pool: add Instance info to connection ConnectionInfo

Instance info in ConnectionInfo enables pool state monitoring and dynamic tarantool topology tracking.

CHANGELOG.md

@@ -11,6 +11,7 @@ Versioning](http://semver.org/spec/v2.0.0.html) except to the first release.
 ### Added
 
 - Extend box with replication information (#427).
+- The Instance info has been added to ConnectionInfo for GetInfo response (#429).
 
 ### Changed
 

pool/connection_pool.go

@@ -93,6 +93,7 @@ ConnectionInfo structure for information about connection statuses:
 type ConnectionInfo struct {
 	ConnectedNow bool
 	ConnRole     Role
+	Instance     Instance
 }
 
 /*
@@ -393,13 +394,25 @@ func (p *ConnectionPool) GetInfo() map[string]ConnectionInfo {
 		return info
 	}
 
-	for name := range p.ends {
+	for name, end := range p.ends {
 		conn, role := p.getConnectionFromPool(name)
+
+		connInfo := ConnectionInfo{
+			ConnectedNow: false,
+			ConnRole:     UnknownRole,
+			Instance: Instance{
+				Name:   name,
+				Dialer: end.dialer,
+				Opts:   end.opts,
+			},
+		}
+
 		if conn != nil {
-			info[name] = ConnectionInfo{ConnectedNow: conn.ConnectedNow(), ConnRole: role}
-		} else {
-			info[name] = ConnectionInfo{ConnectedNow: false, ConnRole: UnknownRole}
+			connInfo.ConnRole = role
+			connInfo.ConnectedNow = conn.ConnectedNow()
 		}
+
+		info[name] = connInfo
 	}
 
 	return info

pool/connection_pool_test.go

@@ -242,7 +242,9 @@ func TestConnect_empty(t *testing.T) {
 func TestConnect_unavailable(t *testing.T) {
 	servers := []string{"err1", "err2"}
 	ctx, cancel := test_helpers.GetPoolConnectContext()
-	connPool, err := pool.Connect(ctx, makeInstances([]string{"err1", "err2"}, connOpts))
+	insts := makeInstances([]string{"err1", "err2"}, connOpts)
+
+	connPool, err := pool.Connect(ctx, insts)
 	cancel()
 
 	if connPool != nil {
@@ -252,8 +254,10 @@ func TestConnect_unavailable(t *testing.T) {
 	require.NoError(t, err, "failed to create a pool")
 	require.NotNilf(t, connPool, "pool is nil after Connect")
 	require.Equal(t, map[string]pool.ConnectionInfo{
-		servers[0]: pool.ConnectionInfo{ConnectedNow: false, ConnRole: pool.UnknownRole},
-		servers[1]: pool.ConnectionInfo{ConnectedNow: false, ConnRole: pool.UnknownRole},
+		servers[0]: pool.ConnectionInfo{
+			ConnectedNow: false, ConnRole: pool.UnknownRole, Instance: insts[0]},
+		servers[1]: pool.ConnectionInfo{
+			ConnectedNow: false, ConnRole: pool.UnknownRole, Instance: insts[1]},
 	}, connPool.GetInfo())
 }
 
@@ -1156,15 +1160,19 @@ func TestConnectionHandlerOpenError(t *testing.T) {
 	}
 	ctx, cancel := test_helpers.GetPoolConnectContext()
 	defer cancel()
-	connPool, err := pool.ConnectWithOpts(ctx, makeInstances(poolServers, connOpts), poolOpts)
+
+	insts := makeInstances(poolServers, connOpts)
+	connPool, err := pool.ConnectWithOpts(ctx, insts, poolOpts)
 	if err == nil {
 		defer connPool.Close()
 	}
 	require.NoError(t, err, "failed to connect")
 	require.NotNil(t, connPool, "pool expected")
 	require.Equal(t, map[string]pool.ConnectionInfo{
-		servers[0]: pool.ConnectionInfo{ConnectedNow: false, ConnRole: pool.UnknownRole},
-		servers[1]: pool.ConnectionInfo{ConnectedNow: false, ConnRole: pool.UnknownRole},
+		servers[0]: pool.ConnectionInfo{
+			ConnectedNow: false, ConnRole: pool.UnknownRole, Instance: insts[0]},
+		servers[1]: pool.ConnectionInfo{
+			ConnectedNow: false, ConnRole: pool.UnknownRole, Instance: insts[1]},
 	}, connPool.GetInfo())
 	connPool.Close()
 
@@ -3495,6 +3503,37 @@ func runTestMain(m *testing.M) int {
 	return m.Run()
 }
 
+func TestConnectionPool_GetInfo_equal_instance_info(t *testing.T) {
+	var tCases [][]pool.Instance
+
+	tCases = append(tCases, makeInstances([]string{servers[0], servers[1]}, connOpts))
+	tCases = append(tCases, makeInstances([]string{
+		servers[0],
+		servers[1],
+		servers[3]},
+		connOpts))
+	tCases = append(tCases, makeInstances([]string{servers[0]}, connOpts))
+
+	for _, tc := range tCases {
+		ctx, cancel := test_helpers.GetPoolConnectContext()
+		connPool, err := pool.Connect(ctx, tc)
+		cancel()
+		require.Nilf(t, err, "failed to connect")
+		require.NotNilf(t, connPool, "conn is nil after Connect")
+
+		info := connPool.GetInfo()
+
+		var infoInstances []pool.Instance
+
+		for _, infoInst := range info {
+			infoInstances = append(infoInstances, infoInst.Instance)
+		}
+
+		require.ElementsMatch(t, tc, infoInstances)
+		connPool.Close()
+	}
+}
+
 func TestMain(m *testing.M) {
 	code := runTestMain(m)
 	os.Exit(code)