[libbeat/management]: support filebeat inputs to report their status …

…to elastic-agent (elastic#39209)

* feat(management): implement support for reporting input health including multiple streams

* fix: add missing file licenses

* feat(tests): update also units revision number

* feat: make stream statuses explicit in reported payload

* feat: define new env vars to allow overriding scheme and ssl verification in integration framework

* feat: utilise the es stack used through integration framework in CEL integration test

* fix: remove logging from integration test to reduce verbosity

* chore: move UpdateStatus closer to error logging

* Revert "feat: define new env vars to allow overriding scheme and ssl verification in integration framework"

This reverts commit 214cdd1.

* fix: change configStateIdx and a field in the source of input units to match the behavior of elastic-agent

* fix: invoke stringer directly with go run

* fix: add in godoc that StatusReporter for standalone Beat execution is expected to be nil

* fix(linter): preallocate slice for list of names registered

* doc: update CHANGELOG.next.asciidoc

* fix(linter): disable typecheck for rest in walkMap

* fix: return client.UnitStateFailed for unknown statuses

* chore: rename application to unit in statuses godoc to capture better their scope

* fix: do not rely on event["error"] to mark the status of cel input as running

* fix: remove usage of testify assert and require packages

* fix: move integration_test.go to parent directory and add comments to improve the code readability

* fix: improve readability by code minor restructuring and comments revisiting

* fix: remove stubborn t.Logf

* fix: simplify code in calcState

* fix: log when a unit is not found during a unit change event

* feat: add unit ID in the unit-state named logger

* feat: add unit-tests for unit.go

* feat: introduce UpdateStatus at v2.Context

* fix: add missing license header

* feat: report at the unit level the error msg of the first FAILED or DEGRADED stream

CHANGELOG.next.asciidoc

@@ -273,6 +273,7 @@ https://github.com/elastic/beats/compare/v8.8.1\...main[Check the HEAD diff]
 - Ensure all responses sent by HTTP Endpoint are HTML-escaped. {pull}39329[39329]
 - Update CEL mito extensions to v1.11.0 to improve type checking. {pull}39460[39460]
 - Improve logging of request and response with request trace logging in error conditions. {pull}39455[39455]
+- Implement Elastic Agent status and health reporting for CEL Filebeat input. {pull}39209[39209]
 - Add HTTP metrics to CEL input. {issue}39501[39501] {pull}39503[39503]
 - Add default user-agent to CEL HTTP requests. {issue}39502[39502] {pull}39587[39587]
 - Improve reindexing support in security module pipelines. {issue}38224[38224] {pull}[]

filebeat/input/v2/compat/compat.go

@@ -31,6 +31,7 @@ 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/management/status"
 	conf "github.com/elastic/elastic-agent-libs/config"
 	"github.com/elastic/elastic-agent-libs/logp"
 	"github.com/elastic/go-concert/ctxtool"
@@ -50,13 +51,14 @@ type factory struct {
 // 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       ctxtool.CancelContext
-	input     v2.Input
-	connector beat.PipelineConnector
+	id             string
+	log            *logp.Logger
+	agent          *beat.Info
+	wg             sync.WaitGroup
+	sig            ctxtool.CancelContext
+	input          v2.Input
+	connector      beat.PipelineConnector
+	statusReporter status.StatusReporter
 }
 
 // RunnerFactory creates a cfgfile.RunnerFactory from an input Loader that is
@@ -109,6 +111,10 @@ func (f *factory) Create(
 	}, nil
 }
 
