From 1a4c7b5f3cc307ced6e3f22d3a386d38332ca0ce Mon Sep 17 00:00:00 2001
From: John Gardiner Myers <jgmyers@proofpoint.com>
Date: Mon, 12 Jun 2023 19:29:34 -0700
Subject: [PATCH] Support DynamoDB tables in other regions

---
 docs/registry/dynamodb.md     | 1 +
 main.go                       | 7 ++++++-
 pkg/apis/externaldns/types.go | 3 +++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/docs/registry/dynamodb.md b/docs/registry/dynamodb.md
index 92f90de69..9e5f8331f 100644
--- a/docs/registry/dynamodb.md
+++ b/docs/registry/dynamodb.md
@@ -6,6 +6,7 @@ The DynamoDB registry stores DNS record metadata in an AWS DynamoDB table.
 
 By default, the DynamoDB registry stores data in the table named `external-dns`.
 A different table may be specified using the `--dynamodb-table` flag.
+A different region may be specified using the `--dynamodb-region` flag.
 
 The table must have a partition (hash) key named `k` and string type.
 The table must not have a sort (range) key.
diff --git a/main.go b/main.go
index 65dbb3e7e..d83a4e25d 100644
--- a/main.go
+++ b/main.go
@@ -25,6 +25,7 @@ import (
 	"syscall"
 	"time"
 
+	awsSDK "github.com/aws/aws-sdk-go/aws"
 	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/dynamodb"
 	"github.com/aws/aws-sdk-go/service/route53"
@@ -397,7 +398,11 @@ func main() {
 	var r registry.Registry
 	switch cfg.Registry {
 	case "dynamodb":
-		r, err = registry.NewDynamoDBRegistry(p, cfg.TXTOwnerID, dynamodb.New(awsSession), cfg.AWSDynamoDBTable, cfg.TXTCacheInterval)
+		config := awsSDK.NewConfig()
+		if cfg.AWSDynamoDBRegion != "" {
+			config = config.WithRegion(cfg.AWSDynamoDBRegion)
+		}
+		r, err = registry.NewDynamoDBRegistry(p, cfg.TXTOwnerID, dynamodb.New(awsSession, config), cfg.AWSDynamoDBTable, cfg.TXTCacheInterval)
 	case "noop":
 		r, err = registry.NewNoopRegistry(p)
 	case "txt":
diff --git a/pkg/apis/externaldns/types.go b/pkg/apis/externaldns/types.go
index a45d9ad30..0b022ef6e 100644
--- a/pkg/apis/externaldns/types.go
+++ b/pkg/apis/externaldns/types.go
@@ -93,6 +93,7 @@ type Config struct {
 	AWSPreferCNAME                     bool
 	AWSZoneCacheDuration               time.Duration
 	AWSSDServiceCleanup                bool
+	AWSDynamoDBRegion                  string
 	AWSDynamoDBTable                   string
 	AzureConfigFile                    string
 	AzureResourceGroup                 string
@@ -256,6 +257,7 @@ var defaultConfig = &Config{
 	AWSPreferCNAME:              false,
 	AWSZoneCacheDuration:        0 * time.Second,
 	AWSSDServiceCleanup:         false,
+	AWSDynamoDBRegion:           "",
 	AWSDynamoDBTable:            "external-dns",
 	AzureConfigFile:             "/etc/kubernetes/azure.json",
 	AzureResourceGroup:          "",
@@ -581,6 +583,7 @@ func (cfg *Config) ParseFlags(args []string) error {
 	app.Flag("txt-wildcard-replacement", "When using the TXT registry, a custom string that's used instead of an asterisk for TXT records corresponding to wildcard DNS records (optional)").Default(defaultConfig.TXTWildcardReplacement).StringVar(&cfg.TXTWildcardReplacement)
 	app.Flag("txt-encrypt-enabled", "When using the TXT registry, set if TXT records should be encrypted before stored (default: disabled)").BoolVar(&cfg.TXTEncryptEnabled)
 	app.Flag("txt-encrypt-aes-key", "When using the TXT registry, set TXT record decryption and encryption 32 byte aes key (required when --txt-encrypt=true)").Default(defaultConfig.TXTEncryptAESKey).StringVar(&cfg.TXTEncryptAESKey)
+	app.Flag("dynamodb-region", "When using the DynamoDB registry, the AWS region of the DynamoDB table (optional)").Default(cfg.AWSDynamoDBRegion).StringVar(&cfg.AWSDynamoDBRegion)
 	app.Flag("dynamodb-table", "When using the DynamoDB registry, the name of the DynamoDB table (default: \"external-dns\")").Default(defaultConfig.AWSDynamoDBTable).StringVar(&cfg.AWSDynamoDBTable)
 
 	// Flags related to the main control loop