Practical Microservices

Validating Eventually Consistent Data

While you are successfully recording user registration requests, we still haven’t justified the decision to use the View Data to validate that the emails supplied during registration aren’t duplicates, a direct contradiction of what we saidhere when first discussing the pieces of our architecture.

When making decisions like this, it’s important to ask a series of questions because the truth is, there is no single, correct-for-all-systems answer. There isn’t even a correct-for-all-kinds-of-data-within-the-same-system answer. There are always trade-offs, but if you’re asking the right questions, you can get answers that work for your needs. Consider:

• How likely is the thing you’re trying to prevent?
• How bad ...