+func (r *runner) SetStatusReporter(reported status.StatusReporter) {
+	r.statusReporter = reported
+}
+
 func (r *runner) String() string { return r.input.Name() }
 
 func (r *runner) Start() {
@@ -121,10 +127,11 @@ func (r *runner) Start() {
 		log.Infof("Input '%s' starting", name)
 		err := r.input.Run(
 			v2.Context{
-				ID:          r.id,
-				Agent:       *r.agent,
-				Logger:      log,
-				Cancelation: r.sig,
+				ID:             r.id,
+				Agent:          *r.agent,
+				Logger:         log,
+				Cancelation:    r.sig,
+				StatusReporter: r.statusReporter,
 			},
 			r.connector,
 		)
@@ -140,6 +147,7 @@ func (r *runner) Stop() {
 	r.sig.Cancel()
 	r.wg.Wait()
 	r.log.Infof("Input '%s' stopped (runner)", r.input.Name())
+	r.statusReporter = nil
 }
 
 func configID(config *conf.C) (string, error) {

filebeat/input/v2/input.go

@@ -22,6 +22,7 @@ import (
 	"time"
 
 	"github.com/elastic/beats/v7/libbeat/beat"
+	"github.com/elastic/beats/v7/libbeat/management/status"
 	conf "github.com/elastic/elastic-agent-libs/config"
 	"github.com/elastic/elastic-agent-libs/logp"
 
@@ -83,6 +84,17 @@ type Context struct {
 
 	// Cancelation is used by Beats to signal the input to shutdown.
 	Cancelation Canceler
+
+	// StatusReporter provides a method to update the status of the underlying unit
+	// that maps to the config. Note: Under standalone execution of Filebeat this is
+	// expected to be nil.
+	StatusReporter status.StatusReporter
+}
+
+func (c Context) UpdateStatus(status status.Status, msg string) {
+	if c.StatusReporter != nil {
+		c.StatusReporter.UpdateStatus(status, msg)
+	}
 }
 
 // TestContext provides the Input Test function with common environmental

libbeat/cfgfile/list.go

@@ -29,6 +29,7 @@ import (
 	"github.com/elastic/beats/v7/libbeat/common"
 	"github.com/elastic/beats/v7/libbeat/common/diagnostics"
 	"github.com/elastic/beats/v7/libbeat/common/reload"
+	"github.com/elastic/beats/v7/libbeat/management/status"
 	"github.com/elastic/beats/v7/libbeat/publisher/pipetool"
 	"github.com/elastic/elastic-agent-libs/config"
 	"github.com/elastic/elastic-agent-libs/logp"
@@ -153,6 +154,12 @@ func (r *RunnerList) Reload(configs []*reload.ConfigWithMeta) error {
 
 		r.logger.Debugf("Starting runner: %s", runner)
 		r.runners[hash] = runner
+		if config.StatusReporter != nil {
+			if runnerWithStatus, ok := runner.(status.WithStatusReporter); ok {
+				runnerWithStatus.SetStatusReporter(config.StatusReporter)
+			}
+		}
+
 		runner.Start()
 		moduleStarts.Add(1)
 		if config.DiagCallback != nil {

libbeat/common/reload/reload.go

@@ -21,6 +21,7 @@ import (
 	"fmt"
 	"sync"
 
+	"github.com/elastic/beats/v7/libbeat/management/status"
 	"github.com/elastic/elastic-agent-libs/config"
 	"github.com/elastic/elastic-agent-libs/mapstr"
 )
@@ -47,6 +48,11 @@ type ConfigWithMeta struct {
 
 	// InputUnitID is the unit's ID that generated this ConfigWithMeta
 	InputUnitID string
+
+	// StatusReporter provides a method to update the status of the underlying unit
+	// that maps to the config. Note: Under standalone execution of a Beat this is
+	// expected to be nil.
+	StatusReporter status.StatusReporter
 }
 
 // ReloadableList provides a method to reload the configuration of a list of entities
@@ -160,7 +166,7 @@ func (r *Registry) GetReloadableOutput() Reloadable {
 func (r *Registry) GetRegisteredNames() []string {
 	r.RLock()
 	defer r.RUnlock()
-	var names []string
+	names := make([]string, 0, len(r.confs)+len(r.confsLists))
 
 	for name := range r.confs {
 		names = append(names, name)

libbeat/management/management.go

@@ -21,49 +21,19 @@ import (
 	"sync"
 
