commit 53d1ff8f3c0969c1225b229f74b6d204648fd180
author Vadim Shtayura <vadimsh@chromium.org> Fri Apr 04 19:43:52 2025
committer LUCI CQ <infra-scoped@luci-project-accounts.iam.gserviceaccount.com> Fri Apr 04 19:43:52 2025
tree 0f408c515b279c0973b0d522a427cd45a2cd3003
parent 270d22109d6e93ba6196a7b662a688a7143e7b75

[swarming] Refactor "tasks" package and how it is tested.

The primary motivation is to do all changes to state of
tasks via a single interface tasks.Manager, which is
passed to other server subsystems (botapi, rpcs, scan,
etc). It encapsulates all necessary dependencies to
change tasks (removing the need for callbacks soup added
in https://chromium-review.googlesource.com/c/6427869).

Tests for botapi and other server parts can just mock it
out by using &tasks.MockedManager{}.

But some RPC tests actually rely on implementation of tasks
logic. To avoid breaking (or significantly changing) them,
we need to use the "production" implementation, but mock
some of its bits, in particular all TQ tasks.

To avoid adding back the need to pass extra fields other
than tasks.Manager, and to avoid excessively polluting
tasks implementation with mocks, use tqtesting.Scheduler
infrastructure in tests. This would also eventually allow
to run more high-level integration-like tests (since
tqtesting.Scheduler can actually run full workflows).

Unfortunately, it has its own can of worms: tq.AddTask can
only add tasks that have been registered in the dispatcher,
and there are a bunch of different packages that register
tasks.

To avoid coupling between all these packages, move TQ task
definitions into a dedicated "tqtasks" package that just
exposes all known TQ tasks, without their implementations.

Finally, make API of various existing task operations more
consistent. In particular, cancellation now always require
the caller to open a transaction, just like ClaimOp and
AbandonOp.

To simplify this transactional API, use txndefer.Defer(...)
to register post-transactional work, like metrics reporting,
instead of making callers to call post-txn functions
explicitly.

txndefer.Defer is already used by server/tq implementation,
so it is already a significantly dependency of the server.

R=chanli@chromium.org

Change-Id: Ie016a416d9b0eec10bdd7e96d6a1a39476d6287c
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/6433706
Reviewed-by: Chan Li <chanli@chromium.org>
Commit-Queue: Vadim Shtayura <vadimsh@chromium.org>