GRPC catch error

grpc_error_handling.go

import (
  "github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promauto"
	"google.golang.org/grpc/codes"
	"google.golang.org/grpc/status"
	"reflect"
	"strconv"
)

// GrpcError The interface the same as internal type Error from grpc: internal/status/status.go
type GrpcError interface {
	GRPCStatus() *status.Status
	Error() string
}

func main() {
  // create a metric
  metricApiError = promauto.NewCounterVec(prometheus.CounterOpts{
		Name: "api_error",
	}, []string{"result"})
  prometheus.Register(metricApiError)

  
  err := yourGrpcReuqest(resp)
	if err != nil {
    grpcError, ok := err.(GrpcError)
    if ok {
      code := grpcError.GRPCStatus().Code()
      // Unavailable: "the connection is draining" or "read: connection reset by peer"
      timeoutErr := code == codes.DeadlineExceeded || code == codes.Unavailable
      if timeoutErr {
        Log.Printf("lookup timeout\n")
        metricApiError.WithLabelValues("timeout").Inc()
        return
      }
      errCode := strconv.Itoa(int(code))
      Log.Printf("lookup error %s\n", bidReqId, err.Error())
      metricApiError.WithLabelValues(errCode).Inc()
      return
    }
    // unexpected error, probably never occurred
    errMsg := err.Error()
    errName := reflect.TypeOf(err).String()
    Log.Printf("lookup unexpected error %s %s\n", errName, errMsg)
    metricApiError.WithLabelValues(errName).Inc()
  }
}