Spring Boot vs LoopBack – Node.js for developing Microservices


In this post, we will see comparison between Spring Boot and LoopBack – Node.js for implementing Microservices.

SpringBoot

Spring Boot is an open source Java-based framework used to create Microservices. It is developed by Pivotal Team and is used to build stand-alone and production ready spring applications.

Microservices architecture using Java Spring Boot

LoopBack – Node.js

Events and event-driven programming

Events are actions generated by the user or the system, like a click, a completed file download, or a hardware or software error.

Event-driven programming is a programming paradigm in which the flow of the program is determined by events. An event-driven program performs actions in response to events. When an event occurs it triggers a callback function.

Node.js is a platform that executes server-side JavaScript programs that can communicate with I/O sources like file systems and networks.

LoopBack

LoopBack is a highly extensible, open-source Node.js and TypeScript framework based on Express that enables you to quickly create APIs and microservices composed from backend systems such as databases and SOAP or REST services.

The diagram below demonstrates how LoopBack serves as a composition bridge between incoming requests and outgoing integrations. It also shows the different personas who are interested in various capabilities provided by LoopBack.

Advantages of LoopBack – Node.js and Spring Boot

LoopBack – Node.js Spring Boot
Lightweight, fast – loosely typed Java is statically-typed (type safety)
Javascript Community: growing rapidly Java Community: mature and thriving
Great for I/O tasks. Example: file writing and reading, network calls, Streaming Long-term support and maintainability for memory intensive applications
Single-threaded – low memory utilization Support for multi-threading
npm is constantly growing Many easily usable dependencies using Maven, Gradle

Disadvantages of LoopBack – Node.js and Spring Boot

LoopBack – Node.js

  • Doesn’t support multi-threading
  • Lack of strict type checking can lead to runtime problems
  • Not great for heavy computing – performance bottlenecks

Spring Boot

  • High memory utilization
  • Java is verbose
  • Contains lots of boilerplate code which makes debugging tough
  • May include unused dependencies – huge deployment binary file size.

Industry Usage of these technologies

Companies using Spring Boot

  • Amazon
  • Intuit
  • JP Morgan Chase & Co.
  • Capital One
  • Google
  • Microsoft

Companies using Node.js

  • FlightOffice
  • Symantec
  • Pen Systems
  • GoDaddy.com
  • Sapient

LoopBack vs SpringBoot on various parameters

Criteria / Parameter SpringBoot LoopBack
Performance Long-term support and maintainability for memory intensive applications Great for I/O tasks. Example: file writing and reading, network calls, Streaming
Circuit Breaker Resilience4j Opossum
Hystrix Levee
Soap Client Apache CXF, Camel, Spring WebServiceTemplate loopback-connector-soap
JSON Manipulation/Validation Jackson, Spring Validator payload-validator
Orchestration and Routing support Apache CXF, Camel, Spring WebServiceTemplate, RestTemplate loopback-connector-soap, loopback-connector-rest
Caching support Spring Cache, external cache support Interception – CachingService, external cache support
Open API Contract first, API first both are supported Contract first, API first both are supported
Recommended For Building applications which consists of Memory intensive tasks Building applications which consists of I/O intensive tasks

References:

Spring Boot and Zuul API Gateway Integration


In this post, we will learn how to integrate zuul api gateway to the application developed in microservices architecture.

Our application consists of below components

  • customer-service
  • order-service
  • eureka-server
  • zuul-service

We have already seen how to create customer-service, order-service, eureka-server in the previous post given below

https://malliktalksjava.com/2020/05/28/spring-boot-netflix-eureka-integration/

Let us start integrating zuul api gateway service to the above application.

Firstly, Go to https://start.spring.io , Create SpringBoot Application with below configuration. 

As shown above, Spring Web, Eureka Server, Zuul as dependencies needs to be added.

