Merge pull request #72 from bcwaldon/unit-enable

Address unit enabling issues

Documentation/cloud-config.md

@@ -87,6 +87,7 @@ Arbitrary systemd units may be provided in the `coreos.units` attribute.
 
 - **name**: String representing unit's name. Required.
 - **runtime**: Boolean indicating whether or not to persist the unit across reboots. This is analagous to the `--runtime` argument to `systemd enable`. Default value is false.
+- **enable**: Boolean indicating whether or not to handle the [Install] section of the unit file. This is similar to running `systemctl enable <name>`. Default value is false.
 - **content**: Plaintext string representing entire unit file. If no value is provided, the unit is assumed to exist already.
 - **command**: Command to execute on unit: start, stop, reload, restart, try-restart, reload-or-restart, reload-or-try-restart. Default value is restart.
 

initialize/config.go

@@ -130,16 +130,17 @@ func Apply(cfg CloudConfig, env *Environment) error {
 
 	if len(cfg.Coreos.Units) > 0 {
 		commands := make(map[string]string, 0)
-
 		for _, unit := range cfg.Coreos.Units {
+			dst := system.UnitDestination(&unit, env.Root())
 			if unit.Content != "" {
-				log.Printf("Writing unit %s to filesystem", unit.Name)
+				log.Printf("Writing unit %s to filesystem at path %s", unit.Name, dst)
-				dst, err := system.PlaceUnit(&unit, env.Root())
+				if err := system.PlaceUnit(&unit, dst); err != nil {
-				if err != nil {
 					return err
 				}
 				log.Printf("Placed unit %s at %s", unit.Name, dst)
+			}
 
+			if unit.Enable {
 				if unit.Group() != "network" {
 					log.Printf("Enabling unit file %s", dst)
 					if err := system.EnableUnitFile(dst, unit.Runtime); err != nil {

system/systemd.go

@@ -19,6 +19,7 @@ const fakeMachineID = "42000000000000000000000000000042"
 
 type Unit struct {
 	Name    string
+	Enable  bool
 	Runtime bool
 	Content string
 	Command string
@@ -41,20 +42,27 @@ func (u *Unit) Group() (group string) {
 
 type Script []byte
 
-func PlaceUnit(u *Unit, root string) (string, error) {
+// UnitDestination builds the appropriate absolte file path for
+// the given unit. The root argument indicates the effective base
+// directory of the system (similar to a chroot).
+func UnitDestination(u *Unit, root string) string {
 	dir := "etc"
 	if u.Runtime {
 		dir = "run"
 	}
 
-	dst := path.Join(root, dir, "systemd", u.Group())
+	return path.Join(root, dir, "systemd", u.Group(), u.Name)
-	if _, err := os.Stat(dst); os.IsNotExist(err) {
-		if err := os.MkdirAll(dst, os.FileMode(0755)); err != nil {
-			return "", err
-		}
 }
 
-	dst = path.Join(dst, u.Name)
+// PlaceUnit writes a unit file at the provided destination, creating
+// parent directories as necessary.
+func PlaceUnit(u *Unit, dst string) error {
+	dir := filepath.Dir(dst)
+	if _, err := os.Stat(dir); os.IsNotExist(err) {
+		if err := os.MkdirAll(dir, os.FileMode(0755)); err != nil {
+			return err
+		}
+	}
 
 	file := File{
 		Path: dst,
@@ -64,10 +72,10 @@ func PlaceUnit(u *Unit, root string) (string, error) {
 
 	err := WriteFile(&file)
 	if err != nil {
-		return "", err
+		return err
 	}
 
-	return dst, nil
+	return nil
 }
 
 func EnableUnitFile(file string, runtime bool) error {

system/systemd_test.go

@@ -26,12 +26,17 @@ Address=10.209.171.177/19
 	}
 	defer syscall.Rmdir(dir)
 
-	if _, err := PlaceUnit(&u, dir); err != nil {
+	dst := UnitDestination(&u, dir)
+	expectDst := path.Join(dir, "run", "systemd", "network", "50-eth0.network")
+	if dst != expectDst {
+		t.Fatalf("UnitDestination returned %s, expected %s", dst, expectDst)
+	}
+
+	if err := PlaceUnit(&u, dst); err != nil {
 		t.Fatalf("PlaceUnit failed: %v", err)
 	}
 
-	fullPath := path.Join(dir, "run", "systemd", "network", "50-eth0.network")
+	fi, err := os.Stat(dst)
-	fi, err := os.Stat(fullPath)
 	if err != nil {
 		t.Fatalf("Unable to stat file: %v", err)
 	}
@@ -40,19 +45,19 @@ Address=10.209.171.177/19
 		t.Errorf("File has incorrect mode: %v", fi.Mode())
 	}
 
-	contents, err := ioutil.ReadFile(fullPath)
+	contents, err := ioutil.ReadFile(dst)
 	if err != nil {
 		t.Fatalf("Unable to read expected file: %v", err)
 	}
 
-	expect := `[Match]
+	expectContents := `[Match]
 Name=eth47
 
 [Network]
 Address=10.209.171.177/19
 `
-	if string(contents) != expect {
+	if string(contents) != expectContents {
-		t.Fatalf("File has incorrect contents '%s'.\nExpected '%s'", string(contents), expect)
+		t.Fatalf("File has incorrect contents '%s'.\nExpected '%s'", string(contents), expectContents)
 	}
 }
 
@@ -72,12 +77,17 @@ Where=/media/state
 	}
 	defer syscall.Rmdir(dir)
 
-	if _, err := PlaceUnit(&u, dir); err != nil {
+	dst := UnitDestination(&u, dir)
+	expectDst := path.Join(dir, "etc", "systemd", "system", "media-state.mount")
+	if dst != expectDst {
+		t.Fatalf("UnitDestination returned %s, expected %s", dst, expectDst)
+	}
+
+	if err := PlaceUnit(&u, dst); err != nil {
 		t.Fatalf("PlaceUnit failed: %v", err)
 	}
 
-	fullPath := path.Join(dir, "etc", "systemd", "system", "media-state.mount")
+	fi, err := os.Stat(dst)
-	fi, err := os.Stat(fullPath)
 	if err != nil {
 		t.Fatalf("Unable to stat file: %v", err)
 	}
@@ -86,17 +96,17 @@ Where=/media/state
 		t.Errorf("File has incorrect mode: %v", fi.Mode())
 	}
 
-	contents, err := ioutil.ReadFile(fullPath)
+	contents, err := ioutil.ReadFile(dst)
 	if err != nil {
 		t.Fatalf("Unable to read expected file: %v", err)
 	}
 
-	expect := `[Mount]
+	expectContents := `[Mount]
 What=/dev/sdb1
 Where=/media/state
 `
-	if string(contents) != expect {
+	if string(contents) != expectContents {
-		t.Fatalf("File has incorrect contents '%s'.\nExpected '%s'", string(contents), expect)
+		t.Fatalf("File has incorrect contents '%s'.\nExpected '%s'", string(contents), expectContents)
 	}
 }