[libbeat][processor][append] Update the append processor (elastic#33731)

* Updated the name of the processor. Resolved the issues in the docs. Removed TODO from code.

Co-authored-by: Craig MacKenzie <[email protected]>

libbeat/processors/actions/append.go

@@ -40,19 +40,19 @@ type appendProcessorConfig struct {
 	IgnoreMissing     bool          `config:"ignore_missing"`
 	IgnoreEmptyValues bool          `config:"ignore_empty_values"`
 	FailOnError       bool          `config:"fail_on_error"`
-	AllowDuplicate    bool          `config:"allow_duplicate"` //TODO: Add functionality to remove duplicate
+	AllowDuplicate    bool          `config:"allow_duplicate"`
 }
 
 func init() {
-	processors.RegisterPlugin("append_processor",
+	processors.RegisterPlugin("append",
 		checks.ConfigChecked(NewAppendProcessor,
 			checks.RequireFields("target_field"),
 		),
 	)
 	jsprocessor.RegisterPlugin("AppendProcessor", NewAppendProcessor)
 }
 
-// NewAppendProcessor returns a new append_processor processor.
+// NewAppendProcessor returns a new append processor.
 func NewAppendProcessor(c *conf.C) (processors.Processor, error) {
 	config := appendProcessorConfig{
 		IgnoreMissing:     false,
@@ -67,7 +67,7 @@ func NewAppendProcessor(c *conf.C) (processors.Processor, error) {
 
 	f := &appendProcessor{
 		config: config,
-		logger: logp.NewLogger("append_processor"),
+		logger: logp.NewLogger("append"),
 	}
 	return f, nil
 }
@@ -80,12 +80,12 @@ func (f *appendProcessor) Run(event *beat.Event) (*beat.Event, error) {
 
 	err := f.appendValues(f.config.TargetField, f.config.Fields, f.config.Values, event)
 	if err != nil {
-		errMsg := fmt.Errorf("failed to append fields in append_processor processor: %w", err)
+		errMsg := fmt.Errorf("failed to append fields in append processor: %w", err)
 		f.logger.Debug(errMsg.Error())
 		if f.config.FailOnError {
 			event = backup
 			if _, err := event.PutValue("error.message", errMsg.Error()); err != nil {
-				return nil, fmt.Errorf("failed to append fields in append_processor processor: %w", err)
+				return nil, fmt.Errorf("failed to append fields in append processor: %w", err)
 			}
 			return event, err
 		}
@@ -152,7 +152,7 @@ func (f *appendProcessor) appendValues(target string, fields []string, values []
 }
 
 func (f *appendProcessor) String() string {
-	return "append_processor=" + fmt.Sprintf("%+v", f.config.TargetField)
+	return "append=" + fmt.Sprintf("%+v", f.config.TargetField)
 }
 
 // this function will remove all the empty strings and nil values from the array

libbeat/processors/actions/append_test.go

@@ -99,6 +99,28 @@ func Test_appendProcessor_appendValues(t *testing.T) {
 			},
 			wantErr: false,
 		},
+		{
+			description: "processor with no fields or values",
+			args: args{
+				target: "target",
+				event: &beat.Event{
+					Meta: mapstr.M{},
+					Fields: mapstr.M{
+						"field": "value",
+					},
+				},
+			},
+			fields: fields{
+				logger: log,
+				config: appendProcessorConfig{
+					IgnoreEmptyValues: false,
+					IgnoreMissing:     false,
+					AllowDuplicate:    true,
+					FailOnError:       true,
+				},
+			},
+			wantErr: false,
+		},
 		{
 			description: "append value in the arrays from an unknown field",
 			args: args{
@@ -361,7 +383,7 @@ func Test_appendProcessor_Run(t *testing.T) {
 				Meta: mapstr.M{},
 				Fields: mapstr.M{
 					"error": mapstr.M{
-						"message": "failed to append fields in append_processor processor: could not fetch value for key: missing-field, Error: key not found",
+						"message": "failed to append fields in append processor: could not fetch value for key: missing-field, Error: key not found",
 					},
 				},
 			},

libbeat/processors/actions/docs/append.asciidoc

@@ -2,13 +2,13 @@
 === Append Processor
 
 ++++
-<titleabbrev>append_processor</titleabbrev>
+<titleabbrev>append</titleabbrev>
 ++++
 
-The `append_processor` processor appends one or more values to an existing array if the target field already exists and it is an array. COnverts a scaler to an array and appends one or more values to it if the field exists and it is a scaler. Here the values can either be one or more static values or one or more values from the fields listed under 'fields' key.
+The `append` processor appends one or more values to an existing array if the target field already exists and it is an array. Converts a scaler to an array and appends one or more values to it if the field exists and it is a scaler. Here the values can either be one or more static values or one or more values from the fields listed under 'fields' key.
 
 `target_field`:: The field in which you want to append the data.
-`fields`:: () List of fields from which you want to copy data from. If the value is of a concrete type it will be appended directly to the target. 
+`fields`:: (Optional) List of fields from which you want to copy data from. If the value is of a concrete type it will be appended directly to the target. 
 However, if the value is an array, all the elements of the array are pushed individually to the target field.
 `values`:: (Optional) List of static values you want to append to target field.
 `ignore_empty_values`:: (Optional) If set to `true`, all the `""` and `nil` are omitted from being appended to the target field.  
@@ -29,7 +29,7 @@ processors:
   - decode_json_fields:
       fields: message
       target: ""
-  - append_processor:
+  - append:
       target_field: my-target-field
       fields: 
         - concrete.field