Second Step, Import the project in the Eclipse, go to application.properties and add below properties

spring.application.name=zuul-service
zuul.routes.order.url=http://localhost:8080
eureka.client.serviceUrl.defaultZone=http://localhost:8090/eureka
server.port=8079

Next step is to create following filters

  • ErrorFilter
  • PreFilter
  • PostFilter
  • RouteFilter

Below diagram depicts flow of Request & Response intercepted by Zuul filters

Zuul_FlowDFilters creation step 1: Create ErrorFilter by extending ZuulFilter and override methods and shown below

package com.venkat.filters;

import com.netflix.zuul.ZuulFilter;

public class ErrorFilter extends ZuulFilter {

@Override
public String filterType() {
        return "error";
}

@Override
public int filterOrder() {
       return 0;
}

@Override
public boolean shouldFilter() {
       return true;
}

@Override
public Object run() {
        System.out.println(" ############# Using Error Filter ##################");               
return null;
}

}

Filters creation step 2: Create PreFilter by extending ZuulFilter and override methods and shown below

package com.venkat.filters;
import javax.servlet.http.HttpServletRequest;
import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;

public class PreFilter extends ZuulFilter {

@Override
public String filterType() {
return "pre";
}

@Override
public int filterOrder() {
return 0;
}

@Override
public boolean shouldFilter() {
return true;
}

@Override
public Object run() {
RequestContext ctx = RequestContext.getCurrentContext();
HttpServletRequest request = ctx.getRequest();
System.out.println(" ############# In Pre Filter ################## ");
System.out.println(
"Request Method : " + request.getMethod() + " Request URL : " + request.getRequestURL().toString());

return null;
}

}

Filters creation step 3: Create PostFilter by extending ZuulFilter and override methods and shown below

package com.venkat.filters;

import java.io.IOException;
import java.io.InputStreamReader;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.google.common.io.CharStreams;
import com.netflix.zuul.ZuulFilter;
import com.netflix.zuul.context.RequestContext;

public class PostFilter extends ZuulFilter {

@Override
public String filterType() {
return "post";
}

@Override
public int filterOrder() {
return 0;
}

@Override
public boolean shouldFilter() {
return true;
}

@Override
public Object run() {
RequestContext ctx = RequestContext.getCurrentContext();
System.out.println(" ############# In Post Filter ################## ");
try {
System.out.println(
"Response Status Code : " + ctx.getResponseStatusCode() + " Response Body : " + CharStreams.toString(new InputStreamReader(ctx.getResponseDataStream(), "UTF-8")));
} catch (IOException e) {

}

return null;
}

}

Filters creation step 4: Create RouteFilter by extending ZuulFilter and override methods and shown below

package com.venkat.filters;

import com.netflix.zuul.ZuulFilter;

public class RouteFilter extends ZuulFilter {

@Override
public String filterType() {
return "route";
}

@Override
public int filterOrder() {
return 0;
}

@Override
public boolean shouldFilter() {
return true;
}

@Override
public Object run() {
System.out.println("Using Route Filter");

return null;
}

}

Next, Add @EnableZuulProxy to ZuulProxyApplication class in zuul-service and add bean configurations for Filters which we have created as shown below

package com.venkat;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cloud.netflix.eureka.EnableEurekaClient;
import org.springframework.cloud.netflix.zuul.EnableZuulProxy;
import org.springframework.context.annotation.Bean;

@SpringBootApplication
@EnableEurekaClient
@EnableZuulProxy
public class ZuulProxyApplication {

public static void main(String[] args) {
SpringApplication.run(ZuulProxyApplication.class, args);
}

@Bean
public PreFilter preFilter() {
return new PreFilter();
}

@Bean
public PostFilter postFilter() {
return new PostFilter();
}

@Bean
public ErrorFilter errorFilter() {
return new ErrorFilter();
}

@Bean
public RouteFilter routeFilter() {
return new RouteFilter();
}
}

Once we are done creating all the filters package structure of our
zuul-service will be as shown as shown below

Now we will see changes to done to the customer-service application to enable requests
pass via zuul-service filters.

Go to CusomerControllerClient.java in customer-service replace

List<ServiceInstance> instances = discoveryClient.getInstances("ORDER-SERVICE");

with

List<ServiceInstance> instances = discoveryClient.getInstances("ZUUL-SERVICE");

and 

String completeURL = baseURL + "/customerorder";

with 

String completeURL = baseURL + "/order/customerorder";

Upon completion of all the code changes/additons discussed above run all the services, eureka-server, order-service, customer-service, zuul-service.

