munchclient/rpc.go

package main

import (
	"context"
	"log"
	"math/rand"
	"time"

	"git.scraperwall.com/scw/data"
	"google.golang.org/grpc"

	pb "git.scraperwall.com/scw/grpc/scw"
)

// ScwRPC sends incoming requests to an RPC server
type ScwRPC struct {
	Connection *grpc.ClientConn
	Client     pb.SCWProtosClient
	RChan      chan *data.Request
	RChanCap   int
}

// Connect creates a new connection to the RPC server
func (s *ScwRPC) Connect(addr string) error {
	var err error

	s.Connection, err = grpc.Dial(addr, grpc.WithInsecure())
	if err != nil {
		return err
	}

	// defer conn.Close()

	s.Client = pb.NewSCWProtosClient(s.Connection)

	return nil
}

func (s *ScwRPC) sendRequest(req *data.Request) {
	ctx, cancel := context.WithTimeout(context.Background(), 500*time.Millisecond)

	_, err := s.Client.SendRequest(ctx, req)
	defer cancel()
	if err != nil {
		if rand.Intn(100) == 0 {
			log.Printf("sending request failed: %s\n", err)
		}
		return
	}
}

// NewScwRPC generates a new ScwRPC instance
func NewScwRPC(addr string) (*ScwRPC, error) {
	s := &ScwRPC{}

	err := s.Connect(addr)
	if err != nil {
		return nil, err
	}

	s.RChanCap = 5000
	s.RChan = make(chan *data.Request, s.RChanCap)

	go func() {
		for r := range s.RChan {
			go s.sendRequest(r)
		}

	}()

	return s, nil
}