Input v2 compatibility layer (elastic#19401)

(cherry picked from commit c9a9bf5)

filebeat/input/v2/compat/compat.go

@@ -0,0 +1,153 @@
+// 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 compat provides helpers for integrating the input/v2 API with
+// existing input based features like autodiscovery, config file reloading, or
+// filebeat modules.
+package compat
+
+import (
+	"fmt"
+	"sync"
+
+	"github.com/mitchellh/hashstructure"
+
+	v2 "github.com/elastic/beats/v7/filebeat/input/v2"
+	"github.com/elastic/beats/v7/libbeat/beat"
+	"github.com/elastic/beats/v7/libbeat/cfgfile"
+	"github.com/elastic/beats/v7/libbeat/common"
+	"github.com/elastic/beats/v7/libbeat/logp"
+	"github.com/elastic/go-concert"
+)
+
+// factory implements the cfgfile.RunnerFactory interface and wraps the
+// v2.Loader to create cfgfile.Runner instances based on available v2 inputs.
+type factory struct {
+	log    *logp.Logger
+	info   beat.Info
+	loader *v2.Loader
+}
+
+// runner wraps a v2.Input, starting a go-routine
+// On start the runner spawns a go-routine that will call (v2.Input).Run with
+// the `sig` setup for shutdown signaling.
+// On stop the runner triggers the shutdown signal and waits until the input
+// has returned.
+type runner struct {
+	id        string
+	log       *logp.Logger
+	agent     *beat.Info
+	wg        sync.WaitGroup
+	sig       *concert.OnceSignaler
+	input     v2.Input
+	connector beat.PipelineConnector
+}
+
+// RunnerFactory creates a cfgfile.RunnerFactory from an input Loader that is
+// compatible with config file based input reloading, autodiscovery, and filebeat modules.
+// The RunnerFactory is can be used to integrate v2 inputs into existing Beats.
+func RunnerFactory(
+	log *logp.Logger,
+	info beat.Info,
+	loader *v2.Loader,
+) cfgfile.RunnerFactory {
+	return &factory{log: log, info: info, loader: loader}
+}
+
+func (f *factory) CheckConfig(cfg *common.Config) error {
+	_, err := f.loader.Configure(cfg)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (f *factory) Create(
+	p beat.PipelineConnector,
+	config *common.Config,
+) (cfgfile.Runner, error) {
+	input, err := f.loader.Configure(config)
+	if err != nil {
+		return nil, err
+	}
+
+	id, err := configID(config)
+	if err != nil {
+		return nil, err
+	}
+
+	return &runner{
+		id:        id,
+		log:       f.log.Named(input.Name()),
+		agent:     &f.info,
+		sig:       concert.NewOnceSignaler(),
+		input:     input,
+		connector: p,
+	}, nil
+}
+
+func (r *runner) String() string { return r.input.Name() }
+
+func (r *runner) Start() {
+	log := r.log
+	name := r.input.Name()
+
+	go func() {
+		log.Infof("Input %v starting", name)
+		err := r.input.Run(
+			v2.Context{
+				ID:          r.id,
+				Agent:       *r.agent,
+				Logger:      log,
+				Cancelation: r.sig,
+			},
+			r.connector,
+		)
+		if err != nil {
+			log.Errorf("Input '%v' failed with: %+v", name, err)
+		} else {
+			log.Infof("Input '%v' stopped", name)
+		}
+	}()
+}
+
+func (r *runner) Stop() {
+	r.sig.Trigger()
+	r.wg.Wait()
+	r.log.Infof("Input '%v' stopped", r.input.Name())
+}
+
+func configID(config *common.Config) (string, error) {
+	tmp := struct {
+		ID string `config:"id"`
+	}{}
+	if err := config.Unpack(&tmp); err != nil {
+		return "", fmt.Errorf("error extracting ID: %w", err)
+	}
+	if tmp.ID != "" {
+		return tmp.ID, nil
+	}
+
+	var h map[string]interface{}
+	config.Unpack(&h)
+	id, err := hashstructure.Hash(h, nil)
+	if err != nil {
+		return "", fmt.Errorf("can not compute id from configuration: %w", err)
+	}
+
+	return fmt.Sprintf("%16X", id), nil
+}