Following will be output once we hit the REST endpoint /customerorderinfo

zuul-service logs on hitting the REST end point are given below, clearly we can see both Request and Response pass through Pre, Route, Post Filters 

############# In Pre Filter ################## 
Request Method : GET Request URL : http://Dell:8079/order/customerorder
Using Route Filter
############# In Post Filter ##################
Response Status Code : 200 Response Body : {"orderId":"TIF567","itemName":"Dosa","itemType":"Tiffin","cost":40.0}
2020-05-31 18:56:18.494 INFO 3892 --- [trap-executor-0] c.n.d.s.r.aws.ConfigClusterResolver : Resolving eureka endpoints via configuration
############# In Pre Filter ##################
Request Method : GET Request URL : http://Dell:8079/order/customerorder
Using Route Filter
############# In Post Filter ##################
Response Status Code : 200 Response Body : {"orderId":"TIF567","itemName":"Dosa","itemType":"Tiffin","cost":40.0}

Conclusion

In this post, we have seen how to configure Zuul-proxy and make requests from one microservice pass through customized zuul filters. These filters enable us to apply functionality to our edge service. These filters help us perform the following functions:

  • Authentication & Security – identifying authentication requirements for each resource and rejecting requests that do not satisfy them.
  • Monitoring – tracking data and statistics at the edge which gives us a view of production.
  • Dynamic Routing – dynamically routing requests to various back-end clusters.
  • Load Shedding – allocating capacity for each type of request and dropping requests that exceeds the limit set.
  • Stress Testing – increasing the traffic to a cluster to measure its performance.
  • Static Response handling – sending some responses directly at the edge instead of forwarding them to an internal cluster.

Related links:

References:

Spring Boot and Netflix Eureka Integration


In this post we will learn how to integrate applications developed in Spring Boot with Netflix Eureka.

First step is to create two Spring Boot application services

  • customer-service
  • order-service

Go to https://start.spring.io and create order-service app using below config details.

Mainly for our use case, adding Spring Web, Eureka Server dependencies are the required ones

Likewise, create customer-service app with same config details used for order-service by adding Spring Web, Eureka Server dependencies.

Next, create eureka-server app with below config . Adding Eureka Server is main important config for our use case

Next, Import the projects created from the above into Eclipse IDE.

Add @EnableEurekaServer on EurekaServerApplication class as shown Below

package com.venkat;

@SpringBootApplication
@EnableEurekaServer
public class EurekaServerApplication {

public static void main(String[] args) {
SpringApplication.run(EurekaServerApplication.class, args);
}
}

Add below properties to the application.properties

server.port=8090
eureka.client.register-with-eureka=false
eureka.client.fetch-registry=false

Next, Add @EnableEurekaClient on CustomerServiceApplication class in customer-service  app as shown below

@SpringBootApplication
@EnableEurekaClient
public class CustomerServiceApplication {
public static void main(String[] args) throws RestClientException, IOException {
SpringApplication.run(CustomerServiceApplication.class, args);
}

@Bean
public ConsumerControllerClient consumerControllerClient()
{
return new ConsumerControllerClient();
}
}

Likewise, Add @EnableEurekaClient on OrderServiceApplication class in order-service app as shown below

@SpringBootApplication
@EnableEurekaClient
public class OrderSerivceApplication {

public static void main(String[] args) {
SpringApplication.run(OrderSerivceApplication.class, args);
}
}

Next, Add below configuration in customer-service and order-service
application.properties files

customer-service

spring.application.name=customer-service
server.port=8091
eureka.client.serviceUrl.defaultZone=http://localhost:8090/eureka

order-service

spring.application.name=order-service
server.port=8080
eureka.client.serviceUrl.defaultZone=http://localhost:8090/eureka

Next, Create Order.java in model package as shown below with orderId, itemName, itemType, Cost attributes.

