Default error handling

IBM® App Connect Enterprise provides basic error handling for all your message flows.

When an exception is detected within a message flow node, the message and the exception information are propagated to the Failure terminal on the node. If the node does not have a Failure terminal, or is not connected, App Connect Enterprise throws an exception and returns control to the closest upstream node that can process it. The default behavior is that the message is returned to the input node.

The actions taken by the input node are protocol-dependent; if your message flow starts with an MQInput, its error handling is different from the error handling provided by a FileInput node. For more information, review the terminals and properties in the reference topic for the input node type.

The actions also depend on whether you have configured the message flow to be transactional. Some message flow nodes support transactions; others are non-transactional. If the flow is transactional, the message is returned to its source; for example, it is restored on the IBM MQ queue. For an overview of IBM MQ connection behavior, see IBM MQ topologies.

If basic error processing is not sufficient, and you want to take specific action in response to certain error conditions and situations, you can enhance your message flows to provide your own error handling. For example, you can add in a sequence of nodes to deal with one or more errors that you might expect to occur in your flow. You can also configure your flow to handle unexpected errors (exceptions). For more details about the actions that you can take, see Handling errors in message flows.