Go example that removes all S3 buckets with given prefix (#964)

Go example that removes all S3 buckets with given prefix, including first removing all objects in the buckets

go/example_code/s3/delete-buckets-by-prefix/README.md

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+# AWS SDK for Go Code Examples for Amazon S3
+
+## Purpose
+
+This example demonstrates how to delete all of the Amazon S3 buckets you own that begin with a given prefix.
+
+## Prerequisites
+
+You must have an AWS account, and have your default credentials and AWS Region
+configured as described in
+[Configuring the AWS SDK for Go](https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/configuring-sdk.html)
+in the AWS SDK for Go Developer Guide.
+
+## Running the Code
+
+### Syntax
+
+`go run s3_delete_buckets -p` *PREFIX*
+
+- *PREFIX* is the first characters of the names of the Amazon S3 buckets to delete.
+
+For example, if you call `go run s3_delete_buckets.go -p dummy-`,
+it first removes all of the objects in the Amazon S3 buckets with names starting with *dummy-*,
+then deletes all of those S3 buckets.
+
+### Notes
+
+- We recommend that you grant this code least privilege,
+  or at most the minimum  permissions required to perform the task.
+  For more information, see
+  [Grant Least Privilege](https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html#grant-least-privilege)
+  in the AWS Identity and Access Management User Guide.
+- This code has not been tested in all Regions.
+  Some AWS services are available only in specific 
+  [Regions](https://aws.amazon.com/about-aws/global-infrastructure/regional-product-services).
+- Running this code might result in charges to your AWS account.
+
+## Running the Unit Tests
+
+Unit tests should delete any resources they create.
+However, they might result in charges to your 
+AWS account.
+
+The unit test:
+
+1. Creates three S3 buckets,
+   with a name starting with *dummy-*,
+   followed by a GUID, and then the numbers 0-2.
+2. Lists all of the buckets with a name starting with *dummy-*
+3. Removes all objects in the S3 buckets with names starting with *dummy-*
+4. Deletes all S3 buckets with names starting with *dummy-*
+5. Lists all of the buckets with a name starting with *dummy-*
+
+To run the unit test, enter:
+
+`go test`
+
+You should see something like the following,
+where PATH is the path to folder containing the Go files:
+
+```
+PASS
+ok      PATH 6.593s
+```
+
+If you want to see any log messages, enter:
+
+`go test -test.v`
+
+You should see some additional log messages.
+The last two lines should be similar to the previous output shown.
+
+You can confirm it has deleted any resources it created by running:
+
+Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. SPDX-License-Identifier: Apache-2.0

go/example_code/s3/delete-buckets-by-prefix/metadata.yaml

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+---
+created: 2020-02-14
+files:
+  - path: s3_delete_buckets.go
+    apis:
+      - service: s3
+        operations:
+          - ListBuckets
+          - DeleteBucket
+          - WaitUntilBucketNotExists

go/example_code/s3/delete-buckets-by-prefix/s3_delete_buckets.go

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+/*
+   Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+   This file is licensed under the Apache License, Version 2.0 (the "License").
+   You may not use this file except in compliance with the License. A copy of
+   the License is located at
+
+    http://aws.amazon.com/apache2.0/
+
+   This file is distributed on an "AS IS" BASIS, 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 main
+
+import (
+	"flag"
+	"fmt"
+	"strings"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-sdk-go/service/s3"
+	"github.com/aws/aws-sdk-go/service/s3/s3manager"
+)
+
+func deleteBucketsByPrefix(sess *session.Session, prefix string) error {
+	// Create Amazon S3 service client
+	svc := s3.New(sess)
+
+	// Empty list to hold names of S3 buckets with prefix
+	bucketList := make([]string, 0)
+
+	result, err := svc.ListBuckets(nil)
+	if err != nil {
+		return err
+	}
+
+	for _, b := range result.Buckets {
+		// Does bucket name start with prefix
+		if strings.HasPrefix(*b.Name, prefix) {
+			bucketList = append(bucketList, *b.Name)
+		}
+	}
+
+	for _, b := range bucketList {
+		// First delete any objects in the bucket
+		iter := s3manager.NewDeleteListIterator(svc, &s3.ListObjectsInput{
+			Bucket: aws.String(b),
+		})
+
+		err := s3manager.NewBatchDeleteWithClient(svc).Delete(aws.BackgroundContext(), iter)
+		if err != nil {
+			return err
+		}
+
+		_, err = svc.DeleteBucket(&s3.DeleteBucketInput{
+			Bucket: aws.String(b),
+		})
+		if err != nil {
+			return err
+		}
+
+		err = svc.WaitUntilBucketNotExists(&s3.HeadBucketInput{
+			Bucket: aws.String(b),
+		})
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// Deletes any S3 buckets in the default AWS Region
+// that start with the given text
+//
+// Usage:
+//    go run s3_delete_buckets -p PREFIX
+func main() {
+	prefixPtr := flag.String("p", "", "The prefix of the buckets to delete")
+	flag.Parse()
+	prefix := *prefixPtr
+
+	if prefix == "" {
+		fmt.Println("You must supply a bucket prefix")
+		return
+	}
+
+	// Initialize a session that the SDK uses to load
+	// credentials from the shared credentials file (~/.aws/credentials)
+	sess := session.Must(session.NewSessionWithOptions(session.Options{
+		SharedConfigState: session.SharedConfigEnable,
+	}))
+
+	err := deleteBucketsByPrefix(sess, prefix)
+	if err != nil {
+		fmt.Println("Could not delete buckets with prefix " + prefix)
+	} else {
+		fmt.Println("Deleted buckets with prefix " + prefix)
+	}
+}

