Today I will continue to talk about how we write microservices. The last time the emphasis was on the theory: it was necessary to recall how the code was written before, to understand the essence of architecture and communication applications.
This half of the article will focus on the experience of our BellSoft team. Let's talk about how we interact with the world of microservices: here will be about the universal Java runtime, and about tiny containers, and about Spring. I will decompose the microservice into layers, assemble it into an image, run it and show what affects its speed.
Remember the result
We easily use tiny pieces of code to interconnect remote systems such as different microservices, data stores, or message queues. And to keep in touch with clients using common protocols.
@RestController
public class HelloController {
@Autowired
private WebClient webClient;
@RequestMapping(path = "/", method = RequestMethod.GET)
public CompletableFuture<String> greet(Principal principal) {
return webClient.get()
.uri("http://api/persons/{id}", principal.getName())
.accept(MediaType.APPLICATION_JSON)
.exchange()
.flatMap(response -> response.bodyToMono(Person.class))
.map(person -> "Hello, " + person.getFirstName())
.toFuture();
}
}
In this example, the ID obtained after authentication is used to request information about a person from another service and respond with a greeting. Reactive code is assumed to run asynchronously. The chosen framework, along with additional components (for example, the service registry), adds service address discovery, load balancing, etc.
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|
|
|
RAM |
|
thin jar unoptimized |
13 kb thin jar + 17,4 MB libs + 107 MB |
135 MB |
2,197 |
thin jar optimized |
13 kb jar + 17,4 MB libs + 107 MB + 50 MB jsa (CDS archive) |
70 MB |
1,156 |
fat jar unoptimized |
18,02 MB jar + 107 MB |
135 MB |
3,811 |
Native Image |
89,22 MB |
35 MB |
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The tools available for building Java microservices are varied and constantly evolving. Also, the language itself and its support in the IDE are evolving. At the virtual machine level, changes are being made right now that will help not only future developments, but also existing code.
Among all these processes, the JVM continues to be central to building software solutions. When choosing among the great alternatives in the Java world, you just need to be clear about the challenges and constraints. And you can always ask the opinion of professionals. May everything work out this year, no matter what method of launching applications you choose, and less to all hs_err.