package com.venkat.model;

public class Order {
private String orderId;
private String itemName;
private String itemType;
private double cost;

public Order() {
}

public String getOrderId() {
return orderId;
}

public void setOrderId(String orderId) {
this.orderId = orderId;
}

public String getItemName() {
return itemName;
}

public void setItemName(String itemName) {
this.itemName = itemName;
}

public String getItemType() {
return itemType;
}

public void setItemType(String itemType) {
this.itemType = itemType;
}

public double getCost() {
return cost;
}

public void setCost(double cost) {
this.cost = cost;
}
}

Create OrderController with a REST GET mapping for /customerorder to return Order object

package com.venkat.controllers;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import com.venkat.model.Order;

@RestController
public class OrderController {

@RequestMapping(value = "/customerorder", method = RequestMethod.GET)
public Order customerOrder() {
Order order = new Order();
order.setOrderId("TIF567");
order.setItemName("Dosa");
order.setItemType("Tiffin");
order.setCost(40.00);
return order;
}
}

Create a ConsumerControllerClient.java class as shown below

package com.venkat.controllers;

import java.io.IOException;
import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cloud.client.ServiceInstance;
import org.springframework.cloud.client.discovery.DiscoveryClient;
import org.springframework.http.HttpEntity;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.client.RestClientException;
import org.springframework.web.client.RestTemplate;

@RestController
public class ConsumerControllerClient {

@Autowired
private DiscoveryClient discoveryClient;

@GetMapping(path="/customerorderinfo")
public String getCustomerOrder() throws RestClientException, IOException {

List<ServiceInstance> instances = discoveryClient.getInstances("ORDER-SERVICE");

// Creating URL for calling order-service
ServiceInstance serviceInstance = instances.get(0);
String baseURL = serviceInstance.getUri().toString();
String completeURL = baseURL + "/customerorder";

// Calling order-service
RestTemplate restTemplate = new RestTemplate();
ResponseEntity<String> response = null;
try {
response = restTemplate.exchange(completeURL, HttpMethod.GET, getHeaders(), String.class);
} catch (Exception ex) {
System.out.println(ex);
}
System.out.println(response.getBody());
return response.getBody();
}

private static HttpEntity<?> getHeaders() throws IOException {
HttpHeaders headers = new HttpHeaders();
headers.set("Accept", MediaType.APPLICATION_JSON_VALUE);
return new HttpEntity<>(headers);
}

}

Final step is to Run EurekaServer, order-service, customer-service apps

Open http://localhost:8090 (port on which eureka server is running). Here you will see
order-service,customer-service app instances registered with it.

Output on hitting REST Endpoint http://localhost:8091/customerorderinfo is given below

Conclusion

In the above post we have seen how to register two service applications with Netflix Eureka
Server and communicate between the services via Eureka server registry without knowing the
host, port info of the service to which we are communicating with.

Spring Boot Starter dependencies


Spring Boot provides a number of starters which allow us to add jars in the classpath. Spring Boot Starters are the dependency descriptors. Spring Boot built-in starters make development easier, rapid and easily maintainable.

Naming Pattern

In the Spring Boot framework, all the starters follow a similar naming pattern: spring-boot-starter-*, where * denotes a particular type of application.

Example, if we require to use Spring and JPA for database access, spring-boot-starter-data-jpa dependency in our pom.xml file of the project can be included.

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

If we are developing REST API, spring-boot-starter-web dependency can be used.

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>

If gradle is being used as build tool, then following can be added to build.gradle file in the project.

dependencies {
implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
implementation 'org.springframework.boot:spring-boot-starter-web'
}

Below are the jars which are added to project’s classpath on adding “spring-boot-starter-data-jpa”

Spring Boot Starters can be broadly classified into three categories

  1. Production Starters
  2. Application Starters
  3. Technical Starters

Below is complete list of the starters available in above categories

Spring Boot Production Starters

Name

Description

spring-boot-starter-actuator This provides production-ready features to help you monitor and manage your application.
spring-boot-starter-remote-shell This is used for the CRaSH remote shell to monitor and manage your application over SSH. Deprecated since 1.5.

