image: support compression on all live image types

Apply "xz" compression to any artifact pipeline if it's specified in the
image type.  The image filename should be applied to the pipeline only
if it's the last one, so we need to skip this assignment if we're going
to add a compression pipeline at the end.

This is a bit dirty but the plan is to remove artifact compression from
manifests and perform it during the export in osbuild-composer, so this
should go away soon.

internal/image/live.go

@@ -46,33 +46,46 @@ func (img *LiveImage) InstantiateManifest(m *manifest.Manifest,
 	imagePipeline := manifest.NewRawImage(m, buildPipeline, osPipeline)
 
 	var artifact *artifact.Artifact
+	var artifactPipeline manifest.Pipeline
 	switch img.Platform.GetImageFormat() {
 	case platform.FORMAT_RAW:
-		switch img.Compression {
-		case "xz":
-			xzPipeline := manifest.NewXZ(m, buildPipeline, imagePipeline)
-			xzPipeline.Filename = img.Filename
-			artifact = xzPipeline.Export()
-		default:
+		if img.Compression == "" {
 			imagePipeline.Filename = img.Filename
-			artifact = imagePipeline.Export()
 		}
+		artifactPipeline = imagePipeline
+		artifact = imagePipeline.Export()
 	case platform.FORMAT_QCOW2:
 		qcow2Pipeline := manifest.NewQCOW2(m, buildPipeline, imagePipeline)
-		qcow2Pipeline.Filename = img.Filename
+		if img.Compression == "" {
+			qcow2Pipeline.Filename = img.Filename
+		}
 		qcow2Pipeline.Compat = img.Platform.GetQCOW2Compat()
+		artifactPipeline = qcow2Pipeline
 		artifact = qcow2Pipeline.Export()
 	case platform.FORMAT_VHD:
 		vpcPipeline := manifest.NewVPC(m, buildPipeline, imagePipeline)
-		vpcPipeline.Filename = img.Filename
+		if img.Compression == "" {
+			vpcPipeline.Filename = img.Filename
+		}
+		artifactPipeline = vpcPipeline
 		artifact = vpcPipeline.Export()
 	case platform.FORMAT_VMDK:
 		vmdkPipeline := manifest.NewVMDK(m, buildPipeline, imagePipeline)
-		vmdkPipeline.Filename = img.Filename
+		if img.Compression == "" {
+			vmdkPipeline.Filename = img.Filename
+		}
+		artifactPipeline = vmdkPipeline
 		artifact = vmdkPipeline.Export()
 	default:
 		panic("invalid image format for image kind")
 	}
 
+	switch img.Compression {
+	case "xz":
+		xzPipeline := manifest.NewXZ(m, buildPipeline, artifactPipeline)
+		xzPipeline.Filename = img.Filename
+		artifact = xzPipeline.Export()
+	}
+
 	return artifact, nil
 }