provider/ignition: allowing empty systemd.content when a dropin is provided (hashicorp#11216)

Author: mcuadros

builtin/providers/ignition/provider.go

@@ -6,7 +6,6 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
-	"io"
 	"net/url"
 	"sync"
 
@@ -166,23 +165,20 @@ func getUInt(d *schema.ResourceData, key string) *uint {
 	return uid
 }
 
-func validateUnit(content string) error {
-	r := bytes.NewBuffer([]byte(content))
+var errEmptyUnit = fmt.Errorf("invalid or empty unit content")
 
-	u, err := unit.Deserialize(r)
-	if len(u) == 0 {
-		return fmt.Errorf("invalid or empty unit content")
-	}
-
-	if err == nil {
-		return nil
+func validateUnitContent(content string) error {
+	c := bytes.NewBufferString(content)
+	unit, err := unit.Deserialize(c)
+	if err != nil {
+		return fmt.Errorf("invalid unit content: %s", err)
 	}
 
-	if err == io.EOF {
-		return fmt.Errorf("unexpected EOF reading unit content")
+	if len(unit) == 0 {
+		return errEmptyUnit
 	}
 
-	return err
+	return nil
 }
 
 func buildURL(raw string) (types.Url, error) {

builtin/providers/ignition/provider_test.go

@@ -18,15 +18,15 @@ func TestProvider(t *testing.T) {
 }
 
 func TestValidateUnit(t *testing.T) {
-	if err := validateUnit(""); err == nil {
+	if err := validateUnitContent(""); err == nil {
 		t.Fatalf("error not found, expected error")
 	}
 
-	if err := validateUnit("[foo]qux"); err == nil {
+	if err := validateUnitContent("[foo]qux"); err == nil {
 		t.Fatalf("error not found, expected error")
 	}
 
-	if err := validateUnit("[foo]\nqux=foo\nfoo"); err == nil {
+	if err := validateUnitContent("[foo]\nqux=foo\nfoo"); err == nil {
 		t.Fatalf("error not found, expected error")
 	}
 }

builtin/providers/ignition/resource_ignition_networkd_unit.go

@@ -55,7 +55,7 @@ func resourceNetworkdUnitRead(d *schema.ResourceData, meta interface{}) error {
 }
 
 func buildNetworkdUnit(d *schema.ResourceData, c *cache) (string, error) {
-	if err := validateUnit(d.Get("content").(string)); err != nil {
+	if err := validateUnitContent(d.Get("content").(string)); err != nil {
 		return "", err
 	}
 

builtin/providers/ignition/resource_ignition_systemd_unit.go

@@ -30,7 +30,7 @@ func resourceSystemdUnit() *schema.Resource {
 			},
 			"content": &schema.Schema{
 				Type:     schema.TypeString,
-				Required: true,
+				Optional: true,
 				ForceNew: true,
 			},
 			"dropin": &schema.Schema{
@@ -85,15 +85,11 @@ func resourceSystemdUnitRead(d *schema.ResourceData, meta interface{}) error {
 }
 
 func buildSystemdUnit(d *schema.ResourceData, c *cache) (string, error) {
-	if err := validateUnit(d.Get("content").(string)); err != nil {
-		return "", err
-	}
-
 	var dropins []types.SystemdUnitDropIn
 	for _, raw := range d.Get("dropin").([]interface{}) {
 		value := raw.(map[string]interface{})
 
-		if err := validateUnit(value["content"].(string)); err != nil {
+		if err := validateUnitContent(value["content"].(string)); err != nil {
 			return "", err
 		}
 
@@ -103,6 +99,12 @@ func buildSystemdUnit(d *schema.ResourceData, c *cache) (string, error) {
 		})
 	}
 
+	if err := validateUnitContent(d.Get("content").(string)); err != nil {
+		if err != errEmptyUnit || (err == errEmptyUnit && len(dropins) == 0) {
+			return "", err
+		}
+	}
+
 	return c.addSystemdUnit(&types.SystemdUnit{
 		Name:     types.SystemdUnitName(d.Get("name").(string)),
 		Contents: d.Get("content").(string),

builtin/providers/ignition/resource_ignition_systemd_unit_test.go

@@ -56,3 +56,41 @@ func TestIngnitionSystemdUnit(t *testing.T) {
 		return nil
 	})
 }
+
+func TestIngnitionSystemdUnitEmptyContentWithDropIn(t *testing.T) {
+	testIgnition(t, `
+		resource "ignition_systemd_unit" "foo" {
+			name = "foo.service"
+			dropin {
+				name = "foo.conf"
+				content = "[Match]\nName=eth0\n\n[Network]\nAddress=10.0.1.7\n"
+			}
+		}
+
+		resource "ignition_config" "test" {
+			systemd = [
+				"${ignition_systemd_unit.foo.id}",
+			]
+		}
+	`, func(c *types.Config) error {
+		if len(c.Systemd.Units) != 1 {
+			return fmt.Errorf("systemd, found %d", len(c.Systemd.Units))
+		}
+
+		u := c.Systemd.Units[0]
+
+		if u.Name != "foo.service" {
+			return fmt.Errorf("name, found %q", u.Name)
+		}
+
+		if u.Contents != "" {
+			return fmt.Errorf("content, found %q", u.Contents)
+		}
+
+		if len(u.DropIns) != 1 {
+			return fmt.Errorf("dropins, found %q", u.DropIns)
+		}
+
+		return nil
+	})
+}

website/source/docs/providers/ignition/r/systemd_unit.html.md

@@ -29,12 +29,12 @@ The following arguments are supported:
 
 * `mask` - (Optional) Whether or not the service shall be masked. When true, the service is masked by symlinking it to _/dev/null_.
 
-* `content` - (Required) The contents of the unit.
+* `content` - (Required) The contents of the unit. Optional when a dropin is provided.
 
 * `dropin` - (Optional) The list of drop-ins for the unit.
 
 The `dropin` block supports:
- 
+
 * `name` - (Required) The name of the drop-in. This must be suffixed with _.conf_.
 
 * `content` - (Optional) The contents of the drop-in.