Workflow VS message-db

I was part of that debate, I remember a rather interesting point of discussion: Is the main operation "apply" or "dedup"

Apply seems to be the common notion of event sourcing: There is a function apply that takes a state an event and yields a new state. Then, starting in an init state and iteratively applying the entire event history, boom, latest state restored.

Dedup has a lot of charm though: Run and rerun your code, if that step of your code is executed for the first time (no corresponding event in the event history) execute the step and store its result as an event in the history, however, if that step of your code is executed for the second, third time (there is a corresponding event in the event history) do not execute the step and return its result from the event in the history. The Haskell Workflow Package (https://hackage.haskell.org/package/Workflow) is a good example

Temporal follows the second approach, so "proper" Event Sourcing? You be the judge :)

I’m addition to the alternatives mentioned, here’s another Postgres-only ES implementation: https://github.com/message-db/message-db

Thalo is a new Rust library that provides a runtime for WASM-based event sourcing. With Thalo, developers can compile their aggregates and components into WASM modules and use them in the runtime to handle commands and persist events to an event store. The library is built on top of Wasmtime and Message DB, and uses the ESDL schema language to define aggregates. While Thalo is not yet ready for real-world use, it has the potential to make event sourcing more accessible to a wider range of languages that compile to WASM, allowing for a language-agnostic runtime. Give it a try and let us know what you think! https://github.com/thalo-rs/thalo

Its built on top of Wasmtime for wasm execution, and MessageDb which is a message store for Postgres.

We are using message db which is uses postgres under the hood, and provides a few useful postgres functions. We use it with `postgres-simple` and have a small internal library. However my colleague is working on abstracting our logic and open sourcing into a library here: https://github.com/Disco-Dave/message-db

Check out MessageDB https://github.com/message-db/message-db. It's basically Postgres and can be installed into any Postgres DB.

Trying a new language or framework is fun experiments that you spend a few hours on. I have been enjoying implementing Message DB[0] in a hobby project. My current job is not in programming, and not looking for one.

[0]https://github.com/message-db/message-db