resource/aws_dax_cluster: Refactor now invalid validateElastiCacheClu…

…sterId into inline ValidateFunc

Reference: #8424

Output from acceptance testing:

```
--- PASS: TestAccAWSDAXCluster_encryption_disabled (739.98s)
--- PASS: TestAccAWSDAXCluster_basic (756.03s)
--- PASS: TestAccAWSDAXCluster_importBasic (796.86s)
--- PASS: TestAccAWSDAXCluster_encryption_enabled (865.80s)
--- PASS: TestAccAWSDAXCluster_resize (1414.26s)
```

aws/resource_aws_dax_cluster.go

@@ -3,6 +3,7 @@ package aws
 import (
 	"fmt"
 	"log"
+	"regexp"
 	"sort"
 	"strings"
 	"time"
@@ -11,6 +12,7 @@ import (
 	"github.com/aws/aws-sdk-go/service/dax"
 	"github.com/hashicorp/terraform/helper/resource"
 	"github.com/hashicorp/terraform/helper/schema"
+	"github.com/hashicorp/terraform/helper/validation"
 )
 
 func resourceAwsDaxCluster() *schema.Resource {
@@ -41,8 +43,13 @@ func resourceAwsDaxCluster() *schema.Resource {
 				StateFunc: func(val interface{}) string {
 					return strings.ToLower(val.(string))
 				},
-				// DAX follows the same naming convention as ElastiCache clusters
-				ValidateFunc: validateElastiCacheClusterId,
+				ValidateFunc: validation.All(
+					validation.StringLenBetween(1, 20),
+					validation.StringMatch(regexp.MustCompile(`^[0-9a-z-]+$`), "must contain only lowercase alphanumeric characters and hyphens"),
+					validation.StringMatch(regexp.MustCompile(`^[a-z]`), "must begin with a lowercase letter"),
+					validateStringNotMatch(regexp.MustCompile(`--`), "cannot contain two consecutive hyphens"),
+					validateStringNotMatch(regexp.MustCompile(`-$`), "cannot end with a hyphen"),
+				),
 			},
 			"iam_role_arn": {
 				Type:         schema.TypeString,

aws/validators.go

@@ -218,31 +218,6 @@ func validateNeptuneEngine() schema.SchemaValidateFunc {
 	}, false)
 }
 
-func validateElastiCacheClusterId(v interface{}, k string) (ws []string, errors []error) {
-	value := v.(string)
-	if (len(value) < 1) || (len(value) > 20) {
-		errors = append(errors, fmt.Errorf(
-			"%q (%q) must contain from 1 to 20 alphanumeric characters or hyphens", k, value))
-	}
-	if !regexp.MustCompile(`^[0-9a-z-]+$`).MatchString(value) {
-		errors = append(errors, fmt.Errorf(
-			"only lowercase alphanumeric characters and hyphens allowed in %q (%q)", k, value))
-	}
-	if !regexp.MustCompile(`^[a-z]`).MatchString(value) {
-		errors = append(errors, fmt.Errorf(
-			"first character of %q (%q) must be a letter", k, value))
-	}
-	if regexp.MustCompile(`--`).MatchString(value) {
-		errors = append(errors, fmt.Errorf(
-			"%q (%q) cannot contain two consecutive hyphens", k, value))
-	}
-	if regexp.MustCompile(`-$`).MatchString(value) {
-		errors = append(errors, fmt.Errorf(
-			"%q (%q) cannot end with a hyphen", k, value))
-	}
-	return
-}
-
 func validateASGScheduleTimestamp(v interface{}, k string) (ws []string, errors []error) {
 	value := v.(string)
 	_, err := time.Parse(awsAutoscalingScheduleTimeLayout, value)

aws/validators_test.go

@@ -630,46 +630,6 @@ func TestValidateSagemakerName(t *testing.T) {
 	}
 }
 
-func TestResourceAWSElastiCacheClusterIdValidation(t *testing.T) {
-	cases := []struct {
-		Value    string
-		ErrCount int
-	}{
-		{
-			Value:    "tEsting",
-			ErrCount: 1,
-		},
-		{
-			Value:    "t.sting",
-			ErrCount: 1,
-		},
-		{
-			Value:    "t--sting",
-			ErrCount: 1,
-		},
-		{
-			Value:    "1testing",
-			ErrCount: 1,
-		},
-		{
-			Value:    "testing-",
-			ErrCount: 1,
-		},
-		{
-			Value:    randomString(65),
-			ErrCount: 1,
-		},
-	}
-
-	for _, tc := range cases {
-		_, errors := validateElastiCacheClusterId(tc.Value, "aws_elasticache_cluster_cluster_id")
-
-		if len(errors) != tc.ErrCount {
-			t.Fatalf("Expected the ElastiCache Cluster cluster_id to trigger a validation error")
-		}
-	}
-}
-
 func TestValidateDbEventSubscriptionName(t *testing.T) {
 	validNames := []string{
 		"valid-name",