Removing env var credentials provider.

SnapStart uses a different credentials provider so when it is hardcoded like this, the default will fail.

Author: msailes

powertools-idempotency/src/main/java/software/amazon/lambda/powertools/idempotency/Constants.java

@@ -17,4 +17,5 @@ public class Constants {
     public static final String LAMBDA_FUNCTION_NAME_ENV = "AWS_LAMBDA_FUNCTION_NAME";
     public static final String AWS_REGION_ENV = "AWS_REGION";
     public static final String IDEMPOTENCY_DISABLED_ENV = "POWERTOOLS_IDEMPOTENCY_DISABLED";
+    public static final String AWS_LAMBDA_INITIALIZATION_TYPE = "AWS_LAMBDA_INITIALIZATION_TYPE";
 }

powertools-idempotency/src/main/java/software/amazon/lambda/powertools/idempotency/persistence/DynamoDBPersistenceStore.java

@@ -88,6 +88,14 @@ private DynamoDBPersistenceStore(String tableName,
                 DynamoDbClientBuilder ddbBuilder = DynamoDbClient.builder()
                         .httpClient(UrlConnectionHttpClient.builder().build())
                         .region(Region.of(System.getenv(AWS_REGION_ENV)));
+
+                // AWS_LAMBDA_INITIALIZATION_TYPE has two values on-demand and snap-start
+                // when using snap-start mode, the env var creds provider isn't used and causes a fatal error
+                // fall back to the default provider chain if the mode is anything other than on-demand.
+                if (System.getenv().get(Constants.AWS_LAMBDA_INITIALIZATION_TYPE) == "on-demand") {
+                    ddbBuilder.credentialsProvider(EnvironmentVariableCredentialsProvider.create());
+                }
+
                 this.dynamoDbClient = ddbBuilder.build();
             } else {
                 // we do not want to create a DynamoDbClient if idempotency is disabled