime = System.nanoTime();
+
+            try (Response response = client.newCall(request).execute()) {
+                if (!response.isSuccessful()) {
+                    throw new RuntimeException("Unexpected response code: " + response);
+                }
+
+                long durationInMillis = TimeUnit.NANOSECONDS.toMillis(System.nanoTime() - startTime);
+                NewRelic.addCustomParameter("RatesAPI/ResponseTime", durationInMillis);
+
+
+                String rawResponse = response.body().string();
+                ExchangeRateResponse exchangeResponse = objectMapper.readValue(rawResponse, ExchangeRateResponse.class);
+
+                logger.info("Response headers:");
+                response.headers().toMultimap().forEach((k, v) -> logger.info("{}: {}", k, v));
+
+                String eTagHeaderField = response.header("ETag");
+                logger.info(eTagHeaderField);
+
+                NewRelic.addCustomParameter(cacheKey, eTagHeaderField);
+
+                if (exchangeResponse != null && exchangeResponse.getRates() != null) {
+                    Map<String, Double> rates = exchangeResponse.getRates();
+                    Double targetRate = rates.get(targetCurrency);
+
+                    if (targetRate == null) {
+                        logger.error("Target currency {} not found in rates", targetCurrency);
+                        throw new IllegalArgumentException("Target currency not found in rates.");
+                    }
+
+                    // Cache the rate before returning
+                    redisTemplate.opsForValue().set(cacheKey, targetRate, Duration.ofHours(24));
+                    logger.info("Cached exchange rate for key: {}", cacheKey);
+
+                    return amount * targetRate;
+                }
+
+                logger.error("Failed to get exchange rate response");
+                throw new RuntimeException("Could not retrieve exchange rate.");
+            }
+        } catch (Exception e) {
+            logger.error("Error converting currency: {}", e.getMessage(), e);
+            NewRelic.noticeError(e);
+            throw new RuntimeException("Error converting currency", e);
+        }
+    }
+}

libraries-apm/new-relic/currency-converter/src/main/resources/application.properties

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+spring.application.name=Currency Converter
+
+# Redis Configuration
+spring.redis.host=localhost
+spring.redis.port=6379
+# spring.redis.password=
+spring.redis.timeout=2000
+
+# Cache Configuration
+spring.cache.type=redis
+
+# Open Exchange Rates API Configuration
+openexchangerates.url=https://openexchangerates.org
+openexchangerates.app_id=<APPLICATION_ID>
+openexchangerates.base_currency=USD

libraries-apm/new-relic/pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+    xmlns="http://maven.apache.org/POM/4.0.0"
+    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+    <groupId>com.baeldung.new-relic</groupId>
+    <artifactId>new-relic</artifactId>
+    <packaging>pom</packaging>
+    <name>new-relic</name>
+
+    <parent>
+        <groupId>com.baeldung</groupId>
+        <artifactId>libraries-apm</artifactId>
+        <version>1.0.0-SNAPSHOT</version>
+    </parent>
+
+    <modules>
+        <module>currency-converter</module>
+    </modules>
+
+</project>