Add `name_prefix` support to `aws_cloudwatch_log_group` (#13273)

builtin/providers/aws/resource_aws_cloudwatch_log_group.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log"
 
+	"github.com/hashicorp/terraform/helper/resource"
 	"github.com/hashicorp/terraform/helper/schema"
 
 	"github.com/aws/aws-sdk-go/aws"
@@ -25,10 +26,18 @@ func resourceAwsCloudWatchLogGroup() *schema.Resource {
 		Schema: map[string]*schema.Schema{
 			"name": {
 				Type:          schema.TypeString,
-				Required:     true,
+				Optional:      true,
+				Computed:      true,
 				ForceNew:      true,
+				ConflictsWith: []string{"name_prefix"},
 				ValidateFunc:  validateLogGroupName,
 			},
+			"name_prefix": {
+				Type:         schema.TypeString,
+				Optional:     true,
+				ForceNew:     true,
+				ValidateFunc: validateLogGroupNamePrefix,
+			},
 
 			"retention_in_days": {
 				Type:     schema.TypeInt,
@@ -49,10 +58,19 @@ func resourceAwsCloudWatchLogGroup() *schema.Resource {
 func resourceAwsCloudWatchLogGroupCreate(d *schema.ResourceData, meta interface{}) error {
 	conn := meta.(*AWSClient).cloudwatchlogsconn
 
-	log.Printf("[DEBUG] Creating CloudWatch Log Group: %s", d.Get("name").(string))
+	var logGroupName string
+	if v, ok := d.GetOk("name"); ok {
+		logGroupName = v.(string)
+	} else if v, ok := d.GetOk("name_prefix"); ok {
+		logGroupName = resource.PrefixedUniqueId(v.(string))
+	} else {
+		logGroupName = resource.UniqueId()
+	}
+
+	log.Printf("[DEBUG] Creating CloudWatch Log Group: %s", logGroupName)
 
 	_, err := conn.CreateLogGroup(&cloudwatchlogs.CreateLogGroupInput{
-		LogGroupName: aws.String(d.Get("name").(string)),
+		LogGroupName: aws.String(logGroupName),
 	})
 	if err != nil {
 		if awsErr, ok := err.(awserr.Error); ok && awsErr.Code() == "ResourceAlreadyExistsException" {
@@ -61,7 +79,7 @@ func resourceAwsCloudWatchLogGroupCreate(d *schema.ResourceData, meta interface{
 		return fmt.Errorf("Creating CloudWatch Log Group failed: %s '%s'", err, d.Get("name"))
 	}
 
-	d.SetId(d.Get("name").(string))
+	d.SetId(logGroupName)
 
 	log.Println("[INFO] CloudWatch Log Group created")
 

builtin/providers/aws/resource_aws_cloudwatch_log_group_test.go

@@ -2,6 +2,7 @@ package aws
 
 import (
 	"fmt"
+	"regexp"
 	"testing"
 
 	"github.com/aws/aws-sdk-go/service/cloudwatchlogs"
@@ -30,6 +31,43 @@ func TestAccAWSCloudWatchLogGroup_basic(t *testing.T) {
 	})
 }
 
+func TestAccAWSCloudWatchLogGroup_namePrefix(t *testing.T) {
+	var lg cloudwatchlogs.LogGroup
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckAWSCloudWatchLogGroupDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccAWSCloudWatchLogGroup_namePrefix,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckCloudWatchLogGroupExists("aws_cloudwatch_log_group.test", &lg),
+					resource.TestMatchResourceAttr("aws_cloudwatch_log_group.test", "name", regexp.MustCompile("^tf-test-")),
+				),
+			},
+		},
+	})
+}
+
+func TestAccAWSCloudWatchLogGroup_generatedName(t *testing.T) {
+	var lg cloudwatchlogs.LogGroup
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckAWSCloudWatchLogGroupDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccAWSCloudWatchLogGroup_generatedName,
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckCloudWatchLogGroupExists("aws_cloudwatch_log_group.test", &lg),
+				),
+			},
+		},
+	})
+}
+
 func TestAccAWSCloudWatchLogGroup_retentionPolicy(t *testing.T) {
 	var lg cloudwatchlogs.LogGroup
 	rInt := acctest.RandInt()
@@ -256,3 +294,13 @@ resource "aws_cloudwatch_log_group" "charlie" {
 }
 `, rInt, rInt+1, rInt+2)
 }
+
+const testAccAWSCloudWatchLogGroup_namePrefix = `
+resource "aws_cloudwatch_log_group" "test" {
+    name_prefix = "tf-test-"
+}
+`
+
+const testAccAWSCloudWatchLogGroup_generatedName = `
+resource "aws_cloudwatch_log_group" "test" {}
+`

builtin/providers/aws/validators.go

@@ -483,6 +483,26 @@ func validateLogGroupName(v interface{}, k string) (ws []string, errors []error)
 	return
 }
 
