[FAB-4855]Print error if MSP config folder missing

Currently on peer start if MSP configuration folder is misconfigured or
missing peer simply crashes with panic rather than providing an error
message, this commit add check to see if MSP folders actually exists and
provides error message instead of panicing crashing the peer + UT.

Change-Id: Ic0e133603e7ec924225b6bfb4b08ebceaced5a55
Signed-off-by: Artem Barger <bartem@il.ibm.com>

peer/common/common.go

@@ -18,6 +18,7 @@ package common
 
 import (
 	"fmt"
+	"os"
 
 	"github.com/hyperledger/fabric/bccsp/factory"
 	"github.com/hyperledger/fabric/common/configtx"
@@ -33,7 +34,7 @@ import (
 	pcommon "github.com/hyperledger/fabric/protos/common"
 	pb "github.com/hyperledger/fabric/protos/peer"
 	putils "github.com/hyperledger/fabric/protos/utils"
-	logging "github.com/op/go-logging"
+	"github.com/op/go-logging"
 	"github.com/spf13/viper"
 	"golang.org/x/net/context"
 )
@@ -85,16 +86,24 @@ func InitConfig(cmdRoot string) error {
 
 //InitCrypto initializes crypto for this peer
 func InitCrypto(mspMgrConfigDir string, localMSPID string) error {
+	var err error
+	// Check whenever msp folder exists
+	_, err = os.Stat(mspMgrConfigDir)
+	if os.IsNotExist(err) {
+		// No need to try to load MSP from folder which is not available
+		return fmt.Errorf("cannot init crypto, missing %s folder", mspMgrConfigDir)
+	}
+
 	// Init the BCCSP
 	var bccspConfig *factory.FactoryOpts
-	err := viperutil.EnhancedExactUnmarshalKey("peer.BCCSP", &bccspConfig)
+	err = viperutil.EnhancedExactUnmarshalKey("peer.BCCSP", &bccspConfig)
 	if err != nil {
-		return fmt.Errorf("Could not parse YAML config [%s]", err)
+		return fmt.Errorf("could not parse YAML config [%s]", err)
 	}
 
 	err = mspmgmt.LoadLocalMsp(mspMgrConfigDir, bccspConfig, localMSPID)
 	if err != nil {
-		return fmt.Errorf("Error when setting up MSP from directory %s: err %s", mspMgrConfigDir, err)
+		return fmt.Errorf("error when setting up MSP from directory %s: err %s", mspMgrConfigDir, err)
 	}
 
 	return nil

peer/common/common_test.go

@@ -7,8 +7,11 @@ SPDX-License-Identifier: Apache-2.0
 package common_test
 
 import (
+	"fmt"
+	"os"
 	"testing"
 
+	"github.com/hyperledger/fabric/common/util"
 	"github.com/hyperledger/fabric/core/config"
 	"github.com/hyperledger/fabric/msp"
 	"github.com/hyperledger/fabric/peer/common"
@@ -50,6 +53,13 @@ func TestInitConfig(t *testing.T) {
 	}
 }
 
+func TestINitCryptoMissingDir(t *testing.T) {
+	dir := os.TempDir() + "/" + util.GenerateUUID()
+	err := common.InitCrypto(dir, "DEFAULT")
+	assert.Error(t, err, "Should be able to initialize crypto with non-existing directory")
+	assert.Contains(t, err.Error(), fmt.Sprintf("missing %s folder", dir))
+}
+
 func TestInitCrypto(t *testing.T) {
 
 	mspConfigPath, err := config.GetDevMspDir()

peer/main.go

@@ -110,7 +110,8 @@ func main() {
 	var mspID = viper.GetString("peer.localMspId")
 	err = common.InitCrypto(mspMgrConfigDir, mspID)
 	if err != nil { // Handle errors reading the config file
-		panic(err.Error())
+		logger.Errorf("Cannot run peer because %s", err.Error())
+		os.Exit(1)
 	}
 	// On failure Cobra prints the usage message and error string, so we only
 	// need to exit with a non-0 status