Reversing Dependency: Implementing Untyped-RPC on Top of Typed-RPC (draft)

dune-project

@@ -29,7 +29,8 @@
  (synopsis "A modular gRPC library")
  (description
   "This library builds some of the signatures and implementations of gRPC functionality. This is used in the more specialised package `grpc-lwt` which has more machinery, however this library can also be used to do some bits yourself.")
- (tags (network rpc serialisation))
+ (tags
+  (network rpc serialisation))
  (depends
   (ocaml
    (>= 4.08))
@@ -44,7 +45,8 @@
  (synopsis "An Lwt implementation of gRPC")
  (description
   "Functionality for building gRPC services and rpcs with `lwt`.")
- (tags (network rpc serialisation))
+ (tags
+  (network rpc serialisation))
  (depends
   (grpc
    (= :version))
@@ -57,57 +59,98 @@
  (synopsis "An Async implementation of gRPC")
  (description
   "Functionality for building gRPC services and rpcs with `async`.")
- (tags (network rpc serialisation))
+ (tags
+  (network rpc serialisation))
  (depends
   (ocaml
    (>= 4.11))
   (grpc
    (= :version))
-  (async (>= v0.16))
+  (async
+   (>= v0.16))
   stringext))
 
 (package
  (name grpc-eio)
  (synopsis "An Eio implementation of gRPC")
  (description
-   "Functionality for building gRPC services and rpcs with `eio`.")
+  "Functionality for building gRPC services and rpcs with `eio`.")
  (depends
   (grpc
    (= :version))
-  (eio (>= 0.12))
-   stringext))
+  (eio
+   (>= 0.12))
+  stringext))
+
+(package
+ (name grpc-protoc-plugin)
+ (synopsis "An implementation of gRPC using ocaml-protoc-plugin")
+ (description
+  "Functionality for building gRPC services and rpcs with `ocaml-protoc-plugin`")
+ (depends
+  (grpc
+   (= :version))
+  (ocaml-protoc-plugin
+   (>= 4.5))))
+
+(package
+ (name grpc-protoc)
+ (synopsis "An implementation of gRPC using ocaml-protoc")
+ (description
+  "Functionality for building gRPC services and rpcs with `ocaml-protoc`")
+ (depends
+  (grpc
+   (= :version))
+  (ocaml-protoc
+   (>= 3.0))
+  (pbrt
+   (>= 3.0))
+  (pbrt_services
+   (>= 3.0))))
 
 (package
  (name grpc-examples)
  (synopsis "Various gRPC examples")
  (description "Various gRPC examples.")
- (tags (network rpc serialisation))
+ (tags
+  (network rpc serialisation))
  (depends
   grpc-lwt
   h2-lwt-unix
   grpc-async
   h2-async
   grpc-eio
   h2-eio
-  (ocaml-protoc-plugin (>= 4.5))
+  (ocaml-protoc-plugin
+   (>= 4.5))
   ppx_deriving_yojson
   conduit-lwt-unix
   cohttp-lwt-unix
   tls-async
-  (lwt_ssl (>= 1.2.0))
-  (mdx (and (>= 2.2.1) :with-test))
-  (eio_main (>= 0.12))
+  (lwt_ssl
+   (>= 1.2.0))
+  (mdx
+   (and
+    (>= 2.2.1)
+    :with-test))
+  (eio_main
+   (>= 0.12))
   stringext))
 
 (package
  (name grpc-bench)
  (synopsis "Benchmarking package for gRPC")
  (description "Benchmarking package for gRPC.")
- (tags (network rpc serialisation benchmark))
+ (tags
+  (network rpc serialisation benchmark))
  (depends
   grpc
-  (bechamel(>= 0.4.0))
+  (bechamel
+   (>= 0.4.0))
   notty
-  (bechamel-notty (>= 0.4.0))
-  (bigstringaf (>= 0.9.1))
-  (notty (>= 0.2.3))))
+  (bechamel-notty
+   (>= 0.4.0))
+  (bigstringaf
+   (>= 0.9.1))
+  (notty
+   (>= 0.2.3))))

examples/greeter-client-eio/dune

@@ -1,3 +1,3 @@
 (executable
  (name greeter_client_eio)
- (libraries grpc grpc-eio ocaml-protoc-plugin eio_main greeter h2 h2-eio))
+ (libraries grpc grpc-eio grpc-protoc-plugin eio_main greeter h2 h2-eio))

examples/greeter-client-eio/greeter_client_eio.ml

@@ -19,31 +19,23 @@ let main env =
       H2_eio.Client.create_connection ~sw ~error_handler:ignore socket
     in
 
-    let open Ocaml_protoc_plugin in
     let open Greeter.Mypackage in
-    let encode, decode = Service.make_client_functions Greeter.sayHello in
-    let encoded_request =
-      HelloRequest.make ~name () |> encode |> Writer.contents
-    in
+    let request = HelloRequest.make ~name () in
 
