add --debug to show queries and error details

main.go

@@ -49,6 +49,7 @@ func parseArgs(searchRequest *pb.SearchRequest) *server.Args {
 	parser := argparse.NewParser("hub", "hub server and client")
 
 	serveCmd := parser.NewCommand("serve", "start the hub server")
+	debug := parser.Flag("", "debug", &argparse.Options{Required: false, Help: "enable debug logging", Default: false})
 
 	host := parser.String("", "rpchost", &argparse.Options{Required: false, Help: "RPC host", Default: defaultHost})
 	port := parser.String("", "rpcport", &argparse.Options{Required: false, Help: "RPC port", Default: defaultPort})
@@ -79,6 +80,7 @@ func parseArgs(searchRequest *pb.SearchRequest) *server.Args {
 		EsHost:  *esHost,
 		EsPort:  *esPort,
 		EsIndex: *esIndex,
+		Debug:   *debug,
 	}
 
 	if esHost, ok := environment["ELASTIC_HOST"]; ok {

server/search.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	"log"
 	"math"
+	"os"
 	"reflect"
 	"strings"
 	"time"
@@ -146,7 +147,11 @@ func (s *Server) Search(ctx context.Context, in *pb.SearchRequest) (*pb.Outputs,
 	var client *elastic.Client = nil
 	if s.EsClient == nil {
 		esUrl := s.Args.EsHost + ":" + s.Args.EsPort
-		tmpClient, err := elastic.NewClient(elastic.SetURL(esUrl), elastic.SetSniff(false))
+		opts := []elastic.ClientOptionFunc{elastic.SetSniff(false), elastic.SetURL(esUrl)}
+		if s.Args.Debug {
+			opts = append(opts, elastic.SetTraceLog(log.New(os.Stderr, "[[ELASTIC]]", 0)))
+		}
+		tmpClient, err := elastic.NewClient(opts...)
 		if err != nil {
 			log.Println(err)
 			return nil, err

server/server.go

@@ -25,6 +25,7 @@ type Args struct {
 	EsHost  string
 	EsPort  string
 	EsIndex string
+	Debug   bool
 }
 
 /*