add a discard output

libbeat/outputs/discard/config.go

@@ -0,0 +1,30 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. 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 discard
+
+import (
+	"github.com/elastic/elastic-agent-libs/config"
+)
+
+type discardOutConfig struct {
+	Queue config.Namespace `config:"queue"`
+}
+
+func defaultConfig() discardOutConfig {
+	return discardOutConfig{}
+}

libbeat/outputs/discard/discard.go

@@ -0,0 +1,83 @@
+// Licensed to Elasticsearch B.V. under one or more contributor
+// license agreements. See the NOTICE file distributed with
+// this work for additional information regarding copyright
+// ownership. Elasticsearch B.V. 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 discard
+
+import (
+	"context"
+
+	"github.com/elastic/beats/v7/libbeat/beat"
+	"github.com/elastic/beats/v7/libbeat/outputs"
+	"github.com/elastic/beats/v7/libbeat/publisher"
+	"github.com/elastic/elastic-agent-libs/config"
+	"github.com/elastic/elastic-agent-libs/logp"
+)
+
+func init() {
+	outputs.RegisterType("discard", makeDiscard)
+}
+
+type discardOutput struct {
+	log      *logp.Logger
+	beat     beat.Info
+	observer outputs.Observer
+}
+
+func makeDiscard(
+	_ outputs.IndexManager,
+	beat beat.Info,
+	observer outputs.Observer,
+	cfg *config.C,
+) (outputs.Group, error) {
+	out := &discardOutput{
+		log:      logp.NewLogger("discard"),
+		beat:     beat,
+		observer: observer,
+	}
+	out.log.Infof("discard output before config")
+	doConfig := defaultConfig()
+	if err := cfg.Unpack(&doConfig); err != nil {
+		return outputs.Fail(err)
+	}
+
+	// disable bulk support in publisher pipeline
+	_ = cfg.SetInt("bulk_max_size", -1, -1)
+	out.log.Infof("Initialized discard output")
+	return outputs.Success(doConfig.Queue, -1, 0, out)
+}
+
+// Implement Outputer
+func (out *discardOutput) Close() error {
+	return nil
+}
+
+func (out *discardOutput) Publish(_ context.Context, batch publisher.Batch) error {
+	defer batch.ACK()
+
+	st := out.observer
+	events := batch.Events()
+	st.NewBatch(len(events))
+	for range events {
+		st.WriteError(nil)
+	}
+	st.Acked(len(events))
+	return nil
+}
+
+func (out *discardOutput) String() string {
+	return "discard"
+}

libbeat/publisher/includes/includes.go

@@ -22,6 +22,7 @@ import (
 	_ "github.com/elastic/beats/v7/libbeat/outputs/codec/format"
 	_ "github.com/elastic/beats/v7/libbeat/outputs/codec/json"
 	_ "github.com/elastic/beats/v7/libbeat/outputs/console"
+	_ "github.com/elastic/beats/v7/libbeat/outputs/discard"
 	_ "github.com/elastic/beats/v7/libbeat/outputs/elasticsearch"
 	_ "github.com/elastic/beats/v7/libbeat/outputs/fileout"
 	_ "github.com/elastic/beats/v7/libbeat/outputs/kafka"