Ray: [java] Documentation for Java?

[tungwini]

[jovany-wang]

What kinds of documentation do you refer to?

[ggdupont]

Not sure about the request by @tungwini but on my end I would be glad to have a kind of quickstart for java application setup over ray. Not really on the API usage part (it's already quite clear with the examples in tutorial), but more on the steps to setup and deploy a standalone application from scratch.

@robertnishihara started something here: https://github.com/ray-project/ray/pull/2094 but it seems not up-to-date.

[tungwini]

It's been a while, but I believe I was looking for quick start instructions for java (like Python)

[raulchen]

@tungwini @ggdupont sorry for missing this issue. In the README file under java directory, there're some docs that may be helpful for you:

• Installation guide
• API doc
• Tutorial with more examples

Please let me know if what you're interested in is missing. We're working on enhancing the docs.

[jovany-wang]

@tungwini @ggdupont
If I understand it correctly, you need a tutorial how to start a Java cluster and then how to run your App on it?

We can start a Java cluster like the way of starting Python cluster in the near future.
@raulchen but it looks like that we don't have this kind of tutorial right now?

[ggdupont]

@jovany-wang yes that would be great.

Right now I'm trying to follow this process by @robertnishihara : https://github.com/ray-project/ray/pull/2094#issuecomment-391912704

I updated the procedure and intend to submit a PR, but I'm still having issues with unsatisfied libraries... Getting it to work on a cluster is the next step.

[jovany-wang]

@ggdupont
Maybe you can request your PR first, then we could solve the issues together based your PR.

[raulchen]

@ggdupont that comment is out-dated now.

If you only want to run Ray Java on a single node, you can just write your driver code like this example.

To run Ray Java in a cluster, the command-line tool isn't convenient to use at this moment. (Here's a script that run tests in cluster: https://github.com/ray-project/ray/blob/master/java/test_cluster.sh . We don't recommend using this.) We're working on integrating Java support into the ray start CLI command. Then you can start a Java cluster by ray start --head --include-java. The PR should come in a few days.

Also, regarding the unsatisfied libs, thanks for reporting and fixing this issue. I left a small comment in your PR.

[ggdupont]

@raulchen yes the comment from @robertnishihara is not up-to-date. However it goes a bit further than the examples from the java exercises: it's was really java app from scratch. The exercises are running fine on my end but I can't build my app inside the maven tutorial project. I really want an independent application with my own libs and all. I'll try to work on it in the next days.

Then for the cluster part, I can wait on the PR you mentioned.

[jovany-wang]

@ggdupont
This https://github.com/ray-project/ray/pull/3838 PR may help you to start a Ray cluster to run Java codes.

[richardliaw]

Should be done.

[raulchen]

@tungwini Please see https://docs.ray.io/en/master/ for the latest Java doc.