[Elastic-Agent] Enable introspecting configuration (#18124)

* introspection

* changelog

* mage fmt

* introspect -> inspect

* follow -c argument

* conflicts

x-pack/elastic-agent/CHANGELOG.asciidoc

@@ -47,4 +47,5 @@
 - Use data subfolder as default for process logs {pull}17960[17960]
 - Do not require unnecessary configuration {pull}18003[18003]
 - Enable debug log level for Metricbeat and Filebeat when run under the Elastic Agent. {pull}17935[17935]
+- Enable introspecting configuration {pull}18124[18124]
 - Follow home path for all config files {pull}18161[18161]

x-pack/elastic-agent/pkg/agent/application/emitter.go

@@ -26,7 +26,11 @@ type configModifiers struct {
 	Decorators []decoratorFunc
 }
 
-func emitter(log *logger.Logger, router *router, modifiers *configModifiers, reloadables ...reloadable) emitterFunc {
+type programsDispatcher interface {
+	Dispatch(id string, grpProg map[routingKey][]program.Program) error
+}
+
+func emitter(log *logger.Logger, router programsDispatcher, modifiers *configModifiers, reloadables ...reloadable) emitterFunc {
 	return func(c *config.Config) error {
 		if err := InjectAgentConfig(c); err != nil {
 			return err

x-pack/elastic-agent/pkg/agent/application/introspect_config_cmd.go

@@ -0,0 +1,131 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+package application
+
+import (
+	"fmt"
+
+	yaml "gopkg.in/yaml.v2"
+
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/application/info"
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/errors"
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/storage"
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/config"
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/fleetapi"
+)
+
+// IntrospectConfigCmd is an introspect subcommand that shows configurations of the agent.
+type IntrospectConfigCmd struct {
+	cfgPath string
+}
+
+// NewIntrospectConfigCmd creates a new introspect command.
+func NewIntrospectConfigCmd(configPath string,
+) (*IntrospectConfigCmd, error) {
+	return &IntrospectConfigCmd{
+		cfgPath: configPath,
+	}, nil
+}
+
+// Execute introspects agent configuration.
+func (c *IntrospectConfigCmd) Execute() error {
+	return c.introspectConfig()
+}
+
+func (c *IntrospectConfigCmd) introspectConfig() error {
+	cfg, err := loadConfig(c.cfgPath)
+	if err != nil {
+		return err
+	}
+
+	isLocal, err := isLocalMode(cfg)
+	if err != nil {
+		return err
+	}
+
+	if isLocal {
+		return printConfig(cfg)
+	}
+
+	fleetConfig, err := loadFleetConfig(cfg)
+	if err != nil {
+		return err
+	} else if fleetConfig == nil {
+		return errors.New("no fleet config retrieved yet")
+	}
+
+	return printMapStringConfig(fleetConfig)
+}
+
+func loadConfig(configPath string) (*config.Config, error) {
+	rawConfig, err := config.LoadYAML(configPath)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := InjectAgentConfig(rawConfig); err != nil {
+		return nil, err
+	}
+
+	return rawConfig, nil
+}
+
+func loadFleetConfig(cfg *config.Config) (map[string]interface{}, error) {
+	log, err := newErrorLogger()
+	if err != nil {
+		return nil, err
+	}
+
+	as, err := newActionStore(log, storage.NewDiskStore(info.AgentActionStoreFile()))
+	if err != nil {
+		return nil, err
+	}
+
+	for _, c := range as.Actions() {
+		cfgChange, ok := c.(*fleetapi.ActionConfigChange)
+		if !ok {
+			continue
+		}
+
+		fmt.Println("Action ID:", cfgChange.ID())
+		return cfgChange.Config, nil
+	}
+	return nil, nil
+}
+
+func isLocalMode(rawConfig *config.Config) (bool, error) {
+	c := localDefaultConfig()
+	if err := rawConfig.Unpack(&c); err != nil {
+		return false, errors.New(err, "initiating application")
+	}
+
+	managementConfig := struct {
+		Mode string `config:"mode" yaml:"mode"`
+	}{}
+
+	if err := c.Management.Unpack(&managementConfig); err != nil {
+		return false, errors.New(err, "initiating application")
+	}
+	return managementConfig.Mode == "local", nil
+}
+
+func printMapStringConfig(mapStr map[string]interface{}) error {
+	data, err := yaml.Marshal(mapStr)
+	if err != nil {
+		return errors.New(err, "could not marshal to YAML")
+	}
+
+	fmt.Println(string(data))
+	return nil
+}
+
+func printConfig(cfg *config.Config) error {
+	mapStr, err := cfg.ToMapStr()
+	if err != nil {
+		return err
+	}
+
+	return printMapStringConfig(mapStr)
+}

