Skip to content

Instantly share code, notes, and snippets.

@joaoferrao joaoferrao/caws.go
Last active Mar 11, 2019

Embed
What would you like to do?
AWS Resource Crawler
package main
import (
"fmt"
"github.com/aws/aws-sdk-go/aws"
"github.com/aws/aws-sdk-go/aws/session"
"github.com/aws/aws-sdk-go/service/resourcegroupstaggingapi"
"github.com/olekukonko/tablewriter"
"os"
"strings"
)
// TraceableRegions is a list of AWS regions we want to crawl
//var TraceableRegions = [...]string{"us-east-1", "us-east-2", "us-west-1", "us-west-2", "ca-central-1", "eu-central-1", "eu-west-1", "eu-west-2", "eu-west-3", "eu-north-1", "ap-northeast-1", "ap-northeast-2", "ap-northeast-3", "ap-southeast-1", "ap-southeast-2", "ap-south-1", "sa-east-1"}
var TraceableRegions = [...]string{"eu-west-1"}
// SingleResource defines how we want to describe each AWS resource
type SingleResource struct {
Region *string
Service *string
Product *string
Details *string
ID *string
ARN *string
}
// PrettyPrintResources makes use of a nice golang library to show
// tables on stdout. Check it out: github.com/olekukonko/tablewriter
func PrettyPrintResources(resources []*SingleResource) {
var data [][]string
for _, r := range resources {
row := []string{
DerefNilPointerStrings(r.Region),
DerefNilPointerStrings(r.Service),
DerefNilPointerStrings(r.Product),
DerefNilPointerStrings(r.ID),
}
data = append(data, row)
}
table := tablewriter.NewWriter(os.Stdout)
table.SetHeader([]string{"Region", "Service", "Product", "ID"})
table.SetBorder(true) // Set Border to false
table.AppendBulk(data)
table.Render()
}
// GetServiceFromArn removes the arn:aws: component string of
// the name and returns the first keyword that appears, svc
func ServiceNameFromARN(arn *string) *string {
shortArn := strings.Replace(*arn, "arn:aws:", "", -1)
sliced := strings.Split(shortArn, ":")
return &sliced[0]
}
// Short ARN removes the unnecessary info from the ARN we already
// know at this point like region, account id and the service name.
func ShortArn(arn *string) string {
slicedArn := strings.Split(*arn, ":")
shortArn := slicedArn[5:] // the first 5 we already have
return strings.Join(shortArn, "/")
}
// awsEC2 type is created for ARNs belonging to the EC2 service
type awsEC2 string
// awsECS type is created for ARNs belonging to the ECS service
type awsECS string
// awsGeneric is a is a generic AWS for services ARNs that don't have
// a dedicated type within our application.
type awsGeneric string
// Generic Resource Handler
func (aws *awsGeneric) ConverToResource(shortArn, svc, rgn *string) *SingleResource {
return &SingleResource{ARN: shortArn, Region: rgn, Service: svc, ID: shortArn,}
}
// ConvertToRow converts EC2 shortened ARNs to to a SingleResource type
func (aws *awsEC2) ConvertToResource(shortArn, svc, rgn *string) *SingleResource {
// ec2 instance/i-23123jj1k1k23jh12
// ec2 security-group/sg-23bn1m231233123m1
// ec2 subnet/subnet-92i3i1i23i1ih1v23
// ec2 vpc/vpc-12i3o1ijkj12jh123
s := strings.Split(*shortArn, "/")
return &SingleResource{ARN: shortArn, Region: rgn, Service: svc, Product: &s[0], ID: &s[1],}
}
// ConvertToRow converts ECS shortened ARNs to to a SingleResource type
func (aws *awsECS) ConvertToResource(shortArn, svc, rgn *string) *SingleResource {
// ecs cluster/some-ecs-cluster
s := strings.Split(*shortArn, "/")
return &SingleResource{ARN: shortArn, Region: rgn, Service: svc, Product: &s[0], ID: &s[1],}
}
// GetResourceRow shortens the ARN and assigns it to the right
// service type calling its "ConvertToRow" method. Since we have
// a default behaviour funneled towards our awsGeneric type, all
// services will be handled.
func ConvertArnToSingleResource(arn, svc, rgn *string) *SingleResource {
shortArn := ShortArn(arn)
switch *svc {
case "ec2":
res := awsEC2(*svc)
return res.ConvertToResource(&shortArn, svc, rgn)
case "ecs":
res := awsECS(*svc)
return res.ConvertToResource(&shortArn, svc, rgn)
default:
res := awsGeneric(*svc)
return res.ConverToResource(&shortArn, svc, rgn)
}
}
// DerefNilPointerStrings utility func to make sure we don't run into
// a "nil pointer dereference" issue during runtime.
func DerefNilPointerStrings(s *string) string {
if s == nil {
return ""
}
return *s
}
func main() {
var resources []*SingleResource
for _, region := range TraceableRegions {
// We need to create a new CFG for each region. We
// could actually update the region after the fact
// but let's focus on the purpose, here :)
cfg := aws.Config{Region: aws.String(region)}
s := session.Must(session.NewSessionWithOptions(session.Options{
SharedConfigState: session.SharedConfigEnable,
Config: cfg,
}))
// Creating the actual AWS client from the SDK
r := resourcegroupstaggingapi.New(s)
// The results will come paginated, so we create an empty
// one outside the next for loop so we can keep updating
// it and check if there are still more results to come or
// not. We could isolate this function and call it recursively
// if we wanted to tidy up our code.
var paginationToken string = ""
var in *resourcegroupstaggingapi.GetResourcesInput
var out *resourcegroupstaggingapi.GetResourcesOutput
var err error
// Let's start an infinite for loop until there are no
for {
if len(paginationToken) == 0 {
in = &resourcegroupstaggingapi.GetResourcesInput{
ResourcesPerPage: aws.Int64(50),
}
out, err = r.GetResources(in)
if err != nil {
fmt.Println(err)
}
} else {
in = &resourcegroupstaggingapi.GetResourcesInput{
ResourcesPerPage: aws.Int64(50),
PaginationToken: &paginationToken,
}
}
out, err = r.GetResources(in)
if err != nil {
fmt.Println(err)
}
for _, resource := range out.ResourceTagMappingList {
svc := ServiceNameFromARN(resource.ResourceARN)
rgn := region
resources = append(resources, ConvertArnToSingleResource(resource.ResourceARN, svc, &rgn))
}
paginationToken = *out.PaginationToken
if *out.PaginationToken == "" {
break
}
}
}
// Finally print the results
PrettyPrintResources(resources)
}
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.