### First-Class Providers
These changes implement support for first-class providers. First-class
providers are provider plugins that are exposed as resources via the
Pulumi programming model so that they may be explicitly and multiply
instantiated. Each instance of a provider resource may be configured
differently, and configuration parameters may be source from the
outputs of other resources.
### Provider Plugin Changes
In order to accommodate the need to verify and diff provider
configuration and configure providers without complete configuration
information, these changes adjust the high-level provider plugin
interface. Two new methods for validating a provider's configuration
and diffing changes to the same have been added (`CheckConfig` and
`DiffConfig`, respectively), and the type of the configuration bag
accepted by `Configure` has been changed to a `PropertyMap`.
These changes have not yet been reflected in the provider plugin gRPC
interface. We will do this in a set of follow-up changes. Until then,
these methods are implemented by adapters:
- `CheckConfig` validates that all configuration parameters are string
or unknown properties. This is necessary because existing plugins
only accept string-typed configuration values.
- `DiffConfig` either returns "never replace" if all configuration
values are known or "must replace" if any configuration value is
unknown. The justification for this behavior is given
[here](https://github.com/pulumi/pulumi/pull/1695/files#diff-a6cd5c7f337665f5bb22e92ca5f07537R106)
- `Configure` converts the config bag to a legacy config map and
configures the provider plugin if all config values are known. If any
config value is unknown, the underlying plugin is not configured and
the provider may only perform `Check`, `Read`, and `Invoke`, all of
which return empty results. We justify this behavior becuase it is
only possible during a preview and provides the best experience we
can manage with the existing gRPC interface.
### Resource Model Changes
Providers are now exposed as resources that participate in a stack's
dependency graph. Like other resources, they are explicitly created,
may have multiple instances, and may have dependencies on other
resources. Providers are referred to using provider references, which
are a combination of the provider's URN and its ID. This design
addresses the need during a preview to refer to providers that have not
yet been physically created and therefore have no ID.
All custom resources that are not themselves providers must specify a
single provider via a provider reference. The named provider will be
used to manage that resource's CRUD operations. If a resource's
provider reference changes, the resource must be replaced. Though its
URN is not present in the resource's dependency list, the provider
should be treated as a dependency of the resource when topologically
sorting the dependency graph.
Finally, `Invoke` operations must now specify a provider to use for the
invocation via a provider reference.
### Engine Changes
First-class providers support requires a few changes to the engine:
- The engine must have some way to map from provider references to
provider plugins. It must be possible to add providers from a stack's
checkpoint to this map and to register new/updated providers during
the execution of a plan in response to CRUD operations on provider
resources.
- In order to support updating existing stacks using existing Pulumi
programs that may not explicitly instantiate providers, the engine
must be able to manage the "default" providers for each package
referenced by a checkpoint or Pulumi program. The configuration for
a "default" provider is taken from the stack's configuration data.
The former need is addressed by adding a provider registry type that is
responsible for managing all of the plugins required by a plan. In
addition to loading plugins froma checkpoint and providing the ability
to map from a provider reference to a provider plugin, this type serves
as the provider plugin for providers themselves (i.e. it is the
"provider provider").
The latter need is solved via two relatively self-contained changes to
plan setup and the eval source.
During plan setup, the old checkpoint is scanned for custom resources
that do not have a provider reference in order to compute the set of
packages that require a default provider. Once this set has been
computed, the required default provider definitions are conjured and
prepended to the checkpoint's resource list. Each resource that
requires a default provider is then updated to refer to the default
provider for its package.
While an eval source is running, each custom resource registration,
resource read, and invoke that does not name a provider is trapped
before being returned by the source iterator. If no default provider
for the appropriate package has been registered, the eval source
synthesizes an appropriate registration, waits for it to complete, and
records the registered provider's reference. This reference is injected
into the original request, which is then processed as usual. If a
default provider was already registered, the recorded reference is
used and no new registration occurs.
### SDK Changes
These changes only expose first-class providers from the Node.JS SDK.
- A new abstract class, `ProviderResource`, can be subclassed and used
to instantiate first-class providers.
- A new field in `ResourceOptions`, `provider`, can be used to supply
a particular provider instance to manage a `CustomResource`'s CRUD
operations.
- A new type, `InvokeOptions`, can be used to specify options that
control the behavior of a call to `pulumi.runtime.invoke`. This type
includes a `provider` field that is analogous to
`ResourceOptions.provider`.
