Is Feign threadsafe...?

Question

Is instance of Feign thread safe...? I couldn't find any documentation that supports this. Do anyone out there think otherwise?

Here is the standard example posted on github repo for Feign...

interface GitHub {
  @RequestLine("GET /repos/{owner}/{repo}/contributors")
  List<Contributor> contributors(@Param("owner") String owner, @Param("repo") String repo);
}

static class Contributor {
  String login;
  int contributions;
}

public static void main(String... args) {
  GitHub github = Feign.builder()
                       .decoder(new GsonDecoder())
                       .target(GitHub.class, "https://api.github.com");

  // Fetch and print a list of the contributors to this library.
  List<Contributor> contributors = github.contributors("netflix", "feign");
  for (Contributor contributor : contributors) {
    System.out.println(contributor.login + " (" + contributor.contributions + ")");
  }
}

Should I change this to following... Is it thread safe...?

interface GitHub {
  @RequestLine("GET /repos/{owner}/{repo}/contributors")
  List<Contributor> contributors(@Param("owner") String owner, @Param("repo") String repo);
}

static class Contributor {
  String login;
  int contributions;
}

@Component
public class GithubService {

  GitHub github = null;

  @PostConstruct
  public void postConstruct() {
    github = Feign.builder()
                .decoder(new GsonDecoder())
                .target(GitHub.class, "https://api.github.com");
  }

  public void callMeForEveryRequest() {
    github.contributors... // Is this thread-safe...?
  }
}

For the example above... I've used spring based components to highlight a singleton. Thanks in advance...

Answer 1

This discussion seems to suggest that it is thread safe. (Talks about creating a new object being inefficient) Had a look at the source and there doesn't seem to be any state that would make it unsafe. This is expected as it is modelled on the jersey Target. But you should get a confirmation from the Feign devs or do your own tests and review before using it in an unsafe way.