Fetch machine identity fewer times

`resource.OS` was fetching `Name` and `Version` which were never used.
`os.OS.IDs()` was fetching UUIDs again, even though they had just been fetched.
Remove the code that implemented this, and a test that relied on it.

pkg/apis/wksprovider/machine/os/os.go

@@ -82,22 +82,13 @@ type Identifiers struct {
 	SystemUUID string
 }
 
-// IDs returns this machine's ID (see also OS#GetMachineID) and system UUID (see
-// also: OS#GetSystemUUID).
+// IDs returns this machine's ID system UUID.
 func (o OS) IDs() (*Identifiers, error) {
 	osres, err := resource.NewOS(o.runner)
 	if err != nil {
 		return nil, err
 	}
-	machineID, err := osres.GetMachineID(o.runner)
-	if err != nil {
-		return nil, errors.Wrapf(err, "failed to read machine's ID")
-	}
-	systemUUID, err := osres.GetSystemUUID(o.runner)
-	if err != nil {
-		return nil, errors.Wrapf(err, "failed to read machine's system UUID")
-	}
-	return &Identifiers{MachineID: machineID, SystemUUID: systemUUID}, nil
+	return &Identifiers{MachineID: osres.MachineID, SystemUUID: osres.SystemUUID}, nil
 }
 
 type crdFile struct {

pkg/plan/resource/os.go

@@ -12,16 +12,6 @@ import (
 
 // OS is a set of OS properties.
 type OS struct {
-
-	// Name is the OS name, eg. 'centos' or 'debian'. On systemd OSes, this is the ID
-	// field of /etc/os-release. See:
-	//   https://www.freedesktop.org/software/systemd/man/os-release.html
-	Name string `structs:"Name"`
-
-	// Version the OS version. On systemd OSes, this is the VERSION_ID field of
-	// /etc/os-release. See:
-	//   https://www.freedesktop.org/software/systemd/man/os-release.html
-	Version    string `structs:"Version"`
 	MachineID  string `structs:"MachineID"`
 	SystemUUID string `structs:"SystemUUID"`
 
@@ -124,7 +114,6 @@ func (p *OS) State() plan.State {
 }
 
 var gatherFuncs []GatherFactFunc = []GatherFactFunc{
-	getOSRelease,
 	getMachineID,
 	getSystemUUID,
 }
@@ -170,26 +159,6 @@ func (p *OS) Undo(r plan.Runner, current plan.State) error {
 	return nil
 }
 
-func getOSRelease(p *OS, r plan.Runner) error {
-	output, err := r.RunCommand("cat /etc/os-release", nil)
-	if err != nil {
-		return err
-	}
-	name := keyval(output, "ID")
-	if name == "" {
-		return fmt.Errorf("os: getOSRelease: could not query ID from output %s\n", output)
-	}
-	err = reflections.SetField(p, "Name", name)
-	if err != nil {
-		return err
-	}
-	version := keyval(output, "VERSION_ID")
-	if version == "" {
-		return errors.New("os: getOSRelease: could not query VERSION_ID")
-	}
-	return reflections.SetField(p, "Version", version)
-}
-
 func (p *OS) HasCommand(cmd string) (bool, error) {
 	// http://stackoverflow.com/questions/592620/how-to-check-if-a-program-exists-from-a-bash-script
 	_, err := p.runner.RunCommand(fmt.Sprintf("command -v -- %q >/dev/null 2>&1", cmd), nil)
@@ -253,34 +222,10 @@ func (p *OS) IsOSInContainerVM() (bool, error) {
 	return strings.Contains(output, "container=docker"), err
 }
 
-func (p *OS) GetMachineID(r plan.Runner) (string, error) {
-	err := getMachineID(p, r)
-	if err != nil {
-		return "", err
-	}
-	id, err := p.State().GetString("MachineID")
-	if err != nil {
-		return "", err
-	}
-	return id, nil
-}
-
 func getMachineID(p *OS, r plan.Runner) error {
 	return p.getValueFromFileContents(machineIDParams, r)
 }
 
-func (p *OS) GetSystemUUID(r plan.Runner) (string, error) {
-	err := getSystemUUID(p, r)
-	if err != nil {
-		return "", err
-	}
-	id, err := p.State().GetString("SystemUUID")
-	if err != nil {
-		return "", err
-	}
-	return id, nil
-}
-
 func getSystemUUID(p *OS, r plan.Runner) error {
 	return p.getValueFromFileContents(sysUuidParams, r)
 }

pkg/utilities/envcfg/envcfg_test.go

@@ -258,22 +258,6 @@ func TestGetEnvSpecificConfig(t *testing.T) {
 			wantLockYUMPkgs:          false,
 			wantNamespace:            "foo",
 		},
-		{
-			name:    "os-release error",
-			pkgType: resource.PkgTypeRPM,
-			runner: &fakeRunner{
-				value: map[string]runnerResult{
-					cmdOsRel:             {out: relUbuntu, err: errors.New("kaboom")},
-					cmdEnv:               {},
-					cmdSELinuxFound:      {},
-					cmdMachineID:         {out: "01234567"},
-					cmdUUID:              {out: "01234567"},
-					cmdSELinuxPermissive: {},
-					cmdSELinuxEnforcing:  {},
-				},
-			},
-			wantError: true,
-		},
 		{
 			name:    "environ error",
 			pkgType: resource.PkgTypeRPM,