go/example_code/s3/delete-buckets-by-prefix/s3_delete_buckets_test.go

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+/*
+   Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+   This file is licensed under the Apache License, Version 2.0 (the "License").
+   You may not use this file except in compliance with the License. A copy of
+   the License is located at
+
+    http://aws.amazon.com/apache2.0/
+
+   This file is distributed on an "AS IS" BASIS, 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 main
+
+import (
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/google/uuid"
+
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/aws/aws-sdk-go/service/s3"
+	"github.com/aws/aws-sdk-go/service/s3/s3manager"
+)
+
+func createBucket(sess *session.Session, bucketName string) error {
+	// Create Amazon S3 service client
+	svc := s3.New(sess)
+
+	// Create the S3 Bucket
+	_, err := svc.CreateBucket(&s3.CreateBucketInput{
+		Bucket: aws.String(bucketName),
+	})
+	if err != nil {
+		return err
+	}
+
+	// Wait until bucket is created before finishing
+	return svc.WaitUntilBucketExists(&s3.HeadBucketInput{
+		Bucket: aws.String(bucketName),
+	})
+}
+
+func populateBucket(sess *session.Session, bucket string) error {
+	s3Svc := s3.New(sess)
+
+	// Create an uploader with S3 client and default options
+	uploader := s3manager.NewUploaderWithClient(s3Svc)
+
+	// Add some dummy data to the bucket
+	text := "abc"
+	body := strings.NewReader(text)
+
+	upParams := &s3manager.UploadInput{
+		Bucket: &bucket,
+		Key:    aws.String("dummy"),
+		Body:   body,
+	}
+
+	_, err := uploader.Upload(upParams)
+	return err
+}
+
+// listBuckets lists the S3 buckets with the given prefix
+func listBuckets(sess *session.Session, prefix string, t *testing.T) error {
+	// Create S3 service client
+	svc := s3.New(sess)
+
+	result, err := svc.ListBuckets(nil)
+	if err != nil {
+		t.Log("Could not list buckets")
+		return err
+	}
+
+	for _, b := range result.Buckets {
+		if strings.HasPrefix(*b.Name, prefix) {
+			t.Log(*b.Name)
+		}
+	}
+
+	return nil
+}
+
+func TestDeleteBuckets(t *testing.T) {
+	// When the test started
+	thisTime := time.Now()
+	nowString := thisTime.Format("20060102150405")
+	t.Log("Starting unit test at " + nowString)
+
+	// Initialize a session that the SDK uses to load
+	// credentials from the shared credentials file (~/.aws/credentials)
+	sess := session.Must(session.NewSessionWithOptions(session.Options{
+		SharedConfigState: session.SharedConfigEnable,
+	}))
+
+	// Create a unique GUID
+	id := uuid.New()
+	defaultName := id.String()
+
+	// Create 3 dummy buckets with prefix "dummy-"
+	prefix := "dummy-"
+
+	for i := 0; i < 3; i++ {
+		name := prefix + defaultName + strconv.Itoa(i)
+
+		err := createBucket(sess, name)
+		if err != nil {
+			t.Fatal("Could not create bucket: " + name)
+		}
+
+		t.Log("Created bucket " + name)
+
+		err = populateBucket(sess, name)
+		if err != nil {
+			t.Fatal("Could not populate bucket")
+		}
+	}
+
+	// List the buckets
+	t.Log("Buckets that start with " + prefix + ":")
+	err := listBuckets(sess, prefix, t)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Now delete them
+	err = deleteBucketsByPrefix(sess, prefix)
+	if err != nil {
+		t.Log("You might have to delete these buckets with:")
+		t.Log("go run s3_delete_buckets.go -p dummy-")
+		t.Fatal(err)
+	} else {
+		t.Log("Deleted buckets with prefix " + prefix)
+	}
+
+	// List the buckets
+	t.Log("Now here are your buckets that start with " + prefix + ":")
+	err = listBuckets(sess, prefix, t)
+	if err != nil {
+		t.Fatal(err)
+	}
+}