# Spring Boot & Jaeger in Action!

In the DevOps space, Observability is crucial to maintain a healthy and reliable solution. With logs, metrics, and traces, you can implement a setup that takes you from fixing your code issues on production to foreseeing issues before they even happen.

I developed a small Spring Boot microservice for this showcase that consumes data from two external APIs. In front of this service, I implemented a simple API-Gateway to accept and authenticate requests. Both services communicate with each other and produce traces to be visualized later on via our observability setup (Jaeger UI).

## Prerequisites and external dependencies

* [JDK17](https://openjdk.org/projects/jdk/17/) & Gradle 7.5+
    
* Docker & Docker-compose
    
* rapidapi.com API key ([Developer dashboard](https://rapidapi.com/developer/security/default-application_4204327))
    

![c5673b2-Key_Rotation.png](https://cdn.hashnode.com/res/hashnode/image/upload/v1667899348187/3GNXZ_nOc.png align="left")

## Setting up Spring with OpenTracing

Java with Spring Boot provides a solid base to make it among the easiest technologies to instrument traces and visualize them using any UI of your choice. In this case, it will be Jaeger!

* For starters, pick your instrumentation and add it as a dependency:
    

```plaintext
implementation 'io.opentracing.contrib:opentracing-spring-jaeger-cloud-starter:3.3.1'
```

* In this case, we will have out-of-the-box support to get traces for all requests to the API Gateway. For other services, add these beans:
    

```java
	@Bean
	public RestTemplateBuilder restTemplateBuilder() {
		return new RestTemplateBuilder();
	}

	@Bean
	public RestTemplate restTemplate(RestTemplateBuilder builder){
		return builder.build();
	}
```

* Now to the cherry on top, taking into consideration that you have your Jaeger instance up and running, you will need to add Opentracing configuration to your application.yaml
    

```yaml
opentracing:
  jaeger:
    http-sender:
      url: ${JAEGER_URI:http://localhost:14268/api/traces}
```

## Run a full example

To get everything up and running, you will need the Rapidapi API Key that we mentioned as a prerequisite here. Then you need to subscribe to these two APIs:

* [Meme Generator](https://rapidapi.com/meme-generator-api-meme-generator-api-default/api/meme-generator)
    
* [Dad Jokes](https://rapidapi.com/KegenGuyll/api/dad-jokes)
    

Then, here is an ad-hoc [docker-compose file](https://gist.github.com/HasanKhatib/406a06c709a54d9588f2a4d52ab00d4a) to run the full example locally.

```plaintext
export RAPIDAPI_KEY=YOUR_KEY_HERE
docker-compose up
```

Now, call the api-gateway:

```plaintext
curl --location --request GET 'localhost:8081/random-meme/' \
--header 'Authorization: Basic YWRtaW46cGFzcw=='
```

## Summary

Throughout this showcase, we utilized Spring framework to develop a reactive-web microservice and an API-Gateway. Following that, we dockerized these services and orchestrated them to have a running example. Finally, here is what to expect on JaegerUI after calling the services.

![springboot1.jpg](https://cdn.hashnode.com/res/hashnode/image/upload/v1667900050171/Bi9kJfp5K.jpg align="left")

## Resources

To get a closer look at both services, the Spring Boot memes service and the API Gateway, follow these two links:

* %\[https://github.com/HasanKhatib/random-meme\]
    
* %[https://github.com/HasanKhatib/spring-gateway] 
    

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