-    let f decoder =
-      match decoder with
-      | Some decoder -> (
-          Reader.create decoder |> decode |> function
-          | Ok v -> v
-          | Error e ->
-              failwith
-                (Printf.sprintf "Could not decode request: %s"
-                   (Result.show_error e)))
+    let f response =
+      match response with
+      | Some response -> response
       | None -> Greeter.SayHello.Response.make ()
     in
 
     let result =
-      Grpc_eio.Client.call ~service:"mypackage.Greeter" ~rpc:"SayHello"
+      Grpc_eio.Client.Typed_rpc.call
+        (Grpc_protoc_plugin.Client_rpc.unary (module Greeter.SayHello))
         ~do_request:(H2_eio.Client.request connection ~error_handler:ignore)
-        ~handler:(Grpc_eio.Client.Rpc.unary encoded_request ~f)
+        ~handler:(Grpc_eio.Client.Typed_rpc.unary request ~f)
         ()
     in
+
     Eio.Promise.await (H2_eio.Client.shutdown connection);
     result
   in

examples/greeter-protoc-client-eio/dune

@@ -0,0 +1,3 @@
+(executable
+ (name greeter_client_eio)
+ (libraries grpc grpc-eio grpc-protoc eio_main greeter_protoc h2 h2-eio))

examples/greeter-protoc-client-eio/greeter_client_eio.ml

@@ -0,0 +1,48 @@
+let main env =
+  let name = if Array.length Sys.argv > 1 then Sys.argv.(1) else "anonymous" in
+  let host = "localhost" in
+  let port = "8080" in
+  let network = Eio.Stdenv.net env in
+  let run sw =
+    let inet, port =
+      Eio_unix.run_in_systhread (fun () ->
+          Unix.getaddrinfo host port [ Unix.(AI_FAMILY PF_INET) ])
+      |> List.filter_map (fun (addr : Unix.addr_info) ->
+             match addr.ai_addr with
+             | Unix.ADDR_UNIX _ -> None
+             | ADDR_INET (addr, port) -> Some (addr, port))
+      |> List.hd
+    in
+    let addr = `Tcp (Eio_unix.Net.Ipaddr.of_unix inet, port) in
+    let socket = Eio.Net.connect ~sw network addr in
+    let connection =
+      H2_eio.Client.create_connection ~sw ~error_handler:ignore socket
+    in
+
+    let request = Greeter_protoc.Greeter.default_hello_request ~name () in
+
+    let f response =
+      match response with
+      | Some response -> response
+      | None -> Greeter_protoc.Greeter.default_hello_reply ()
+    in
+
+    let result =
+      Grpc_eio.Client.Typed_rpc.call
+        (Grpc_protoc.Client_rpc.unary
+           Greeter_protoc.Greeter.Greeter.Client.sayHello)
+        ~do_request:(H2_eio.Client.request connection ~error_handler:ignore)
+        ~handler:(Grpc_eio.Client.Typed_rpc.unary request ~f)
+        ()
+    in
+
+    Eio.Promise.await (H2_eio.Client.shutdown connection);
+    result
+  in
+  Eio.Switch.run run
+
+let () =
+  match Eio_main.run main with
+  | Ok (reply, status) ->
+      Eio.traceln "%s: %s" (Grpc.Status.show status) reply.message
+  | Error err -> Eio.traceln "Error: %a" H2.Status.pp_hum err

examples/greeter-protoc-server-eio/dune

@@ -0,0 +1,3 @@
+(executable
+ (name greeter_server_eio)
+ (libraries grpc grpc-eio grpc-protoc eio_main greeter_protoc h2 h2-eio))

