Some providers (namely Kubernetes) require unbounded parallelism in
order to function correctly. This commit enables the engine to operate
in a mode with unbounded parallelism and switches to that mode by
default.
* Process deletions conservatively in parallel
This commit allows the engine to conservatively delete resources in
parallel when it is sure that it is legal to do so. In the absence of a
true data-flow oriented step scheduler, this approach provides a
significant improvement over the existing serial deletion mechanism.
Instead of processing deletes serially, this commit will partition the
set of condemned resources into sets of resources that are known to be
legally deletable in parallel. The step executor will then execute those
independent lists of steps one-by-one until all steps are complete.
* CR: Make ResourceSet a normal map
* Only use the dependency graph if we can trust it
* Reverse polarity of pendingDeletesAreReplaces
* CR: un-export a few types
* CR: simplify control flow in step generator when scheduling
* CR: parents are dependencies, fix loop index
* CR: Remove ParentOf, add new test for parent dependencies
* Serialize SourceEvents coming from the refresh source
The engine requires that a source event coming from a source be "ready
to execute" at the moment that it is sent to the engine. Since the
refresh source sent all goal states eagerly through its source iterator,
the engine assumed that it was legal to execute them all in parallel and
did so. This is a problem for the snapshot, since the snapshot expects
to be in an order that is a legal topological ordering of the dependency
DAG.
This PR fixes the issue by sending refresh source events one-at-a-time
through the refresh source iterator, only unblocking to send the next
step as soon as the previous step completes.
* Fix deadlock in refresh test
* Fix an issue where the engine "completed" steps too early
By signalling that a step is done before committing the step's results
to the snapshot, the engine was left with a race where dependent
resources could find themselves completely executed and committed before
a resource that they depend on has been committed.
Fixespulumi/pulumi#1726
* Fix an issue with Replace steps at the end of a plan
If the last step that was executed successfully was a Replace, we could
end up in a situation where we unintentionally left the snapshot
invalid.
* Add a test
* CR: pass context.Context as first parameter to Iterate
* CR: null->nil
* Execute chains of steps in parallel
Fixespulumi/pulumi#1624. Since register resource steps are known to be
ready to execute the moment the engine sees them, we can effectively
parallelize all incoming step chains. This commit adds the machinery
necessary to do so - namely a step executor and a plan executor.
* Remove dead code
* CR: use atomic.Value to be explicit about what values are atomically loaded and stored
* CR: Initialize atomics to 'false'
* Add locks around data structures in event callbacks
* CR: Add DegreeOfParallelism method on Options and add comment on select in Execute
* CR: Use context.Context for cancellation instead of cancel.Source
* CR: improve cancellation
* Rebase against master: execute read steps in parallel
* Please gometalinter
* CR: Inline a few methods in stepExecutor
* CR: Feedback and bug fixes
1. Simplify step_executor.go by 'bubbling' up errors as far as possible
and reporting diagnostics and cancellation in one place
2. Fix a bug where the CLI claimed that a plan was cancelled even if it
wasn't (it just has an error)
* Comments
* CR: Add comment around problematic select, move workers.Add outside of goroutine, return instead of break
