terraform: helpers on ResourceConfig

builtin/providers/aws/resource_provider.go

@@ -7,8 +7,13 @@ import (
 type ResourceProvider struct {
 }
 
-func (p *ResourceProvider) Validate(*terraform.ResourceConfig) ([]string, []error) {
-	return nil, nil
+func (p *ResourceProvider) Validate(c *terraform.ResourceConfig) ([]string, []error) {
+	errs := c.CheckSet([]string{
+		"access_key",
+		"secret_key",
+	})
+
+	return nil, errs
 }
 
 func (p *ResourceProvider) Configure(*terraform.ResourceConfig) error {

terraform/resource_provider.go

@@ -1,6 +1,10 @@
 package terraform
 
 import (
+	"fmt"
+	"reflect"
+	"strings"
+
 	"github.com/hashicorp/terraform/config"
 )
 
@@ -66,6 +70,69 @@ func NewResourceConfig(c *config.RawConfig) *ResourceConfig {
 	}
 }
 
+// CheckSet checks that the given list of configuration keys is
+// properly set. If not, errors are returned for each unset key.
+//
+// This is useful to be called in the Validate method of a ResourceProvider.
+func (c *ResourceConfig) CheckSet(keys []string) []error {
+	var errs []error
+
+	for _, k := range keys {
+		if !c.IsSet(k) {
+			errs = append(errs, fmt.Errorf("%s must be set", k))
+		}
+	}
+
+	return errs
+}
+
+// Get looks up a configuration value by key and returns the value.
+//
+// The second return value is true if the get was successful. Get will
+// not succeed if the value is being computed.
+func (c *ResourceConfig) Get(k string) (interface{}, bool) {
+	parts := strings.Split(k, ".")
+
+	var current interface{} = c.Raw
+	for _, part := range parts {
+		if current == nil {
+			return nil, false
+		}
+
+		cv := reflect.ValueOf(current)
+		switch cv.Kind() {
+		case reflect.Map:
+			v := cv.MapIndex(reflect.ValueOf(part))
+			if !v.IsValid() {
+				return nil, false
+			}
+			current = v.Interface()
+		}
+	}
+
+	return current, true
+}
+
+// IsSet checks if the key in the configuration is set. A key is set if
+// it has a value or the value is being computed (is unknown currently).
+//
+// This function should be used rather than checking the keys of the
+// raw configuration itself, since a key may be omitted from the raw
+// configuration if it is being computed.
+func (c *ResourceConfig) IsSet(k string) bool {
+	for _, ck := range c.ComputedKeys {
+		if ck == k {
+			return true
+		}
+	}
+
+	if _, ok := c.Get(k); ok {
+		return true
+	}
+
+	return false
+}
+
 func ProviderSatisfies(p ResourceProvider, n string) bool {
 	for _, rt := range p.Resources() {
 		if rt.Name == n {

terraform/resource_provider_test.go

@@ -0,0 +1,103 @@
+package terraform
+
+import (
+	"testing"
+)
+
+func TestResourceConfig_CheckSet(t *testing.T) {
+	cases := []struct {
+		Raw      map[string]interface{}
+		Computed []string
+		Input    []string
+		Errs     bool
+	}{
+		{
+			map[string]interface{}{
+				"foo": "bar",
+			},
+			nil,
+			[]string{"foo"},
+			false,
+		},
+		{
+			map[string]interface{}{
+				"foo": "bar",
+			},
+			nil,
+			[]string{"foo", "bar"},
+			true,
+		},
+		{
+			map[string]interface{}{
+				"foo": "bar",
+			},
+			[]string{"bar"},
+			[]string{"foo", "bar"},
+			false,
+		},
+	}
+
+	for i, tc := range cases {
+		rc := &ResourceConfig{
+			ComputedKeys: tc.Computed,
+			Raw:          tc.Raw,
+		}
+
+		errs := rc.CheckSet(tc.Input)
+		if tc.Errs != (len(errs) > 0) {
+			t.Fatalf("bad: %d", i)
+		}
+	}
+}
+
+func TestResourceConfig_IsSet(t *testing.T) {
+	cases := []struct {
+		Raw      map[string]interface{}
+		Computed []string
+		Input    string
+		Output   bool
+	}{
+		{
+			map[string]interface{}{
+				"foo": "bar",
+			},
+			nil,
+			"foo",
+			true,
+		},
+		{
+			map[string]interface{}{},
+			nil,
+			"foo",
+			false,
+		},
+		{
+			map[string]interface{}{},
+			[]string{"foo"},
+			"foo",
+			true,
+		},
+		{
+			map[string]interface{}{
+				"foo": map[interface{}]interface{}{
+					"bar": "baz",
+				},
+			},
+			nil,
+			"foo.bar",
+			true,
+		},
+	}
+
+	for i, tc := range cases {
+		rc := &ResourceConfig{
+			ComputedKeys: tc.Computed,
+			Raw:          tc.Raw,
+		}
+
+		actual := rc.IsSet(tc.Input)
+		if actual != tc.Output {
+			t.Fatalf("fail case: %d", i)
+		}
+	}
+}