chore: extract Attach elastic-agent installer to a struct method

e2e/_suites/fleet/fleet.go

@@ -85,7 +85,7 @@ func (fts *FleetTestSuite) afterScenario() {
 		if !fts.StandAlone {
 			// for the centos/debian flavour we need to retrieve the internal log files for the elastic-agent, as they are not
 			// exposed as container logs. For that reason we need to go through the installer abstraction
-			agentInstaller, _ := installer.Attach(fts.currentContext, fts.deployer, agentService, fts.InstallerType)
+			agentInstaller, _ := installer.NewElasticAgentDeployer(fts.deployer).AttachInstaller(fts.currentContext, agentService, fts.InstallerType)
 
 			if log.IsLevelEnabled(log.DebugLevel) {
 				err := agentInstaller.Logs(fts.currentContext)
@@ -362,7 +362,7 @@ func (fts *FleetTestSuite) anStaleAgentIsDeployedToFleetWithInstaller(version, i
 
 func (fts *FleetTestSuite) installCerts() error {
 	agentService := deploy.NewServiceRequest(common.ElasticAgentServiceName)
-	agentInstaller, _ := installer.Attach(fts.currentContext, fts.deployer, agentService, fts.InstallerType)
+	agentInstaller, _ := installer.NewElasticAgentDeployer(fts.deployer).AttachInstaller(fts.currentContext, agentService, fts.InstallerType)
 
 	err := agentInstaller.InstallCerts(fts.currentContext)
 	if err != nil {
@@ -536,7 +536,7 @@ func (fts *FleetTestSuite) anAgentIsDeployedToFleetWithInstallerAndFleetServer(i
 		return err
 	}
 
-	agentInstaller, _ := installer.Attach(fts.currentContext, fts.deployer, agentService, fts.InstallerType)
+	agentInstaller, _ := installer.NewElasticAgentDeployer(fts.deployer).AttachInstaller(fts.currentContext, agentService, fts.InstallerType)
 	err = deployAgentToFleet(fts.currentContext, agentInstaller, fts.CurrentToken)
 	if err != nil {
 		return err
@@ -546,7 +546,7 @@ func (fts *FleetTestSuite) anAgentIsDeployedToFleetWithInstallerAndFleetServer(i
 
 func (fts *FleetTestSuite) processStateChangedOnTheHost(process string, state string) error {
 	agentService := deploy.NewServiceRequest(common.ElasticAgentServiceName)
-	agentInstaller, _ := installer.Attach(fts.currentContext, fts.deployer, agentService, fts.InstallerType)
+	agentInstaller, _ := installer.NewElasticAgentDeployer(fts.deployer).AttachInstaller(fts.currentContext, agentService, fts.InstallerType)
 	if state == "started" {
 		err := agentInstaller.Start(fts.currentContext)
 		return err
@@ -836,7 +836,7 @@ func theAgentIsListedInFleetWithStatus(ctx context.Context, desiredStatus string
 
 func (fts *FleetTestSuite) theFileSystemAgentFolderIsEmpty() error {
 	agentService := deploy.NewServiceRequest(common.ElasticAgentServiceName)
-	agentInstaller, _ := installer.Attach(fts.currentContext, fts.deployer, agentService, fts.InstallerType)
+	agentInstaller, _ := installer.NewElasticAgentDeployer(fts.deployer).AttachInstaller(fts.currentContext, agentService, fts.InstallerType)
 
 	pkgManifest, _ := agentInstaller.Inspect()
 	cmd := []string{
@@ -946,7 +946,7 @@ func (fts *FleetTestSuite) theAgentIsReenrolledOnTheHost() error {
 	log.Trace("Re-enrolling the agent on the host with same token")
 
 	agentService := deploy.NewServiceRequest(common.ElasticAgentServiceName)
-	agentInstaller, _ := installer.Attach(fts.currentContext, fts.deployer, agentService, fts.InstallerType)
+	agentInstaller, _ := installer.NewElasticAgentDeployer(fts.deployer).AttachInstaller(fts.currentContext, agentService, fts.InstallerType)
 
 	err := agentInstaller.Enroll(fts.currentContext, fts.CurrentToken)
 	if err != nil {
@@ -1298,7 +1298,7 @@ func (fts *FleetTestSuite) anAttemptToEnrollANewAgentFails() error {
 		return err
 	}
 
-	agentInstaller, _ := installer.Attach(fts.currentContext, fts.deployer, agentService, fts.InstallerType)
+	agentInstaller, _ := installer.NewElasticAgentDeployer(fts.deployer).AttachInstaller(fts.currentContext, agentService, fts.InstallerType)
 	err = deployAgentToFleet(fts.currentContext, agentInstaller, fts.CurrentToken)
 
 	if err == nil {

e2e/_suites/fleet/stand-alone.go

@@ -98,7 +98,7 @@ func (fts *FleetTestSuite) startStandAloneAgent(image string, flavour string, en
 		// a. downloaded from the GCP bucket
 		// b. fetched from the local beats binaries
 		agentService := deploy.NewServiceRequest(common.ElasticAgentServiceName)
-		dockerInstaller, _ := installer.Attach(fts.currentContext, fts.deployer, agentService, "docker")
+		dockerInstaller, _ := installer.NewElasticAgentDeployer(fts.deployer).AttachInstaller(fts.currentContext, agentService, "docker")
 		dockerInstaller.Preinstall(fts.currentContext)
 
 		arch := types.Architectures[types.GetArchitecture()]

internal/installer/base.go

@@ -17,9 +17,21 @@ import (
 	"go.elastic.co/apm"
 )
 
-// Attach will attach a installer to a deployment allowing
+// ElasticAgentDeployer struct representing the deployer for an elastic-agent
+type ElasticAgentDeployer struct {
+	deployer deploy.Deployer
+}
+
+// NewElasticAgentDeployer retrives a new instance of the elastic-agent deployer
+func NewElasticAgentDeployer(deployer deploy.Deployer) ElasticAgentDeployer {
+	return ElasticAgentDeployer{
+		deployer: deployer,
+	}
+}
+
+// AttachInstaller will attach an Elastic Agent installer to a deployment allowing
 // the installation of a package to be transparently configured no matter the backend
-func Attach(ctx context.Context, deployer deploy.Deployer, service deploy.ServiceRequest, installType string) (deploy.ServiceOperator, error) {
+func (ead ElasticAgentDeployer) AttachInstaller(ctx context.Context, service deploy.ServiceRequest, installType string) (deploy.ServiceOperator, error) {
 	span, _ := apm.StartSpanOptions(ctx, "Attaching installer to host", "elastic-agent.installer.attach", apm.SpanOptions{
 		Parent: apm.SpanFromContext(ctx).TraceContext(),
 	})
@@ -30,6 +42,8 @@ func Attach(ctx context.Context, deployer deploy.Deployer, service deploy.Servic
 		"installType": installType,
 	}).Trace("Attaching service for configuration")
 
+	deployer := ead.deployer
+
 	if strings.EqualFold(service.Name, "elastic-agent") {
 		switch installType {
 		case "tar":