feat(compose/agent): add stack.agent.ports option in config.yml to publish ports for agent

Author: pkoutsovasilis

internal/profile/_static/config.yml.example

@@ -18,3 +18,8 @@
 # Flag to enable logstash in elastic-package stack profile config
 # stack.logstash_enabled: true
 
+## Specify agent ports to publish
+## port definition schema https://docs.docker.com/compose/compose-file/compose-file-v2/#ports
+# stack.agent.ports:
+# - 127.0.0.1:1514:1514/udp
+

internal/profile/config.go

@@ -5,6 +5,7 @@
 package profile
 
 import (
+	"encoding/json"
 	"errors"
 	"fmt"
 	"os"
@@ -48,3 +49,24 @@ func (c *config) get(name string) (string, bool) {
 		return fmt.Sprintf("%v", v), true
 	}
 }
+
+func (c *config) Unmarshal(name string, out any) error {
+	v, err := c.settings.GetValue(name)
+	if err != nil {
+		if errors.Is(err, common.ErrKeyNotFound) {
+			return nil
+		}
+		return err
+	}
+
+	data, err := json.Marshal(v)
+	if err != nil {
+		return err
+	}
+
+	if err := json.Unmarshal(data, out); err != nil {
+		return err
+	}
+
+	return nil
+}

internal/profile/profile.go

@@ -141,13 +141,13 @@ type Profile struct {
 }
 
 // Path returns an absolute path to the given file
-func (profile Profile) Path(names ...string) string {
+func (profile *Profile) Path(names ...string) string {
 	elems := append([]string{profile.ProfilePath}, names...)
 	return filepath.Join(elems...)
 }
 
 // Config returns a configuration setting, or its default if setting not found
-func (profile Profile) Config(name string, def string) string {
+func (profile *Profile) Config(name string, def string) string {
 	v, found := profile.overrides[name]
 	if found {
 		return v
@@ -161,6 +161,10 @@ func (profile Profile) Config(name string, def string) string {
 	return def
 }
 
+func (profile *Profile) Unmarshal(name string, dst any) error {
+	return profile.config.Unmarshal(name, dst)
+}
+
 // RuntimeOverrides defines configuration overrides for the current session.
 func (profile *Profile) RuntimeOverrides(overrides map[string]string) {
 	profile.overrides = overrides
@@ -171,7 +175,7 @@ var ErrNotAProfile = errors.New("not a profile")
 
 // ComposeEnvVars returns a list of environment variables that can be passed
 // to docker-compose for the sake of filling out paths and names in the snapshot.yml file.
-func (profile Profile) ComposeEnvVars() []string {
+func (profile *Profile) ComposeEnvVars() []string {
 	return []string{
 		fmt.Sprintf("PROFILE_NAME=%s", profile.ProfileName),
 	}

internal/stack/_static/docker-compose-stack.yml.tmpl

@@ -139,6 +139,9 @@ services:
       interval: 5s
     hostname: docker-fleet-agent
     env_file: "./elastic-agent.env"
+    {{- if eq (fact "agent_has_publish_ports") "true" }}
+    ports: {{ fact "agent_publish_ports" }}
+    {{- end }}
     volumes:
     - "../certs/ca-cert.pem:/etc/ssl/certs/elastic-package.pem"
     - type: bind

internal/stack/resources.go

@@ -135,7 +135,7 @@ func applyResources(profile *profile.Profile, stackVersion string) error {
 	stackDir := filepath.Join(profile.ProfilePath, ProfileStackPath)
 
 	resourceManager := resource.NewManager()
-	resourceManager.AddFacter(resource.StaticFacter{
+	facter := resource.StaticFacter{
 		"registry_base_image":   PackageRegistryBaseImage,
 		"elasticsearch_version": stackVersion,
 		"kibana_version":        stackVersion,
@@ -152,9 +152,25 @@ func applyResources(profile *profile.Profile, stackVersion string) error {
 		"geoip_dir":            profile.Config(configGeoIPDir, "./ingest-geoip"),
 		"logstash_enabled":     profile.Config(configLogstashEnabled, "false"),
 		"self_monitor_enabled": profile.Config(configSelfMonitorEnabled, "false"),
-	})
+	}
+
+	var agentPorts []string
+	if err := profile.Unmarshal("stack.agent.ports", &agentPorts); err != nil {
+		return fmt.Errorf("failed to unmarshal stack.agent.ports: %w", err)
+	}
 
-	os.MkdirAll(stackDir, 0755)
+	if len(agentPorts) > 0 {
+		facter["agent_has_publish_ports"] = "true"
+		facter["agent_publish_ports"] = fmt.Sprintf("[%s]", strings.Join(agentPorts, ","))
+	} else {
+		facter["agent_has_publish_ports"] = "false"
+	}
+
+	resourceManager.AddFacter(facter)
+
+	if err := os.MkdirAll(stackDir, 0755); err != nil {
+		return fmt.Errorf("failed to create stack directory: %w", err)
+	}
 	resourceManager.RegisterProvider("file", &resource.FileProvider{
 		Prefix: stackDir,
 	})