Httpjson v2 changes: (elastic#23069)

- Initialize header and body on transform if not set
- Avoid first page being '0'
- Do not send empty events if root split has no values
- Add option to reuse request body for pagination requests

x-pack/filebeat/docs/inputs/input-httpjson.asciidoc

@@ -530,6 +530,11 @@ Valid when used with `type: map`. When not empty, defines a new field where the
 
 Nested split operation. Split operations can be nested at will. An event won't be created until the deepest split operation is applied.
 
+[float]
+==== `response.request_body_on_pagination`
+
+If set to true, the values in `request.body` are sent for pagination requests. Default: `false`.
+
 [[response-pagination]]
 [float]
 ==== `response.pagination`

x-pack/filebeat/input/httpjson/internal/v2/config_response.go

@@ -15,9 +15,10 @@ const (
 )
 
 type responseConfig struct {
-	Transforms transformsConfig `config:"transforms"`
-	Pagination transformsConfig `config:"pagination"`
-	Split      *splitConfig     `config:"split"`
+	RequestBodyOnPagination bool             `config:"request_body_on_pagination"`
+	Transforms              transformsConfig `config:"transforms"`
+	Pagination              transformsConfig `config:"pagination"`
+	Split                   *splitConfig     `config:"split"`
 }
 
 type splitConfig struct {

x-pack/filebeat/input/httpjson/internal/v2/input_test.go

@@ -162,7 +162,7 @@ func TestInput(t *testing.T) {
 				},
 			},
 			handler:  defaultHandler("GET", ""),
-			expected: []string{`{"hello":[{"world":"moon"},{"space":[{"cake":"pumpkin"}]}]}`},
+			expected: []string{},
 		},
 		{
 			name: "Test date cursor",
@@ -309,6 +309,12 @@ func TestInput(t *testing.T) {
 			timeout := time.NewTimer(5 * time.Second)
 			t.Cleanup(func() { _ = timeout.Stop() })
 
+			if len(tc.expected) == 0 {
+				cancel()
+				assert.NoError(t, g.Wait())
+				return
+			}
+
 			var receivedCount int
 		wait:
 			for {

x-pack/filebeat/input/httpjson/internal/v2/pagination.go

@@ -37,9 +37,18 @@ func newPagination(config config, httpClient *httpClient, log *logp.Logger) *pag
 
 	rts, _ := newBasicTransformsFromConfig(config.Request.Transforms, requestNamespace, log)
 	pts, _ := newBasicTransformsFromConfig(config.Response.Pagination, paginationNamespace, log)
+
+	body := func() *common.MapStr {
+		if config.Response.RequestBodyOnPagination {
+			return config.Request.Body
+		}
+		return &common.MapStr{}
+	}()
+
 	requestFactory := newPaginationRequestFactory(
 		config.Request.Method,
 		*config.Request.URL.URL,
+		body,
 		append(rts, pts...),
 		config.Auth,
 		log,
@@ -48,12 +57,12 @@ func newPagination(config config, httpClient *httpClient, log *logp.Logger) *pag
 	return pagination
 }
 
-func newPaginationRequestFactory(method string, url url.URL, ts []basicTransform, authConfig *authConfig, log *logp.Logger) *requestFactory {
+func newPaginationRequestFactory(method string, url url.URL, body *common.MapStr, ts []basicTransform, authConfig *authConfig, log *logp.Logger) *requestFactory {
 	// config validation already checked for errors here
 	rf := &requestFactory{
 		url:        url,
 		method:     method,
-		body:       &common.MapStr{},
+		body:       body,
 		transforms: ts,
 		log:        log,
 	}
@@ -143,6 +152,7 @@ func (iter *pageIterator) getPage() (*response, error) {
 		return nil, err
 	}
 	iter.resp.Body.Close()
+	iter.n += 1
 
 	var r response
 	r.header = iter.resp.Header
@@ -155,7 +165,5 @@ func (iter *pageIterator) getPage() (*response, error) {
 		}
 	}
 
