Document/Refactor code (#3)

* Document/Refactor code.
nirdosh17 · Aug 21, 2021 · 1f8f6d2 · 1f8f6d2
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diff --git a/README.md b/README.md
@@ -1,4 +1,7 @@
 # CFN Teardown
+[![Go Report Card](https://goreportcard.com/badge/github.com/nirdosh17/cfn-teardown)](https://goreportcard.com/report/github.com/nirdosh17/cfn-teardown)
+[![License: Apache-2.0](https://img.shields.io/badge/License-Apache-yellow.svg)](https://opensource.org/licenses/Apache-2.0)
+![Latest GitHub Release](https://img.shields.io/github/release/nirdosh17/cfn-teardown)
 
 CFN Teardown is a tool to delete matching CloudFormation stacks respecting stack dependencies.
 

diff --git a/cmd/deleteStacks.go b/cmd/deleteStacks.go
@@ -13,6 +13,8 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
+
+// Package cmd provides interface to register and define actions for all cli commands
 package cmd
 
 import (

diff --git a/cmd/listDependencies.go b/cmd/listDependencies.go
@@ -13,6 +13,8 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
+
+// Package cmd provides interface to register and define actions for all cli commands
 package cmd
 
 import (

diff --git a/cmd/root.go b/cmd/root.go
@@ -13,6 +13,8 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
+
+// Package cmd provides interface to register and define actions for all cli commands
 package cmd
 
 import (

diff --git a/cmd/version.go b/cmd/version.go
@@ -13,6 +13,8 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
+
+// Package cmd provides interface to register and define actions for all cli commands
 package cmd
 
 import (
@@ -21,6 +23,8 @@ import (
 	"github.com/spf13/cobra"
 )
 
+// Version is the current CLI version.
+// This is overwrriten by semantic version tag while building binaries.
 var Version = "development"
 
 // versionCmd represents the version command

diff --git a/models/cfn.go b/models/cfn.go
@@ -13,47 +13,94 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
+
+// Package models has definition of entities used in the process of teardown
 package models
 
+// StackDetails represents a cloudformation stack, it's state and dependencies.
 type StackDetails struct {
 	StackName             string
 	Status                string
 	StackStatusReason     string // useful for failed cases
 	DeleteStartedAt       string
-	DeleteCompletedAt     string // must be fetched from describe status command. Wait time should not be considered
-	DeletionTimeInMinutes string // total minutes taken to delete the stack
+	DeleteCompletedAt     string
+	DeletionTimeInMinutes string
 	DeleteAttempt         int16
 	Exports               []string
-	ActiveImporterStacks  map[string]struct{} // active(not deleted) stacks which are importing exports from THIS stack
+	ActiveImporterStacks  map[string]struct{} // active(not deleted) stacks which are importing exports from this stack
 	CFNConsoleLink        string
 }
 
