fix: Avoid memory copy in RESTful search and query (#37674)

Custom `jsonRender` that encodes JSON data directly into the response
stream, it uses less memory since it does not buffer the entire JSON
structure before sending it, unlike `c.JSON` in `HTTPReturn`, which
serializes the JSON fully in memory before writing it to the response.
Benchmark testing shows that, using the custom render incurs no
performance loss and reduces memory consumption by nearly 50%.

issue: https://github.com/milvus-io/milvus/issues/37671

---------

Signed-off-by: bigsheeper <yihao.dai@zilliz.com>

internal/distributed/proxy/httpserver/constant.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (

internal/distributed/proxy/httpserver/handler.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (

internal/distributed/proxy/httpserver/handler_test.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (

internal/distributed/proxy/httpserver/handler_v1.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (
@@ -538,7 +554,7 @@ func (h *HandlersV1) query(c *gin.Context) {
 				HTTPReturnMessage: merr.ErrInvalidSearchResult.Error() + ", error: " + err.Error(),
 			})
 		} else {
-			HTTPReturn(c, http.StatusOK, gin.H{HTTPReturnCode: http.StatusOK, HTTPReturnData: outputData})
+			HTTPReturnStream(c, http.StatusOK, gin.H{HTTPReturnCode: http.StatusOK, HTTPReturnData: outputData})
 		}
 	}
 }
@@ -610,7 +626,7 @@ func (h *HandlersV1) get(c *gin.Context) {
 				HTTPReturnMessage: merr.ErrInvalidSearchResult.Error() + ", error: " + err.Error(),
 			})
 		} else {
-			HTTPReturn(c, http.StatusOK, gin.H{HTTPReturnCode: http.StatusOK, HTTPReturnData: outputData})
+			HTTPReturnStream(c, http.StatusOK, gin.H{HTTPReturnCode: http.StatusOK, HTTPReturnData: outputData})
 		}
 	}
 }
@@ -956,7 +972,7 @@ func (h *HandlersV1) search(c *gin.Context) {
 					HTTPReturnMessage: merr.ErrInvalidSearchResult.Error() + ", error: " + err.Error(),
 				})
 			} else {
-				HTTPReturn(c, http.StatusOK, gin.H{HTTPReturnCode: http.StatusOK, HTTPReturnData: outputData})
+				HTTPReturnStream(c, http.StatusOK, gin.H{HTTPReturnCode: http.StatusOK, HTTPReturnData: outputData})
 			}
 		}
 	}

internal/distributed/proxy/httpserver/handler_v1_test.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (
@@ -514,7 +530,7 @@ func TestQuery(t *testing.T) {
 		name:         "query success",
 		mp:           mp5,
 		exceptCode:   200,
-		expectedBody: "{\"code\":200,\"data\":[{\"book_id\":1,\"book_intro\":[0.1,0.11],\"word_count\":1000},{\"book_id\":2,\"book_intro\":[0.2,0.22],\"word_count\":2000},{\"book_id\":3,\"book_intro\":[0.3,0.33],\"word_count\":3000}]}",
+		expectedBody: "{\"code\":200,\"data\":[{\"book_id\":1,\"book_intro\":[0.1,0.11],\"word_count\":1000},{\"book_id\":2,\"book_intro\":[0.2,0.22],\"word_count\":2000},{\"book_id\":3,\"book_intro\":[0.3,0.33],\"word_count\":3000}]}\n",
 	})
 
 	for _, tt := range testCases {
@@ -1263,7 +1279,7 @@ func TestSearch(t *testing.T) {
 		name:         "search success",
 		mp:           mp5,
 		exceptCode:   200,
-		expectedBody: "{\"code\":200,\"data\":[{\"book_id\":1,\"book_intro\":[0.1,0.11],\"distance\":0.01,\"word_count\":1000},{\"book_id\":2,\"book_intro\":[0.2,0.22],\"distance\":0.04,\"word_count\":2000},{\"book_id\":3,\"book_intro\":[0.3,0.33],\"distance\":0.09,\"word_count\":3000}]}",
+		expectedBody: "{\"code\":200,\"data\":[{\"book_id\":1,\"book_intro\":[0.1,0.11],\"distance\":0.01,\"word_count\":1000},{\"book_id\":2,\"book_intro\":[0.2,0.22],\"distance\":0.04,\"word_count\":2000},{\"book_id\":3,\"book_intro\":[0.3,0.33],\"distance\":0.09,\"word_count\":3000}]}\n",
 	})
 
