distro: add Distro.Name()

Right now, there is no way to get at the name from a Distro instance.
We will need this to include the distro's name in the job we pass to the
worker, for instance.

internal/distro/distro.go

@@ -16,6 +16,10 @@ import (
 )
 
 type Distro interface {
+	// Returns the name of the distro. This is the same name that was
+	// passed to New().
+	Name() string
+
 	// Returns a list of repositories from which this distribution gets its
 	// content.
 	Repositories(arch string) []rpmmd.RepoConfig
@@ -40,8 +44,8 @@ var registered map[string]Distro
 
 func init() {
 	registered = map[string]Distro{
-		"fedora-30": fedora30.New(),
-		"rhel-8.2":  rhel82.New(),
+		fedora30.Name: fedora30.New(),
+		rhel82.Name:   rhel82.New(),
 	}
 }
 

internal/distro/fedora30/distro.go

@@ -37,6 +37,8 @@ type output struct {
 	Assembler        func(uefi bool) *pipeline.Assembler
 }
 
+const Name = "fedora-30"
+
 func New() *Fedora30 {
 	r := Fedora30{
 		arches:  map[string]arch{},
@@ -240,6 +242,10 @@ func New() *Fedora30 {
 	return &r
 }
 
+func (r *Fedora30) Name() string {
+	return Name
+}
+
 func (r *Fedora30) Repositories(arch string) []rpmmd.RepoConfig {
 	return []rpmmd.RepoConfig{
 		{

internal/distro/rhel82/distro.go

@@ -38,6 +38,8 @@ type output struct {
 	Assembler        func(uefi bool) *pipeline.Assembler
 }
 
+const Name = "rhel-8.2"
+
 func New() *RHEL82 {
 	const GigaByte = 1024 * 1024 * 1024
 
@@ -392,6 +394,10 @@ func New() *RHEL82 {
 	return &r
 }
 
+func (r *RHEL82) Name() string {
+	return Name
+}
+
 func (r *RHEL82) Repositories(arch string) []rpmmd.RepoConfig {
 	return []rpmmd.RepoConfig{
 		{

internal/distro/test/distro.go

@@ -11,8 +11,14 @@ import (
 
 type TestDistro struct{}
 
+const Name = "test"
+
 func init() {
-	distro.Register("test", &TestDistro{})
+	distro.Register(Name, &TestDistro{})
+}
+
+func (d *TestDistro) Name() string {
+	return Name
 }
 
 func (d *TestDistro) Repositories(arch string) []rpmmd.RepoConfig {