x-pack/elastic-agent/pkg/agent/application/introspect_output_cmd.go

@@ -0,0 +1,211 @@
+// Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+// or more contributor license agreements. Licensed under the Elastic License;
+// you may not use this file except in compliance with the Elastic License.
+
+package application
+
+import (
+	"fmt"
+
+	"github.com/urso/ecslog"
+	"github.com/urso/ecslog/backend"
+	"github.com/urso/ecslog/backend/appender"
+	"github.com/urso/ecslog/backend/layout"
+
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/application/filters"
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/errors"
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/agent/program"
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/config"
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/core/logger"
+	"github.com/elastic/beats/v7/x-pack/elastic-agent/pkg/core/plugin/app/monitoring/noop"
+)
+
+// IntrospectOutputCmd is an introspect subcommand that shows configurations of the agent.
+type IntrospectOutputCmd struct {
+	cfgPath string
+	output  string
+	program string
+}
+
+// NewIntrospectOutputCmd creates a new introspect command.
+func NewIntrospectOutputCmd(configPath, output, program string) (*IntrospectOutputCmd, error) {
+	return &IntrospectOutputCmd{
+		cfgPath: configPath,
+		output:  output,
+		program: program,
+	}, nil
+}
+
+// Execute tries to enroll the agent into Fleet.
+func (c *IntrospectOutputCmd) Execute() error {
+	if c.output == "" {
+		return c.introspectOutputs()
+	}
+
+	return c.introspectOutput()
+}
+
+func (c *IntrospectOutputCmd) introspectOutputs() error {
+	cfg, err := loadConfig(c.cfgPath)
+	if err != nil {
+		return err
+	}
+
+	isLocal, err := isLocalMode(cfg)
+	if err != nil {
+		return err
+	}
+
+	l, err := newErrorLogger()
+	if err != nil {
+		return err
+	}
+
+	if isLocal {
+		return listOutputsFromConfig(l, cfg)
+	}
+
+	fleetConfig, err := loadFleetConfig(cfg)
+	if err != nil {
+		return err
+	} else if fleetConfig == nil {
+		return errors.New("no fleet config retrieved yet")
+	}
+
+	return listOutputsFromMap(l, fleetConfig)
+}
+
+func listOutputsFromConfig(log *logger.Logger, cfg *config.Config) error {
+	programsGroup, err := getProgramsFromConfig(log, cfg)
+	if err != nil {
+		return err
+
+	}
+
+	for k := range programsGroup {
+		fmt.Println(k)
+	}
+
+	return nil
+}
+
+func listOutputsFromMap(log *logger.Logger, cfg map[string]interface{}) error {
+	c, err := config.NewConfigFrom(cfg)
+	if err != nil {
+		return err
+	}
+
+	return listOutputsFromConfig(log, c)
+}
+
+func (c *IntrospectOutputCmd) introspectOutput() error {
+	cfg, err := loadConfig(c.cfgPath)
+	if err != nil {
+		return err
+	}
+
+	l, err := newErrorLogger()
+	if err != nil {
+		return err
+	}
+
+	isLocal, err := isLocalMode(cfg)
+	if err != nil {
+		return err
+	}
+
+	if isLocal {
+		return printOutputFromConfig(l, c.output, c.program, cfg)
+	}
+
+	fleetConfig, err := loadFleetConfig(cfg)
+	if err != nil {
+		return err
+	} else if fleetConfig == nil {
+		return errors.New("no fleet config retrieved yet")
+	}
+
+	return printOutputFromMap(l, c.output, c.program, fleetConfig)
+}
+
+func printOutputFromConfig(log *logger.Logger, output, programName string, cfg *config.Config) error {
+	programsGroup, err := getProgramsFromConfig(log, cfg)
+	if err != nil {
+		return err
+
+	}
+
+	for k, programs := range programsGroup {
+		if k != output {
+			continue
+		}
+
+		var programFound bool
+		for _, p := range programs {
+			if programName != "" && programName != p.Spec.Cmd {
+				continue
+			}
+
+			programFound = true
+			fmt.Printf("[%s] %s:\n", k, p.Spec.Cmd)
+			printMapStringConfig(p.Configuration())
+			fmt.Println("---")
+		}
+
+		if !programFound {
+			fmt.Printf("program '%s' is not recognized within output '%s', try running `elastic-agent introspect output` to find available outputs.\n",
+				programName,
+				output)
+		}
+		return nil
+	}
+
+	fmt.Printf("output '%s' is not recognized, try running `elastic-agent introspect output` to find available outputs.\n", output)
+
+	return nil
+}
+
+func printOutputFromMap(log *logger.Logger, output, programName string, cfg map[string]interface{}) error {
+	c, err := config.NewConfigFrom(cfg)
+	if err != nil {
+		return err
+	}
+
+	return printOutputFromConfig(log, output, programName, c)
+}
+
+func getProgramsFromConfig(log *logger.Logger, cfg *config.Config) (map[string][]program.Program, error) {
+	monitor := noop.NewMonitor()
+	router := &inmemRouter{}
+	emit := emitter(
+		log,
+		router,
+		&configModifiers{
+			Decorators: []decoratorFunc{injectMonitoring},
+			Filters:    []filterFunc{filters.ConstraintFilter},
+		},
+		monitor,
+	)
+
+	if err := emit(cfg); err != nil {
+		return nil, err
+	}
+	return router.programs, nil
+}
+
+type inmemRouter struct {
+	programs map[string][]program.Program
+}
+
+func (r *inmemRouter) Dispatch(id string, grpProg map[routingKey][]program.Program) error {
+	r.programs = grpProg
+	return nil
+}
+
+func newErrorLogger() (*logger.Logger, error) {
+	backend, err := appender.Console(backend.Error, layout.Text(true))
+	if err != nil {
+		return nil, err
+	}
+	return ecslog.New(backend), nil
+}

x-pack/elastic-agent/pkg/agent/cmd/common.go

@@ -61,6 +61,7 @@ func NewCommandWithArgs(args []string, streams *cli.IOStreams) *cobra.Command {
 	cmd.AddCommand(basecmd.NewDefaultCommandsWithArgs(args, streams)...)
 	cmd.AddCommand(newRunCommandWithArgs(flags, args, streams))
 	cmd.AddCommand(newEnrollCommandWithArgs(flags, args, streams))
+	cmd.AddCommand(newIntrospectCommandWithArgs(flags, args, streams))
 
 	return cmd
 }