Spring Boot Application Starters

Name

Description

spring-boot-starter-thymeleaf For building MVC web applications using Thymeleaf views.
spring-boot-starter-data-couchbase For the Couchbase document-oriented database and Spring Data Couchbase.
spring-boot-starter-artemis For JMS messaging using Apache Artemis.
spring-boot-starter-web-services For Spring Web Services.
spring-boot-starter-mail To support Java Mail and Spring Framework’s email sending.
spring-boot-starter-data-redis Used for Redis key-value data store with Spring Data Redis and the Jedis client.
spring-boot-starter-web For building the web application, including RESTful applications using Spring MVC. It uses Tomcat as the default embedded container.
spring-boot-starter-data-gemfire Used to GemFire distributed data store and Spring Data GemFire.
spring-boot-starter-activemq For JMS messaging using Apache ActiveMQ.
spring-boot-starter-data-elasticsearch For Elasticsearch search and analytics engine and Spring Data Elasticsearch.
spring-boot-starter-integration It is used for Spring Integration.
spring-boot-starter-test Used to test Spring Boot applications with libraries, including JUnit, Hamcrest, and Mockito.
spring-boot-starter-jdbc Used for JDBC with the Tomcat JDBC connection pool.
spring-boot-starter-mobile Used for building web applications using Spring Mobile.
spring-boot-starter-validation Used for Java Bean Validation with Hibernate Validator.
spring-boot-starter-hateoas Used to build a hypermedia-based RESTful web application with Spring MVC and Spring HATEOAS.
spring-boot-starter-jersey Used to build RESTful web applications using JAX-RS and Jersey. An alternative to spring-boot-starter-web.
spring-boot-starter-data-neo4j Used for the Neo4j graph database and Spring Data Neo4j.
spring-boot-starter-data-ldap Used for Spring Data LDAP.
spring-boot-starter-websocket Used for building the WebSocket applications. It uses Spring Framework’s WebSocket support.
spring-boot-starter-aop For aspect-oriented programming with Spring AOP and AspectJ.
spring-boot-starter-amqp For Spring AMQP and Rabbit MQ.
spring-boot-starter-data-cassandra For Cassandra distributed database and Spring Data Cassandra.
spring-boot-starter-social-facebook For Spring Social Facebook.
spring-boot-starter-jta-atomikos For JTA transactions using Atomikos.
spring-boot-starter-security It is used for Spring Security.
spring-boot-starter-mustache It is used for building MVC web applications using Mustache views.
spring-boot-starter-data-jpa Used for Spring Data JPA with Hibernate.
spring-boot-starter Used for core starter, including auto-configuration support, logging, and YAML.
spring-boot-starter-groovy-templates Used for building MVC web applications using Groovy Template views.
spring-boot-starter-freemarker It is used for building MVC web applications using FreeMarker views.
spring-boot-starter-batch For Spring Batch.
spring-boot-starter-social-linkedin For Spring Social LinkedIn.
spring-boot-starter-cache For Spring Framework’s caching support.
spring-boot-starter-data-solr It is used for the Apache Solr search platform with Spring Data Solr.
spring-boot-starter-data-mongodb It is used for MongoDB document-oriented database and Spring Data MongoDB.
spring-boot-starter-jooq Used for jOOQ to access SQL databases. An alternative to spring-boot-starter-data-jpa or spring-boot-starter-jdbc.
spring-boot-starter-jta-narayana Used for Spring Boot Narayana JTA Starter.
spring-boot-starter-cloud-connectors It is used for Spring Cloud Connectors that simplifies connecting to services in cloud platforms like Cloud Foundry and Heroku.
spring-boot-starter-jta-bitronix It is used for JTA transactions using Bitronix.
spring-boot-starter-social-twitter For Spring Social Twitter.
spring-boot-starter-data-rest For exposing Spring Data repositories over REST using Spring Data REST.

Spring Boot Technical Starters

Name Description
spring-boot-starter-undertow Used for Undertow as the embedded servlet container. An alternative to spring-boot-starter-tomcat.
spring-boot-starter-jetty Used for Jetty as the embedded servlet container. An alternative to spring-boot-starter-tomcat.
spring-boot-starter-logging Used for logging using Logback. Default logging starter.
spring-boot-starter-tomcat Used for Tomcat as the embedded servlet container. Default servlet container starter used by spring-boot-starter-web.
spring-boot-starter-log4j2 Used for Log4j2 for logging. An alternative to spring-boot-starter-logging.