filebeat/input/v2/compat/compat_test.go

@@ -0,0 +1,120 @@
+// 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 compat
+
+import (
+	"sync"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	"github.com/elastic/beats/v7/libbeat/beat"
+	"github.com/elastic/beats/v7/libbeat/common"
+	"github.com/elastic/beats/v7/libbeat/logp"
+
+	v2 "github.com/elastic/beats/v7/filebeat/input/v2"
+	"github.com/elastic/beats/v7/filebeat/input/v2/internal/inputest"
+)
+
+func TestRunnerFactory_CheckConfig(t *testing.T) {
+	t.Run("does not run or test configured input", func(t *testing.T) {
+		log := logp.NewLogger("test")
+		var countConfigure, countTest, countRun int
+
+		// setup
+		plugins := inputest.SinglePlugin("test", &inputest.MockInputManager{
+			OnConfigure: func(_ *common.Config) (v2.Input, error) {
+				countConfigure++
+				return &inputest.MockInput{
+					OnTest: func(_ v2.TestContext) error { countTest++; return nil },
+					OnRun:  func(_ v2.Context, _ beat.PipelineConnector) error { countRun++; return nil },
+				}, nil
+			},
+		})
+		loader := inputest.MustNewTestLoader(t, plugins, "type", "test")
+		factory := RunnerFactory(log, beat.Info{}, loader.Loader)
+
+		// run
+		err := factory.CheckConfig(common.NewConfig())
+		if err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+
+		// validate: configured an input, but do not run test or run
+		assert.Equal(t, 1, countConfigure)
+		assert.Equal(t, 0, countTest)
+		assert.Equal(t, 0, countRun)
+	})
+
+	t.Run("fail if input type is unknown to loader", func(t *testing.T) {
+		log := logp.NewLogger("test")
+		plugins := inputest.SinglePlugin("test", inputest.ConstInputManager(nil))
+		loader := inputest.MustNewTestLoader(t, plugins, "type", "")
+		factory := RunnerFactory(log, beat.Info{}, loader.Loader)
+
+		// run
+		err := factory.CheckConfig(common.MustNewConfigFrom(map[string]interface{}{
+			"type": "unknown",
+		}))
+		assert.Error(t, err)
+	})
+}
+
+func TestRunnerFactory_CreateAndRun(t *testing.T) {
+	t.Run("runner can correctly start and stop inputs", func(t *testing.T) {
+		log := logp.NewLogger("test")
+		var countRun int
+		var wg sync.WaitGroup
+		plugins := inputest.SinglePlugin("test", inputest.ConstInputManager(&inputest.MockInput{
+			OnRun: func(ctx v2.Context, _ beat.PipelineConnector) error {
+				defer wg.Done()
+				countRun++
+				<-ctx.Cancelation.Done()
+				return nil
+			},
+		}))
+		loader := inputest.MustNewTestLoader(t, plugins, "type", "test")
+		factory := RunnerFactory(log, beat.Info{}, loader.Loader)
+
+		runner, err := factory.Create(nil, common.MustNewConfigFrom(map[string]interface{}{
+			"type": "test",
+		}))
+		require.NoError(t, err)
+
+		wg.Add(1)
+		runner.Start()
+		runner.Stop()
+		wg.Wait()
+		assert.Equal(t, 1, countRun)
+	})
+
+	t.Run("fail if input type is unknown to loader", func(t *testing.T) {
+		log := logp.NewLogger("test")
+		plugins := inputest.SinglePlugin("test", inputest.ConstInputManager(nil))
+		loader := inputest.MustNewTestLoader(t, plugins, "type", "")
+		factory := RunnerFactory(log, beat.Info{}, loader.Loader)
+
+		// run
+		runner, err := factory.Create(nil, common.MustNewConfigFrom(map[string]interface{}{
+			"type": "unknown",
+		}))
+		assert.Nil(t, runner)
+		assert.Error(t, err)
+	})
+}

filebeat/input/v2/compat/composed.go

@@ -0,0 +1,77 @@
+// 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 compat
+
+import (
+	v2 "github.com/elastic/beats/v7/filebeat/input/v2"
+	"github.com/elastic/beats/v7/libbeat/beat"
+	"github.com/elastic/beats/v7/libbeat/cfgfile"
+	"github.com/elastic/beats/v7/libbeat/common"
+)
+
+// composeFactory combines to factories. Instances are created using the Combine function.
+// For each operation the configured factory will be tried first. If the
+// operation failed (for example the input type is unknown) the fallback factory is tried.
+type composeFactory struct {
+	factory  cfgfile.RunnerFactory
+	fallback cfgfile.RunnerFactory
+}
+
+// Combine takes two RunnerFactory instances and creates a new RunnerFactory.
+// The new factory will first try to create an input using factory. If this operation fails fallback will be used.
+//
+// The new RunnerFactory will return the error of fallback only if factory did
+// signal that the input type is unknown via v2.ErrUnknown.
+//
+// XXX: This RunnerFactory is used for combining the v2.Loader with the
+// existing RunnerFactory for inputs in Filebeat. The Combine function should be removed once the old RunnerFactory is removed.
+func Combine(factory, fallback cfgfile.RunnerFactory) cfgfile.RunnerFactory {
+	return composeFactory{factory: factory, fallback: fallback}
+}
+
+func (f composeFactory) CheckConfig(cfg *common.Config) error {
+	err := f.factory.CheckConfig(cfg)
+	if !v2.IsUnknownInputError(err) {
+		return err
+	}
+	return f.fallback.CheckConfig(cfg)
+}
+
+func (f composeFactory) Create(
+	p beat.PipelineConnector,
+	config *common.Config,
+) (cfgfile.Runner, error) {
+	var runner cfgfile.Runner
+	var err1, err2 error
+
+	runner, err1 = f.factory.Create(p, config)
+	if err1 == nil {
+		return runner, nil
+	}
+
+	runner, err2 = f.fallback.Create(p, config)
+	if err2 == nil {
+		return runner, nil
+	}
+
+	// return err2 only if err1 indicates that the input type is not known to f.factory
+	if v2.IsUnknownInputError(err1) {
+		return nil, err2
+	}
+	return nil, err1
+}