pool: add Instance info to connection ConnectionInfo

The Instance info has been added to ConnectionInfo, which is necessary to monitor the current state of the pool. This should help implement dynamic tracking of tarantool topology changes.

Author: maksim.konovalov

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
 }
 
 /*
@@ -393,12 +394,26 @@ 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)
 		if conn != nil {
-			info[name] = ConnectionInfo{ConnectedNow: conn.ConnectedNow(), ConnRole: role}
+			info[name] = ConnectionInfo{
+				ConnectedNow: conn.ConnectedNow(),
+				ConnRole:     role,
+				Instance: Instance{
+					Name:   name,
+					Dialer: end.dialer,
+					Opts:   end.opts,
+				}}
 		} else {
-			info[name] = ConnectionInfo{ConnectedNow: false, ConnRole: UnknownRole}
+			info[name] = ConnectionInfo{
+				ConnectedNow: false,
+				ConnRole:     UnknownRole,
+				Instance: Instance{
+					Name:   name,
+					Dialer: end.dialer,
+					Opts:   end.opts,
+				}}
 		}
 	}
 

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 +254,8 @@ 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 +1158,17 @@ 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 +3499,39 @@ func runTestMain(m *testing.M) int {
 	return m.Run()
 }
 
+func TestConnectionPool_GetInfo(t *testing.T) {
+	t.Run("equal instance info", func(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)