Add byte length comparison in do_if (#617)

* Add bytes length comparison in do_if

* Fix misspell

* Add doc

* Rename funcs

* Add tests for 'Check' method

* Add tree building tests

* Fix tree building tests. Add tests for method 'IsEqualTo'

* Add tests for parsing

* Refactor. Edit error msg

* Make empty field selector valid

---------

Co-authored-by: george pogosyan <[email protected]>

.gitignore

@@ -5,3 +5,5 @@ ozon*
 dist/
 tests-offsets
 testdata
+
+.idea/

fd/util.go

@@ -205,6 +205,9 @@ var (
 		"suffix":   struct{}{},
 		"regex":    struct{}{},
 	}
+	doIfBytesLengthCmpNodes = map[string]struct{}{
+		"byte_len_cmp": struct{}{},
+	}
 )
 
 func extractFieldOpVals(jsonNode *simplejson.Json) [][]byte {
@@ -248,6 +251,52 @@ func extractFieldOpNode(opName string, jsonNode *simplejson.Json) (pipeline.DoIf
 	return result, nil
 }
 
+func noRequiredFieldError(field string) error {
+	return fmt.Errorf("no required field: %s", field)
+}
+
+const (
+	fieldNameField    = "field"
+	fieldNameCmpOp    = "cmp_op"
+	fieldNameCmpValue = "value"
+)
+
+func extractByteLengthCmpOpNode(_ string, jsonNode *simplejson.Json) (pipeline.DoIfNode, error) {
+	fieldPathNode, has := jsonNode.CheckGet(fieldNameField)
+	if !has {
+		return nil, noRequiredFieldError(fieldNameField)
+	}
+	fieldPath, err := fieldPathNode.String()
+	if err != nil {
+		return nil, err
+	}
+
+	cmpOpNode, has := jsonNode.CheckGet(fieldNameCmpOp)
+	if !has {
+		return nil, noRequiredFieldError(fieldNameCmpOp)
+	}
+	cmpOp, err := cmpOpNode.String()
+	if err != nil {
+		return nil, err
+	}
+
+	cmpValueNode, has := jsonNode.CheckGet(fieldNameCmpValue)
+	if !has {
+		return nil, noRequiredFieldError(fieldNameCmpValue)
+	}
+	cmpValue, err := cmpValueNode.Int()
+	if err != nil {
+		return nil, err
+	}
+
+	result, err := pipeline.NewByteLengthCmpNode(fieldPath, cmpOp, cmpValue)
+	if err != nil {
+		return nil, fmt.Errorf("failed to init bytes length cmp op: %w", err)
+	}
+
+	return result, nil
+}
+
 func extractLogicalOpNode(opName string, jsonNode *simplejson.Json) (pipeline.DoIfNode, error) {
 	var result, operand pipeline.DoIfNode
 	var err error
@@ -278,6 +327,8 @@ func extractDoIfNode(jsonNode *simplejson.Json) (pipeline.DoIfNode, error) {
 		return extractLogicalOpNode(opName, jsonNode)
 	} else if _, has := doIfFieldOpNodes[opName]; has {
 		return extractFieldOpNode(opName, jsonNode)
+	} else if _, has := doIfBytesLengthCmpNodes[opName]; has {
+		return extractByteLengthCmpOpNode(opName, jsonNode)
 	}
 	return nil, fmt.Errorf("unknown op %q", opName)
 }

fd/util_test.go

@@ -46,18 +46,22 @@ type doIfTreeNode struct {
 
 	logicalOp string
 	operands  []*doIfTreeNode
+
+	byteLenCmpOp string
+	cmpValue     int
 }
 
 // nolint:gocritic
 func buildDoIfTree(node *doIfTreeNode) (pipeline.DoIfNode, error) {
-	if node.fieldOp != "" {
+	switch {
+	case node.fieldOp != "":
 		return pipeline.NewFieldOpNode(
 			node.fieldOp,
 			node.fieldName,
 			node.caseSensitive,
 			node.values,
 		)
-	} else if node.logicalOp != "" {
+	case node.logicalOp != "":
 		operands := make([]pipeline.DoIfNode, 0)
 		for _, operandNode := range node.operands {
 			operand, err := buildDoIfTree(operandNode)
@@ -70,8 +74,11 @@ func buildDoIfTree(node *doIfTreeNode) (pipeline.DoIfNode, error) {
 			node.logicalOp,
 			operands,
 		)
+	case node.byteLenCmpOp != "":
+		return pipeline.NewByteLengthCmpNode(node.fieldName, node.byteLenCmpOp, node.cmpValue)
+	default:
+		return nil, errors.New("unknown type of node")
 	}
-	return nil, errors.New("unknown type of node")
 }
 
