Hi Stephen, Thanks for considering the change.
We would be more inclined towards the first approach since the having a ping/pong websocket message can be a bit noisy and requires sophisticated handling on the client driver side. For handling multiple response messages. I would suggest to rely on last message as these are the metadata for request execution. Partial response is very internal to the client drivers (based on limited understanding of tinkerpop client drivers :) , correct me if you differ) and can be exposed separately (if really needed later). For implementation, Let us know if we can chip in there and submit PR. The high level approach to achieve this is to have corresponding SubmitAsynWithHeaders() for every SubmitAsync() that returns a encapsulated result with attributes and IReadOnlyCollectio<T>. Let me know if you see any concerns adding a new API. Thanks a lot, Ashwini Singh Software Engineer @ Azure Cosmos DB -----Original Message----- From: Stephen Mallette <spmalle...@gmail.com> Sent: Friday, February 23, 2018 5:13 PM To: dev@tinkerpop.apache.org Subject: Re: [Discuss] Expose metadata from Gremlin Server to Clients. Adding those kinds of details was the reason we had the ResponseStatus.attributes Map. I can really only speak for the java driver as I only know that one really well (we might need other TinkerPop experts to chime in for python, .net and c#). The java driver doesn't really present ways to get that information easily under usage that doesn't deal directly with RequestMessage directly (which people typically don't do). Another thing to think about is that since a single request might return multiple ResponseMessage instances you might not want to return that kind of data on every response - maybe just to be returned on the first (or last message) and then we somehow preserve that information and make it accessible on the result somehow....we sorta have some kinda of precedent for that with side-effect data generated by bytecode based traversals - we can probably build in something similar for this sort of thing. I also toyed with the idea of using ping/pong websocket messages to carry general information about the server to the client. Not sure if any of the metadata you want to send back would fit in there, but that could be another option. Does any of that sound helpful? On Fri, Feb 23, 2018 at 3:41 PM, Ashwini Singh < ashws...@microsoft.com.invalid> wrote: > Hi All, > > We are working on to expose metadata as part of gremlin to response to > client. The metadata is simply a property bag to provide special > message/hints to the client. But currently client libraries strip off > everything and only return the data to the client. > > Specifically, We want to expose details like Request Charge, Rate > limiting/Retry policy details etc. In the other scenarios in Cosmos DB > we provide these details to the client is through response headers. We > did some investigation around this and one of the options is expose > these is through response attributes. Gremlin Server can add metadata > as part of gremlin response attributes (For example, set the property > bag on ResponseStatus.Attributes for Gremlin.Net) that can be > serialized by the client drivers to the clients. > > We would like to learn more if there are precedence around this and > if there are any recommended ways to achieve this in Gremlin protocol > and client drivers. > > Thanks a lot, > Ashwini Singh > Software Engineer @ Azure Cosmos DB > >
