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Fetch status from either headers or trailers #5

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Merged
merged 4 commits into from
Apr 10, 2022
Merged

Fetch status from either headers or trailers #5

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a5fdc47
Fetch status from headers or trailers
dimitris-m Mar 27, 2022
f790382
Add @mbacarella's check for complete absence of grpc-status
dimitris-m Mar 27, 2022
0dd6749
Fix: Lwt default status
dimitris-m Mar 27, 2022
730dca8
Simplify Lwt client, avoid @@
dimitris-m Mar 28, 2022
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45 changes: 23 additions & 22 deletions lib/grpc-async/client.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -25,18 +25,6 @@ let call ~service ~rpc ?(scheme = "https") ~handler ~do_request
let read_body_ivar = Ivar.create () in
let handler_res_ivar = Ivar.create () in
let out_ivar = Ivar.create () in
let response_handler (response : H2.Response.t) (body : [ `read ] H2.Body.t) =
Ivar.fill read_body_ivar body;
don't_wait_for
(match response.status with
| `OK ->
let%bind handler_res = Ivar.read handler_res_ivar in
Ivar.fill out_ivar (Ok handler_res);
return ()
| _ ->
Ivar.fill out_ivar (Error (Grpc.Status.v Grpc.Status.Unknown));
return ())
in
let trailers_status_ivar = Ivar.create () in
let trailers_handler headers =
let code =
Expand All @@ -49,10 +37,26 @@ let call ~service ~rpc ?(scheme = "https") ~handler ~do_request
in
match code with
| None -> ()
| Some code ->
let message = H2.Headers.get headers "grpc-message" in
let status = Grpc.Status.v ?message code in
Ivar.fill trailers_status_ivar status
| Some code ->
match Ivar.is_empty trailers_status_ivar with
| true ->
let message = H2.Headers.get headers "grpc-message" in
let status = Grpc.Status.v ?message code in
Ivar.fill trailers_status_ivar status
| _ -> (* This should never happen, but just in case. *) ()
in
let response_handler (response : H2.Response.t) (body : [ `read ] H2.Body.t) =
Ivar.fill read_body_ivar body;
don't_wait_for
(match response.status with
| `OK ->
let%bind handler_res = Ivar.read handler_res_ivar in
Ivar.fill out_ivar (Ok handler_res);
return ()
| _ ->
Ivar.fill out_ivar (Error (Grpc.Status.v Grpc.Status.Unknown));
return ());
don't_wait_for (return (trailers_handler response.headers))
in
let write_body : [ `write ] H2.Body.t =
do_request ?trailers_handler:(Some trailers_handler) request
Expand All @@ -64,13 +68,10 @@ let call ~service ~rpc ?(scheme = "https") ~handler ~do_request
return ());
let%bind out = Ivar.read out_ivar in
let%bind trailers_status =
(* trailers_status_ivar is not always filled at this point, because
* trailers_handler is not always called. Perhaps because there are no
* trailers in some cases? For one example, it happens in lnd when
* QueryRoutes returns an empty list. In this case, we let the call return
* with an unknown status. *)
(* In case no grpc-status appears in headers or trailers. *)
if Ivar.is_full trailers_status_ivar then Ivar.read trailers_status_ivar
else return (Grpc.Status.v Grpc.Status.Unknown)
else return (
Grpc.Status.v ~message:"Server did not return grpc-status" Grpc.Status.Unknown)
in
match out with
| Error _ as e -> return e
Expand Down
40 changes: 25 additions & 15 deletions lib/grpc-lwt/client.ml
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Original file line number Diff line number Diff line change
Expand Up @@ -24,17 +24,6 @@ let call ~service ~rpc ?(scheme = "https") ~handler ~do_request
let read_body, read_body_notify = Lwt.wait () in
let handler_res, handler_res_notify = Lwt.wait () in
let out, out_notify = Lwt.wait () in
let response_handler (response : H2.Response.t) body =
Lwt.wakeup_later read_body_notify body;
Lwt.async (fun () ->
if response.status <> `OK then (
Lwt.wakeup_later out_notify
(Error (Grpc.Status.v Grpc.Status.Unknown));
Lwt.return_unit)
else
let+ handler_res in
Lwt.wakeup_later out_notify (Ok handler_res))
in
let status, status_notify = Lwt.wait () in
let trailers_handler headers =
let code =
Expand All @@ -48,9 +37,24 @@ let call ~service ~rpc ?(scheme = "https") ~handler ~do_request
match code with
| None -> ()
| Some code ->
let message = H2.Headers.get headers "grpc-message" in
let status = Grpc.Status.v ?message code in
Lwt.wakeup_later status_notify status
match Lwt.state status with
| Sleep ->
let message = H2.Headers.get headers "grpc-message" in
let status = Grpc.Status.v ?message code in
Lwt.wakeup_later status_notify status
| _ -> (* This should never happen, but just in case. *) ()
in
let response_handler (response : H2.Response.t) body =
Lwt.wakeup_later read_body_notify body;
Lwt.async (fun () ->
if response.status <> `OK then (
Lwt.wakeup_later out_notify
(Error (Grpc.Status.v Grpc.Status.Unknown));
Lwt.return_unit)
else
let+ handler_res in
Lwt.wakeup_later out_notify (Ok handler_res));
Lwt.async(fun () -> Lwt.return (trailers_handler response.headers))
in
let write_body =
do_request ?trailers_handler:(Some trailers_handler) request
Expand All @@ -60,7 +64,13 @@ let call ~service ~rpc ?(scheme = "https") ~handler ~do_request
let+ handler_res = handler write_body read_body in
Lwt.wakeup_later handler_res_notify handler_res);
let* out in
let+ status in
let+ status =
match Lwt.is_sleeping status with
(* In case no grpc-status appears in headers or trailers. *)
| false -> status
| true -> Lwt.return (
Grpc.Status.v ~message:"Server did not return grpc-status" Grpc.Status.Unknown)
in
match out with Error _ as e -> e | Ok out -> Ok (out, status)

module Rpc = struct
Expand Down