+// ---------- Stack statuses and their eligibility for deletion ------------
 // https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/using-cfn-describing-stacks.html
-// Stack status and eligibility for deletion
-var CREATE_IN_PROGRESS string = "CREATE_IN_PROGRESS"                                                     // Wait
-var CREATE_FAILED string = "CREATE_FAILED"                                                               // Eligible for deletion
-var CREATE_COMPLETE string = "CREATE_COMPLETE"                                                           // Eligible for deletion
-var ROLLBACK_IN_PROGRESS string = "ROLLBACK_IN_PROGRESS"                                                 // Wait
-var ROLLBACK_FAILED string = "ROLLBACK_FAILED"                                                           // Eligible for deletion
-var ROLLBACK_COMPLETE string = "ROLLBACK_COMPLETE"                                                       // Eligible for deletion
-var DELETE_IN_PROGRESS string = "DELETE_IN_PROGRESS"                                                     // Wait
-var DELETE_FAILED string = "DELETE_FAILED"                                                               // Cannot be deleted. Manual Intervention Required. Post Message in RC.
-var DELETE_COMPLETE string = "DELETE_COMPLETE"                                                           // Skip
-var UPDATE_IN_PROGRESS string = "UPDATE_IN_PROGRESS"                                                     // Wait
-var UPDATE_COMPLETE_CLEANUP_IN_PROGRESS string = "UPDATE_COMPLETE_CLEANUP_IN_PROGRESS"                   // Wait
-var UPDATE_COMPLETE string = "UPDATE_COMPLETE"                                                           // Eligible for deletion
-var UPDATE_ROLLBACK_IN_PROGRESS string = "UPDATE_ROLLBACK_IN_PROGRESS"                                   // Wait
-var UPDATE_ROLLBACK_FAILED string = "UPDATE_ROLLBACK_FAILED"                                             // Cannot be deleted. Manual Intervention Required. Post Message in RC.
-var UPDATE_ROLLBACK_COMPLETE_CLEANUP_IN_PROGRESS string = "UPDATE_ROLLBACK_COMPLETE_CLEANUP_IN_PROGRESS" // Wait
-var UPDATE_ROLLBACK_COMPLETE string = "UPDATE_ROLLBACK_COMPLETE"                                         // Eligible for deletion
-var REVIEW_IN_PROGRESS string = "REVIEW_IN_PROGRESS"                                                     // Wait
-var IMPORT_IN_PROGRESS string = "IMPORT_IN_PROGRESS"                                                     // Wait
-var IMPORT_COMPLETE string = "IMPORT_COMPLETE"                                                           // Wait
-var IMPORT_ROLLBACK_IN_PROGRESS string = "IMPORT_ROLLBACK_IN_PROGRESS"                                   // Wait
-var IMPORT_ROLLBACK_FAILED string = "IMPORT_ROLLBACK_FAILED"                                             // Cannot be deleted. Manual Intervention Required. Post Message in RC.
-var IMPORT_ROLLBACK_COMPLETE string = "IMPORT_ROLLBACK_COMPLETE"                                         // Wait
-
-// all statuses except DELETE_COMPLETE
+
+// CREATE_IN_PROGRESS stack status requires waiting before sending delete request.
+var CREATE_IN_PROGRESS string = "CREATE_IN_PROGRESS"
+
+// CREATE_FAILED stack status is eligible for deletion.
+var CREATE_FAILED string = "CREATE_FAILED"
+
+// CREATE_COMPLETE stack status is eligible for deletion.
+var CREATE_COMPLETE string = "CREATE_COMPLETE"
+
+// ROLLBACK_IN_PROGRESS stack status requires waiting before sending delete request.
+var ROLLBACK_IN_PROGRESS string = "ROLLBACK_IN_PROGRESS"
+
+// ROLLBACK_FAILED stack status is eligible for deletion.
+var ROLLBACK_FAILED string = "ROLLBACK_FAILED"
+
+// ROLLBACK_COMPLETE stack status is eligible for deletion.
+var ROLLBACK_COMPLETE string = "ROLLBACK_COMPLETE"
+
+// DELETE_IN_PROGRESS stack status requires waiting before taking any action
+var DELETE_IN_PROGRESS string = "DELETE_IN_PROGRESS"
+
+// DELETE_FAILED stack status after max delete attempts is unactionable and requires manual intervention
+var DELETE_FAILED string = "DELETE_FAILED"
+
+// DELETE_COMPLETE stack status can be skipped as the stack has already been deleted
+var DELETE_COMPLETE string = "DELETE_COMPLETE"
+
+// UPDATE_IN_PROGRESS stack status requires waiting before sending delete request.
+var UPDATE_IN_PROGRESS string = "UPDATE_IN_PROGRESS"
+
+// UPDATE_COMPLETE_CLEANUP_IN_PROGRESS stack status requires waiting before sending delete request.
+var UPDATE_COMPLETE_CLEANUP_IN_PROGRESS string = "UPDATE_COMPLETE_CLEANUP_IN_PROGRESS"
+
+// UPDATE_COMPLETE stack status is eligible for deletion.
+var UPDATE_COMPLETE string = "UPDATE_COMPLETE"
+
+// UPDATE_ROLLBACK_IN_PROGRESS stack status requires waiting before sending delete request.
+var UPDATE_ROLLBACK_IN_PROGRESS string = "UPDATE_ROLLBACK_IN_PROGRESS"
+
+// UPDATE_ROLLBACK_FAILED stack status is eligible for deletion.
+var UPDATE_ROLLBACK_FAILED string = "UPDATE_ROLLBACK_FAILED"
+
+// UPDATE_ROLLBACK_COMPLETE_CLEANUP_IN_PROGRESS stack status requires waiting before sending delete request.
+var UPDATE_ROLLBACK_COMPLETE_CLEANUP_IN_PROGRESS string = "UPDATE_ROLLBACK_COMPLETE_CLEANUP_IN_PROGRESS"
+
+// UPDATE_ROLLBACK_COMPLETE stack status is eligible for deletion.
+var UPDATE_ROLLBACK_COMPLETE string = "UPDATE_ROLLBACK_COMPLETE"
+
+// REVIEW_IN_PROGRESS stack status requires waiting before sending delete request.
+var REVIEW_IN_PROGRESS string = "REVIEW_IN_PROGRESS"
+
+// IMPORT_IN_PROGRESS stack status requires waiting before sending delete request.
+var IMPORT_IN_PROGRESS string = "IMPORT_IN_PROGRESS"
+
+// IMPORT_COMPLETE stack status requires waiting before sending delete request.
+var IMPORT_COMPLETE string = "IMPORT_COMPLETE"
+
+// IMPORT_ROLLBACK_IN_PROGRESS stack status requires waiting before sending delete request.
+var IMPORT_ROLLBACK_IN_PROGRESS string = "IMPORT_ROLLBACK_IN_PROGRESS"
+
+// IMPORT_ROLLBACK_FAILED stack status is eligible for deletion.
+var IMPORT_ROLLBACK_FAILED string = "IMPORT_ROLLBACK_FAILED"
+
+// IMPORT_ROLLBACK_COMPLETE stack status requires waiting before sending delete request.
+var IMPORT_ROLLBACK_COMPLETE string = "IMPORT_ROLLBACK_COMPLETE"
+
+// ActiveStatuses includes all stack statuses except DELETE_COMPLETE
 var ActiveStatuses = []*string{
 	&CREATE_IN_PROGRESS,
 	&CREATE_FAILED,

