validation: Add ValidateRFC3339TimeString

helper/validation/validation.go

@@ -6,6 +6,7 @@ import (
 	"reflect"
 	"regexp"
 	"strings"
+	"time"
 
 	"github.com/hashicorp/terraform/helper/schema"
 	"github.com/hashicorp/terraform/helper/structure"
@@ -210,3 +211,12 @@ func ValidateRegexp(v interface{}, k string) (ws []string, errors []error) {
 	}
 	return
 }
+
+// ValidateRFC3339TimeString is a ValidateFunc that ensures a string parses
+// as time.RFC3339 format
+func ValidateRFC3339TimeString(v interface{}, k string) (ws []string, errors []error) {
+	if _, err := time.Parse(time.RFC3339, v.(string)); err != nil {
+		errors = append(errors, fmt.Errorf("%q: %s", k, err))
+	}
+	return
+}

helper/validation/validation_test.go

@@ -144,6 +144,58 @@ func TestValidationRegexp(t *testing.T) {
 	})
 }
 
+func TestValidateRFC3339TimeString(t *testing.T) {
+	runTestCases(t, []testCase{
+		{
+			val: "2018-03-01T00:00:00Z",
+			f:   ValidateRFC3339TimeString,
+		},
+		{
+			val: "2018-03-01T00:00:00-05:00",
+			f:   ValidateRFC3339TimeString,
+		},
+		{
+			val: "2018-03-01T00:00:00+05:00",
+			f:   ValidateRFC3339TimeString,
+		},
+		{
+			val:         "03/01/2018",
+			f:           ValidateRFC3339TimeString,
+			expectedErr: regexp.MustCompile(regexp.QuoteMeta(`cannot parse "1/2018" as "2006"`)),
+		},
+		{
+			val:         "03-01-2018",
+			f:           ValidateRFC3339TimeString,
+			expectedErr: regexp.MustCompile(regexp.QuoteMeta(`cannot parse "1-2018" as "2006"`)),
+		},
+		{
+			val:         "2018-03-01",
+			f:           ValidateRFC3339TimeString,
+			expectedErr: regexp.MustCompile(regexp.QuoteMeta(`cannot parse "" as "T"`)),
+		},
+		{
+			val:         "2018-03-01T",
+			f:           ValidateRFC3339TimeString,
+			expectedErr: regexp.MustCompile(regexp.QuoteMeta(`cannot parse "" as "15"`)),
+		},
+		{
+			val:         "2018-03-01T00:00:00",
+			f:           ValidateRFC3339TimeString,
+			expectedErr: regexp.MustCompile(regexp.QuoteMeta(`cannot parse "" as "Z07:00"`)),
+		},
+		{
+			val:         "2018-03-01T00:00:00Z05:00",
+			f:           ValidateRFC3339TimeString,
+			expectedErr: regexp.MustCompile(regexp.QuoteMeta(`extra text: 05:00`)),
+		},
+		{
+			val:         "2018-03-01T00:00:00Z-05:00",
+			f:           ValidateRFC3339TimeString,
+			expectedErr: regexp.MustCompile(regexp.QuoteMeta(`extra text: -05:00`)),
+		},
+	})
+}
+
 func TestValidateJsonString(t *testing.T) {
 	type testCases struct {
 		Value    string