pullbased

Pullbased, commonly written as pull-based, refers to a model in which data, updates, or tasks are retrieved by clients on demand rather than being pushed to them by producers. In a pull-based system, the consumer initiates requests to fetch the desired information, and the server responds with the available data. The model contrasts with push-based approaches where producers publish updates to subscribers or channels without a direct request from the consumer.

Key characteristics of pull-based systems include control over fetch rate, delayed delivery relative to production time, and the ability to cache or batch requests. This can simplify backpressure handling, reduce unnecessary data transfer, and support offline or intermittent connectivity scenarios. However, latency can be higher because data is not delivered until the next poll, and polling can create redundant requests if data has not changed.

Common domains and patterns that use pull-based approaches include web feeds (RSS/Atom) where clients fetch content by requesting a feed URL, distributed version control systems like Git where clients pull commits from remote repositories, and package managers that retrieve dependencies on demand. APIs may also employ polling endpoints for state checks or batch jobs, and some durability or caching layers use periodic pulls to synchronize state.

Advantages of pull-based designs include simplicity, explicit control over timing, and easier scalability for consumers. Drawbacks include potential inefficiency from frequent polling, higher latency for updates, and increased load on servers during polling surges. Hybrid models exist, such as long polling or server-sent events, to reduce latency while maintaining a mostly pull-based philosophy.