Merge pull request #1033 from hashicorp/f-self

core: Self Variables

config/config.go

@@ -477,6 +477,22 @@ func (c *Config) Validate() error {
 		}
 	}
 
+	// Validate the self variable
+	for source, rc := range c.rawConfigs() {
+		// Ignore provisioners. This is a pretty brittle way to do this,
+		// but better than also repeating all the resources.
+		if strings.Contains(source, "provision") {
+			continue
+		}
+
+		for _, v := range rc.Variables {
+			if _, ok := v.(*SelfVariable); ok {
+				errs = append(errs, fmt.Errorf(
+					"%s: cannot contain self-reference %s", source, v.FullKey()))
+			}
+		}
+	}
+
 	if len(errs) > 0 {
 		return &multierror.Error{Errors: errs}
 	}

config/config_test.go

@@ -214,6 +214,20 @@ func TestConfigValidate_provSplatSelf(t *testing.T) {
 	}
 }
 
+func TestConfigValidate_resourceProvVarSelf(t *testing.T) {
+	c := testConfig(t, "validate-resource-prov-self")
+	if err := c.Validate(); err != nil {
+		t.Fatalf("should be valid: %s", err)
+	}
+}
+
+func TestConfigValidate_resourceVarSelf(t *testing.T) {
+	c := testConfig(t, "validate-resource-self")
+	if err := c.Validate(); err == nil {
+		t.Fatal("should not be valid")
+	}
+}
+
 func TestConfigValidate_unknownThing(t *testing.T) {
 	c := testConfig(t, "validate-unknownthing")
 	if err := c.Validate(); err == nil {

config/interpolate.go

@@ -68,6 +68,14 @@ type ResourceVariable struct {
 	key string
 }
 
+// SelfVariable is a variable that is referencing the same resource
+// it is running on: "${self.address}"
+type SelfVariable struct {
+	Field string
+
+	key string
+}
+
 // A UserVariable is a variable that is referencing a user variable
 // that is inputted from outside the configuration. This looks like
 // "${var.foo}"
@@ -83,6 +91,8 @@ func NewInterpolatedVariable(v string) (InterpolatedVariable, error) {
 		return NewCountVariable(v)
 	} else if strings.HasPrefix(v, "path.") {
 		return NewPathVariable(v)
+	} else if strings.HasPrefix(v, "self.") {
+		return NewSelfVariable(v)
 	} else if strings.HasPrefix(v, "var.") {
 		return NewUserVariable(v)
 	} else if strings.HasPrefix(v, "module.") {
@@ -199,6 +209,24 @@ func (v *ResourceVariable) FullKey() string {
 	return v.key
 }
 
+func NewSelfVariable(key string) (*SelfVariable, error) {
+	field := key[len("self."):]
+
+	return &SelfVariable{
+		Field: field,
+
+		key: key,
+	}, nil
+}
+
+func (v *SelfVariable) FullKey() string {
+	return v.key
+}
+
+func (v *SelfVariable) GoString() string {
+	return fmt.Sprintf("*%#v", *v)
+}
+
 func NewUserVariable(key string) (*UserVariable, error) {
 	name := key[len("var."):]
 	elem := ""

config/interpolate_test.go

@@ -54,6 +54,14 @@ func TestNewInterpolatedVariable(t *testing.T) {
 			},
 			false,
 		},
+		{
+			"self.address",
+			&SelfVariable{
+				Field: "address",
+				key:   "self.address",
+			},
+			false,
+		},
 	}
 
 	for i, tc := range cases {

config/test-fixtures/validate-resource-prov-self/main.tf

@@ -0,0 +1,11 @@
+resource "aws_instance" "foo" {
+    foo = "bar"
+
+    connection {
+        host = "${self.foo}"
+    }
+
+    provisioner "shell" {
+        value = "${self.foo}"
+    }
+}

config/test-fixtures/validate-resource-self/main.tf

@@ -0,0 +1,3 @@
+resource "aws_instance" "foo" {
+    foo = "${self.bar}"
+}

terraform/context_test.go

@@ -3766,6 +3766,112 @@ func TestContext2Apply_provisionerResourceRef(t *testing.T) {
 	}
 }
 
