[Agent] Enable post install hooks

go.sum

@@ -215,6 +215,7 @@ github.com/eapache/queue v1.1.0 h1:YOEu7KNc61ntiQlcEeUIoDTJ2o8mQznoNvUhiigpIqc=
 github.com/eapache/queue v1.1.0/go.mod h1:6eCeP0CKFpHLu8blIFXhExK/dRa7WDZfr6jVFPTqq+I=
 github.com/eclipse/paho.mqtt.golang v1.2.1-0.20200121105743-0d940dd29fd2 h1:DW6WrARxK5J+o8uAKCiACi5wy9EK1UzrsCpGBPsKHAA=
 github.com/eclipse/paho.mqtt.golang v1.2.1-0.20200121105743-0d940dd29fd2/go.mod h1:H9keYFcgq3Qr5OUJm/JZI/i6U7joQ8SYLhZwfeOo6Ts=
+github.com/elastic/beats v7.6.1+incompatible h1:4iPVpFr8BSJW2fUVi+/tYXQ4v/IYVx0k2PPLTg8cfks=
 github.com/elastic/dhcp v0.0.0-20200227161230-57ec251c7eb3 h1:lnDkqiRFKm0rxdljqrj3lotWinO9+jFmeDXIC4gvIQs=
 github.com/elastic/dhcp v0.0.0-20200227161230-57ec251c7eb3/go.mod h1:aPqzac6AYkipvp4hufTyMj5PDIphF3+At8zr7r51xjY=
 github.com/elastic/ecs v1.5.0 h1:/VEIBsRU4ecq2+U3RPfKNc6bFyomP6qnthYEcQZu8GU=

x-pack/agent/CHANGELOG.asciidoc

@@ -19,3 +19,4 @@
 
 - Generate index name in a format type-dataset-namespace {pull}16903[16903]
 - OS agnostic default configuration {pull}17016[17016]
+- Introduced post install hooks {pull}17241[17241]

x-pack/agent/pkg/agent/program/spec.go

@@ -27,12 +27,13 @@ var ErrMissingWhen = errors.New("program must define a 'When' expression")
 // NOTE: Current spec are build at compile time, we want to revisit that to allow other program
 // to register their spec in a secure way.
 type Spec struct {
-	Name         string               `yaml:"name"`
-	Cmd          string               `yaml:"cmd"`
-	Configurable string               `yaml:"configurable"`
-	Args         []string             `yaml:"args"`
-	Rules        *transpiler.RuleList `yaml:"rules"`
-	When         string               `yaml:"when"`
+	Name             string               `yaml:"name"`
+	Cmd              string               `yaml:"cmd"`
+	Configurable     string               `yaml:"configurable"`
+	Args             []string             `yaml:"args"`
+	Rules            *transpiler.RuleList `yaml:"rules"`
+	PostInstallSteps *transpiler.StepList `yaml:"post_install"`
+	When             string               `yaml:"when"`
 }
 
 // ReadSpecs reads all the specs that match the provided globbing path.

x-pack/agent/pkg/agent/transpiler/rules.go

@@ -85,7 +85,7 @@ func (r *RuleList) MarshalYAML() (interface{}, error) {
 	return doc, nil
 }
 
-// UnmarshalYAML unmashal a YAML document into a RuleList.
+// UnmarshalYAML unmarshal a YAML document into a RuleList.
 func (r *RuleList) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	var unpackTo []map[string]interface{}
 

