Expose output disk queue settings when running under agent (#40857)

* Expose output disk queue settings when running under agent

libbeat/outputs/util.go

@@ -25,6 +25,7 @@ import (
  "github.com/elastic/beats/v7/libbeat/publisher/queue/diskqueue"
  "github.com/elastic/beats/v7/libbeat/publisher/queue/memqueue"
  "github.com/elastic/elastic-agent-libs/config"
+ "github.com/elastic/elastic-agent-libs/logp"
 )
 
 // Fail helper can be used by output factories, to create a failure response when
@@ -47,7 +48,8 @@ func Success(cfg config.Namespace, batchSize, retry int, encoderFactory queue.En
  q = memqueue.FactoryForSettings(settings)
  case diskqueue.QueueType:
  if management.UnderAgent() {
- return Group{}, fmt.Errorf("disk queue not supported under agent")
+ logger := logp.NewLogger("output")
+ logger.Warn("Disk queue configuration found while running under agent: this configuration is unsupported and in technical preview.")
  }
  settings, err := diskqueue.SettingsForUserConfig(cfg.Config())
  if err != nil {

libbeat/outputs/util_test.go

@@ -0,0 +1,104 @@
+// 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 outputs
+
+import (
+ "fmt"
+ "path/filepath"
+ "testing"
+
+ "github.com/stretchr/testify/assert"
+ "github.com/stretchr/testify/require"
+ "go.uber.org/zap/zapcore"
+
+ "github.com/elastic/beats/v7/libbeat/management"
+ "github.com/elastic/beats/v7/libbeat/publisher/queue"
+ "github.com/elastic/elastic-agent-libs/config"
+ "github.com/elastic/elastic-agent-libs/logp"
+)
+
+func TestDiskQueueUnderAgent(t *testing.T) {
+
+ type args struct {
+ cfg string
+ batchSize int
+ retry int
+ encoderFactory queue.EncoderFactory
+ clients []Client
+ }
+ tests := []struct {
+ name string
+ args args
+ want Group
+ wantErr bool
+ }{
+ {
+ name: "Happy path",
+ args: args{
+ cfg: `
+ disk:
+ max_size: 100MB
+ path: %s
+ `,
+ clients: []Client{},
+ batchSize: 10,
+ retry: 3,
+ },
+ },
+ }
+ for _, tt := range tests {
+ t.Run(tt.name, func(t *testing.T) {
+ previousUnderAgent := management.UnderAgent()
+ t.Cleanup(func() {
+ management.SetUnderAgent(previousUnderAgent)
+ })
+
+ tempDir := t.TempDir()
+
+ queueConfig := config.Namespace{}
+ conf, err := config.NewConfigFrom(fmt.Sprintf(tt.args.cfg, tempDir))
+ require.NoError(t, err, "error parsing queue config")
+ err = queueConfig.Unpack(conf)
+ require.NoError(t, err, "error unpacking queue config")
+
+ management.SetUnderAgent(true)
+
+ actualGroup, err := Success(queueConfig, tt.args.batchSize, tt.args.retry, tt.args.encoderFactory, tt.args.clients...)
+ if (err != nil) != tt.wantErr {
+ t.Errorf("Success() error = %v, wantErr %v", err, tt.wantErr)
+ return
+ }
+
+ if tt.wantErr {
+ // if an error was expected, we need no more assertions: return
+ return
+ }
+
+ require.NotNil(t, actualGroup)
+ require.NotNil(t, actualGroup.QueueFactory)
+
+ testlogger, _ := logp.NewInMemory("test-diskqueue", zapcore.EncoderConfig{})
+
+ actualQueue, err := actualGroup.QueueFactory(testlogger, nil, 1, nil)
+ require.NoError(t, err)
+ require.NotNil(t, actualQueue)
+ // assert that the file exists in the path we specified
+ assert.FileExists(t, filepath.Join(tempDir, "state.dat"))
+ })
+ }
+}