Decouple the init of Crypto Plugin and KeyProvider in Registry (#18270)

Signed-off-by: Gulshan <kumargu@amazon.com>
Signed-off-by: Gulshan Kumar <kumargu@amazon.com>
Signed-off-by: Craig Perkins <cwperx@amazon.com>
Co-authored-by: Craig Perkins <cwperx@amazon.com>

Author: kumargu

CHANGELOG.md

@@ -21,6 +21,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Enable testing for ExtensiblePlugins using classpath plugins ([#16908](https://github.com/opensearch-project/OpenSearch/pull/16908))
 - Introduce system generated ingest pipeline ([#17817](https://github.com/opensearch-project/OpenSearch/pull/17817)))
 - Support create mode in pull-based ingestion and add retries for transient failures ([#18250](https://github.com/opensearch-project/OpenSearch/pull/18250)))
+- Decouple the init of Crypto Plugin and KeyProvider in CryptoRegistry ([18270](https://github.com/opensearch-project/OpenSearch/pull18270)))
 
 ### Changed
 

server/src/main/java/org/opensearch/crypto/CryptoHandlerRegistry.java

@@ -52,16 +52,17 @@ protected CryptoHandlerRegistry(
         List<CryptoKeyProviderPlugin> cryptoKeyProviderPlugins,
         Settings settings
     ) {
-        if (cryptoPlugins == null || cryptoPlugins.size() == 0) {
-            return;
-        }
-        if (cryptoPlugins.size() > 1) {
-            // We can remove this to support multiple implementations in future if needed.
-            throw new IllegalStateException("More than 1 implementation of crypto plugin found.");
+        if (cryptoPlugins != null && !cryptoPlugins.isEmpty()) {
+            if (cryptoPlugins.size() > 1) {
+                // We can remove this to support multiple implementations in future if needed.
+                throw new IllegalStateException("More than 1 implementation of crypto plugin found.");
+            }
+            cryptoHandlerPlugin.set(cryptoPlugins.get(0));
         }
 
-        cryptoHandlerPlugin.set(cryptoPlugins.get(0));
-        registry.set(loadCryptoFactories(cryptoKeyProviderPlugins));
+        if (cryptoKeyProviderPlugins != null && !cryptoKeyProviderPlugins.isEmpty()) {
+            registry.set(loadCryptoFactories(cryptoKeyProviderPlugins));
+        }
     }
 
     public static CryptoHandlerRegistry getInstance() {