I have given an issue before #44. I said I found the solution; actually, it isn't.

The PR #45 give the cffi the name of the lib it needs to load. (:default "libgrpc") let it load the libgrpc.dylib which homebrew installed. However, libraries.lisp need to load the grpc.so it compiled inside this repo.

;; Load the C wrapper directly from the source directory.
    (t (:default #.(namestring
                    (asdf:system-relative-pathname "grpc" "grpc"))))

let cffi read the grpc.dylib when in :darwin platform. But the Makefile compiles the grpc.so in the source folder rather than .dylib file. So my PR only let this package doesn't give the error, but it cannot work.

I made some changes and wrote a demo, found the way that libraries.lisp read successfully and can work.

solution 1:
let libraries.lisp read the .so file in :darwin

(:darwin #.(namestring
		      (asdf:system-relative-pathname "grpc" "grpc.so")))

it is the easiest way to make it I think.

solution 2:
let makefile compile .dylib file in :darwin.

default_target: grpc.so => default_target: grpc.dylib.

Give a condition that compiles .dylib when in macos. However, it has to change the makefile.

What do you guys think? If you guys also agree the first way is acceptable, I can give the PR to fix it (which is the issue I made, sorry about that).

I am looking to use this library connect a common lisp service to a bunch of gRPC servers.

As a first step, I am trying to get a minimal product working, specifically an insecure connection using unary calls.

I have the below c++ helloworld server running and can successfully connect the below c++ client to it. However the common lisp client does not connect.

My Environment is:

• RHEL 8.6
• SBCL 2.2.2
• GRPC 1.45.0
• qitab/grpc main

Client Error

Below is the error I receive when attempting to connect. I get this error regardless of whether the server is running or not.

I get this error with the common lisp client regardless of whether the server is running or not.

The C++ client works when the server is running and gives me correct error 14: failed to connect to all addresses when the server is not running.

For troubleshooting I pointed the common lisp client and the c++ client to a netcat instance to capture of the connection traffic. Unfortunately it looks like the common lisp client doesn't attempt a network connection whereas the c++ client does send some data to netcat.

I have exhausted my troubleshooting efforts, any hints from your end would be greatly appreciated.

GRPC CALL ERROR: GRPC-STATUS-UNAVAILABLE.
   [Condition of type GRPC::GRPC-CALL-ERROR]

Restarts:
 0: [RETRY] Retry SLY mREPL evaluation request.
 1: [*ABORT] Return to SLY's top level.
 2: [ABORT] abort thread (#<THREAD "sly-channel-1-mrepl-remote-1" RUNNING {1001530003}>)

Backtrace:
 0: (GRPC::CHECK-SERVER-STATUS #.(SB-SYS:INT-SAP #X7FA35C0855C0) 1)
      Locals:
        OPS = #.(SB-SYS:INT-SAP #X7FA35C0855C0)
        RECEIVE-STATUS-ON-CLIENT-INDEX = 1
 1: (GRPC::SEND-MESSAGE #S(GRPC::CALL :C-CALL #.(SB-SYS:INT-SAP #X7FA35C07CBB0) :C-TAG #.(SB-SYS:INT-SAP #X7FA35C07CAF0) :C-OPS #.(SB-SYS:INT-SAP #X7FA35C0855C0) :OPS-PLIST (:RECV-METADATA 2 :CLIENT-RE\
CV-..
      Locals:
        BYTES-TO-SEND = #(10 3 78 101 111)
        CALL = #S(GRPC::CALL ..)
 2: (GRPC:GRPC-CALL #.(SB-SYS:INT-SAP #X7FA35C085250) "/helloworld.Greeter/SayHello" #(10 3 78 101 111) NIL NIL)
      Locals:
        BYTES-TO-SEND = #(10 3 78 101 111)
        CALL = #S(GRPC::CALL ..)
        CHANNEL = #.(SB-SYS:INT-SAP #X7FA35C085250)
        CLIENT-STREAM = NIL
        SERVER-STREAM = NIL
        SERVICE-METHOD-NAME = "/helloworld.Greeter/SayHello"
 3: ((:METHOD GRPC::START-CALL (T T T T)) #.(SB-SYS:INT-SAP #X7FA35C085250) #<CL-PROTOBUFS:METHOD-DESCRIPTOR CL-PROTOBUFS.HELLOWORLD::SAY-HELLO (CL-PROTOBUFS.HELLOWORLD:HELLO-REQUEST) => (CL-PROTOBUFS.\
HEL..
      Locals:
        GRPC::CHANNEL = #.(SB-SYS:INT-SAP #X7FA35C085250)
        #:G10 = NIL
        METHOD = #<CL-PROTOBUFS:METHOD-DESCRIPTOR CL-PROTOBUFS.HELLOWORLD::SAY-HELLO (CL-PROTOBUFS.HELLOWORLD:HELLO-REQUEST) => (CL-PROTOBUFS.HELLOWORLD:HELLO-REPLY) {1002C1ACE3}>
        GRPC::OUTPUT-TYPE = CL-PROTOBUFS.HELLOWORLD:HELLO-REPLY
        GRPC::REQUEST = #S(CL-PROTOBUFS.HELLOWORLD:HELLO-REQUEST :%%SKIPPED-BYTES NIL :%NAME "Neo" :%%BYTES NIL :%%IS-SET #*)
        GRPC::RESPONSE = NIL
        GRPC::SERVER-STREAM = NIL
 4: (AGENTS::GRPC-MAIN)
      Locals:
        CHANNEL = #.(SB-SYS:INT-SAP #X7FA35C085250)
 5: (SB-INT:SIMPLE-EVAL-IN-LEXENV (AGENTS::GRPC-MAIN) #<NULL-LEXENV>)
 6: (EVAL (AGENTS::GRPC-MAIN))
 7: ((LAMBDA NIL :IN SLYNK-MREPL::MREPL-EVAL-1))
 --more--

