Peer RPCs for bucket notifications (#2877)

* Implements a Peer RPC router that sends info to all Minio servers in the cluster.
* Bucket notifications are propagated to all nodes via this RPC router.
* Bucket listener configuration is persisted to separate object layer
  file (`listener.json`) and peer RPCs are used to communicate changes
  throughout the cluster.
* When events are generated, RPC calls to send them to other servers
  where bucket listeners may be connected is implemented.
* Some bucket notification tests are now disabled as they cannot work in
  the new design.
* Minor fix in `funcFromPC` to use `path.Join`

cmd/utils_test.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"net/http"
 	"reflect"
+	"runtime"
 	"testing"
 )
 
@@ -174,3 +175,65 @@ func TestMaxPartID(t *testing.T) {
 		}
 	}
 }
+
+// Tests fetch local address.
+func TestLocalAddress(t *testing.T) {
+	if runtime.GOOS == "windows" {
+		return
+	}
+	// need to set this to avoid stale values from other tests.
+	globalMinioPort = 9000
+	testCases := []struct {
+		srvCmdConfig serverCmdConfig
+		localAddr    string
+	}{
+		// Test 1 - local address is found.
+		{
+			srvCmdConfig: serverCmdConfig{
+				isDistXL: true,
+				disks: []string{
+					"localhost:/mnt/disk1",
+					"1.1.1.2:/mnt/disk2",
+					"1.1.2.1:/mnt/disk3",
+					"1.1.2.2:/mnt/disk4",
+				},
+			},
+			localAddr: fmt.Sprintf("localhost:%d", globalMinioPort),
+		},
+		// Test 2 - local address is everything.
+		{
+			srvCmdConfig: serverCmdConfig{
+				isDistXL: false,
+				disks: []string{
+					"/mnt/disk1",
+					"/mnt/disk2",
+					"/mnt/disk3",
+					"/mnt/disk4",
+				},
+			},
+			localAddr: fmt.Sprintf(":%d", globalMinioPort),
+		},
+		// Test 3 - local address is not found.
+		{
+			srvCmdConfig: serverCmdConfig{
+				isDistXL: true,
+				disks: []string{
+					"1.1.1.1:/mnt/disk1",
+					"1.1.1.2:/mnt/disk2",
+					"1.1.2.1:/mnt/disk3",
+					"1.1.2.2:/mnt/disk4",
+				},
+			},
+			localAddr: "",
+		},
+	}
+
+	// Validates fetching local address.
+	for i, testCase := range testCases {
+		localAddr := getLocalAddress(testCase.srvCmdConfig)
+		if localAddr != testCase.localAddr {
+			t.Fatalf("Test %d: Expected %s, got %s", i+1, testCase.localAddr, localAddr)
+		}
+	}
+
+}