[skip ci]Fix golint warnings in flowgraph (#9234)

Signed-off-by: Xiangyu Wang <xiangyu.wang@zilliz.com>

internal/util/flowgraph/input_node.go

@@ -32,6 +32,7 @@ func (inNode *InputNode) IsInputNode() bool {
 	return true
 }
 
+// Start is used to start input msgstream
 func (inNode *InputNode) Start() {
 	inNode.inStream.Start()
 }
@@ -54,7 +55,7 @@ func (inNode *InputNode) InStream() msgstream.MsgStream {
 	return inNode.inStream
 }
 
-// empty input and return one *Msg
+// Operate consume a message pack from msgstream and return
 func (inNode *InputNode) Operate(in []Msg) []Msg {
 	msgPack := inNode.inStream.Consume()
 

internal/util/flowgraph/message.go

@@ -15,10 +15,12 @@ import (
 	"github.com/milvus-io/milvus/internal/msgstream"
 )
 
+// Msg is an abstract class that contains a method to get the time tick of this message
 type Msg interface {
 	TimeTick() Timestamp
 }
 
+// MsgStreamMsg is a wrapper of TsMsg in flowgraph
 type MsgStreamMsg struct {
 	tsMessages     []msgstream.TsMsg
 	timestampMin   Timestamp
@@ -27,6 +29,7 @@ type MsgStreamMsg struct {
 	endPositions   []*MsgPosition
 }
 
+// GenerateMsgStreamMsg is used to create a new MsgStreamMsg object
 func GenerateMsgStreamMsg(tsMessages []msgstream.TsMsg, timestampMin, timestampMax Timestamp, startPos []*MsgPosition, endPos []*MsgPosition) *MsgStreamMsg {
 	return &MsgStreamMsg{
 		tsMessages:     tsMessages,
@@ -37,30 +40,37 @@ func GenerateMsgStreamMsg(tsMessages []msgstream.TsMsg, timestampMin, timestampM
 	}
 }
 
+// TimeTick returns the timetick of this message
 func (msMsg *MsgStreamMsg) TimeTick() Timestamp {
 	return msMsg.timestampMax
 }
 
+// DownStreamNodeIdx returns 0
 func (msMsg *MsgStreamMsg) DownStreamNodeIdx() int {
 	return 0
 }
 
+// TsMessages returns the origin TsMsg object list
 func (msMsg *MsgStreamMsg) TsMessages() []msgstream.TsMsg {
 	return msMsg.tsMessages
 }
 
+// TimestampMin returns the minimal timestamp in the TsMsg list
 func (msMsg *MsgStreamMsg) TimestampMin() Timestamp {
 	return msMsg.timestampMin
 }
 
+// TimestampMax returns the maximal timestamp in the TsMsg list
 func (msMsg *MsgStreamMsg) TimestampMax() Timestamp {
 	return msMsg.timestampMax
 }
 
+// StartPositions returns the start position of TsMsgs
 func (msMsg *MsgStreamMsg) StartPositions() []*MsgPosition {
 	return msMsg.startPositions
 }
 
+// EndPositions returns the end position of TsMsgs
 func (msMsg *MsgStreamMsg) EndPositions() []*MsgPosition {
 	return msMsg.endPositions
 }

internal/util/flowgraph/node.go

@@ -183,18 +183,22 @@ func (nodeCtx *nodeCtx) collectInputMessages() {
 	}
 }
 
+// MaxQueueLength returns the maximal queue length
 func (node *BaseNode) MaxQueueLength() int32 {
 	return node.maxQueueLength
 }
 
+// MaxParallelism returns the maximal parallelism
 func (node *BaseNode) MaxParallelism() int32 {
 	return node.maxParallelism
 }
 
+// SetMaxQueueLength is used to set the maximal queue length
 func (node *BaseNode) SetMaxQueueLength(n int32) {
 	node.maxQueueLength = n
 }
 
+// SetMaxParallelism is used to set the maximal parallelism
 func (node *BaseNode) SetMaxParallelism(n int32) {
 	node.maxParallelism = n
 }
@@ -207,5 +211,5 @@ func (node *BaseNode) IsInputNode() bool {
 // Start implementing Node, base node does nothing when starts
 func (node *BaseNode) Start() {}
 
-// Stop, implementing Node, base node does nothing when stops
+// Close implementing Node, base node does nothing when stops
 func (node *BaseNode) Close() {}