Merge pull request #12 from wata727/aws_instance_subnet_deep_detector

add invalid subnet deep detector

detector/aws_instance_invalid_subnet.go

@@ -0,0 +1,61 @@
+package detector
+
+import (
+	"fmt"
+
+	"github.com/aws/aws-sdk-go/service/ec2"
+	"github.com/wata727/tflint/issue"
+)
+
+type AwsInstanceInvalidSubnetDetector struct {
+	*Detector
+}
+
+func (d *Detector) CreateAwsInstanceInvalidSubnetDetector() *AwsInstanceInvalidSubnetDetector {
+	return &AwsInstanceInvalidSubnetDetector{d}
+}
+
+func (d *AwsInstanceInvalidSubnetDetector) Detect(issues *[]*issue.Issue) {
+	if !d.Config.DeepCheck {
+		d.Logger.Info("skip this rule.")
+		return
+	}
+
+	validSubnets := map[string]bool{}
+	if d.ResponseCache.DescribeSubnetsOutput == nil {
+		resp, err := d.AwsClient.Ec2.DescribeSubnets(&ec2.DescribeSubnetsInput{})
+		if err != nil {
+			d.Logger.Error(err)
+			d.Error = true
+		}
+		d.ResponseCache.DescribeSubnetsOutput = resp
+	}
+	for _, subnet := range d.ResponseCache.DescribeSubnetsOutput.Subnets {
+		validSubnets[*subnet.SubnetId] = true
+	}
+
+	for filename, list := range d.ListMap {
+		for _, item := range list.Filter("resource", "aws_instance").Items {
+			subnetToken, err := hclLiteralToken(item, "subnet_id")
+			if err != nil {
+				d.Logger.Error(err)
+				continue
+			}
+			subnet, err := d.evalToString(subnetToken.Text)
+			if err != nil {
+				d.Logger.Error(err)
+				continue
+			}
+
+			if !validSubnets[subnet] {
+				issue := &issue.Issue{
+					Type:    "ERROR",
+					Message: fmt.Sprintf("\"%s\" is invalid subnet ID.", subnet),
+					Line:    subnetToken.Pos.Line,
+					File:    filename,
+				}
+				*issues = append(*issues, issue)
+			}
+		}
+	}
+}

detector/aws_instance_invalid_subnet_test.go

@@ -0,0 +1,89 @@
+package detector
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/service/ec2"
+	"github.com/golang/mock/gomock"
+	"github.com/wata727/tflint/awsmock"
+	"github.com/wata727/tflint/config"
+	"github.com/wata727/tflint/issue"
+)
+
+func TestDetectAwsInstanceInvalidSubnet(t *testing.T) {
+	cases := []struct {
+		Name     string
+		Src      string
+		Response []*ec2.Subnet
+		Issues   []*issue.Issue
+	}{
+		{
+			Name: "Subnet ID is invalid",
+			Src: `
+resource "aws_instance" "web" {
+    subnet_id = "subnet-1234abcd"
+}`,
+			Response: []*ec2.Subnet{
+				&ec2.Subnet{
+					SubnetId: aws.String("subnet-12345678"),
+				},
+				&ec2.Subnet{
+					SubnetId: aws.String("subnet-abcdefgh"),
+				},
+			},
+			Issues: []*issue.Issue{
+				&issue.Issue{
+					Type:    "ERROR",
+					Message: "\"subnet-1234abcd\" is invalid subnet ID.",
+					Line:    3,
+					File:    "test.tf",
+				},
+			},
+		},
+		{
+			Name: "key name is valid",
+			Src: `
+resource "aws_instance" "web" {
+    subnet_id = "subnet-1234abcd"
+}`,
+			Response: []*ec2.Subnet{
+				&ec2.Subnet{
+					SubnetId: aws.String("subnet-1234abcd"),
+				},
+				&ec2.Subnet{
+					SubnetId: aws.String("subnet-abcd1234"),
+				},
+			},
+			Issues: []*issue.Issue{},
+		},
+	}
+
+	for _, tc := range cases {
+		c := config.Init()
+		c.DeepCheck = true
+
+		awsClient := c.NewAwsClient()
+		ctrl := gomock.NewController(t)
+		defer ctrl.Finish()
+		ec2mock := awsmock.NewMockEC2API(ctrl)
+		ec2mock.EXPECT().DescribeSubnets(&ec2.DescribeSubnetsInput{}).Return(&ec2.DescribeSubnetsOutput{
+			Subnets: tc.Response,
+		}, nil)
+		awsClient.Ec2 = ec2mock
+
+		var issues = []*issue.Issue{}
+		TestDetectByCreatorName(
+			"CreateAwsInstanceInvalidSubnetDetector",
+			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

@@ -33,6 +33,7 @@ var detectors = map[string]string{
 	"aws_instance_invalid_iam_profile":                "CreateAwsInstanceInvalidIAMProfileDetector",
 	"aws_instance_invalid_ami":                        "CreateAwsInstanceInvalidAMIDetector",
 	"aws_instance_invalid_key_name":                   "CreateAwsInstanceInvalidKeyNameDetector",
+	"aws_instance_invalid_subnet":                     "CreateAwsInstanceInvalidSubnetDetector",
 }
 
 func NewDetector(listMap map[string]*ast.ObjectList, c *config.Config) (*Detector, error) {

detector/response_cache.go

@@ -8,5 +8,6 @@ import (
 type ResponseCache struct {
 	DescribeImagesOutput       *ec2.DescribeImagesOutput
 	DescribeKeyPairsOutput     *ec2.DescribeKeyPairsOutput
+	DescribeSubnetsOutput      *ec2.DescribeSubnetsOutput
 	ListInstanceProfilesOutput *iam.ListInstanceProfilesOutput
 }

docs/AWS_Instance_Invalid_Subnet.md

@@ -0,0 +1,33 @@
+# AWS Instance Invalid Subnet
+Report this issue if you have specified the invalid subnet ID. This issue type is ERROR. This issue is enable only with deep check.
+
+## Example
+```
+resource "aws_instance" "web" {
+  ami                  = "ami-1234abcd"
+  instance_type        = "t2.micro"
+  iam_instance_profile = "app-user"
+  key_name             = "secret"
+  subnet_id            = "subnet-1234abcd" # This subnet ID does not exists
+
+  tags {
+    Name = "HelloWorld"
+  }
+}
+```
+
+The following is the execution result of TFLint: 
+
+```
+$ tflint --deep
+template.tf
+        ERROR:6 "subnet-1234abcd" is invalid subnet ID.
+
+Result: 1 issues  (1 errors , 0 warnings , 0 notices)
+```
+
+## Why
+If an invalid subnet ID is specified, an error will occur at `terraform apply`.
+
+## How to fix
+Check your subnets and select a valid subnet ID again.

docs/README.md

@@ -19,6 +19,7 @@ Issues are classified into the following three types.
     - [Default Standard Volume](AWS_Instance_Default_Standard_Volume.md)
     - [Invalid AMI](AWS_Instance_Invalid_AMI.md)
     - [Invalid Key Name](AWS_Instance_Invalid_Key_Name.md)
+    - [Invalid Subnet](AWS_Instance_Invalid_Subnet.md)
 - AWS DB Instance
     - [Default Parameter Group](AWS_DB_Instance_Default_Parameter_Group.md)
 - AWS Elasticache Cluster