 	for _, tt := range testCases {

internal/distributed/proxy/httpserver/handler_v2.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (
@@ -660,7 +676,7 @@ func (h *HandlersV2) query(ctx context.Context, c *gin.Context, anyReq any, dbNa
 				HTTPReturnMessage: merr.ErrInvalidSearchResult.Error() + ", error: " + err.Error(),
 			})
 		} else {
-			HTTPReturn(c, http.StatusOK, gin.H{
+			HTTPReturnStream(c, http.StatusOK, gin.H{
 				HTTPReturnCode: merr.Code(nil),
 				HTTPReturnData: outputData,
 				HTTPReturnCost: proxy.GetCostValue(queryResp.GetStatus()),
@@ -708,7 +724,7 @@ func (h *HandlersV2) get(ctx context.Context, c *gin.Context, anyReq any, dbName
 				HTTPReturnMessage: merr.ErrInvalidSearchResult.Error() + ", error: " + err.Error(),
 			})
 		} else {
-			HTTPReturn(c, http.StatusOK, gin.H{
+			HTTPReturnStream(c, http.StatusOK, gin.H{
 				HTTPReturnCode: merr.Code(nil),
 				HTTPReturnData: outputData,
 				HTTPReturnCost: proxy.GetCostValue(queryResp.GetStatus()),
@@ -1037,7 +1053,7 @@ func (h *HandlersV2) search(ctx context.Context, c *gin.Context, anyReq any, dbN
 					HTTPReturnMessage: merr.ErrInvalidSearchResult.Error() + ", error: " + err.Error(),
 				})
 			} else {
-				HTTPReturn(c, http.StatusOK, gin.H{HTTPReturnCode: merr.Code(nil), HTTPReturnData: outputData, HTTPReturnCost: cost})
+				HTTPReturnStream(c, http.StatusOK, gin.H{HTTPReturnCode: merr.Code(nil), HTTPReturnData: outputData, HTTPReturnCost: cost})
 			}
 		}
 	}
@@ -1129,7 +1145,7 @@ func (h *HandlersV2) advancedSearch(ctx context.Context, c *gin.Context, anyReq
 					HTTPReturnMessage: merr.ErrInvalidSearchResult.Error() + ", error: " + err.Error(),
 				})
 			} else {
-				HTTPReturn(c, http.StatusOK, gin.H{HTTPReturnCode: merr.Code(nil), HTTPReturnData: outputData, HTTPReturnCost: cost})
+				HTTPReturnStream(c, http.StatusOK, gin.H{HTTPReturnCode: merr.Code(nil), HTTPReturnData: outputData, HTTPReturnCost: cost})
 			}
 		}
 	}

internal/distributed/proxy/httpserver/handler_v2_test.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (

internal/distributed/proxy/httpserver/json_render.go

@@ -0,0 +1,44 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package httpserver
+
+import (
+	"net/http"
+
+	"github.com/milvus-io/milvus/internal/json"
+)
+
+var jsonContentType = []string{"application/json; charset=utf-8"}
+
+type jsonRender struct {
+	Data any
+}
+
+// Render writes data with custom ContentType.
+func (r jsonRender) Render(w http.ResponseWriter) error {
+	r.WriteContentType(w)
+	encoder := json.NewEncoder(w)
+	return encoder.Encode(r.Data)
+}
+
+// WriteContentType writes JSON ContentType.
+func (r jsonRender) WriteContentType(w http.ResponseWriter) {
+	header := w.Header()
+	if val := header["Content-Type"]; len(val) == 0 {
+		header["Content-Type"] = jsonContentType
+	}
+}