This change includes a bunch of refactorings I made in prep for
doing refresh (first, the command, see pulumi/pulumi#1081):
* The primary change is to change the way the engine's core update
functionality works with respect to deploy.Source. This is the
way we can plug in new sources of resource information during
planning (and, soon, diffing). The way I intend to model refresh
is by having a new kind of source, deploy.RefreshSource, which
will let us do virtually everything about an update/diff the same
way with refreshes, which avoid otherwise duplicative effort.
This includes changing the planOptions (nee deployOptions) to
take a new SourceFunc callback, which is responsible for creating
a source specific to the kind of plan being requested.
Preview, Update, and Destroy now are primarily differentiated by
the kind of deploy.Source that they return, rather than sprinkling
things like `if Destroying` throughout. This tidies up some logic
and, more importantly, gives us precisely the refresh hook we need.
* Originally, we used the deploy.NullSource for Destroy operations.
This simply returns nothing, which is how Destroy works. For some
reason, we were no longer doing this, and instead had some
`if Destroying` cases sprinkled throughout the deploy.EvalSource.
I think this is a vestige of some old way we did configuration, at
least judging by a comment, which is apparently no longer relevant.
* Move diff and diff-printing logic within the engine into its own
pkg/engine/diff.go file, to prepare for upcoming work.
* I keep noticing benign diffs anytime I regenerate protobufs. I
suspect this is because we're also on different versions. I changed
generate.sh to also dump the version into grpc_version.txt. At
least we can understand where the diffs are coming from, decide
whether to take them (i.e., a newer version), and ensure that as
a team we are monotonically increasing, and not going backwards.
* I also tidied up some tiny things I noticed while in there, like
comments, incorrect types, lint suppressions, and so on.
When a stack has secrets, we now take the secret values and construct
a regular expression which is just an alternation of all the secret
values. Then, before pushing any string data into an Event, we run the
regular expression and replace all matches with '[secret]'.
Fixes#747
The engine now emits events with richer metadata during the
ResourceOutputs and ResourcePre callbacks. The CLI can then use this
information to decide if it should display the event or not and how
much of the event to display.
Options dealing with what to display and how to display it have moved
into the CLI and the engine now emits all information for each event.
The engine now unconditionally emits a new type of event, a
PreludeEvent, which contains the configuration for a stack as well as
an indication if the stack is being previewed or updated. The
responsibility for interpreting the --show-config flag on the command
line is now handled by the CLI, which uses this to decide if it should
print the configuration or not, and then writes the "Previewing
changes" or "Deploying chanages" header.
The existing logic would flow colorization information into the
engine, so depending on the settings in the CLI, the engine may or may
not have emitted colorized events. This coupling is not great and we
want to start moving to a world where the presentation happens
exclusively at the CLI level.
With this change, the engine will always produce strings that have the
colorization formatting directives (i.e. the directives that
reconquest/loreley understands) and the CLI will apply
colorization (which could mean either running loreley to turn the
directives into ANSI escape codes, or drop them or retain them, for
debuging purposes).
Fixes#742
Our recent changes to colorization changed from a boolean to a tri-valued
enum (Always, Never, Raw). The events from the service, however, are still
boolean-valued. This changes the message payload to carry the full values.
Part of the work to make it easier to tests of diff output. Specifically, we now allow users to pass --color=option for several pulumi commands. 'option' can be one of 'always', 'never', 'raw', and 'auto' (the default).
The meaning of these flags are:
1. auto: colorize normally, unless in --debug
2. always: always colorize no matter what
3. never: never colorize no matter what.
4. raw: colorize, but preserve the original "<{%%}>" style control codes and not the translated platform specific codes. This is for testing purposes and ensures we can have test for this stuff across platform.
The change to use a Goroutine for pumping output causes a hang
when an error occurs. This is because we unconditionally block
on the <-done channel, even though the failure means the done
will actually never occur. This changes the logic to only wait
on the channel if we successfully began the operation in question.
Previously, the engine would write to io.Writer's to display output.
When hosted in `pulumi` these writers were tied to os.Stdout and
os.Stderr, but other applications hosting the engine could send them
other places (e.g. a log to be sent to an another application later).
While much better than just using the ambient streams, this was still
not the best. It would be ideal if the engine could just emit strongly
typed events and whatever is hosting the engine could care about
displaying them.
As a first step down that road, we move to a model where operations on
the engine now take a `chan engine.Event` and during the course of the
operation, events are written to this channel. It is the
responsibility of the caller of the method to read from the channel
until it is closed (singifying that the operation is complete).
The events we do emit are still intermingle presentation with data,
which is unfortunate, but can be improved over time. Most of the
events today are just colorized in the client and printed to stdout or
stderr without much thought.