x-pack/agent/pkg/agent/transpiler/steps.go

@@ -0,0 +1,185 @@
+// 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 transpiler
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/pkg/errors"
+	"gopkg.in/yaml.v2"
+)
+
+// StepList is a container that allow the same tree to be executed on multiple defined Step.
+type StepList struct {
+	Steps []Step
+}
+
+// Step is an execution step which needs to be run.
+type Step interface {
+	Execute(rootDir string) error
+}
+
+// Execute executes a list of steps.
+func (r *StepList) Execute(rootDir string) error {
+	var err error
+	for _, step := range r.Steps {
+		err = step.Execute(rootDir)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// MarshalYAML marsharl a steps list to YAML.
+func (r *StepList) MarshalYAML() (interface{}, error) {
+	doc := make([]map[string]Step, 0, len(r.Steps))
+
+	for _, step := range r.Steps {
+		var name string
+		switch step.(type) {
+		case *DeleteFileStep:
+			name = "delete_file"
+		case *MoveFileStep:
+			name = "move_file"
+
+		default:
+			return nil, fmt.Errorf("unknown rule of type %T", step)
+		}
+
+		subdoc := map[string]Step{
+			name: step,
+		}
+
+		doc = append(doc, subdoc)
+	}
+	return doc, nil
+}
+
+// UnmarshalYAML unmarshal a YAML document into a RuleList.
+func (r *StepList) UnmarshalYAML(unmarshal func(interface{}) error) error {
+	var unpackTo []map[string]interface{}
+
+	err := unmarshal(&unpackTo)
+	if err != nil {
+		return err
+	}
+
+	// NOTE(ph): this is a bit of a hack because I want to make sure
+	// the unpack strategy stay in the struct implementation and yaml
+	// doesn't have a RawMessage similar to the JSON package, so partial unpack
+	// is not possible.
+	unpack := func(in interface{}, out interface{}) error {
+		b, err := yaml.Marshal(in)
+		if err != nil {
+			return err
+		}
+		fmt.Println(string(b))
+		return errors.Wrap(yaml.Unmarshal(b, out), "ajaj")
+	}
+
+	var steps []Step
+
+	for _, m := range unpackTo {
+		ks := keys(m)
+		if len(ks) > 1 {
+			return fmt.Errorf("unknown rule identifier, expecting one identifier and received %d", len(ks))
+		}
+
+		name := ks[0]
+		fields := m[name]
+
+		var s Step
+		switch name {
+		case "delete_file":
+			s = &DeleteFileStep{}
+		case "move_file":
+			s = &MoveFileStep{}
+		default:
+			return fmt.Errorf("unknown rule of type %s", name)
+		}
+
+		if err := unpack(fields, s); err != nil {
+			return err
+		}
+
+		steps = append(steps, s)
+	}
+	r.Steps = steps
+	return nil
+}
+
+// DeleteFileStep removes a file from disk.
+type DeleteFileStep struct {
+	Path string
+	// FailOnMissing fails if file is already missing
+	FailOnMissing bool
+}
+
+// Execute executes delete file step.
+func (r *DeleteFileStep) Execute(rootDir string) error {
+	path := filepath.Join(rootDir, filepath.FromSlash(r.Path))
+	err := os.Remove(path)
+
+	if os.IsNotExist(err) && r.FailOnMissing {
+		// is not found and should be reported
+		return err
+	}
+
+	if err != nil && !os.IsNotExist(err) {
+		// report others
+		return err
+	}
+
+	return nil
+}
+
+// DeleteFile creates a DeleteFileStep
+func DeleteFile(path string, failOnMissing bool) *DeleteFileStep {
+	return &DeleteFileStep{
+		Path:          path,
+		FailOnMissing: failOnMissing,
+	}
+}
+
+// MoveFileStep moves a file to a new location.
+type MoveFileStep struct {
+	Path   string
+	Target string
+	// FailOnMissing fails if file is already missing
+	FailOnMissing bool `yaml:"fail_on_missing" config:"fail_on_missing"`
+}
+
+// Execute executes move file step.
+func (r *MoveFileStep) Execute(rootDir string) error {
+	path := filepath.Join(rootDir, filepath.FromSlash(r.Path))
+	target := filepath.Join(rootDir, filepath.FromSlash(r.Target))
+
+	err := os.Rename(path, target)
+
+	if os.IsNotExist(err) && r.FailOnMissing {
+		// is not found and should be reported
+		return err
+	}
+
+	if err != nil && !os.IsNotExist(err) {
+		// report others
+		return err
+	}
+
+	return nil
+}
+
+// MoveFile creates a MoveFileStep
+func MoveFile(path, target string, failOnMissing bool) *MoveFileStep {
+	return &MoveFileStep{
+		Path:          path,
+		Target:        target,
+		FailOnMissing: failOnMissing,
+	}
+}

x-pack/agent/pkg/artifact/install/hooks/hooks_installer.go

@@ -0,0 +1,57 @@
+// 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 hooks
+
+import (
+	"strings"
+
+	"github.com/elastic/beats/v7/x-pack/agent/pkg/agent/program"
+)
+
+type embeddedInstaller interface {
+	Install(programName, version, installDir string) error
+}
+
+// Installer or zip packages
+type Installer struct {
+	installer embeddedInstaller
+}
+
+// NewInstaller creates an installer able to install zip packages
+func NewInstaller(i embeddedInstaller) (*Installer, error) {
+	return &Installer{
+		installer: i,
+	}, nil
+}
+
+// Install performs installation of program in a specific version.
+// It expects package to be already downloaded.
+func (i *Installer) Install(programName, version, installDir string) error {
+	if err := i.installer.Install(programName, version, installDir); err != nil {
+		return err
+	}
+
+	// post install hooks
+	nameLower := strings.ToLower(programName)
+	_, isSupported := program.SupportedMap[nameLower]
+	if !isSupported {
+		return nil
+	}
+
+	for _, spec := range program.Supported {
+		if strings.ToLower(spec.Name) != nameLower {
+			continue
+		}
+
+		if spec.PostInstallSteps != nil {
+			return spec.PostInstallSteps.Execute(installDir)
+		}
+
+		// only one spec for type
+		break
+	}
+
+	return nil
+}

x-pack/agent/pkg/artifact/install/installer.go

@@ -9,6 +9,7 @@ import (
 	"runtime"
 
 	"github.com/elastic/beats/v7/x-pack/agent/pkg/artifact"
+	"github.com/elastic/beats/v7/x-pack/agent/pkg/artifact/install/hooks"
 	"github.com/elastic/beats/v7/x-pack/agent/pkg/artifact/install/tar"
 	"github.com/elastic/beats/v7/x-pack/agent/pkg/artifact/install/zip"
 )
@@ -36,9 +37,17 @@ func NewInstaller(config *artifact.Config) (Installer, error) {
 		return nil, ErrConfigNotProvided
 	}
 
+	var installer Installer
+	var err error
 	if runtime.GOOS == "windows" {
-		return zip.NewInstaller(config)
+		installer, err = zip.NewInstaller(config)
+	} else {
+		installer, err = tar.NewInstaller(config)
 	}
 
-	return tar.NewInstaller(config)
+	if err != nil {
+		return nil, err
+	}
+
+	return hooks.NewInstaller(installer)
 }

x-pack/agent/spec/metricbeat.yml

@@ -2,6 +2,10 @@ name: Metricbeat
 cmd: metricbeat
 args: ["-E", "setup.ilm.enabled=false", "-E", "setup.template.enabled=false", "-E", "management.mode=x-pack-fleet", "-E", "management.enabled=true"]
 configurable: grpc
+post_install:
+  - move_file:
+      path: "modules.d/system.yml"
+      target: "modules.d/system.yml.disabled"
 rules:
 - inject_index:
     type: metrics