As documented in issue #616, the inputs/defaults/outputs model we have
today has fundamental problems. The crux of the issue is that our
current design requires that defaults present in the old state of a
resource are applied to the new inputs for that resource.
Unfortunately, it is not possible for the engine to decide which
defaults remain applicable and which do not; only the provider has that
knowledge.
These changes take a more tactical approach to resolving this issue than
that originally proposed in #616 that avoids breaking compatibility with
existing checkpoints. Rather than treating the Pulumi inputs as the
provider input properties for a resource, these inputs are first
translated by `Check`. In order to accommodate provider defaults that
were chosen for the old resource but should not change for the new,
`Check` now takes the old provider inputs as well as the new Pulumi
inputs. Rather than the Pulumi inputs and provider defaults, the
provider inputs returned by `Check` are recorded in the checkpoint file.
Put simply, these changes remove defaults as a first-class concept
(except inasmuch as is required to retain the ability to read old
checkpoint files) and move the responsibilty for manging and
merging defaults into the provider that supplies them.
Fixes#616.
This change adds a new manifest section to the checkpoint files.
The existing time moves into it, and we add to it the version of
the Pulumi CLI that created it, along with the names, types, and
versions of all plugins used to generate the file. There is a
magic cookie that we also use during verification.
This is to help keep us sane when debugging problems "in the wild,"
and I'm sure we will add more to it over time (checksum, etc).
For example, after an up, you can now see this in `pulumi stack`:
```
Current stack is demo:
Last updated at 2017-12-01 13:48:49.815740523 -0800 PST
Pulumi version v0.8.3-79-g1ab99ad
Plugin pulumi-provider-aws [resource] version v0.8.3-22-g4363e77
Plugin pulumi-langhost-nodejs [language] version v0.8.3-79-g77bb6b6
Checkpoint file is /Users/joeduffy/dev/code/src/github.com/pulumi/pulumi-aws/.pulumi/stacks/webserver/demo.json
```
This addresses pulumi/pulumi#628.
This change simplifies the necessary RPC changes for components.
Instead of a Begin/End pair, which complicates the whole system
because now we have the opportunity of a missing End call, we will
simply let RPCs come in that append outputs to existing states.
This change brings back component outputs to the overall system again.
In doing so, it generally overhauls the way we do resource RPCs a bit:
* Instead of RegisterResource and CompleteResource, we call these
BeginRegisterResource and EndRegisterResource, which begins to model
these as effectively "asynchronous" resource requests. This should also
help with parallelism (https://github.com/pulumi/pulumi/issues/106).
* Flip the CLI/engine a little on its head. Rather than it driving the
planning and deployment process, we move more to a model where it
simply observes it. This is done by implementing an event handler
interface with three events: OnResourceStepPre, OnResourceStepPost,
and OnResourceComplete. The first two are invoked immediately before
and after any step operation, and the latter is invoked whenever a
EndRegisterResource comes in. The reason for the asymmetry here is
that the checkpointing logic in the deployment engine is largely
untouched (intentionally, as this is a sensitive part of the system),
and so the "begin"/"end" nature doesn't flow through faithfully.
* Also make the engine more event-oriented in its terminology and the
way it handles the incoming BeginRegisterResource and
EndRegisterResource events from the language host. This is the first
step down a long road of incrementally refactoring the engine to work
this way, a necessary prerequisite for parallelism.
This change adds back component output properties. Doing so
requires splitting the RPC interface for creating resources in
half, with an initial RegisterResource which contains all of the
input properties, and a final CompleteResource which optionally
contains any output properties synthesized by the component.
This change switches from child lists to parent pointers, in the
way resource ancestries are represented. This cleans up a fair bit
of the old parenting logic, including all notion of ambient parent
scopes (and will notably address pulumi/pulumi#435).
This lets us show a more parent/child display in the output when
doing planning and updating. For instance, here is an update of
a lambda's text, which is logically part of a cloud timer:
* cloud:timer:Timer: (same)
[urn=urn:pulumi:malta::lm-cloud:☁️timer:Timer::lm-cts-malta-job-CleanSnapshots]
* cloud:function:Function: (same)
[urn=urn:pulumi:malta::lm-cloud:☁️function:Function::lm-cts-malta-job-CleanSnapshots]
* aws:serverless:Function: (same)
[urn=urn:pulumi:malta::lm-cloud::aws:serverless:Function::lm-cts-malta-job-CleanSnapshots]
~ aws:lambda/function:Function: (modify)
[id=lm-cts-malta-job-CleanSnapshots-fee4f3bf41280741]
[urn=urn:pulumi:malta::lm-cloud::aws:lambda/function:Function::lm-cts-malta-job-CleanSnapshots]
- code : archive(assets:2092f44) {
// etc etc etc
Note that we still get walls of text, but this will be actually
quite nice when combined with pulumi/pulumi#454.
I've also suppressed printing properties that didn't change during
updates when --detailed was not passed, and also suppressed empty
strings and zero-length arrays (since TF uses these as defaults in
many places and it just makes creation and deletion quite verbose).
Note that this is a far cry from everything we can possibly do
here as part of pulumi/pulumi#340 (and even pulumi/pulumi#417).
But it's a good start towards taming some of our output spew.
