Add kubernetes auth method

[seanmalloy]

This is a work in progress. I'm not really a Java programmer. I have not tested this code yet. I'll be testing this code in a next few days.

Any feedback on this pull request would be greatly appreciated.

https://www.vaultproject.io/docs/auth/kubernetes.html

[seanmalloy]

I have it compiling now. Both of the below commands now execute with out error.

$ ./gradlew build
$ ./gradlew jar

Next step is to test it to see if if works.

[seanmalloy]

I have successfully tested the code, and it is working now. Ready for review.

[seanmalloy]

@steve-perkins this PR is now ready for review. Let me know if any changes are needed.

[seanmalloy]

Here is the example program I created for testing this.

/*
 *
 * javac -cp ".:/home/sean/projects/vault-java-driver/build/libs/vault-java-driver-3.1.0.jar" HelloWorld.java 
 * java -cp ".:/home/sean/projects/vault-java-driver/build/libs/vault-java-driver-3.1.0.jar" HelloWorld
 *
 */
import com.bettercloud.vault.*;
import java.nio.file.*;

public class HelloWorld {

    public static void main(String[] args) throws Exception {
	final VaultConfig config = new VaultConfig().address("http://192.168.1.193:8200").build();
	final Vault vault = new Vault(config);

	// read kube jwt from file
	String jwt = new String(Files.readAllBytes(Paths.get("/var/run/secrets/kubernetes.io/serviceaccount/token")));
	System.out.print(jwt);

	// get vault token
	String token = vault.auth().loginByKubernetes("demo", jwt, "foo").getAuthClientToken();

	System.out.print(token);
    }

}

[jetersen]

@seanmalloy seems #164 is the better approach? reusing what had JWT knowledge 😓

Duplicate of #164

[seanmalloy]

@Casz I agree #164 looks better, has less code duplication. I'll leave this open, so the project maintainer can decide which approach they like best.

[jetersen]

Duplicate of #164

[steve-perkins]

Thanks, @seanmalloy! We've had a number of PR's for this popular feature! It was ultimately merged as part of #164, and will go out to Maven Central in the next couple of days.