+func validateLogGroupNamePrefix(v interface{}, k string) (ws []string, errors []error) {
+	value := v.(string)
+
+	if len(value) > 483 {
+		errors = append(errors, fmt.Errorf(
+			"%q cannot be longer than 483 characters: %q", k, value))
+	}
+
+	// http://docs.aws.amazon.com/AmazonCloudWatchLogs/latest/APIReference/API_CreateLogGroup.html
+	pattern := `^[\.\-_/#A-Za-z0-9]+$`
+	if !regexp.MustCompile(pattern).MatchString(value) {
+		errors = append(errors, fmt.Errorf(
+			"%q isn't a valid log group name (alphanumeric characters, underscores,"+
+				" hyphens, slashes, hash signs and dots are allowed): %q",
+			k, value))
+	}
+
+	return
+}
+
 func validateS3BucketLifecycleTimestamp(v interface{}, k string) (ws []string, errors []error) {
 	value := v.(string)
 	_, err := time.Parse(time.RFC3339, fmt.Sprintf("%sT00:00:00Z", value))

builtin/providers/aws/validators_test.go

@@ -410,7 +410,7 @@ func TestValidateLogGroupName(t *testing.T) {
 	for _, v := range validNames {
 		_, errors := validateLogGroupName(v, "name")
 		if len(errors) != 0 {
-			t.Fatalf("%q should be a valid Log Metric Filter Transformation Name: %q", v, errors)
+			t.Fatalf("%q should be a valid Log Group name: %q", v, errors)
 		}
 	}
 
@@ -427,7 +427,42 @@ func TestValidateLogGroupName(t *testing.T) {
 	for _, v := range invalidNames {
 		_, errors := validateLogGroupName(v, "name")
 		if len(errors) == 0 {
-			t.Fatalf("%q should be an invalid Log Metric Filter Transformation Name", v)
+			t.Fatalf("%q should be an invalid Log Group name", v)
+		}
+	}
+}
+
+func TestValidateLogGroupNamePrefix(t *testing.T) {
+	validNames := []string{
+		"ValidLogGroupName",
+		"ValidLogGroup.Name",
+		"valid/Log-group",
+		"1234",
+		"YadaValid#0123",
+		"Also_valid-name",
+		strings.Repeat("W", 483),
+	}
+	for _, v := range validNames {
+		_, errors := validateLogGroupNamePrefix(v, "name_prefix")
+		if len(errors) != 0 {
+			t.Fatalf("%q should be a valid Log Group name prefix: %q", v, errors)
+		}
+	}
+
+	invalidNames := []string{
+		"Here is a name with: colon",
+		"and here is another * invalid name",
+		"also $ invalid",
+		"This . is also %% invalid@!)+(",
+		"*",
+		"",
+		// length > 483
+		strings.Repeat("W", 484),
+	}
+	for _, v := range invalidNames {
+		_, errors := validateLogGroupNamePrefix(v, "name_prefix")
+		if len(errors) == 0 {
+			t.Fatalf("%q should be an invalid Log Group name prefix", v)
 		}
 	}
 }

website/source/docs/providers/aws/r/cloudwatch_log_group.html.markdown

@@ -27,7 +27,8 @@ resource "aws_cloudwatch_log_group" "yada" {
 
 The following arguments are supported:
 
-* `name` - (Required) The name of the log group
+* `name` - (Optional, Forces new resource) The name of the log group. If omitted, Terraform will assign a random, unique name.
+* `name_prefix` - (Optional, Forces new resource) Creates a unique name beginning with the specified prefix. Conflicts with `name`.
 * `retention_in_days` - (Optional) Specifies the number of days
   you want to retain log events in the specified log group.
 * `tags` - (Optional) A mapping of tags to assign to the resource.