internal/distributed/proxy/httpserver/json_render_test.go

@@ -0,0 +1,101 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package httpserver
+
+import (
+	"math/rand"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/gin-gonic/gin"
+)
+
+var testResult = gin.H{
+	"message": "This is a test message",
+	"data":    make(map[string]interface{}),
+}
+
+func init() {
+	const chunkSize = 1024
+	rs := randomString(chunkSize)
+	var sb strings.Builder
+	for sb.Len() < 10*1024*1024 {
+		sb.WriteString(rs)
+	}
+	testResult["data"] = sb.String()
+}
+
+func randomString(length int) string {
+	const charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
+	var result strings.Builder
+	for i := 0; i < length; i++ {
+		result.WriteByte(charset[rand.Intn(len(charset))])
+	}
+	return result.String()
+}
+
+func BenchmarkHTTPReturn(b *testing.B) {
+	// Set Gin to test mode to prevent output to stdout
+	gin.SetMode(gin.TestMode)
+
+	b.Run("test HTTPReturn", func(b *testing.B) {
+		router := gin.New()
+		router.GET("/test1", func(c *gin.Context) {
+			HTTPReturn(c, http.StatusOK, testResult)
+		})
+
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			req := httptest.NewRequest("GET", "/test1", nil)
+			w := httptest.NewRecorder()
+			router.ServeHTTP(w, req)
+		}
+
+		b.ReportAllocs()
+	})
+
+	b.Run("test HTTPReturnStream", func(b *testing.B) {
+		router := gin.New()
+		router.GET("/test2", func(c *gin.Context) {
+			HTTPReturnStream(c, http.StatusOK, testResult)
+		})
+
+		b.ResetTimer()
+		for i := 0; i < b.N; i++ {
+			req := httptest.NewRequest("GET", "/test2", nil)
+			w := httptest.NewRecorder()
+			router.ServeHTTP(w, req)
+		}
+
+		b.ReportAllocs()
+	})
+}
+
+// goos: linux
+// goarch: amd64
+// pkg: github.com/milvus-io/milvus/internal/distributed/proxy/httpserver
+// cpu: Intel(R) Core(TM) i7-8700 CPU @ 3.20GHz
+// BenchmarkHTTPReturn
+// BenchmarkHTTPReturn/test_HTTPReturn
+// BenchmarkHTTPReturn/test_HTTPReturn-12         	      87	  13127452 ns/op	27992718 B/op	      34 allocs/op
+// BenchmarkHTTPReturn/test_HTTPReturnStream
+// BenchmarkHTTPReturn/test_HTTPReturnStream-12   	      87	  12804875 ns/op	14361636 B/op	      31 allocs/op
+// PASS
+//
+// Process finished with the exit code 0

internal/distributed/proxy/httpserver/request.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 type CreateCollectionReq struct {

internal/distributed/proxy/httpserver/request_v2.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (

internal/distributed/proxy/httpserver/timeout_middleware.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (

internal/distributed/proxy/httpserver/utils.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (
@@ -44,6 +60,17 @@ func HTTPReturn(c *gin.Context, code int, result gin.H) {
 	c.JSON(code, result)
 }
 
+// HTTPReturnStream uses custom jsonRender that encodes JSON data directly into the response stream,
+// it uses less memory since it does not buffer the entire JSON structure before sending it,
+// unlike c.JSON in HTTPReturn, which serializes the JSON fully in memory before writing it to the response.
+func HTTPReturnStream(c *gin.Context, code int, result gin.H) {
+	c.Set(HTTPReturnCode, result[HTTPReturnCode])
+	if errorMsg, ok := result[HTTPReturnMessage]; ok {
+		c.Set(HTTPReturnMessage, errorMsg)
+	}
+	c.Render(code, jsonRender{Data: result})
+}
+
 func HTTPAbortReturn(c *gin.Context, code int, result gin.H) {
 	c.Set(HTTPReturnCode, result[HTTPReturnCode])
 	if errorMsg, ok := result[HTTPReturnMessage]; ok {

internal/distributed/proxy/httpserver/utils_test.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (

internal/distributed/proxy/httpserver/wrap_request.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (

internal/distributed/proxy/httpserver/wrap_request_test.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (

internal/distributed/proxy/httpserver/wrapper.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (

internal/distributed/proxy/httpserver/wrapper_test.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package httpserver
 
 import (

internal/distributed/proxy/listener_manager.go

@@ -1,3 +1,19 @@
+// Licensed to the LF AI & Data foundation under one
+// or more contributor license agreements. See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership. The ASF licenses this file
+// to you under the Apache License, Version 2.0 (the
+// "License"); you may not use this file except in compliance
+// with the License. You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
 package grpcproxy
 
 import (