diff --git a/models/nuke.go b/models/nuke.go
@@ -13,6 +13,8 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
+
+// Package models has definition of entities used in the process of teardown
 package models
 
 // Config represents all the parameters supported by cfn-teardown

diff --git a/utils/cloudformation.go b/utils/cloudformation.go
@@ -13,6 +13,8 @@ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */
+
+// Package utils provides cli specifics methods for interacting with AWS services
 package utils
 
 import (
@@ -26,9 +28,10 @@ import (
 	"github.com/aws/aws-sdk-go/service/cloudformation"
 	"github.com/aws/aws-sdk-go/service/sts"
 
-	. "github.com/nirdosh17/cfn-teardown/models"
+	"github.com/nirdosh17/cfn-teardown/models"
 )
 
+// CFNManager exposes methods to interact with CloudFormation via SDK.
 type CFNManager struct {
 	TargetAccountId string
 	NukeRoleARN     string
@@ -37,6 +40,7 @@ type CFNManager struct {
 	AWSRegion       string
 }
 
+// DescribeStack returns description for particular stack.
 func (dm CFNManager) DescribeStack(stackName string) (*cloudformation.Stack, error) {
 	cfn, err := dm.Session()
 	if err != nil {
@@ -50,6 +54,7 @@ func (dm CFNManager) DescribeStack(stackName string) (*cloudformation.Stack, err
 	return resp.Stacks[0], err
 }
 
+// ListStackResources lists description of all resources in a stack.
 func (dm CFNManager) ListStackResources(stackName string) ([]*cloudformation.StackResourceSummary, error) {
 	cfn, err := dm.Session()
 	if err != nil {
@@ -81,6 +86,7 @@ func (dm CFNManager) ListStackResources(stackName string) ([]*cloudformation.Sta
 	return resp.StackResourceSummaries, err
 }
 
+// ListImports lists all stacks importing given exported names.
 func (dm CFNManager) ListImports(exportNames []string) (map[string]struct{}, error) {
 	importers := make(map[string]struct{})
 	var err error
@@ -106,8 +112,8 @@ func (dm CFNManager) ListImports(exportNames []string) (map[string]struct{}, err
 	return importers, err
 }
 
-// No error means, delete request sent to cloudformation
-// If the stack we are trying to delete has already been deleted, returns success
+// DeleteStack sends delete request for a stack.
+// Returns success if the stack we are trying to delete has already been deleted.
 func (dm CFNManager) DeleteStack(stackName string) error {
 	fmt.Printf("Submitting delete request for stack: %v\n", stackName)
 	cfn, err := dm.Session()
@@ -117,21 +123,25 @@ func (dm CFNManager) DeleteStack(stackName string) error {
 	input := cloudformation.DeleteStackInput{StackName: &stackName}
 	// stack delete output is an empty struct
 	_, err = cfn.DeleteStack(&input)
+
+	// No error only means that the delete request was sent
+	// It does not gurantee that the stack will be deleted
 	return err
 }
 
-func (dm CFNManager) ListEnvironmentStacks() (map[string]StackDetails, error) {
+// ListEnvironmentStacks lists matching stacks for the given regex.
+func (dm CFNManager) ListEnvironmentStacks() (map[string]models.StackDetails, error) {
 	CFNConsoleBaseURL := "https://console.aws.amazon.com/cloudformation/home?region=" + dm.AWSRegion + "#/stacks/stackinfo?stackId="
 
