add invalid option group detector for RDS

detector/aws_db_instance_invalid_option_group.go

@@ -0,0 +1,60 @@
+package detector
+
+import (
+	"fmt"
+
+	"github.com/aws/aws-sdk-go/service/rds"
+	"github.com/wata727/tflint/issue"
+)
+
+type AwsDBInstanceInvalidOptionGroupDetector struct {
+	*Detector
+}
+
+func (d *Detector) CreateAwsDBInstanceInvalidOptionGroupDetector() *AwsDBInstanceInvalidOptionGroupDetector {
+	return &AwsDBInstanceInvalidOptionGroupDetector{d}
+}
+
+func (d *AwsDBInstanceInvalidOptionGroupDetector) Detect(issues *[]*issue.Issue) {
+	if !d.isDeepCheck("resource", "aws_db_instance") {
+		return
+	}
+
+	validOptionGroups := map[string]bool{}
+	if d.ResponseCache.DescribeOptionGroupsOutput == nil {
+		resp, err := d.AwsClient.Rds.DescribeOptionGroups(&rds.DescribeOptionGroupsInput{})
+		if err != nil {
+			d.Logger.Error(err)
+			d.Error = true
+		}
+		d.ResponseCache.DescribeOptionGroupsOutput = resp
+	}
+	for _, optionGroup := range d.ResponseCache.DescribeOptionGroupsOutput.OptionGroupsList {
+		validOptionGroups[*optionGroup.OptionGroupName] = true
+	}
+
+	for filename, list := range d.ListMap {
+		for _, item := range list.Filter("resource", "aws_db_instance").Items {
+			optionGroupToken, err := hclLiteralToken(item, "option_group_name")
+			if err != nil {
+				d.Logger.Error(err)
+				continue
+			}
+			optionGroup, err := d.evalToString(optionGroupToken.Text)
+			if err != nil {
+				d.Logger.Error(err)
+				continue
+			}
+
+			if !validOptionGroups[optionGroup] {
+				issue := &issue.Issue{
+					Type:    "ERROR",
+					Message: fmt.Sprintf("\"%s\" is invalid option group name.", optionGroup),
+					Line:    optionGroupToken.Pos.Line,
+					File:    filename,
+				}
+				*issues = append(*issues, issue)
+			}
+		}
+	}
+}

detector/aws_db_instance_invalid_option_group_test.go

@@ -0,0 +1,92 @@
+package detector
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/service/rds"
+	"github.com/golang/mock/gomock"
+	"github.com/wata727/tflint/awsmock"
+	"github.com/wata727/tflint/config"
+	"github.com/wata727/tflint/issue"
+)
+
+func TestDetectAwsDBInstanceInvalidOptionGroup(t *testing.T) {
+	cases := []struct {
+		Name     string
+		Src      string
+		Response []*rds.OptionGroup
+		Issues   []*issue.Issue
+	}{
+		{
+			Name: "option_group is invalid",
+			Src: `
+resource "aws_db_instance" "mysql" {
+    option_group_name = "app-server"
+}`,
+			Response: []*rds.OptionGroup{
+				&rds.OptionGroup{
+					OptionGroupName: aws.String("app-server1"),
+				},
+				&rds.OptionGroup{
+					OptionGroupName: aws.String("app-server2"),
+				},
+			},
+			Issues: []*issue.Issue{
+				&issue.Issue{
+					Type:    "ERROR",
+					Message: "\"app-server\" is invalid option group name.",
+					Line:    3,
+					File:    "test.tf",
+				},
+			},
+		},
+		{
+			Name: "option_group is valid",
+			Src: `
+resource "aws_db_instance" "mysql" {
+    option_group_name = "app-server"
+}`,
+			Response: []*rds.OptionGroup{
+				&rds.OptionGroup{
+					OptionGroupName: aws.String("app-server1"),
+				},
+				&rds.OptionGroup{
+					OptionGroupName: aws.String("app-server2"),
+				},
+				&rds.OptionGroup{
+					OptionGroupName: aws.String("app-server"),
+				},
+			},
+			Issues: []*issue.Issue{},
+		},
+	}
+
+	for _, tc := range cases {
+		c := config.Init()
+		c.DeepCheck = true
+
+		awsClient := c.NewAwsClient()
+		ctrl := gomock.NewController(t)
+		defer ctrl.Finish()
+		rdsmock := awsmock.NewMockRDSAPI(ctrl)
+		rdsmock.EXPECT().DescribeOptionGroups(&rds.DescribeOptionGroupsInput{}).Return(&rds.DescribeOptionGroupsOutput{
+			OptionGroupsList: tc.Response,
+		}, nil)
+		awsClient.Rds = rdsmock
+
+		var issues = []*issue.Issue{}
+		TestDetectByCreatorName(
+			"CreateAwsDBInstanceInvalidOptionGroupDetector",
+			tc.Src,
+			c,
+			awsClient,
+			&issues,
+		)
+
+		if !reflect.DeepEqual(issues, tc.Issues) {
+			t.Fatalf("Bad: %s\nExpected: %s\n\ntestcase: %s", issues, tc.Issues, tc.Name)
+		}
+	}
+}

