System architecture

Recommended

• Write each quality goal as a scenario with a number

  ARC-86

  Write each quality goal that shapes the design as a scenario with a measure. Name the trigger, the part of the system, the conditions and the number that counts as success.

• Check each architecture decision with a fitness function

  ARC-87

  Turn each architecture decision that code can break into a test the build runs, called a fitness function. Module borders inside one app get one first.

• Choose how fresh each piece of shared data must be

  ARC-89

  For each piece of data that two parts of the system read, write down the consistency it needs. Choose strong, read-your-writes or eventual, and give the longest delay you accept.

• Give each outside dependency its own pool

  ARC-90

  Give each outside service the app calls its own connection pool or limit on calls at once. A slow or failing service then uses up only its own share.

• Run a change across services as a saga with undo steps

  ARC-91

  When one business action changes data owned by two or more services, run it as a saga. Each step commits locally, and each step that can fail later has an undo step that runs on failure.