What is stream?

Stream is a library for Go developers who want to build applications using "event sourcing" and store their data in Amazon's DynamoDB. Event sourcing is a way of building software where, instead of just saving the latest state of your data, you save a running log of every single thing that has ever happened. Think of it like a bank transaction ledger: rather than just recording your current balance, you record every deposit and withdrawal, and the current balance is simply the sum of all those events. The way this library works is that you define a "state model", a piece of code that receives incoming events and decides what should happen next. For example, it might collect a certain number of inputs, and once it hits a threshold, it produces an output event. The library handles the plumbing of saving these events to DynamoDB, and it can be wired up to other Amazon services so that whenever your state model produces an outgoing event, it automatically gets sent along to the next part of your system. A developer would use this when they are building a system that needs a reliable, auditable history of changes, like an inventory system that tracks every stock movement, or a financial application where you need a perfect record of every transaction. Instead of writing all the database and event-routing logic from scratch, they can use this library to handle the repetitive plumbing work. The project is built specifically for the Amazon Web Services ecosystem. It uses DynamoDB as the underlying storage engine and is designed to connect to DynamoDB Streams, which can then forward outgoing events to Amazon EventBridge. This makes it a good fit for teams already invested in AWS infrastructure, though it does mean the library is tightly coupled to that specific cloud provider. The README doesn't go into detail on setup or configuration beyond pointing to an example directory in the code.