Can I break this?: Writing resilient “save” methods
summary
A concrete claim: improbable failures happen often enough to cost real money—one example is a job that charged a customer 12 times—so extract the persistence into a single save method and ask “can I break this.” Use ActiveRecord transactions and row locks to avoid partial writes, push side effects into a database-backed queue or outbox, and make async retries safe with an item potency key. The patterns produce a transactionally “green” save and prevent duplicate charges.
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