Introducing WoGu: workflow correctness for Temporal

Temporal workflows are replayed: whenever a worker needs to reconstruct a workflow's state, it re-executes the workflow's code from the beginning of event history. That requirement — determinism — is easy to state and surprisingly easy to violate. A stray UUID.randomUUID(), a Thread.sleep(), a System.currentTimeMillis() call three method calls deep in a service class your workflow happens to invoke — any of these can produce a NonDeterministicException the first time a worker restarts or hands off a replay, often long after the code shipped and long after the pull request that introduced it was approved.

Today we're releasing WoGu v0.1.0 on Maven Central: a build plugin that checks for exactly this class of bug, the same way a coverage or static-analysis gate already runs in your build.

What ships today

Ten Determinism rules for the Temporal Java SDK — WG001 through WG010 — covering non-deterministic randomness, wall-clock reads, blocking sleeps, and unmanaged threads and executors. Every rule is built on the same recursive call-graph analysis: starting from a workflow's entry point, WoGu follows every method call it can resolve to source in your project, however many hops deep, and stops exactly at the boundary of a Temporal Activity implementation — because Activities aren't replayed, and shouldn't be flagged.

Why a build plugin, not a linter you run by hand

A rule that only runs when someone remembers to run it doesn't catch anything in practice. Binding to mvn verify (and gradle build, once the Gradle plugin is installed) means the check runs on every build, the same build your tests already run in — no separate step to forget, no separate CI job to wire up.

Try it

mvn verify

Add the plugin, per Installation, and that command is the whole setup. See Quick Start for a walkthrough of a real violation and its fix.

WoGu is Apache 2.0 licensed and built in the open — the rule engine, the report generator, and every rule's YAML definition are in the public repository.