Fix SNS pattern regex to correctly valid sns fifo topic ARNs

Signed-off-by: Surya Sashank Nistala <snistala@amazon.com>

Author: eirsep

src/main/kotlin/org/opensearch/commons/notifications/model/Sns.kt

@@ -58,7 +58,7 @@ data class Sns(val topicArn: String, val roleArn: String?) : BaseConfigData {
         private val log by logger(Sns::class.java)
 
         private val SNS_ARN_REGEX =
-            Pattern.compile("^arn:aws(-[^:]+)?:sns:([a-zA-Z0-9-]+):([0-9]{12}):([a-zA-Z0-9-_]+)$")
+            Pattern.compile("^arn:aws(-[^:]+)?:sns:([a-zA-Z0-9-]+):([0-9]{12}):([a-zA-Z_0-9+=,.@\\-_/]+)$")
 
         /**
          * reader to create instance of class from writable.

src/test/kotlin/org/opensearch/commons/notifications/model/SnsTests.kt

@@ -8,6 +8,7 @@ package org.opensearch.commons.notifications.model
 import com.fasterxml.jackson.core.JsonParseException
 import org.junit.jupiter.api.Assertions
 import org.junit.jupiter.api.Assertions.assertThrows
+import org.junit.jupiter.api.Assertions.fail
 import org.junit.jupiter.api.Test
 import org.opensearch.commons.utils.createObjectFromJsonString
 import org.opensearch.commons.utils.getJsonString
@@ -49,6 +50,18 @@ internal class SnsTests {
         }
     }
 
+    @Test
+    fun `test SNS correctly validates SNS FIFO topic ARN`() {
+        try {
+            Sns(
+                "arn:aws:sns:ap-southeast-2:333654771707:sns-fifo-alerting.fifo",
+                "arn:aws:iam::012345678912:role/iam-test"
+            )
+        } catch (e: Exception) {
+            fail("Expected fifo sns topic ARN to be validated successfully", e)
+        }
+    }
+
     @Test
     fun `SNS serialize and deserialize transport object should be equal`() {
         val sampleSns = Sns("arn:aws:sns:us-east-1:012345678912:topic-test", "arn:aws:iam::012345678912:role/iam-test")