distro/rhel86: imagetypes and packages per RHEL version

Added utility function for comparing RHEL version strings.

Conditions added:
- greenboot subpackages were changed between RHEL 8.5 and RHEL 8.6.
- fido client packages aren't available in RHEL prior to 8.6.
- the ec2 SAP image type is not supported in RHEL prior to 8.6.
- the edge-simplified-installer and edge-raw-image image types are not
  supported in RHEL prior to 8.6.
    - They were previously supported in 8.5 without FDO support, but now
      it's dropped from 8.5 completely.

internal/distro/rhel86/distro.go

@@ -18,6 +18,36 @@ import (
 	"github.com/osbuild/osbuild-composer/internal/rpmmd"
 )
 
+// Returns true if the version represented by the first argument is
+// semantically older than the second.
+// Meant to be used for comparing RHEL versions for differences between minor
+// releases.
+// Evaluates to false if a and b are equal.
+// Assumes any missing components are 0, so 8 < 8.1.
+func versionLessThan(a, b string) bool {
+	aParts := strings.Split(a, ".")
+	bParts := strings.Split(b, ".")
+
+	// pad shortest argument with zeroes
+	for len(aParts) < len(bParts) {
+		aParts = append(aParts, "0")
+	}
+	for len(bParts) < len(aParts) {
+		bParts = append(bParts, "0")
+	}
+
+	for idx := 0; idx < len(aParts); idx++ {
+		if aParts[idx] < bParts[idx] {
+			return true
+		} else if aParts[idx] > bParts[idx] {
+			return false
+		}
+	}
+
+	// equal
+	return false
+}
+
 const (
 	// package set names
 
@@ -1762,8 +1792,6 @@ func newDistro(distroName string) distro.Distro {
 		edgeCommitImgType,
 		edgeInstallerImgType,
 		edgeOCIImgType,
-		edgeRawImgType,
-		edgeSimplifiedInstallerImgType,
 		gceImgType,
 		imageInstaller,
 		ociImgType,
@@ -1779,8 +1807,6 @@ func newDistro(distroName string) distro.Distro {
 		edgeCommitImgType,
 		edgeInstallerImgType,
 		edgeOCIImgType,
-		edgeRawImgType,
-		edgeSimplifiedInstallerImgType,
 		imageInstaller,
 		openstackImgType,
 		qcow2ImgType,
@@ -1802,7 +1828,15 @@ func newDistro(distroName string) distro.Distro {
 		x86_64.addImageTypes(azureRhuiImgType)
 
 		// add ec2 image types to RHEL distro only
-		x86_64.addImageTypes(ec2ImgTypeX86_64, ec2HaImgTypeX86_64, ec2SapImgTypeX86_64)
+		x86_64.addImageTypes(ec2ImgTypeX86_64, ec2HaImgTypeX86_64)
+		if !versionLessThan(rd.osVersion, "8.6") {
+			x86_64.addImageTypes(ec2SapImgTypeX86_64)
+
+			// edge simplified installer is only available on 8.6 and later on RHEL
+			x86_64.addImageTypes(edgeSimplifiedInstallerImgType, edgeRawImgType)
+			aarch64.addImageTypes(edgeSimplifiedInstallerImgType, edgeRawImgType)
+		}
+
 		aarch64.addImageTypes(ec2ImgTypeAarch64)
 
 		// add GCE RHUI image to RHEL only
@@ -1810,6 +1844,9 @@ func newDistro(distroName string) distro.Distro {
 
 		// add s390x to RHEL distro only
 		rd.addArches(s390x)
+	} else {
+		x86_64.addImageTypes(edgeSimplifiedInstallerImgType, edgeRawImgType)
+		aarch64.addImageTypes(edgeSimplifiedInstallerImgType, edgeRawImgType)
 	}
 	rd.addArches(x86_64, aarch64, ppc64le)
 	return &rd

internal/distro/rhel86/package_sets.go

@@ -760,7 +760,6 @@ func edgeCommitPackageSet(t *imageType) rpmmd.PackageSet {
 			"glibc-minimal-langpack",
 			"gnupg2",
 			"greenboot",
-			"greenboot-default-health-checks",
 			"gzip",
 			"hostname",
 			"ima-evm-utils",
@@ -806,9 +805,6 @@ func edgeCommitPackageSet(t *imageType) rpmmd.PackageSet {
 			"vim-minimal",
 			"wpa_supplicant",
 			"xz",
-
-			"fdo-client",
-			"fdo-owner-cli",
 		},
 		Exclude: []string{"rng-tools"},
 	}
@@ -823,6 +819,26 @@ func edgeCommitPackageSet(t *imageType) rpmmd.PackageSet {
 		ps = ps.Append(aarch64EdgeCommitPackageSet(t))
 	}
 
+	if t.arch.distro.isRHEL() && versionLessThan(t.arch.distro.osVersion, "8.6") {
+		ps = ps.Append(rpmmd.PackageSet{
+			Include: []string{
+				"greenboot-grub2",
+				"greenboot-reboot",
+				"greenboot-rpm-ostree-grub2",
+				"greenboot-status",
+			},
+		})
+	} else {
+		// 8.6+ and CS8
+		ps = ps.Append(rpmmd.PackageSet{
+			Include: []string{
+				"fdo-client",
+				"fdo-owner-cli",
+				"greenboot-default-health-checks",
+			},
+		})
+	}
+
 	return ps
 
 }