+func TestContext2Apply_provisionerSelfRef(t *testing.T) {
+	m := testModule(t, "apply-provisioner-self-ref")
+	p := testProvider("aws")
+	pr := testProvisioner()
+	p.ApplyFn = testApplyFn
+	p.DiffFn = testDiffFn
+	pr.ApplyFn = func(rs *InstanceState, c *ResourceConfig) error {
+		val, ok := c.Config["command"]
+		if !ok || val != "bar" {
+			t.Fatalf("bad value for command: %v %#v", val, c)
+		}
+
+		return nil
+	}
+
+	ctx := testContext2(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+		Provisioners: map[string]ResourceProvisionerFactory{
+			"shell": testProvisionerFuncFixed(pr),
+		},
+	})
+
+	if _, err := ctx.Plan(nil); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	state, err := ctx.Apply()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(state.String())
+	expected := strings.TrimSpace(testTerraformApplyProvisionerSelfRefStr)
+	if actual != expected {
+		t.Fatalf("bad: \n%s", actual)
+	}
+
+	// Verify apply was invoked
+	if !pr.ApplyCalled {
+		t.Fatalf("provisioner not invoked")
+	}
+}
+
+func TestContext2Apply_provisionerMultiSelfRef(t *testing.T) {
+	var lock sync.Mutex
+	commands := make([]string, 0, 5)
+
+	m := testModule(t, "apply-provisioner-multi-self-ref")
+	p := testProvider("aws")
+	pr := testProvisioner()
+	p.ApplyFn = testApplyFn
+	p.DiffFn = testDiffFn
+	pr.ApplyFn = func(rs *InstanceState, c *ResourceConfig) error {
+		lock.Lock()
+		defer lock.Unlock()
+
+		val, ok := c.Config["command"]
+		if !ok {
+			t.Fatalf("bad value for command: %v %#v", val, c)
+		}
+
+		commands = append(commands, val.(string))
+		return nil
+	}
+
+	ctx := testContext2(t, &ContextOpts{
+		Module: m,
+		Providers: map[string]ResourceProviderFactory{
+			"aws": testProviderFuncFixed(p),
+		},
+		Provisioners: map[string]ResourceProvisionerFactory{
+			"shell": testProvisionerFuncFixed(pr),
+		},
+	})
+
+	if _, err := ctx.Plan(nil); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	state, err := ctx.Apply()
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	actual := strings.TrimSpace(state.String())
+	expected := strings.TrimSpace(testTerraformApplyProvisionerMultiSelfRefStr)
+	if actual != expected {
+		t.Fatalf("bad: \n%s", actual)
+	}
+
+	// Verify apply was invoked
+	if !pr.ApplyCalled {
+		t.Fatalf("provisioner not invoked")
+	}
+
+	// Verify our result
+	sort.Strings(commands)
+	expectedCommands := []string{"number 0", "number 1", "number 2"}
+	if !reflect.DeepEqual(commands, expectedCommands) {
+		t.Fatalf("bad: %#v", commands)
+	}
+}
+
 // Provisioner should NOT run on a diff, only create
 func TestContext2Apply_Provisioner_Diff(t *testing.T) {
 	m := testModule(t, "apply-provisioner-diff")

terraform/interpolate.go

@@ -62,6 +62,8 @@ func (i *Interpolater) Values(
 			err = i.valuePathVar(scope, n, v, result)
 		case *config.ResourceVariable:
 			err = i.valueResourceVar(scope, n, v, result)
+		case *config.SelfVariable:
+			err = i.valueSelfVar(scope, n, v, result)
 		case *config.UserVariable:
 			err = i.valueUserVar(scope, n, v, result)
 		default:
@@ -217,6 +219,24 @@ func (i *Interpolater) valueResourceVar(
 	return nil
 }
 