detector/detector.go

@@ -32,6 +32,7 @@ var detectors = map[string]string{
 	"aws_db_instance_invalid_vpc_security_group":      "CreateAwsDBInstanceInvalidVPCSecurityGroupDetector",
 	"aws_db_instance_invalid_db_subnet_group":         "CreateAwsDBInstanceInvalidDBSubnetGroupDetector",
 	"aws_db_instance_invalid_parameter_group":         "CreateAwsDBInstanceInvalidParameterGroupDetector",
+	"aws_db_instance_invalid_option_group":            "CreateAwsDBInstanceInvalidOptionGroupDetector",
 	"aws_elasticache_cluster_default_parameter_group": "CreateAwsElastiCacheClusterDefaultParameterGroupDetector",
 	"aws_instance_invalid_iam_profile":                "CreateAwsInstanceInvalidIAMProfileDetector",
 	"aws_instance_invalid_ami":                        "CreateAwsInstanceInvalidAMIDetector",

detector/response_cache.go

@@ -15,4 +15,5 @@ type ResponseCache struct {
 	DescribeInstancesOutput         *ec2.DescribeInstancesOutput
 	DescribeDBSubnetGroupsOutput    *rds.DescribeDBSubnetGroupsOutput
 	DescribeDBParameterGroupsOutput *rds.DescribeDBParameterGroupsOutput
+	DescribeOptionGroupsOutput      *rds.DescribeOptionGroupsOutput
 }

docs/AWS_DB_Instance_Invalid_Option_Group.md

@@ -0,0 +1,38 @@
+# AWS DB Instance Invalid Option Group
+Report this issue if you have specified the invalid option group name. This issue type is ERROR. This issue is enable only with deep check.
+
+## Example
+```
+resource "aws_db_instance" "mysql" {
+  identifier             = "app"
+  allocated_storage      = 50
+  storage_type           = "gp2"
+  engine                 = "mysql"
+  engine_version         = "5.7.11"
+  instance_class         = "db.m4.large"
+  name                   = "app_db"
+  port                   = 3306
+  publicly_accessible    = false
+  vpc_security_group_ids = ["sg-12345678"]
+  db_subnet_group_name   = "app-subnet-group"
+  parameter_group_name   = "default.mysql5.7"
+  option_group_name      = "invalid_option"
+  multi_az               = true
+}
+```
+
+The following is the execution result of TFLint: 
+
+```
+$ tflint --deep
+template.tf
+        ERROR:14 "invalid_option" is invalid option group name.
+
+Result: 1 issues  (1 errors , 0 warnings , 0 notices)
+```
+
+## Why
+If an invalid option group name is specified, an error will occur at `terraform apply`.
+
+## How to fix
+Check your option groups and select a valid name again.

docs/AWS_DB_Instance_Invalid_Parameter_Group.md

@@ -1,5 +1,5 @@
 # AWS DB Instance Invalid Parameter Group
-Report this issue if you have specified the invalid DB subnet group name. This issue type is ERROR. This issue is enable only with deep check.
+Report this issue if you have specified the invalid parameter name. This issue type is ERROR. This issue is enable only with deep check.
 
 ## Example
 ```

docs/README.md

@@ -33,5 +33,6 @@ Issues are classified into the following three types.
     - [Invalid VPC Security Group](AWS_DB_Instance_Invalid_VPC_Security_Group.md)
     - [Invalid DB Subnet Group](AWS_DB_Instance_Invalid_DB_Subnet_Group.md)
     - [Invalid Parameter Group](AWS_DB_Instance_Invalid_Parameter_Group.md)
+    - [Invalid Option Group](AWS_DB_Instance_Invalid_Option_Group.md)
 - AWS Elasticache Cluster
     - [Default Parameter Group](AWS_Elasticache_Cluster_Default_Parameter_Group.md)