improve plugin logging

go.mod

@@ -20,6 +20,7 @@ require (
 	github.com/gorilla/mux v1.7.4
 	github.com/gorilla/rpc v1.2.0
 	github.com/gorilla/websocket v1.4.2
+	github.com/hashicorp/go-hclog v0.0.0-20180709165350-ff2cf002a8dd
 	github.com/hashicorp/go-plugin v1.3.0
 	github.com/hashicorp/golang-lru v0.5.4 // indirect
 	github.com/huin/goupnp v1.0.0

vms/rpcchainvm/factory.go

@@ -5,13 +5,12 @@ package rpcchainvm
 
 import (
 	"errors"
+	"github.com/ava-labs/gecko/snow"
+	"github.com/hashicorp/go-hclog"
+	"github.com/hashicorp/go-plugin"
 	"io/ioutil"
 	"log"
 	"os/exec"
-
-	"github.com/hashicorp/go-plugin"
-
-	"github.com/ava-labs/gecko/snow"
 )
 
 var (
@@ -33,12 +32,18 @@ func (f *Factory) New(ctx *snow.Context) (interface{}, error) {
 		},
 	}
 	if ctx != nil {
-		// disable go-plugin logging (since it is not controlled by Gecko's own
-		// logging facility)
-		log.SetOutput(ioutil.Discard)
+		log.SetOutput(ctx.Log)
 		config.Stderr = ctx.Log
-		config.SyncStdout = ctx.Log
-		config.SyncStderr = ctx.Log
+		config.Logger = hclog.New(&hclog.LoggerOptions{
+			Output: ctx.Log,
+			Level:  hclog.Info,
+		})
+	} else {
+		log.SetOutput(ioutil.Discard)
+		config.Stderr = ioutil.Discard
+		config.Logger = hclog.New(&hclog.LoggerOptions{
+			Output: ioutil.Discard,
+		})
 	}
 	client := plugin.NewClient(config)