 func Test_extractDoIfChecker(t *testing.T) {
@@ -107,6 +114,12 @@ func Test_extractDoIfChecker(t *testing.T) {
 							"values": ["test-1", "test-2"],
 							"case_sensitive": false
 						},
+						{
+							"op": "byte_len_cmp",
+							"field": "msg",
+							"cmp_op": "gt",
+							"value": 100
+						},
 						{
 							"op": "or",
 							"operands": [
@@ -152,6 +165,11 @@ func Test_extractDoIfChecker(t *testing.T) {
 								values:        [][]byte{[]byte("test-1"), []byte("test-2")},
 								caseSensitive: false,
 							},
+							{
+								byteLenCmpOp: "gt",
+								fieldName:    "msg",
+								cmpValue:     100,
+							},
 							{
 								logicalOp: "or",
 								operands: []*doIfTreeNode{
@@ -187,6 +205,17 @@ func Test_extractDoIfChecker(t *testing.T) {
 			},
 			wantErr: false,
 		},
+		{
+			name: "ok_byte_len_cmp_op",
+			args: args{
+				cfgStr: `{"op":"byte_len_cmp","field":"data","cmp_op":"lt","value":10}`,
+			},
+			want: &doIfTreeNode{
+				byteLenCmpOp: "lt",
+				fieldName:    "data",
+				cmpValue:     10,
+			},
+		},
 		{
 			name: "ok_single_val",
 			args: args{
@@ -259,6 +288,58 @@ func Test_extractDoIfChecker(t *testing.T) {
 			},
 			wantErr: true,
 		},
+		{
+			name: "error_byte_len_cmp_op_no_field",
+			args: args{
+				cfgStr: `{"op":"byte_len_cmp","cmp_op":"lt","value":10}`,
+			},
+			wantErr: true,
+		},
+		{
+			name: "error_byte_len_cmp_op_field_is_not_string",
+			args: args{
+				cfgStr: `{"op":"byte_len_cmp","field":123,"cmp_op":"lt","value":10}`,
+			},
+			wantErr: true,
+		},
+		{
+			name: "error_byte_len_cmp_op_no_cmp_op",
+			args: args{
+				cfgStr: `{"op":"byte_len_cmp","field":"data","value":10}`,
+			},
+			wantErr: true,
+		},
+		{
+			name: "error_byte_len_cmp_op_cmp_op_is_not_string",
+			args: args{
+				cfgStr: `{"op":"byte_len_cmp","field":"data","cmp_op":123,"value":10}`,
+			},
+			wantErr: true,
+		},
+		{
+			name: "error_byte_len_cmp_op_no_cmp_value",
+			args: args{
+				cfgStr: `{"op":"byte_len_cmp","field":"data","cmp_op":"lt"}`,
+			},
+			wantErr: true,
+		},
+		{
+			name: "error_byte_len_cmp_op_cmp_value_is_not_integer",
+			args: args{
+				cfgStr: `{"op":"byte_len_cmp","field":"data","cmp_op":"lt","value":"abc"}`,
+			},
+			wantErr: true,
+		},
+		{
+			name:    "error_byte_len_cmp_op_invalid_cmp_op",
+			args:    args{cfgStr: `{"op":"byte_len_cmp","field":"data","cmp_op":"ABC","value":10}`},
+			wantErr: true,
+		},
+		{
+			name:    "error_byte_len_cmp_op_negative_cmp_value",
+			args:    args{cfgStr: `{"op":"byte_len_cmp","field":"data","cmp_op":"lt","value":-1}`},
+			wantErr: true,
+		},
 	}
 	for _, tt := range tests {
 		tt := tt

pipeline/README.idoc.md

@@ -22,3 +22,6 @@ the chain of Match func calls are performed across the whole tree.
 
 ### Logical operations
 @do-if-logical-op|description
+
+### Byte length comparison op node
+@do-if-byte-len-cmp-op-node

pipeline/README.md

@@ -117,6 +117,10 @@ the chain of Match func calls are performed across the whole tree.
 
 <br>
 
+**`ByteLenCmpOp`** Type of node where matching rules for byte lengths of fields are stored.
+
+<br>
+
 **`LogicalOp`** Type of node where logical rules for applying other rules are stored.
 
 <br>
@@ -388,4 +392,47 @@ result:
 <br>
 
 
+### Byte length comparison op node
+DoIf byte length comparison op node is considered to always be a leaf in the DoIf tree like DoIf field op node.
+It contains operation that compares field length in bytes with certain value.
+
+Params:
+  - `op` - must be `byte_len_cmp`. Required.
+  - `field` - name of the field to apply operation. Required.
+  - `cmp_op` - comparison operation name (see below). Required.
+  - `value` - integer value to compare length with. Required non-negative.
+
+Example:
+```yaml
+pipelines:
+  test:
+    actions:
+      - type: discard
+        do_if:
+          op: byte_len_cmp
+          field: pod_id
+          cmp_op: lt
+          value: 5
+```
+
+result:
+```
+{"pod_id":""}      # discarded
+{"pod_id":123}     # discarded
+{"pod_id":12345}   # not discarded
+{"pod_id":123456}  # not discarded
+```
+
+Possible values of field 'cmp_op': `lt`, `le`, `gt`, `ge`, `eq`, `ne`.
+They denote corresponding comparison operations.
+
+| Name | Op |
+|------|----|
+| `lt` | `<` |
+| `le` | `<=` |
+| `gt` | `>` |
+| `ge` | `>=` |
+| `eq` | `==` |
+| `ne` | `!=` |
+
 <br>*Generated using [__insane-doc__](https://github.com/vitkovskii/insane-doc)*