 	// using stack name as key for easy traversal
-	envStacks := map[string]StackDetails{}
+	envStacks := map[string]models.StackDetails{}
 
 	cfn, err := dm.Session()
 	if err != nil {
 		return envStacks, err
 	}
 
-	input := cloudformation.ListStacksInput{StackStatusFilter: ActiveStatuses}
+	input := cloudformation.ListStacksInput{StackStatusFilter: models.ActiveStatuses}
 	// only returns first 100 stacks. Need to use NextToken
 	listStackOutput, err := cfn.ListStacks(&input)
 	if err != nil {
@@ -142,7 +152,7 @@ func (dm CFNManager) ListEnvironmentStacks() (map[string]StackDetails, error) {
 		// select stacks of our concern
 		stackName := *details.StackName
 		if dm.RegexMatch(stackName) {
-			sd := StackDetails{
+			sd := models.StackDetails{
 				StackName:      stackName,
 				Status:         *details.StackStatus,
 				CFNConsoleLink: (CFNConsoleBaseURL + stackName),
@@ -159,7 +169,7 @@ func (dm CFNManager) ListEnvironmentStacks() (map[string]StackDetails, error) {
 	nextToken := listStackOutput.NextToken
 	for nextToken != nil {
 		// sending next token for pagination
-		input = cloudformation.ListStacksInput{NextToken: nextToken, StackStatusFilter: ActiveStatuses}
+		input = cloudformation.ListStacksInput{NextToken: nextToken, StackStatusFilter: models.ActiveStatuses}
 		listStackOutput, err = cfn.ListStacks(&input)
 		if err != nil {
 			break
@@ -168,7 +178,7 @@ func (dm CFNManager) ListEnvironmentStacks() (map[string]StackDetails, error) {
 			// select stacks of our concern
 			stackName := *details.StackName
 			if dm.RegexMatch(stackName) {
-				sd := StackDetails{
+				sd := models.StackDetails{
 					StackName:      stackName,
 					Status:         *details.StackStatus,
 					CFNConsoleLink: (CFNConsoleBaseURL + stackName),
@@ -185,7 +195,11 @@ func (dm CFNManager) ListEnvironmentStacks() (map[string]StackDetails, error) {
 	return envStacks, err
 }
 
-// { "stack-1-name": ["export-1", "export-2"], "stack-2-name": []}
+// ListEnvironmentExports finds all exported values for our matching stacks in this format:
+// 	{
+//  	 "stack-1-name": ["export-1", "export-2"],
+//   	"stack-2-name": []
+// 	}
 func (dm CFNManager) ListEnvironmentExports() (map[string][]string, error) {
 	exports := map[string][]string{}
 
@@ -232,12 +246,15 @@ func (dm CFNManager) ListEnvironmentExports() (map[string][]string, error) {
 	return exports, err
 }
 
+// RegexMatch matches stack name with the supplied regex so that we can filter desired stacks for deletion.
 func (dm CFNManager) RegexMatch(stackName string) bool {
 	match, _ := regexp.MatchString(dm.StackPattern, stackName)
 	return match
 }
 
-// assumes staging nuke role
+// Session creates a new aws cloudformation session.
+// By default it uses given aws profile and region but it also provides option to assume a different role.
+// It also has validation for target account id to ensure we are deleting in the correct aws account.
 func (dm CFNManager) Session() (*cloudformation.CloudFormation, error) {
 	sess := session.Must(session.NewSessionWithOptions(session.Options{
 		Config:            aws.Config{Region: aws.String(dm.AWSRegion)},
@@ -265,14 +282,15 @@ func (dm CFNManager) Session() (*cloudformation.CloudFormation, error) {
 	if dm.NukeRoleARN == "" {
 		// this means, we are using given aws profile
 		return cloudformation.New(sess), nil
-	} else {
-		// Create the credentials from AssumeRoleProvider if nuke role arn is provided
-		creds := stscreds.NewCredentials(sess, dm.NukeRoleARN)
-		// Create service client value configured for credentials from assumed role.
-		return cloudformation.New(sess, &aws.Config{Credentials: creds, MaxRetries: &AWS_SDK_MAX_RETRY}), nil
 	}
+
+	// Create the credentials from AssumeRoleProvider if nuke role arn is provided
+	creds := stscreds.NewCredentials(sess, dm.NukeRoleARN)
+	// Create service client value configured for credentials from assumed role.
+	return cloudformation.New(sess, &aws.Config{Credentials: creds, MaxRetries: &AWS_SDK_MAX_RETRY}), nil
 }
 
+// AWSSessionAccountID fetches account id from current aws session
 func (dm CFNManager) AWSSessionAccountID(sess *session.Session) (acID string, err error) {
 	svc := sts.New(sess)
 	result, err := svc.GetCallerIdentity(&sts.GetCallerIdentityInput{})