A Transaction Defines What Must Succeed Together

Wed, 01 Feb 2017 00:00:00 +0000

A booking flow reserved funds, completed the remote booking, and captured the funds. Only then did synchronous response processing fail. The remote booking existed, the funds were captured, and the caller received a failure.

The capture was individually valid, and its own database transaction committed cleanly. It was still too early. We had drawn the success boundary around “remote booking returned” while the operation promised something larger: a complete booking result which the caller could use.

A Correlation Identifier Is a Boundary Contract

Thu, 01 Sep 2016 00:00:00 +0000

We had logs everywhere and still could not follow one shipment through the system. It had failed somewhere after payment and before its documents were ready, but the application, queue worker, and remote adapter did not share an identifier.

The investigation started with timestamps, account details, and values which looked related. Payment was plausible, as were several remote calls nearby. Some trails took hours to disprove because they belonged to different requests which happened at roughly the same time. We did not need more log lines. We needed a chain of custody.

Distributed-Systems on Brian Faust

A Transaction Defines What Must Succeed Together

A Correlation Identifier Is a Boundary Contract