Support Elastic Agent complete wolfi image (#2115)

Update the Elastic Agent complete image used starting in
Elastic stack versions 8.16.0-SNAPSHOT. Starting with that
stack version, complete Elastic Agent image would be based
on wolfi.

internal/install/application_configuration.go

@@ -32,6 +32,7 @@ const (
 	elasticAgentImageName               = "docker.elastic.co/elastic-agent/elastic-agent"
 	elasticAgentCompleteLegacyImageName = "docker.elastic.co/beats/elastic-agent-complete"
 	elasticAgentCompleteImageName       = "docker.elastic.co/elastic-agent/elastic-agent-complete"
+	elasticAgentCompleteWolfiImageName  = "docker.elastic.co/elastic-agent/elastic-agent-complete-wolfi"
 	elasticAgentWolfiImageName          = "docker.elastic.co/elastic-agent/elastic-agent-wolfi"
 	elasticsearchImageName              = "docker.elastic.co/elasticsearch/elasticsearch"
 	kibanaImageName                     = "docker.elastic.co/kibana/kibana"
@@ -162,26 +163,34 @@ func selectElasticAgentImageName(version, agentBaseImage string) string {
 		return elasticAgentWolfiImageName
 	}
 
-	disableWolfiImages := false
-	valueEnv, ok := os.LookupEnv(disableElasticAgentWolfiEnvVar)
-	if ok && strings.ToLower(valueEnv) != "false" {
-		disableWolfiImages = true
-	}
-	switch {
-	case agentBaseImage == "complete":
-		return selectElasticAgentCompleteImageName(v)
-	case agentBaseImage == "systemd":
+	shouldUseWolfiImage := shouldUseWolfiImages(v)
+
+	switch agentBaseImage {
+	case "systemd":
 		return selectElasticAgentSystemDImageName(v)
+	case "complete":
+		if shouldUseWolfiImage {
+			return elasticAgentCompleteWolfiImageName
+		}
+		return selectElasticAgentCompleteImageName(v)
 	default:
-		switch {
-		case !disableWolfiImages && !v.LessThan(elasticAgentWolfiVersion):
+		if shouldUseWolfiImage {
 			return elasticAgentWolfiImageName
-		default:
-			return selectElasticAgentCompleteImageName(v)
 		}
+		return selectElasticAgentCompleteImageName(v)
 	}
 }
 
+func shouldUseWolfiImages(version *semver.Version) bool {
+	disableWolfiImages := false
+	valueEnv, ok := os.LookupEnv(disableElasticAgentWolfiEnvVar)
+	if ok && strings.ToLower(valueEnv) != "false" {
+		disableWolfiImages = true
+	}
+
+	return !disableWolfiImages && !version.LessThan(elasticAgentWolfiVersion)
+}
+
 func selectElasticAgentCompleteImageName(version *semver.Version) string {
 	switch {
 	case !version.LessThan(elasticAgentCompleteOwnNamespaceVersion):

internal/install/application_configuration_test.go

@@ -76,12 +76,18 @@ func TestSelectElasticAgentImageName_EnableWolfiImageEnvVar(t *testing.T) {
 	assert.Equal(t, elasticAgentWolfiImageName, selected)
 }
 
-func TestSelectCompleteElasticAgentImageName_ForceCompleteImage(t *testing.T) {
-	version := stackVersion8160
+func TestSelectCompleteElasticAgentImageName_ForceCompleteImage_NonWolfi(t *testing.T) {
+	version := "8.15.0"
 	selected := selectElasticAgentImageName(version, "complete")
 	assert.Equal(t, elasticAgentCompleteImageName, selected)
 }
 
+func TestSelectCompleteElasticAgentImageName_ForceCompleteImage_Wolfi(t *testing.T) {
+	version := stackVersion8160
+	selected := selectElasticAgentImageName(version, "complete")
+	assert.Equal(t, elasticAgentCompleteWolfiImageName, selected)
+}
+
 func TestSelectCompleteElasticAgentImageName_ForceDefaultImage_DisabledEnvVar(t *testing.T) {
 	version := stackVersion8160
 	t.Setenv(disableElasticAgentWolfiEnvVar, "true")