+func (i *Interpolater) valueSelfVar(
+	scope *InterpolationScope,
+	n string,
+	v *config.SelfVariable,
+	result map[string]ast.Variable) error {
+	rv, err := config.NewResourceVariable(fmt.Sprintf(
+		"%s.%s.%d.%s",
+		scope.Resource.Type,
+		scope.Resource.Name,
+		scope.Resource.CountIndex,
+		v.Field))
+	if err != nil {
+		return err
+	}
+
+	return i.valueResourceVar(scope, n, rv, result)
+}
+
 func (i *Interpolater) valueUserVar(
 	scope *InterpolationScope,
 	n string,

terraform/resource.go

@@ -26,6 +26,13 @@ type ResourceProvisionerConfig struct {
 // its current state, and potentially a desired diff from the state it
 // wants to reach.
 type Resource struct {
+	// These are all used by the new EvalNode stuff.
+	Name       string
+	Type       string
+	CountIndex int
+
+	// These aren't really used anymore anywhere, but we keep them around
+	// since we haven't done a proper cleanup yet.
 	Id           string
 	Info         *InstanceInfo
 	Config       *ResourceConfig
@@ -34,7 +41,6 @@ type Resource struct {
 	Provider     ResourceProvider
 	State        *InstanceState
 	Provisioners []*ResourceProvisionerConfig
-	CountIndex   int
 	Flags        ResourceFlag
 	TaintedIndex int
 }

terraform/terraform_test.go

@@ -359,6 +359,28 @@ aws_instance.bar:
   type = aws_instance
 `
 
+const testTerraformApplyProvisionerSelfRefStr = `
+aws_instance.foo:
+  ID = foo
+  foo = bar
+  type = aws_instance
+`
+
+const testTerraformApplyProvisionerMultiSelfRefStr = `
+aws_instance.foo.0:
+  ID = foo
+  foo = number 0
+  type = aws_instance
+aws_instance.foo.1:
+  ID = foo
+  foo = number 1
+  type = aws_instance
+aws_instance.foo.2:
+  ID = foo
+  foo = number 2
+  type = aws_instance
+`
+
 const testTerraformApplyProvisionerDiffStr = `
 aws_instance.bar:
   ID = foo

terraform/test-fixtures/apply-provisioner-multi-self-ref/main.tf

@@ -0,0 +1,8 @@
+resource "aws_instance" "foo" {
+    count = 3
+    foo = "number ${count.index}"
+
+    provisioner "shell" {
+        command = "${self.foo}"
+    }
+}

terraform/test-fixtures/apply-provisioner-self-ref/main.tf

@@ -0,0 +1,7 @@
+resource "aws_instance" "foo" {
+    foo = "bar"
+
+    provisioner "shell" {
+        command = "${self.foo}"
+    }
+}

terraform/transform_resource.go

@@ -109,7 +109,11 @@ func (n *graphNodeExpandedResource) EvalTree() EvalNode {
 	if index < 0 {
 		index = 0
 	}
-	resource := &Resource{CountIndex: index}
+	resource := &Resource{
+		Name:       n.Resource.Name,
+		Type:       n.Resource.Type,
+		CountIndex: index,
+	}
 
 	seq := &EvalSequence{Nodes: make([]EvalNode, 0, 5)}
 

website/source/docs/configuration/interpolation.html.md

@@ -26,6 +26,11 @@ can reference static keys in the map with the syntax
 get the value of the `us-east-1` key within the `amis` variable
 that is a mapping.
 
+**To reference attributes of your own resource**, the syntax is
+`self.ATTRIBUTE`. For example `${self.private_ip_address}` will
+interpolate that resource's private IP address. Note that this is
+only allowed/valid within provisioners.
+
 **To reference attributes of other resources**, the syntax is
 `TYPE.NAME.ATTRIBUTE`. For example, `${aws_instance.web.id}`
 will interpolate the ID attribute from the "aws\_instance"
@@ -72,8 +77,8 @@ The supported built-in functions are:
       only possible with splat variables from resources with a count
       greater than one. Example: `join(",", aws_instance.foo.*.id)`
 
-  * `split(delim, string)` - Splits the string previously created by `join` 
-      back into a list. This is useful for pushing lists through module 
+  * `split(delim, string)` - Splits the string previously created by `join`
+      back into a list. This is useful for pushing lists through module
       outputs since they currently only support string values.
       Example: `split(",", module.amod.server_ids)`