examples/greeter-protoc-server-eio/greeter_server_eio.ml

@@ -0,0 +1,59 @@
+open Grpc_eio
+
+let sayHello rpc =
+  Grpc_eio.Server.Typed_rpc.unary (Grpc_protoc.Server_rpc.unary rpc)
+    ~f:(fun (request : Greeter_protoc.Greeter.hello_request) ->
+      let message =
+        if request.name = "" then "You forgot your name!"
+        else Format.sprintf "Hello, %s!" request.name
+      in
+      let reply = Greeter_protoc.Greeter.default_hello_reply ~message () in
+      (Grpc.Status.(v OK), Some reply))
+
+let connection_handler server sw =
+  let error_handler client_address ?request:_ _error start_response =
+    Eio.traceln "Error in request from:%a" Eio.Net.Sockaddr.pp client_address;
+    let response_body = start_response H2.Headers.empty in
+    H2.Body.Writer.write_string response_body
+      "There was an error handling your request.\n";
+    H2.Body.Writer.close response_body
+  in
+  let request_handler client_address request_descriptor =
+    Eio.traceln "Handling a request from:%a" Eio.Net.Sockaddr.pp client_address;
+    Eio.Fiber.fork ~sw (fun () ->
+        Grpc_eio.Server.handle_request server request_descriptor)
+  in
+  fun socket addr ->
+    H2_eio.Server.create_connection_handler ?config:None ~request_handler
+      ~error_handler addr ~sw socket
+
+let serve server env =
+  let port = 8080 in
+  let net = Eio.Stdenv.net env in
+  let addr = `Tcp (Eio.Net.Ipaddr.V4.loopback, port) in
+  Eio.Switch.run @@ fun sw ->
+  let handler = connection_handler server sw in
+  let server_socket =
+    Eio.Net.listen net ~sw ~reuse_addr:true ~backlog:10 addr
+  in
+  let rec listen () =
+    Eio.Net.accept_fork ~sw server_socket
+      ~on_error:(fun exn -> Eio.traceln "%s" (Printexc.to_string exn))
+      handler;
+    listen ()
+  in
+  Printf.printf "Listening on port %i for grpc requests\n" port;
+  print_endline "";
+  print_endline "Try running:";
+  print_endline "";
+  print_endline
+    {| dune exec -- examples/greeter-protoc-client-eio/greeter_client_eio.exe <your_name> |};
+  listen ()
+
+let () =
+  let server =
+    Greeter_protoc.Greeter.Greeter.Server.make ~sayHello ()
+    |> Grpc_protoc.handlers |> Server.Typed_rpc.server
+  in
+
+  Eio_main.run (serve server)

examples/greeter-protoc/dune

@@ -0,0 +1,14 @@
+(library
+ (name greeter_protoc)
+ (package grpc-examples)
+ (libraries ocaml-protoc pbrt pbrt_services))
+
+(rule
+ (copy ../greeter/greeter.proto greeter.proto))
+
+(rule
+ (targets greeter.ml greeter.mli)
+ (deps
+  (:proto greeter.proto))
+ (action
+  (run ocaml-protoc %{proto} --binary --pp --services --ml_out .)))

examples/greeter-server-eio/dune

@@ -1,3 +1,3 @@
 (executable
  (name greeter_server_eio)
- (libraries grpc grpc-eio ocaml-protoc-plugin eio_main greeter h2 h2-eio))
+ (libraries grpc grpc-eio grpc-protoc-plugin eio_main greeter h2 h2-eio))

examples/greeter-server-eio/greeter_server_eio.ml

@@ -1,22 +1,16 @@
 open Grpc_eio
 
-let say_hello buffer =
-  let open Ocaml_protoc_plugin in
-  let open Greeter.Mypackage in
-  let decode, encode = Service.make_service_functions Greeter.sayHello in
-  let request =
-    Reader.create buffer |> decode |> function
-    | Ok v -> v
-    | Error e ->
-        failwith
-          (Printf.sprintf "Could not decode request: %s" (Result.show_error e))
-  in
-  let message =
-    if request = "" then "You forgot your name!"
-    else Format.sprintf "Hello, %s!" request
-  in
-  let reply = Greeter.SayHello.Response.make ~message () in
-  (Grpc.Status.(v OK), Some (encode reply |> Writer.contents))
+let say_hello =
+  let module SayHello = Greeter.Mypackage.Greeter.SayHello in
+  Grpc_eio.Server.Typed_rpc.unary
+    (Grpc_protoc_plugin.Server_rpc.unary (module SayHello))
+    ~f:(fun request ->
+      let message =
+        if request = "" then "You forgot your name!"
+        else Format.sprintf "Hello, %s!" request
+      in
+      let reply = SayHello.Response.make ~message () in
+      (Grpc.Status.(v OK), Some reply))
 
 let connection_handler server sw =
   let error_handler client_address ?request:_ _error start_response =
@@ -59,12 +53,8 @@ let serve server env =
   listen ()
 
 let () =
-  let greeter_service =
-    Server.Service.(
-      v () |> add_rpc ~name:"SayHello" ~rpc:(Unary say_hello) |> handle_request)
-  in
   let server =
-    Server.(
-      v () |> add_service ~name:"mypackage.Greeter" ~service:greeter_service)
+    Server.Typed_rpc.server (Grpc_protoc_plugin.handlers [ say_hello ])
   in
+
   Eio_main.run (serve server)

examples/routeguide-protoc/proto/dune

@@ -0,0 +1,24 @@
+(library
+ (name routeguide_protoc)
+ (package grpc-examples)
+ (preprocess
+  (pps ppx_deriving.show ppx_deriving.eq))
+ (libraries ocaml-protoc pbrt pbrt_services))
+
+(rule
+ (copy ../../routeguide/proto/route_guide.proto route_guide.proto))
+
+(rule
+ (targets route_guide.ml route_guide.mli)
+ (deps
+  (:proto route_guide.proto))
+ (action
+  (run
+   ocaml-protoc
+   %{proto}
+   --binary
+   --ocaml_all_types_ppx
+   "deriving show { with_path = false }, eq"
+   --services
+   --ml_out
+   .)))