-	iter.n += 1
-
 	return &r, nil
 }

x-pack/filebeat/input/httpjson/internal/v2/split.go

@@ -14,6 +14,7 @@ import (
 
 var (
 	errEmptyField       = errors.New("the requested field is empty")
+	errEmptyRootField   = errors.New("the requested root field is empty")
 	errExpectedSplitArr = errors.New("split was expecting field to be an array")
 	errExpectedSplitObj = errors.New("split was expecting field to be an object")
 )
@@ -26,6 +27,7 @@ type split struct {
 	child      *split
 	keepParent bool
 	keyField   string
+	isRoot     bool
 }
 
 func newSplitResponse(cfg *splitConfig, log *logp.Logger) (*split, error) {
@@ -37,11 +39,8 @@ func newSplitResponse(cfg *splitConfig, log *logp.Logger) (*split, error) {
 	if err != nil {
 		return nil, err
 	}
-
-	if split.targetInfo.Type != targetBody {
-		return nil, fmt.Errorf("invalid target type: %s", split.targetInfo.Type)
-	}
-
+	// we want to be able to identify which split is the root of the chain
+	split.isRoot = true
 	return split, nil
 }
 
@@ -51,14 +50,18 @@ func newSplit(c *splitConfig, log *logp.Logger) (*split, error) {
 		return nil, err
 	}
 
+	if ti.Type != targetBody {
+		return nil, fmt.Errorf("invalid target type: %s", ti.Type)
+	}
+
 	ts, err := newBasicTransformsFromConfig(c.Transforms, responseNamespace, log)
 	if err != nil {
 		return nil, err
 	}
 
 	var s *split
 	if c.Split != nil {
-		s, err = newSplitResponse(c.Split, log)
+		s, err = newSplit(c.Split, log)
 		if err != nil {
 			return nil, err
 		}
@@ -87,6 +90,9 @@ func (s *split) split(ctx *transformContext, root common.MapStr, ch chan<- maybe
 	}
 
 	if v == nil {
+		if s.isRoot {
+			return errEmptyRootField
+		}
 		ch <- maybeMsg{msg: root}
 		return errEmptyField
 	}
@@ -99,6 +105,9 @@ func (s *split) split(ctx *transformContext, root common.MapStr, ch chan<- maybe
 		}
 
 		if len(varr) == 0 {
+			if s.isRoot {
+				return errEmptyRootField
+			}
 			ch <- maybeMsg{msg: root}
 			return errEmptyField
 		}
@@ -117,6 +126,9 @@ func (s *split) split(ctx *transformContext, root common.MapStr, ch chan<- maybe
 		}
 
 		if len(vmap) == 0 {
+			if s.isRoot {
+				return errEmptyRootField
+			}
 			ch <- maybeMsg{msg: root}
 			return errEmptyField
 		}

x-pack/filebeat/input/httpjson/internal/v2/split_test.go

@@ -276,13 +276,13 @@ func TestSplit(t *testing.T) {
 			},
 		},
 		{
-			name: "First level split skips publish if no events and keep_parent: false",
+			name: "First level split skips publish if no events",
 			config: &splitConfig{
 				Target: "body.response",
 				Type:   "array",
 				Split: &splitConfig{
 					Target:     "body.Event.Attributes",
-					KeepParent: false,
+					KeepParent: true,
 				},
 			},
 			ctx: emptyTransformContext(),
@@ -291,10 +291,8 @@ func TestSplit(t *testing.T) {
 					"response": []interface{}{},
 				},
 			},
-			expectedMessages: []common.MapStr{
-				{"response": []interface{}{}},
-			},
-			expectedErr: errEmptyField,
+			expectedMessages: []common.MapStr{},
+			expectedErr:      errEmptyRootField,
 		},
 		{
 			name: "Changes must be local to parent when nested splits",

x-pack/filebeat/input/httpjson/internal/v2/transform.go

@@ -105,13 +105,13 @@ func (tr transformable) setHeader(v http.Header) {
 func (tr transformable) header() http.Header {
 	val, err := tr.GetValue("header")
 	if err != nil {
-		return http.Header{}
+		// if it does not exist, initialize it
+		header := http.Header{}
+		tr.setHeader(header)
+		return header
 	}
 
-	header, ok := val.(http.Header)
-	if !ok {
-		return http.Header{}
-	}
+	header, _ := val.(http.Header)
 
 	return header
 }
@@ -123,13 +123,13 @@ func (tr transformable) setBody(v common.MapStr) {
 func (tr transformable) body() common.MapStr {
 	val, err := tr.GetValue("body")
 	if err != nil {
-		return common.MapStr{}
+		// if it does not exist, initialize it
+		body := common.MapStr{}
+		tr.setBody(body)
+		return body
 	}
 
-	body, ok := val.(common.MapStr)
-	if !ok {
-		return common.MapStr{}
-	}
+	body, _ := val.(common.MapStr)
 
 	return body
 }