Error Handling

DynamoDBError is a sealed trait that represents all the possible errors that can occur when interacting with DynamoDB and is returned by the DynamoDBQuery execute method.

def execute: ZIO[DynamoDBExecutor, DynamoDBError, Out] = ???

The error hierarchy is as follows:

• DynamoDBError top level sealed trait
  • DynamoDBError.ItemError sealed trait for item level errors
    • DynamoDBError.ItemError.ValueNotFound - returned by get in the High Level API. If you expect items to be missing you can use the maybeFound extension method to return None in this scenario. see Working With get Return Values for more details.
    • DynamoDBError.ItemError.DecodingError - returned by automatic codecs in the High Level API when data does not match the expected type described by the schema
  • DynamoDBError.AWSError - case class that contains the underlying AWS Exception. Typically, you need to pattern match on this when you expect a specific AWS exception eg AWS ConditionalCheckFailedException when you do a strict insert operation by having a condition expression that asserts the primary key does not exist.
  • DynamoDBError.BatchError sealed trait for batch related errors. You need to consider this error if queries result in batching eg if you are using DynamoDBQuery.forEach or manually Zip'ing together DynamoDBQuery's or using utility functions that use DynamoDBQuery.forEach. Note at the point that this error is raised automatic retries have already occurred. For a long running process typical handler actions would be to record the errors and to carry on processing. See Auto batching and parallelisation section for more details.
    • DynamoDBError.BatchError.GetError - case class returned by automatic batching - unprocessedKeys contains a Map of table name to primary key
    • DynamoDBError.BatchError.WriteError - returned by automatic batching - unprocessedItems contains a map of table name to item/primary key
  • DynamoDBError.TransactionError sealed trait for transaction related errors. You need to handle this error if you are using the transaction API ie <dynamoDBQuery>.transaction or <dynamoDBQuery>.safeTransaction
    • DynamoDBError.TransactionError.EmptyTransaction
    • DynamoDBError.TransactionError.MixedTransactionTypes
    • DynamoDBError.TransactionError.InvalidTransactionActions