 	"github.com/elastic/beats/v7/libbeat/common/reload"
+	"github.com/elastic/beats/v7/libbeat/management/status"
 	"github.com/elastic/elastic-agent-client/v7/pkg/client"
 	"github.com/elastic/elastic-agent-libs/config"
 	"github.com/elastic/elastic-agent-libs/logp"
 )
 
-// Status describes the current status of the beat.
-type Status int
-
-//go:generate stringer -type=Status
-const (
-	// Unknown is initial status when none has been reported.
-	Unknown Status = iota
-	// Starting is status describing application is starting.
-	Starting
-	// Configuring is status describing application is configuring.
-	Configuring
-	// Running is status describing application is running.
-	Running
-	// Degraded is status describing application is degraded.
-	Degraded
-	// Failed is status describing application is failed. This status should
-	// only be used in the case the beat should stop running as the failure
-	// cannot be recovered.
-	Failed
-	// Stopping is status describing application is stopping.
-	Stopping
-	// Stopped is status describing application is stopped.
-	Stopped
-)
-
 // DebugK used as key for all things central management
 var DebugK = "centralmgmt"
 
-// StatusReporter provides a method to update current status of the beat.
-type StatusReporter interface {
-	// UpdateStatus called when the status of the beat has changed.
-	UpdateStatus(status Status, msg string)
-}
-
 // Manager interacts with the beat to provide status updates and to receive
 // configurations.
 type Manager interface {
-	StatusReporter
+	status.StatusReporter
 
 	// Enabled returns true if manager is enabled.
 	Enabled() bool
@@ -133,7 +103,7 @@ func NewManager(cfg *config.C, registry *reload.Registry) (Manager, error) {
 	}
 	return &fallbackManager{
 		logger: logp.NewLogger("mgmt"),
-		status: Unknown,
+		status: status.Unknown,
 		msg:    "",
 	}, nil
 }
@@ -152,13 +122,13 @@ func SetManagerFactory(factory ManagerFactory) {
 type fallbackManager struct {
 	logger   *logp.Logger
 	lock     sync.Mutex
-	status   Status
+	status   status.Status
 	msg      string
 	stopFunc func()
 	stopOnce sync.Once
 }
 
-func (n *fallbackManager) UpdateStatus(status Status, msg string) {
+func (n *fallbackManager) UpdateStatus(status status.Status, msg string) {
 	n.lock.Lock()
 	defer n.lock.Unlock()
 	if n.status != status || n.msg != msg {

libbeat/management/status/status.go

@@ -0,0 +1,55 @@
+// 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 status
+
+// Status describes the current status of the beat.
+type Status int
+
+//go:generate go run golang.org/x/tools/cmd/stringer -type=Status
+const (
+	// Unknown is initial status when none has been reported.
+	Unknown Status = iota
+	// Starting is status describing unit is starting.
+	Starting
+	// Configuring is status describing unit is configuring.
+	Configuring
+	// Running is status describing unit is running.
+	Running
+	// Degraded is status describing unit is degraded.
+	Degraded
+	// Failed is status describing unit is failed. This status should
+	// only be used in the case the beat should stop running as the failure
+	// cannot be recovered.
+	Failed
+	// Stopping is status describing unit is stopping.
+	Stopping
+	// Stopped is status describing unit is stopped.
+	Stopped
+)
+
+// StatusReporter provides a method to update current status of a unit.
+type StatusReporter interface {
+	// UpdateStatus updates the status of the unit.
+	UpdateStatus(status Status, msg string)
+}
+
+// WithStatusReporter provides a method to set a status reporter
+type WithStatusReporter interface {
+	// SetStatusReporter sets the status reporter
+	SetStatusReporter(reporter StatusReporter)
+}