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Migrating from Roomservice to runkernel backend

Status​

The runkernel backend is experimental and opt-in.

Roomservice remains the default build backend. Use runkernel when you want to try the workflow-backed build engine while keeping a simple rollback path.

What stays the same​

  • sailr build
  • sailr go
  • --only
  • --ignore
  • --force
  • --plan
  • --dry-run
  • --explain
  • --dump-scope
  • service build config
  • build hooks

What changes​

  • runkernel stores its task cache under .sailr/cache/runkernel; Sailr build outcome records remain under .sailr/cache/build.
  • Roomservice stores cache under .roomservice.
  • runkernel uses SailrBuildPlan plus a runkernel Pipeline internally.
  • service hooks and commands are represented as deterministic phase tasks with IDs such as service:api:run_parallel:0; the aggregate remains service:api:build.
  • service inputs are resolved and sorted before they enter runkernel. Explicit cache keys include command and configuration fingerprints.

Try it​

sailr build --name dev --engine runkernel --plan
sailr build --name dev --engine runkernel --explain
sailr build --name dev --engine runkernel
sailr init --name dev --engine runkernel
sailr migrate --name dev --engine runkernel

You can also opt in through config:

[build]
engine = "runkernel"
fail_fast = false

Roll back​

sailr build --name dev --engine roomservice

Or remove [build].engine = "runkernel" from config.toml; the default backend is still Roomservice.

Known limitations​

  • Roomservice remains the default unless --engine runkernel or [build].engine = "runkernel" is selected.

  • sailr init and sailr migrate preserve Roomservice unless --engine runkernel is explicit. Migration converts schema 0.5.0 and records the engine without switching existing configurations automatically.

  • Deployment hooks can have external side effects and are not automatically reversible.

  • Sailr-scoped runkernel cache metadata is stored under .sailr/cache/runkernel; Sailr build outcome records remain under .sailr/cache/build. Sailr does not create a top-level .runkernel directory.

The runkernel translator exposes command phases as deterministic graph nodes such as service:api:run_parallel:0 and retains service:api:build as the service completion node.