A checkpoint write is unnecessary if it does not change the semantics of
the data currently stored in the checkpoint. We currently perform
unnecessary checkpoint writes in two cases:
- Same steps where no aspect of the resource's state has changed
- Replace steps, which exist solely for display purposes
The former case is particularly bothersome, as it is rather common to
run updates--especially in CI--that consist largely/entirely of these
same steps.
These changes eliminate the checkpoint writes we perform in these two
cases. Some care is needed to ensure that we continue to write the
checkpoint in the case of same steps that do represent meaningful
changes (e.g. changes to a resource's output properties or
dependencies).
Fixes#1769.
* Add a list of in-flight operations to the deployment
This commit augments 'DeploymentV2' with a list of operations that are
currently in flight. This information is used by the engine to keep
track of whether or not a particular deployment is in a valid state.
The SnapshotManager is responsible for inserting and removing operations
from the in-flight operation list. When the engine registers an intent
to perform an operation, SnapshotManager inserts an Operation into this
list and saves it to the snapshot. When an operation completes, the
SnapshotManager removes it from the snapshot. From this, the engine can
infer that if it ever sees a deployment with pending operations, the
Pulumi CLI must have crashed or otherwise abnormally terminated before
seeing whether or not an operation completed successfully.
To remedy this state, this commit also adds code to 'pulumi stack
import' that clears all pending operations from a deployment, as well as
code to plan generation that will reject any deployments that have
pending operations present.
At the CLI level, if we see that we are in a state where pending
operations were in-flight when the engine died, we'll issue a
human-friendly error message that indicates which resources are in a bad
state and how to recover their stack.
* CR: Multi-line string literals, renaming in-flight -> pending
* CR: Add enum to apitype for operation type, also name status -> type for clarity
* Fix the yaml type
* Fix missed renames
* Add implementation for lifecycle_test.go
* Rebase against master
* 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
This change adds some convenience functions and types, to make strongly
typed outputs more pleasant to interact with. It also includes tests
for output generally, in addition to these new functions and types.
* Refactor the SnapshotManager interface
Lift snapshot management out of the engine by delegating it to the
SnapshotManager implementation in pkg/backend.
* Add a event interface for plugin loads and use that interface to record plugins in the snapshot
* Remove dead code
* Add comments to Events
* Add a number of tests for SnapshotManager
* CR feedback: use a successful bit on 'End' instead of having a separate 'Abort' API
* CR feedback
* CR feedback: register plugins one-at-a-time instead of the entire state at once
* Lift snapshot management out of the engine
This PR is a prerequisite for parallelism by addressing a major problem
that the engine has to deal with when performing parallel resource
construction: parallel mutation of the global snapshot. This PR adds
a `SnapshotManager` type that is responsible for maintaining and
persisting the current resource snapshot. It serializes all reads and
writes to the global snapshot and persists the snapshot to persistent
storage upon every write.
As a side-effect of this, the core engine no longer needs to know about
snapshot management at all; all snapshot operations can be handled as
callbacks on deployment events. This will greatly simplify the
parallelization of the core engine.
Worth noting is that the core engine will still need to be able to read
the current snapshot, since it is interested in the dependency graphs
contained within. The full implications of that are out of scope of this
PR.
Remove dead code, Steps no longer need a reference to the plan iterator that created them
Fixing various issues that arise when bringing up pulumi-aws
Line length broke the build
Code review: remove dead field, fix yaml name error
Rebase against master, provide implementation of StackPersister for cloud backend
Code review feedback: comments on MutationStatus, style in snapshot.go
Code review feedback: move SnapshotManager to pkg/backend, change engine to use an interface SnapshotManager
Code review feedback: use a channel for synchronization
Add a comment and a new test
* Maintain two checkpoints, an immutable base and a mutable delta, and
periodically merge the two to produce snapshots
* Add a lot of tests - covers all of the non-error paths of BeginMutation and End
* Fix a test resource provider
* Add a few tests, fix a few issues
* Rebase against master, fixed merge