Common Lisp Client

(defpackage agents
  (:use :cl)
  (:local-nicknames (#:helloworld #:cl-protobufs.helloworld)
                    (#:helloworld-rpc #:cl-protobufs.helloworld-rpc)))

(in-package :agents)

(defun grpc-main ()
  (grpc:init-grpc)
       (grpc:with-insecure-channel
           (channel (concatenate 'string "10.162.22.100" ":" (write-to-string 50051)))

         ;; Unary streaming
         (format nil "Trying unary call")
         (let* ((message (helloworld:make-hello-request :name "Neo"))
                (response (helloworld-rpc:call-say-hello channel message)))
           (format t "Channel: ~A~%" channel)
           (format t "Message: ~S~%"  message)
           (format t "Response: ~S~%"  response)))
  (grpc:shutdown-grpc))

Server

class GreeterServiceImpl final : public Greeter::Service {
  Status SayHello(ServerContext* context, const HelloRequest* request,
                  HelloReply* reply) override {
    std::string prefix("Hello ");
    reply->set_message(prefix + request->name());
    std::cout << prefix + request->name() << std::endl;
    return Status::OK;
  }
};

std::string readFileIntoString(const std::string& path) {
  std::ifstream input_file(path);
  if (!input_file.is_open()) {
    std::cerr << "Could not open the file - '" << path << "'" << std::endl;
  }
  return std::string((std::istreambuf_iterator<char>(input_file)),
                     std::istreambuf_iterator<char>());
}

bool fileExists(const std::string& path) {
  std::ifstream f(path.c_str());
  return f.good();
}

void RunServer() {

  std::string server_address("0.0.0.0:50051");
  GreeterServiceImpl service;

  ServerBuilder builder;
  std::shared_ptr<grpc::ServerCredentials> creds;

  // Set up authentication mechanism (or lack therof) for the server.

  auto auth_mechanism = "insecure";

  if (auth_mechanism == "insecure") {
    creds = grpc::InsecureServerCredentials();
  }

  builder.AddListeningPort(server_address, creds);
  builder.RegisterService(&service);
  std::unique_ptr<Server> server(builder.BuildAndStart());
  std::cout << "Server listening on " << server_address << std::endl;
  server->Wait();
}

int main(int argc, char** argv) {
  RunServer();
  return 0;
}

C++ Client

class GreeterServiceImpl final : public Greeter::Service {
  Status SayHello(ServerContext* context, const HelloRequest* request,
                  HelloReply* reply) override {
    std::string prefix("Hello ");
    reply->set_message(prefix + request->name());
    std::cout << prefix + request->name() << std::endl;
    return Status::OK;
  }
};

std::string readFileIntoString(const std::string& path) {
  std::ifstream input_file(path);
  if (!input_file.is_open()) {
    std::cerr << "Could not open the file - '" << path << "'" << std::endl;
  }
  return std::string((std::istreambuf_iterator<char>(input_file)),
                     std::istreambuf_iterator<char>());
}

bool fileExists(const std::string& path) {
  std::ifstream f(path.c_str());
  return f.good();
}

void RunServer() {

  std::string server_address("0.0.0.0:50051");
  GreeterServiceImpl service;

  ServerBuilder builder;
  std::shared_ptr<grpc::ServerCredentials> creds;

  // Set up authentication mechanism (or lack therof) for the server.

  auto auth_mechanism = "insecure";

  if (auth_mechanism == "insecure") {
    creds = grpc::InsecureServerCredentials();
  }

  builder.AddListeningPort(server_address, creds);
  builder.RegisterService(&service);
  std::unique_ptr<Server> server(builder.BuildAndStart());
  std::cout << "Server listening on " << server_address << std::endl;
  server->Wait();
}

int main(int argc, char** argv) {
  RunServer();
  return 0;
}

syntax = "proto3";

option go_package = "google.golang.org/grpc/examples/helloworld/helloworld";
option java_multiple_files = true;
option java_package = "io.grpc.examples.helloworld";
option java_outer_classname = "HelloWorldProto";

package helloworld;

// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayHello (HelloRequest) returns (HelloReply) {}
}

// The request message containing the user's name.
message HelloRequest {
  string name = 1;
}

// The response message containing the greetings
message HelloReply {
  string message = 1;
}

I'm attempting to add additional metadata alongside my request.

An example utilizing ruby would be

response = stub.rpc_call(req, {metadata: {key1: value1, key2: value2}})

Does similar functionality exist within this library?

I have installed the cl-protobufs and the (ql:quickload "cl-protobufs") has no error in REPL.

But when I was trying to (ql:quickload "grpc"), I get the error message below return

Unable to load foreign library (GRPC-CLIENT-WRAPPER).
  Error opening shared object "/Users/{username}/quicklisp/local-projects/grpc/grpc.dylib":
  dlopen(/Users/{username}/quicklisp/local-projects/grpc/grpc.dylib, 0x000A): tried: '/Users/{username}/quicklisp/local-projects/grpc/grpc.dylib' (no such file).

Do I mess up the path or I need to do something else to generate the grpc.dylib like the protoc-gen-cl-pb in cl-protobufs?

Thank you

grpc and cl-protobufs: master branch version.
protoc: libprotoc 3.21.4
runtime: SBCL
OS: macos 12.5

Hi, guys!

Recently I did a wrapper around JSONRPC to generate OpenRPC spec and CL client for a service described by a spec: https://40ants.com/openrpc/

Don't know if OpenRPC is applicable to gRPC, but in case if you wanna add support, I'll be happy to extend my system and support gRPC besides JSON-RPC.