concurrent

pkg/provisioners/concurrent

Intention

pkg/provisioners/concurrent is the parallel-composition combinator for provisioners that do not depend on each other's ordering and can make progress in the same reconcile pass.

It is intended for reconciler-driven use, where child provisioners are expected to be idempotent, quick to yield, and safe to revisit on later retry passes.

Invariants And Guard Rails

• Provision(ctx) starts all child provisioners concurrently and waits for them all to return.
• Deprovision(ctx) starts all child deprovision operations concurrently and waits for them all to return.
• This combinator does not fail fast at the group level. A failure or yield from one child does not stop siblings that are already running in the same pass.
• The intended model is that child provisioners themselves fail or yield quickly rather than blocking for long periods.
• This package is appropriate only when children are genuinely independent and the system benefits from making parallel progress in one reconcile pass.
• The broader convergence model is still controller-driven retry. Partial progress is expected and later passes are expected to complete the remaining work.

Caveats

• This package does not manage dependencies. If children actually require ordering, the wrong combinator has been chosen.
• The returned error is only the first one preserved by errgroup, even if multiple children failed. The implementation logs child failures individually to reduce observability loss, but the API surface still collapses them.
• Because the group does not try to cancel sibling work on the first failure, this combinator depends on child provisioners being reconciler-friendly and fast to yield instead of sitting in long local retry loops.
• This is not a supervisor for long-running blocking tasks. If children block excessively, concurrent composition amplifies that bad behavior rather than fixing it.